Patent Publication Number: US-2019175064-A1

Title: Nasal and oral respiration sensor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Patent Application No. 62/597,870, filed on Dec. 12, 2017, the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     The present disclosure relates generally to medical sensors. More particularly, the present disclosure relates to respiration sensors for a continuous, long-lasting monitoring of an individual or patient, including measuring and analyzing respiratory condition and movement of the person. 
     The respiration of a person may be monitored for various reasons. For example, knowledge about a patient&#39;s respiration may assist a caregiver in assessing the patient&#39;s stability during surgery and recovery thereafter. Knowledge about a person&#39;s respiration can also assist with therapy related to sleeping. 
     Many approaches to respiration sensors involve cumbersome devices that can obstruct a patient&#39;s respiratory passages. In many applications, the patient is unconscious or semi-conscious and there is a challenge to fix a respiration sensor in place for an extended period of time. Accordingly, in many of the existing systems a nurse is required to frequently check the patient for sensor placement or inadvertent sensor movement. Moreover, due to the physiognomy of the human respiratory passages, many devices tend to produce confused readings relative to either of a patient&#39;s nostrils and mouth, and fail to clearly distinguish and provide differentiated data for inspiration and exhalation steps. 
     SUMMARY 
     In the field of medical care for patients with respiratory dysfunction, it is highly desirable to provide continuous, real-time measurement of the patient&#39;s respiratory cycles. In the measurement of respiratory cycles from patients, one of the challenges is to clearly distinguish between inhalation and exhalation cycles. The complication is compounded by the human physiognomy, which places nasal and oral flows (in and out of the patient) in close proximity to each other, thereby increasing the possibility of flow mix, turbulence, and stagnation in some places. 
     An aspect of the present disclosure provides, but is not limited to, a respiration sensor for monitoring and analysis of an individual or patient&#39;s respiratory condition and cycle, monitoring and analysis to ensure a respiration sensor is positioned as intended, detecting movement of a person using a respiration sensor, detecting and distinguishing between oral and individual nasal air flows, and integration of a respiration sensor and data with a network. 
     In some embodiments, the present disclosure provides a respiration sensor comprising: a housing having a nasal flow passage that extends therethrough, wherein the nasal flow passage is disposed approximately parallel with a nasal respiratory flow direction; and an electronics board comprising a nasal thermistor, the electronics board coupled to the housing such that the nasal thermistor is positioned into the nasal flow passage. 
     In some embodiments, a respiration sensor is disclosed, the respiration sensor comprising: a housing having a first nasal flow passage and a second nasal flow passage that extend therethrough, wherein the nasal flow passages are disposed in parallel to one another with respect to a nasal respiratory flow direction; and an electronics board comprising a first nasal thermistor and a second nasal thermistor, the electronics board coupled to the housing such that the first and second nasal thermistors are positioned into each of the first and second nasal flow passages, respectively. 
     In some embodiments, the present disclosure provides a respiration sensor comprising: one or more thermistors configured to detect at least one of an inspiratory temperature, an expiratory temperature, an ambient temperature adjacent the respiratory sensor, or a temperature of a patient&#39;s skin engaged against the respiratory sensor; an accelerometer configured to detect at least one of a movement of the patient, a position of the patient, a heart rate, or a respiration rate; and an electronics board coupled to the one or more thermistors and the one or more thermistors. 
     In some embodiments, the present disclosure provides a system, comprising: a server having a memory storing commands, and a processor configured to execute the commands to: receive, from a hub, a data indicative of a respiratory condition of a patient; transfer the data into a memory in a remote server; provide the data to a mobile computer device, upon request; and instruct the mobile computer device to graphically display the data, wherein the data comprises a temperature value from at least one of two nasal flow passages, a temperature value from an oral flow passage, a temperature value of a patient&#39;s skin surface, and a temperature value of a patient&#39;s environment. 
     In some embodiments of the present disclosure, a method is disclosed, the method comprising: receiving, from a hub, a data indicative of a respiratory condition of a patient; transferring the data into a memory in a remote server; providing the data to a monitor, upon request; and instructing the monitor to graphically display the data, wherein the data comprises a temperature value from at least one of two nasal flow passages, a temperature value from an oral flow passage, a temperature value of a patient&#39;s skin surface, and a temperature value of a patient&#39;s environment. 
     In some embodiments a respiration sensor system is disclosed, the respiration sensor system comprising: a respiration sensor comprising a housing having a nasal flow passage that extends therethrough, wherein the nasal flow passage is aligned with a nasal respiratory flow direction, and an electronics board comprising a nasal thermistor, the electronics board coupled to the housing such that the nasal thermistor is positioned into the nasal flow passage; and a hub configured to move data between the respiration sensor and a network. 
     Additional features and advantages of the subject technology will be set forth in the description below, and in part will be apparent from the description, or may be learned by practice of the subject technology. The advantages of the subject technology will be realized and attained by the structure particularly pointed out in the written description and embodiments hereof as well as the appended drawings. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the subject technology. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various features of illustrative embodiments of the inventions are described below with reference to the drawings. The illustrated embodiments are intended to illustrate, but not to limit, the inventions. The drawings contain the following figures. 
         FIG. 1  illustrates a front perspective view of a respiration sensor placed on a patient&#39;s head, according to some embodiments. 
         FIG. 2A  illustrates a side plan view of a gas flow exiting from a patient&#39;s nasal cavity, according to some embodiments. 
         FIG. 2B  illustrates a side plan view of a gas flow exiting from a patient&#39;s oral cavity, according to some embodiments. 
         FIG. 3  illustrates a front plan view of a gas flow exiting from a patient&#39;s nasal cavity, according to some embodiments. 
         FIG. 4  illustrates a front perspective view of nasal respiration flows and oral respiration flows in a patient, according to some embodiments. 
         FIG. 5  illustrates a front perspective view of a respiration sensor including nasal flow passages and oral flow passages, according to some embodiments. 
         FIG. 6  illustrates perspective detail views of nasal flow passages and oral flow passages of a respiration sensor, according to some embodiments. 
         FIG. 7  illustrates a cross-sectional view of a laminar respiration flow relative to a thermistor in a respiration sensor, according to some embodiments. 
         FIG. 8  illustrates a schematic view of a flow passage of a respiration sensor, according to some embodiments. 
         FIGS. 9A and 9B  illustrate front and back perspective views of a respiration sensor, according to some embodiments. 
         FIG. 10  illustrates a front perspective view of a respiration sensor placed on a patient&#39;s head, according to some embodiments. 
         FIG. 11  illustrates a front perspective view of a respiration sensor, according to some embodiments. 
         FIG. 12  illustrates a bottom perspective view of the respiration sensor of  FIG. 11 . 
         FIG. 13  illustrates a front perspective detail view of a respiration sensor, according to some embodiments. 
         FIG. 14  illustrates a front perspective cross-sectional view of the respiration sensor of  FIG. 11 . 
         FIG. 15  illustrates a schematic view of a nasal respiration flow and a nasal flow guide, according to some embodiments. 
         FIG. 16  illustrates a schematic view of a nasal flow guide, according to some embodiments. 
         FIG. 17  illustrates a back perspective view of a respiration sensor, according to some embodiments. 
         FIG. 18  illustrates a schematic view of a respiration flow through a cavity of a respiration sensor, according to some embodiments. 
         FIG. 19  illustrates a schematic view of turbulent respiration gas flow through a cavity of a respiration sensor, according to some embodiments. 
         FIG. 20  illustrates a graph showing turbulent noise flow during expiration, according to some embodiments. 
         FIGS. 21A and 21B  illustrate front and side plan views of exit angles for a gas flow exiting from a patient&#39;s nasal cavity, according to some embodiments. 
         FIGS. 22A and 22B  illustrate front and side schematic views of a position of an oral cavity relative to a patient, according to some embodiments. 
         FIG. 23  illustrates a front perspective view of a respiration sensor, according to some embodiments. 
         FIG. 24  illustrates a graph showing measurements for the respiration sensor of  FIG. 23  for different patients, according to some embodiments. 
         FIGS. 25A and 25B  illustrates a front plan views of positions of an oral cavity for a respiration sensor relative to a mouth of different patients, according to some embodiments. 
         FIG. 26  illustrates a front perspective view of a respiration sensor having a strap, according to some embodiments. 
         FIG. 27  illustrates a front perspective view of a respiration sensor having a band, according to some embodiments. 
         FIG. 28  illustrates a front perspective exploded view of a respiration sensor, according to some embodiments. 
         FIG. 29  illustrates a top perspective detail view of an electronics board and frame of a respiration sensor, according to some embodiments. 
         FIG. 30  illustrates a top perspective view of an electronics board of a respiration sensor, according to some embodiments. 
         FIG. 31  illustrates a top perspective detail view of the electronics board of  FIG. 30 , according to some embodiments. 
         FIG. 32  illustrates a bottom perspective view of the electronics board of  FIG. 30 , according to some embodiments. 
         FIG. 33  illustrates a top perspective view of the electronics board of  FIG. 30  coupled with a frame and a battery, according to some embodiments. 
         FIG. 34  illustrates a block diagram of an electronics board of a respiration sensor, according to some embodiments. 
         FIG. 35  illustrates another block diagram of an electronics board of a respiration sensor, according to some embodiments. 
         FIG. 36  illustrates a respiration sensor detection state table for determining the respiration sensor placement and function, according to some embodiments. 
         FIG. 37  illustrates a graph showing breathing during changes in ambient air temperature, according to some embodiments. 
         FIG. 38  illustrates a graph showing breathing during conducting temperature changes, according to some embodiments. 
         FIG. 39  illustrates a respiration sensor in use on a patient transitioning from a seated position, to a moving position, to a fallen position, according to some embodiments. 
         FIG. 40  illustrates a front plan view of a heart and directions of blood circulation therethrough. 
         FIG. 41  illustrates a front plan view of a respiration sensor including an accelerometer for detecting body movement of a patient utilizing the respiration sensor, according to some embodiments. 
         FIG. 42  illustrates a front perspective exploded view of a respiration sensor having EtCO2 sensitive surfaces, according to some embodiments. 
         FIG. 43  illustrates a schematic view of a respiration monitoring system, according to some embodiments. 
         FIG. 44  illustrates a front perspective view of a respiration sensor coupled to a patient and a hub adjacent to the patient according to some embodiments. 
         FIG. 45  illustrates a front perspective view of a respiration sensor and hub coupled to a patient, according to some embodiments. 
         FIG. 46  illustrates perspective detail views of an interaction between a respiration sensor and a hub in a respiration monitoring system, according to some embodiments. 
         FIG. 47  illustrates a front perspective view of a respiration sensor and hub coupled with a headdress, according to some embodiments. 
         FIG. 48  illustrates a side view of a respiration sensor and hub coupled with another headdress, according to some embodiments. 
         FIG. 49  illustrates a front perspective view of a smartphone as a monitor for a respiration monitoring system, according to some embodiments. 
         FIG. 50  illustrates a front perspective view of a central station as another monitor for a respiration monitoring system, according to some embodiments. 
     
    
    
     In the figures, elements having the same or similar reference numeral have the same or similar functionality or configuration, unless expressly stated otherwise. 
     DETAILED DESCRIPTION 
     It is understood that various configurations of the subject technology will become readily apparent to those skilled in the art from the disclosure, wherein various configurations of the subject technology are shown and described by way of illustration. As will be realized, the subject technology is capable of other and different configurations and its several details are capable of modification in various other respects, all without departing from the scope of the subject technology. Accordingly, the summary, drawings, and detailed description are to be regarded as illustrative in nature and not as restrictive. 
     The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology may be practiced. The appended drawings are incorporated herein and constitute a part of the detailed description. The detailed description includes specific details for the purpose of providing a thorough understanding of the subject technology. It will be apparent, however, to one ordinarily skilled in the art that the embodiments of the present disclosure may be practiced without some of these specific details. In other instances, well-known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology, or have not been shown in detail so as not to obscure the disclosure. Like components are labeled with similar element numbers for ease of understanding. 
     In accordance with at least some embodiments disclosed herein is respiration sensor that can: monitor nasal and oral respiration gas flow; monitor patient and ambient conditions; monitor movement of the respiration sensor; distinguish between oral and nasal air flow, and between left and right nasal air flow. The respiration sensor can identify and analyze thermal transfer distinction between inhalation and exhalation gases to provide a clear pattern of the respiratory cycle. 
     In at least some embodiments disclosed herein, any of nasal and oral respiration gas flow, heart rate, respiration rate or cycle, and movement of the respiration sensor and patient are determined. Embodiments of the present disclosure can send and receive data related to the monitoring and analysis by the respiration sensor; indicate a patient&#39;s condition or position; and provide a signal or alarm corresponding to specific conditions. In some embodiments, wireless communication techniques are utilized to provide ubiquitous solutions for respiratory sensing of patients in hospitals, treatment facilities, home-care situations, and the like. 
     I. Embodiments of Respiratory Sensors 
       FIG. 1  illustrates a respiration sensor  10  placed on a patient&#39;s head  20 , according to some embodiments. The respiration sensor  10  is positioned on patient&#39;s face between the mouth and nose to measure nasal and oral breathing gas flow. The gas flow measurement is based on measuring temperature differences between inspiratory and expiratory gas flows. Patient&#39;s skin and ambient air temperatures can also be measured to verify that the respiration sensor  10  is placed appropriately against the patient. Some embodiments, later described, include other sensors, such as capacitive sensors or detectors and accelerometers to ensure that respiration sensor  10  has not fallen out of place, and that respiration sensor  10  is making proper contact with the patient&#39;s physiognomy. A securement string or strap  15  helps maintain the position of respiration sensor  10  relative to the patient&#39;s physiognomy. 
       FIGS. 2A and 3  illustrate regions  200   a ,  200   c  for a gas flow exiting from a patient&#39;s nasal cavities, and  FIG. 2B  illustrates regions  200   b  for a gas flow exiting from a patient&#39;s oral cavity, according to some embodiments. Experiments show that breathing gas flow exits nasal and oral cavities in different regions between different subjects. Accordingly, embodiments of a respiration sensor as disclosed herein include a geometry that may separate each of the different flows through the regions  200   a ,  200   b ,  200   c  to provide a more accurate measure of the respiratory cycles of a patient. Accordingly, a precise determination of the positioning of the respiration sensor  100   a ,  100   b  relative to the patient&#39;s face is highly desirable. 
       FIG. 4  illustrates a portion of nasal respiration flow  600 C and oral respiration flow  600 B for a patient  20 , according to some embodiments. Sensor cavities of the respiration sensor capture nasal and oral breathing gas flow from the patient. The sensor cavities are positioned parallel to the average direction of that specific flow to maintain flow as laminar as possible inside the cavity. Thus, nasal sensor cavities are positioned parallel to each other between the nose and mouth, but also parallel to upper lip. More advantageously, nasal sensor cavities slightly diverge past the middle part of the mouth and upper lip into the average direction of nasal breathing gas flows. An oral sensor cavity is positioned transverse to the nasal cavities, outwards from the mouth. In some embodiments, the oral sensor cavity and the nasal sensor cavities are positioned relative to each other so that a direction of oral respiration flow  600 B through the oral cavity is transverse relative to a direction of nasal respiration flow  600 C through any of the nasal sensor cavities. Sensor cavities are also smooth and straight, or more advantageously slightly tapered, to capture flow from a larger area, since any turn or sudden change in the cross-section of cavity along the flow path generate turbulences that mix inspiratory and expiratory air flow phases degrading the measurement speed, accuracy and response time. 
       FIG. 5  illustrates a respiration sensor  100   a , for example, including nasal flow passages  301  and an oral flow passage  302 . The nasal respiration flow exiting a patient&#39;s nasal cavity, e.g., gas flow regions  200   a ,  200   c , can be captured and guided by a nasal passage  301  parallel to average direction of nasal respiration flow  600 C. Similarly, the oral respiration flow exiting a patient&#39;s mouth, e.g., gas flow region  200   b , can be captured and guided by the oral cavity  302  parallel to direction of the oral respiration flow  600 B. By providing a sensing element inside of each of the different flow passages  301  and  302 , the respiration sensor  100   a  may accurately determine a respiration flow before the nasal flow and the oral flows are mixed together adjacent the patient&#39;s upper lip. 
       FIG. 6  illustrates the respiration sensor  100   a , with portions thereof shown in detail views, including detail views of the nasal flow passages  301  and the oral flow passage  302 . The respiration sensor  100   a  includes thermistors  400 - 1 ,  400 - 2 ,  400 - 3  for sensing inhalation and exhalation flows. A nasal respiratory flow of a patient can be captured by the nasal passages  301  and measured with a first and second nasal thermistors  400 - 1 ,  400 - 2  therein. An oral respiratory flow of the patient can be captured by the oral cavity  302  and measured with thermistor  400 - 3  therein. The resistance of each thermistor changes proportionally to flowing gas heating or cooling down the thermistor, e.g., during inspiration and expiration. 
     Moreover, the nasal flow passages  301  are separated from each other such that nasal thermistors  400 - 1  and  400 - 2  may separately identify and measure the respiration flow associated with each of the patient&#39;s nostrils. By separately identifying respiration flow associated with each of the patient&#39;s nostrils, potential respiratory conditions or patient&#39;s positions can be determined. For example, a blockage of a nasal passage or the respiration device can be identified and corrected. 
     In some embodiments, oral thermistor  400 - 3  is placed on a plane that is transverse or substantially perpendicular to nasal thermistors  400 - 1 ,  400 - 2 . This geometry also enables an accurate and independent measurement between each of the thermistors  400 - 1 ,  400 - 2 ,  400 - 3 , avoiding any mixing or turbulent area. 
     Referring to  FIGS. 7 and 8 , the thermistors  400 - 1 ,  400 - 2 ,  400 - 3  can be located approximately in the middle of its corresponding sensor cavity to maximize accuracy and sensitivity to gas flows. To position the thermistor  400 - 1 ,  400 - 2 ,  400 - 3  in the middle of a corresponding sensor cavity, the thermistor  400 - 1 ,  400 - 2 ,  400 - 3  is coupled to a tip portion of a thin support structure  730 . The support structure can have a proximal portion coupled to an electronics board and a distal portion transverse to a plane defined by the top of the electronics board, wherein the distal portion of the support structure extends into a nasal flow passage. In some embodiments, the respiration sensor  100   a  has a structure and geometry that separates the nasal flow from each nostril separately, to provide a more accurate and detailed picture of the patient&#39;s respiratory condition. 
       FIG. 7  illustrates a cross-section of a laminar respiration flow of a patient through a sensor cavity. Laminar flow speed distribution in a tube is parabolic, thus the speed is maximum at a point approximately in the middle of the tube. The respiration flow is illustrated relative to thermistor  400 - 1  of a respiration sensor  100   a , however, the present disclosure can apply to any thermistor  400 - 1 ,  400 - 2 ,  400 - 3 . By placing thermistor  400 - 1  as close as possible to the middle of the flow cavity in the respiration sensor  100   a , for example, a more accurate measurement is expected, as the velocity of the gas flow is highest at the center of the flow cavity. Accordingly, it is expected that a temperature differential between inhalation and exhalation be highest at the middle point of the flow cavity. Moreover, the convection or radiated thermal energy from surrounding structures is minimized when a thermistor  400 - 1 ,  400 - 2 ,  400 - 3  is located into the middle of cavity by a support structure  730 . 
       FIG. 8  illustrates the respiration sensor  100   a , with a portion thereof shown in a cross-sectional detail view. The cross-sectional view illustrates a support structure  730  extending into the nasal flow passage  301 , and the thermistor  400 - 1  positioned at a distal end portion of the support structure  730 . It should be understood that the present disclosure, including support structures, can apply to any of the thermistors  400 - 1 ,  400 - 2 ,  400 - 3  and flow passages  301 ,  302 . 
     The support structure  730  extends from a portion of the respiration sensor  100   a  into the nasal flow passage  301 . It should be understood that the support structure  730  can extend partially into a flow passage  301 ,  302 . For example, the support structure  730  can extend into a mid-portion of at least one of the two nasal flow passages  301 . In some embodiments of the present disclosure, the support structure  730  extends beyond or across the respective flow passage  301 ,  302 . The support structure  730  can comprise a cantilevered structure that extends into a respective flow passage  301 ,  302 . However, in some embodiments, the support structure  730  can comprise an arch structure partially extending away from an inner surface of the flow passage  301 ,  302  toward the thermistor  400 - 1 , and partially extending from the thermistor  400 - 1  toward the inner surface of the flow cavity. In some embodiments, the support structure  730  and the thermistor  400 - 1  can extend across inner surfaces of the flow cavity. 
     The respiration sensor  100   a  includes walls having an inner surface forming the sensor cavities. The walls of the cavity extend around at least a portion of the thermistors  400 - 1 ,  400 - 2 ,  400 - 3 . The walls protect the sensitive thermistors  400 - 1 ,  400 - 2 ,  400 - 3  from various disturbing ambient gas flows causing error to measured breathing gas flow signal, for example, a caregiver being able to touch or breathe into thermistors or air conditioning in proximity to the thermistor  400 - 1 ,  400 - 2 ,  400 - 3 . In addition, the walls forming the cavities also protect small, mechanically sensitive thermistors from various mechanical forces, stresses, and shocks, such as touching etc. 
       FIGS. 9A and 9B  illustrate the respiration sensor  100   a , for example, including thermistors  500 - 1 ,  500 - 2  for sensing the positioning of the sensor relative to a patient&#39;s physiognomy, according to some embodiments. An ambient thermistor  500 - 1  can be positioned along a front side of the respiration sensor  100   a , adjacent a portion of the respiration sensor  100   a  that faces away from the patient when the respiration sensor  100   a  is worn by a patient. Similarly, a skin thermistor  500 - 2  can be positioned along a back side of the respiration sensor  100   a , adjacent a portion of the respiration sensor  100   a  that faces toward the patient when the respiration sensor  100   a  is worn by a patient. In some embodiments, when the respiration sensor  100   a  is worn by a patient, the thermistor  500 - 1  is distal to the patient&#39;s face, and the thermistor  500 - 2  is proximal to the patient&#39;s upper lip and engaged against the patient&#39;s skin. 
     The respiration sensor  100   a  can include a passage or cavity along any of the front side or the back side thereof. The thermistor  500 - 1  can be positioned in a cavity along the front side of the respiration sensor  100   a  to measure ambient air temperature. The thermistor  500 - 2  can be positioned in a cavity along the back side of the respiration sensor  100   a  to measure the temperature of patient&#39;s skin. 
     In some instances, thermistor  500 - 2  can detect when the sensor  100   a  is properly positioned on the patient while thermistor  500 - 1  can detect the temperature of ambient air. Comparison of temperatures from  500 - 1  and  500 - 2  can be used to indicate a patient condition or proper positioning and function of the sensor  100   a , for example. In some embodiments, when thermistors  500 - 1  and  500 - 2  detect the same temperature, it may be assumed that respiration sensor  100   a  is likely not attached to the patient, or that the patient&#39;s temperature is the same as the ambient temperature, which may indicate a hazardous health condition. 
       FIG. 10  illustrates another embodiment of a respiration sensor  100   b , which is substantially similar to respiration sensor  100   a . Respiration sensor  100   b  is also placed on a patient&#39;s face between the mouth and nose to measure nasal and oral breathing gas flows. Much like the respiration sensor  100   a , the measurement is based on measuring temperature differences between inspiratory and expiratory gas flows. The patient&#39;s skin temperature and the ambient air temperature can also be measured to verify or detect that the respiration sensor  100   b  is placed appropriately with respect to the patient&#39;s nasal and oral breathing gas flows and to the patient&#39;s upper lip. 
     Some embodiments described herein include other sensors, such as capacitive detectors or sensors to detect whether the respiration sensor  100   b  is making proper contact with the patient&#39;s physiognomy and accelerometers to detect movement and position of the respiration sensor  100   b  to ensure, for example, that the respiration sensor  100   b  has not fallen out of place, that the patient has not fallen down, or that the orientation of the patient&#39;s head is not obstructing the nasal and oral breathing gas flows (e.g., patient&#39;s face is downward towards pillow or bed). 
     A string or strap  150   b  helps maintain the position of the respiration sensor  100   b  relative to the patient&#39;s physiognomy. According to some embodiments, the respiration sensor  100   b  can include a nasal flow guide  160  to concentrate and provide laminar inspiratory and expiratory gas flows through the respiration sensor  100   b.    
       FIGS. 11 and 12  illustrate the respiration sensor  100   b  having a housing  2001 , a base  2010 , and a shroud  2012 . The shroud  2012  is positioned between the housing  2001  and the base  2010  to form at least a portion of a cavity. The respiration sensor  100   b  includes nasal flow passages  2018 , which are similar to nasal flow passages  301 , and an oral flow passage  2016 , which is similar to oral flow passages  302  of respiration sensor  100   a . The nasal flow passages  2018  extend from a top portion to a bottom portion of the respiration sensor  100   b . In use, a nasal respiration flow from a patient&#39;s nose can move between the nasal inlet  2024  and the nasal outlet  2026  of each of the nasal flow passages  2018 . The nasal inlet  2024  of each of the nasal flow passages  2018  is where the breathing gas flows into the respiration sensor  100   b  during expiration. The nasal outlet  2026  of each of the nasal flow passages  2018  is where the ambient air flows into the respiration sensor  100   b  during inspiration. 
     The shroud  2012  includes a battery frame  2014 , which extends away from a front surface of the shroud  2012 . The battery frame  2014  encloses a battery, securing it to the base  2010  and divides the area between the shroud  2012  and the housing  2001  into two distinct nasal flow passages  2018 , such that the nasal thermistor  400 - 1  is centrally disposed in one of the nasal flow passages  2018  and the nasal thermistor  400 - 2  is centrally disposed in the other one of the nasal flow passages  2018 . The battery frame  2014  is disposed substantially centrally on the respiration sensor  100   b  and is arranged to be positioned under the septum of a patient&#39;s nose when the respiration sensor  100   b  is placed on or attached adjacent to the upper lip of the patient. 
     Housing  2001  can be made of a paper battery engineered to use a spacer formed largely of cellulose that makes paper batteries flexible and environmentally-friendly. The functioning is similar to conventional chemical batteries with the important difference that they are non-corrosive and do not require extensive housing, but can function as housing. 
     An oral shroud  2017  extends from the shroud  2012 , and includes a passage through a distal portion thereof. The passage forms an oral flow passage  2016  having a thermistor  400 - 3  positioned therein. The oral flow passage  2016  is arranged such that the oral thermistor  400 - 3  is centrally disposed within the oral flow passage  2016 . In use, an oral respiration flow from a patient&#39;s mouth can move between the oral inlet  3036  and the oral outlet  2038 . 
       FIG. 13  illustrates an embodiment the respiration sensor  100   b , showing the base  2010  and the shroud  2012 , with the housing  2001  omitted for clarity. The shroud  2012  encloses an electronics board, securing it to the base  2010 . The thermistors  400 - 1 , extend from the electronics board through the shroud  2012 . The thermistors  400 - 1 ,  400 - 2  are oriented such that a distal portion of the thermistors  400 - 1 ,  400 - 2  extend into a space forming the nasal cavities  1301  when the shroud  2012  and the housing  2001  are coupled together. 
     The respiration sensor  100   b  can include a light-emitting diode (LED)  2013 , which is visible through the shroud  2012 . The LED  2013  can provide a confirmation or an indication of status. For example, the LED  2013  can indicate when the respiration sensor  100   b  is paired with another device. In some embodiments, the LED  2013  can indicate any of a charged or low battery, an indication that the respiration sensor  100   b  is functioning as intended, or an indication that there is a detected problem with the respiration sensor  100   b . The LED  2013  can be used to indicate the location of the patient for example in hospital PACU where there are many patients, respiration sensors and monitoring devices in the same room. The LED  2013  can be turned on or display a series of blinks from the monitoring device to indicate the location of the patient and the connected respiration sensor. This may be important to ensure that a caregiver is looking at the correct monitoring device connected to patient and the respiration sensor. It should be understood that any embodiment of the respiration sensor, such as respiration sensor  100   a ,  100   b , can include an LED  2013 . 
     In some embodiments, a spacer  2019  can be positioned between the battery and a battery contact. The spacer  2019  can maintain the battery contact spaced apart from the battery, thereby preventing electrical conduction therebetween. The spacer  2019  can prevent discharge of the battery before the respiration sensor  100   b  is intended to be used. When the respiration sensor  100   b  is intended to be used, the spacer  2019  can be removed or separated from the respiration sensor  100   b . In some embodiments, the respiration sensor  100   b  can comprise an opening or passage  2015  that extends between the battery and an outer surface of the housing  2001  or the shroud  2012 . The spacer  2019  can be moved through the passage  2015  to separate the spacer  2019  from the respiration sensor  100   b . In some embodiments, the spacer  2019  may comprise a plastic material in the form or a strip or tape. 
       FIG. 14  illustrates an embodiment the respiration sensor  100   b , showing the base  2010 , the shroud  2012 , and the flow guides  160 , with a portion of the housing  2001  and other features omitted for clarity. At least one nasal flow guide  160  is disposed in each of the nasal flow passages  2018  and extends between the shroud  2012  and the housing  2001 , as shown in at least  FIGS. 11 and 12 . 
     In some embodiments, at least one nasal flow guide  160  is disposed proximate a nasal inlet  2024  of each of the nasal flow passages  2018  and at least one nasal flow guide  160  is disposed within each of the nasal flow passages  2018 . A nasal flow guide  160  can be positioned in a nasal flow passage, proximate any of the nasal inlet  2024  and the nasal outlet  2026 . The nasal flow guide  160  is aligned relative to the nasal thermistor  400 - 1  or  400 - 2  to direct a flow of gas toward relative to the nasal thermistor  400 - 1  or  400 - 2 . 
       FIGS. 14 and 15  illustrates flow of gases relative to the respiration sensor  100   b , a patient&#39;s nares, and the ambient environment. Arrows  2028  illustrate a portion of nasal respiration flow from a patient&#39;s nares toward the nasal thermistor  400 - 1 ,  400 - 2  during expiration, and arrows  2029  illustrate a portion of ambient gas directed from the ambient environment toward the nasal thermistor  400 - 1 ,  400 - 2  during inspiration. 
     In more detail, during expiration, the at least one nasal flow guide  160 , disposed proximate the nasal inlet  2024  guides the breathing gas flow through the nasal flow passages  2018  of the respiration sensor  100   b  and concentrates the breathing gas flow toward each of the nasal thermistors  400 - 1 ,  400 - 2  while maintaining the breathing gas flow laminar as it passes each of the nasal thermistors  400 - 1 ,  400 - 2  to minimize turbulent noise. Similarly, during inspiration, the at least one nasal flow guide  160  disposed proximate the nasal outlet  2026  guides the ambient air flow through the nasal flow passages  2018  of the respiration sensor  100   b  and concentrates the ambient air flow toward each of the nasal thermistors  400 - 1 ,  400 - 2  while maintaining the ambient air flow laminar as it passes each of the nasal thermistors  400 - 1 ,  400 - 2  to minimize turbulent noise. 
     The at least one nasal flow guide  160  can prevent undesired objects from entering the nasal flow passages  2018  and disturbing or breaking the nasal thermistors  400 - 1 ,  400 - 2  and/or their associated support structures. The at least one nasal flow guide  160  can also form an air gap around the nasal thermistors  400 - 1 ,  400 - 2  with respect to the housing  2001  and the at least one nasal flow guide  160 , which prevents electro static discharge (ESD) from entering the electronics board  300  via the nasal thermistors  400 - 1 ,  400 - 2  and their associated support structures. 
     In some embodiments, the at least one nasal flow guide  160  includes a thickness that is less than 1 mm and a height that is more than 2 mm. In some embodiments, two or four nasal flow guides  160  are disposed within each of the nasal flow passages  2018  proximate the nasal inlet  2024  and/or two or four nasal flow guides are disposed within each of the nasal flow passages  2018  proximate the nasal outlet  2026 . In some embodiments, the number of nasal flow guides  160  does not exceed five to allow for proper gas flow through the nasal flow passages  2018 . 
       FIG. 16  illustrates a schematic view of a nasal respiration flow guide grid  2030 . The flow guide grid  2030  can function similarly to flow guide  160 , wherein a flow of gas through a cavity of the respiration sensor  100   b  is directed by the flow guide grid  2030 . The flow guide grid  2030  can have walls which intersect and are transverse relative to each other. In some embodiments, a flow guide grid  2030  is disposed proximate the nasal inlet  2024  and a flow guide grid  2030  is disposed proximate the nasal outlet  2026  of each nasal cavity of the nasal flow passages  2018 . 
     Additional sensors of a respiration sensor  100   b  are illustrated in the back, perspective view of the respiration sensor  100   b  in  FIG. 17 . The respiration sensor  100   b  includes a thermistor  500 - 2  and a sensor  1401  located on the back portion of the respiration sensor  100   b . The thermistor  500 - 2  can provide temperature information regarding the patient or an ambient environment adjacent to the back portion of the respiration sensor  100   b . The sensor  1401  is a capacitive plate, which can engage against the patient. The sensor  1401  can engage against a region between a patient&#39;s upper lip and nose, e.g., an area including the philtrum, and provide information to determine a location of the respiration sensor  100   b  relative to the patient&#39;s face. 
     II. Gas Flow Through Respiration Sensors 
     Referring to  FIGS. 17 and 18 , an oral shroud  2017  of the respiration sensor  100   b  can have a cross-sectional area that tapers along a portion thereof or relative to an oral inlet  2036  and an oral outlet  2038 . The oral inlet  2036  is where the breathing gas flows into the oral flow passage  2016  of the respiration sensor during expiration, and the oral outlet  2038  is where the ambient air flows into the oral flow passage  2016  of the respiration sensor during inspiration. 
     In some embodiments, as illustrated in  FIG. 17 , a cross-sectional area of the oral shroud  2017  forms an hourglass shape. For example, a cross-sectional area of the oral shroud  2017  can taper from the oral inlet  2036  toward the oral thermistor  400 - 3 , positioned between the oral inlet  2036  and the oral outlet  2038 , and can taper away from the oral thermistor  400 - 3  toward the oral outlet  2038 . In some embodiments, as illustrated in  FIG. 18 , the cross-sectional area of the oral shroud  2017  can taper from the oral inlet  2036  toward the oral outlet  2038 . The cross-sectional area of the oral shroud  2017  can also taper from the oral outlet  2038  toward the oral inlet  2036 . 
     In some aspects, the oral shroud  2017  can have a cross-sectional profile transverse to a flow through the oral shroud  2017 . The cross-sectional profile of oral shroud  2017  can be any regular or irregular shape, such as an oval, circle, square, or rectangle. 
       FIG. 18  illustrates a detail schematic view of the oral shroud  2017 , including an oral flow guide  2034 . The oral flow passage  2016  of the oral shroud  2017  collects the breathing gas flow ejected from a patient&#39;s mouth. The cross-sectional area of the oral shroud  2017  tapers from the oral inlet  2036  toward the oral thermistor  400 - 3 , and from the oral thermistor  400 - 3  toward the oral outlet  2038 . Alternatively, in some embodiments, the cross-sectional area of the oral shroud  2017  can taper from the oral outlet  2038  to the oral inlet  2036 . 
     The oral flow guide  2034  can direct at least portion of oral respiration flow  2032  moving through the oral flow passage  2016  of the oral shroud  2017 . An oral flow guide  2034  is disposed proximate an oral inlet  2036  of the oral shroud  2017  and an oral flow guide  2034  is disposed proximate an oral outlet  2038  of the oral shroud  2017 . 
     During expiration, the oral flow guide  2034  disposed proximate the oral inlet  2036  guides the breathing gas flow through the oral flow passage  2016  and concentrates the breathing gas flow toward the oral thermistor  400 - 3  while maintaining the breathing gas flow laminar as it passes the oral thermistors  400 - 3  to minimize turbulent noise. Similarly, during inspiration, the oral flow guide  2034  disposed proximate the oral outlet  2038  guides the ambient air flow through the oral flow passage  2016  of the respiration sensor and concentrates the ambient air flow toward the oral thermistor  400 - 3  while maintaining the ambient air flow laminar as it passes the oral thermistor  400 - 3  to minimize turbulent noise. 
     The oral flow guide  2034  extends from the oral shroud  2017  within the oral flow passage  2016 . The oral flow guide  2034  can extend radially inward from an inner surface of the oral shroud  2017 . The oral flow guide  2034  can extend across a portion of the oral flow passage  2016 , or across the oral flow passage  2016  to engage against an opposite inner surface of the oral shroud  2017 . In some embodiments, the oral flow guide  2034  can extend between the oral inlet  2036  and the oral outlet  2038 . The oral flow guide  2034  can comprise a surface that is any of a planar, a convex, and a concave surface. In some embodiments, the oral flow guide  2034  is arranged horizontally. In some embodiments, an oral flow guide  2034  is arranged horizontally and another oral flow guide is arranged vertically. 
       FIG. 19  illustrates a schematic view of the oral flow passage  2016  including an entry angle c that can create gas flow turbulence  2040 . If the entry angle c is too high, the oral shroud  2017  will create the turbulence  2040  in both directions during inspiration and expiration.  FIG. 20  illustrates turbulent noise flow turbulence  2040  during expiration, which is represented by expiration curve  2042  of the measured electrical signal from a thermistor, such as thermistors  400 - 1 ,  400 - 2 ,  400 - 3 ,  500 - 1 ,  500 - 2 . 
     In some embodiments, a cross-sectional area of the oral inlet  2036  mimics a dimension of a patient&#39;s open mouth during sleep, but is much less than a fully open mouth and less than a diameter of a patient&#39;s forefinger. In some embodiments, the oral inlet  2036  is elliptical in the vertical direction. In such embodiments, the height of the elliptical oral inlet  2036  is approximately 9 mm and the width is less than the height, such as approximately 5 mm. In some embodiments, the oral outlet  2038  is elliptical. In some embodiments, the oral outlet  2038  is circular. In some embodiments where the both the oral inlet  2036  and the oral outlet  2038  are elliptical, the entry angle c is relatively small, such that less turbulence is generated, but the gas flow is less concentrated towards the oral thermistor  400 - 3 . In some embodiments, the oral outlet  2038  is approximately 5 mm. 
     Analysis of entry angle and turbulence generation in the flow cavity, can also be used with reference to the nasal flow passages  301 ,  2018 .  FIGS. 21A and 21B  illustrate schematic views of possible nasal expiration flow angles, which can be used to determine the potential for turbulence  2040 . For example, in a flow path to the side of the nose, an angle α determines a flow width W of the flow path and an angle θ determines the direction of the flow path nose. The flow width W is the distance between flow paths from both nostrils. A gas flow column (referred to herein as GFC) is gas flow directed away from the face and the nose. For example, in a flow path directed away from the face and the nose, an angle γ determines a width of the flow path and an angle δ determines the direction of the flow path away from the face and the nose. An area CA defines the cross-sectional surface area of a nostril, which affects the average width of a GFC. In general, a smaller cross-sectional surface area CA of the nostril generates a narrower average width of the GFC. Moreover, turbulence  2040  may be created around the thermistors  400 - 1 ,  400 - 2  by narrow (e.g., low angle α and low cross-sectional surface area CA) breathing GFC that is far to the side of the nose (e.g., high angle β). 
     III. Respiration Sensor Size and Adjustability 
       FIGS. 22A, 22B, 23, and 24 , illustrate potential distances or dimensions of a patient&#39;s facial features or structures, determination of potential dimensions of the respiration sensor using the measured and average patient facial features, and average measurement results for various patient&#39;s facial features or structures. 
       FIGS. 22A and 22B  illustrate potential distances or dimensions of a patient&#39;s facial features relative to an oral cavity  2016  having a thermistor  400 - 3  when the respiration sensor is placed on or attached to the patient. More particularly, the identified dimensions include the patient&#39;s nose width A 1 , isthmus width B 1 , a distance C 1  between the bottom of the nose and the upper lip, a distance D 1  between the bottom of the nose and the oral passage (e.g. mouth), a distance E 1  between the front edge of the nasal passage and the upper lip, and a lip thickness F 1 , e.g., the distance the lip protrudes outwardly relative to the philtrum. 
       FIG. 23  illustrates a respiration sensor, such as, for example, the respiration sensor  100   a ,  100   b , depicting dimensions of the respiration sensor, which can correspond to analysis of the measured features of the patient as shown in  FIGS. 22A and 22B . Accordingly, the measured facial features identified in  FIGS. 22A and 22B  help facilitate the design dimensions of the respiration sensor  100   a ,  100   b . A 2  should be at least A 1 , but preferably A 2  is more than A 1  to ensure capturing flow through the patient&#39;s nostrils. Similarly, B 2  should be no more than B 1 , but preferably B 2  is less than B 1  to ensure that B 2  does not prevent or disturb flow through the patient&#39;s nostrils. 
     The measured facial features shown in  FIGS. 22A and 22B  can be used to select design dimensions of the respiration sensor shown in  FIG. 23 . In some embodiments, measurements of particular patient can be used to select design dimensions for the respiration sensor. In some examples, measurements of a group of patients, such as adults or children, can be used to select design dimensions for an adult respiration sensor or a child respiration sensor. 
     A measured facial feature can correspond to a design dimension of the respiration sensor. For example: a patient nose width A 1  can be used to select the width A 2  of the respiration sensor; a patient isthmus width B 1  can be used to select the battery frame  2014  width B 2 ; the distance C 1  between the bottom of the nose and the upper lip can be used to select a height C 2  of the respiration sensor housing  2001 ; the distance D 1  between the bottom of the nose and the oral passage can be used to select a distance D 2  between the top of the respiration sensor  100   a ,  100   b , adjacent the nasal inlet  2024  and the oral flow passage  2016 ,  302 ; the distance E 1  between the front edge of the nasal passage and the upper lip can be used to select a depth of the respiration sensor  100   a ,  100   b ; and the lip thickness F 1  can be used to select a depth F 2  of the oral flow passage  302 ,  2016 . 
     In some embodiments, the distance C 2  of the respiration sensor  100   a ,  100   b  is less than 20 mm, but preferably less than 15 mm. In some embodiments, the distance C 2  of the respiration sensor  100   a ,  100   b  is approximately 10 mm to accommodate different face structures. In some embodiments, width A 2  of the respiration sensor  100   a ,  100   b  is more than 25 mm, but preferably about 45 mm to adequately capture the gas flow of patients with large width A 2 . In some embodiments, the distance D 2  of the respiration sensor  100   a ,  100   b  is more than 5 mm, but preferably more than 10 mm. In some embodiments, the distance D 2  of the respiration sensor  100   a ,  100   b  is more than 15 mm to capture gas flow coming out from the nostrils. In some embodiments, the cross-sectional area of the nasal flow passages  301 ,  2018  is greater than the cross-sectional area of the nostrils of a patient to capture breathing gas flow. In some embodiments, the battery frame  2014  includes a dimension B 2  corresponding to the isthmus width B 1  and is preferably less than 10 mm, but more preferably less than 5 mm. In some embodiments, the oral flow passage  2016  is located parallel to the breathing gas flow directed from the mouth of the patient. 
       FIG. 24  illustrates a graph  2044  of average measurement results for various facial features of a sample of patients including the patient&#39;s nose width A 1 , the isthmus width B 1 , the distance C 1  between the bottom of the nose and the upper lip, the distance D 1  between the bottom of the nose and the oral passage (e.g. mouth), the distance E 1  between the front edge of the nasal passage and the upper lip, and the patient&#39;s lip height F 1 . The graph  2044  illustrates the measurement results of a group of 45 Caucasian people including women, men, and children between the ages of 0 to 70 years old. The measured values influence the dimensional designs of the respiration sensor  100   a ,  100   b  with respect to the nose and the mouth including the size of nasal passages and the location of the oral passage. It should be understood that measurements for patients may also be outside of the scope of the measured feature in this graph. 
       FIG. 25A  illustrates a respiration sensor, such as, for example, respiration sensor  100   b  that includes the distance D 2  between the top of the respiration sensor  100   b , adjacent the nasal inlet  2024 , and the oral flow passage  2016 ,  302 . The distance D 2  can be approximately equal to 15 mm for patients with a smaller distance D 1 . Such a respiration sensor can accommodate patients including a distance D 1  in the range of approximately 10 mm to 25 mm. In some embodiments, the distance D 1  is between approximately 5 mm to 50 mm. 
       FIG. 25B  illustrates a respiration sensor, such as, for example, the respiration sensor  100   b  that includes the distance D 2  approximately equal to 33 mm for patients with a larger distance D 1 . Such a respiration sensor can accommodate patients including a distance D 1  in the range of approximately 24 mm to 40 mm. In some embodiments, the distance D 1  is between approximately 5 mm to 50 mm. 
       FIGS. 26 and 27  illustrate embodiments of features to attach the respiration sensor  100   a  to a patient. The features to attach the respiration sensor  100   a  can include any of a string, strap, or band, which can maintain a position of respiration sensor  100   a  relative to the patient&#39;s physiognomy. It should be understood that any of the features to attach the respiration sensors  100   a  or  100   b  can include the features to attach the respiration sensor to a patient. 
     A strap  150   a , shown in  FIG. 26 , can have ends that are attached to the respiration sensor  100   a  to form a loop. The strap  150   a  can have a length such that the respiration sensor  100   a  is engaged against a patient&#39;s face when the device is worn by the patient. In some embodiments, an additional strap  150   b  extends from any of the strap  150   a  or the respiration sensor  100   a . The additional strap  150   b  can provide additional support and tension to secure the device with the patient. The strap  150   a  and additional strap  150   b  can be configured such that a portion of the strap  150   a  extends above a patient&#39;s ears, and a portion of the additional strap  150   b  extends below a patient&#39;s ears. 
       FIG. 27  illustrates a respiration sensor  100   a  having a placement band  150   c . In some embodiments, the placement band  150   c  comprises a semi-rigid framework that is configured to guide straps that overlay the placement band  150   c  and extend over preferred placement portions of a patient&#39;s face. In some embodiments, the placement band  150   c  comprises a flexible plastic material that is configured to substantially retain its shape during use. The flexible placement band  150   c  can move, in a first plane, towards or away from a patient&#39;s face. The placement band  150   c  can be moved or biased in the first plane to engage against the patient&#39;s face and adapt to the shape of the patient&#39;s face. The placement band  150   c  is less flexible relative to a second plane, transverse to the first plane, thereby preventing or resisting movement of the placement band  150   c  along the patient&#39;s face or twisting of the band  150   c.    
     The placement band  150   a ,  150   c  can have a width that is approximately 5 mm, but it can be wider or narrower. A wider band can reduce the surface pressure on the face by the band. At least a portion of a surface of the band can be covered with a material that is soft and/or breathable. For example, a surface of the band configured to engage against the face or skin of the patient can comprise a cotton or similar material. 
     The shape of the band  150   c  is configured to extend from the respiration sensor  100   a , below the cheek bones of the patient. The band  150   c  can curve from the area below the cheek bones of the patient toward the patient&#39;s ears, forming a shape of an S-curve or similar. 
     The band  150   c  can be coupled with one or more additional band and/or strap. For example, the band  150   c  can be coupled to any of straps  150   a  and  150   b . When the straps  150   a ,  150   b  pull the band  150   c  and respiration sensor  100   a  towards the patient&#39;s face, a force vector of the respiration sensor  100   a  is approximately straight, towards the face or upper lip of the patient. Accordingly, the band  150   c  can decrease the surface pressure against the patient&#39;s isthmus or another portions of the patient&#39;s face or lip. 
     IV. Respiration Sensor Features for Monitoring and Analysis 
       FIG. 28  illustrates an exploded view of the respiration sensor  100   a ,  100   b  for example, including a housing  2001 , shroud  2012 , and electronics board  300 , according to some embodiments. 
     The electronics board  300  includes the electronic components used in the respiration sensor  100   a ,  100   b . The electronics board  300  can include a battery  1110  and sensors, such as a thermistor  400 - 1 ,  400 - 2 ,  400 - 3 , and a capacitive plate. In some embodiments, the electronics board  300  is made of, for example, glass-reinforced epoxy laminate material (e.g., FR4 substrate) containing automatic machine placed components, commonly used in automated mass series production to make the construction low cost. The electronics board  300  can be coupled to a base plate or frame  320 . In some embodiments, the frame  320  includes plastics, which contains electrically conductive areas or conductors. 
     In some embodiments of the present disclosure, the battery  1110  can be a disposable or rechargeable battery. In some embodiments, the respiration sensor  100   a ,  100   b  is configured to be powered by solar energy. For example, the respiration sensor  100   a ,  100   b  can include a solar panel which can be coupled to a battery. 
     The shroud  2012  defines at least a portion of the nasal flow passages and the oral flow passage of the sensor. In some embodiments, the electronics board  300  is positioned between the frame  320  and the shroud  2012 . Any of the frame  320  and the shroud  2012  can include a cavity to protect the electronics board  300  when the respiration sensor  100   a ,  100   b  is assembled. The frame  320  and/or the shroud  2012  can be made of elastic silicone, plastics, or similar material. 
     In some embodiments, an ambient air thermistor is positioned further away from the breathing gas flow otherwise interfering ambient air measurement. In aspects of the present disclosure, the shroud  2012  can include a perforation  501  that enables ambient air to be in touch with the ambient air thermistor through the shroud  2012  to get fast response time, but also to protect ambient air thermistor for example from touching with a finger or any unwanted air flow, such as air conditioning. 
     Referring to  FIG. 29 , a portion of the frame  320  can form a support structure for the thermistors  400 - 1 ,  400 - 2 . The electronics board  300  may include two perforations that enable two poles of the frame  320  to pierce through the electronics board  300  to form the thermistor support structure. The poles locate and keep the board in place with a mechanical locking mechanism. No screws or similar are needed. The poles also contain electrical contacts on the tip of the poles where thermistors  400 - 1 ,  400 - 2 , which are sensitive to nasal breathing gas flow, are coupled. Electrically conductive connections  1012  on the side surfaces of poles further connect thermistors  400 - 1 ,  400 - 1  to the electronics board  300  via electrical contacts on the top surface of the electronics board  300  next to the poles. When the frame  320  is placed under the electronics board  300 , electrical contacts on the top surface of the frame  320  connect with adjacent electrical contacts on the bottom surface of electronics board  300 . Electrically conductive glue can be used to ensure electrical contact. In some embodiments, a thermistor  400 - 3  sensitive to breathing gas flow through the mouth is located to the tip of the electronics board  300 . A bottom side of frame  320 , adjacent to electronics board  300  contains an inset  303  to enable thermistor  400 - 3  to locate into the middle of the flow cavity. 
     Electrical signals from thermistors  400 - 1 ,  400 - 2 ,  400 - 3  proportional to corresponding ambient, skin, nasal or oral temperature changes are conducted through the electrically conductive connections  1012  and conductors to central processing unit on the electronics board. The central processing unit can convert the analog data into digital form, process and transmit the data wirelessly, for example, via an RF transmitter, to a host where the data can be shown or displayed to a caregiver in a suitable form of numbers and/or waveforms. 
       FIG. 30  illustrates a detailed view of an electronics assembly  1200 , for example, any respiration sensor  100   a ,  100   b  which can include two nasal flow thermistors  400 - 1 ,  400 - 2  and one oral flow thermistor  400 - 3 , according to some embodiments. Thermistors  400 - 1  and  400 - 2  are configured to measure breathing from nostrils. Thermistor  400 - 3  may be configured to measure breathing from the mouth. A thermistor  500 - 1  (see  FIG. 32 ) may also be included in electronics assembly  1200  to measure ambient temperature. 
     Support structures  1230 - 1 ,  1230 - 2 ,  1230 - 3  contain electrical wires on both sides of a strip between electrical connections at both ends of the strips. The support structures can include first and second support structures  1230 - 1 ,  1230 - 2 , which can support the nasal flow thermistors  400 - 1 ,  400 - 2 . Additionally, a third support structure  1230 - 3  can support the oral flow thermistor  400 - 3 . In some embodiments, support structures  1230 - 1 ,  1230 - 2 ,  1230 - 3  may include an electrically and thermally insulating material (e.g., FR4 substrate). Thermistors  400 - 1 ,  400 - 2 ,  400 - 3  can be soldered to electrical connections in the first end of the strips. Second ends of strips are placed into small holes in electronics board  300  and soldered to form electrical connections on the sides of the strip to corresponding electrical contacts on the board to electrically connect thermistors  400 - 1 ,  400 - 2 ,  400 - 3  to sensor electronics in the plane of the electronics board. 
     The cross-sectional areas of copper or similar traces within support structures  1230 - 1 ,  1230 - 2 ,  1230 - 3  are reduced to minimize thermal flow through the electrical conductors from the plane of board to thermistors  400 - 1 ,  400 - 2 ,  400 - 3 . To minimize the thermal mass of the thermistors  400 - 1 ,  400 - 2 ,  400 - 3 , the support structures  1230 - 1 ,  1230 - 2 ,  1230 - 3  can be formed from a thermally non-conductive or insulating material. These optimizations make thermistors  400 - 1 ,  400 - 2 ,  400 - 3  as sensitive as possible to thermal changes caused by the breathing gas flowing past the thermistor during expiration or ambient gas flowing past the thermistor during inspiration. 
       FIG. 31  illustrates a partial view  1300  of an electronics board  300  in, for example, any respiration sensor  100   a ,  100   b  including details of a nasal flow thermistor  400 - 1 , according to some embodiments. Support structure  1230 - 1  may include an FR4 substrate strip with thermistor  400 - 1  placed on the tip of the strip. At the bottom of support structure  1230 - 1 , a soldered contact provides electrical contacts to thermistor  400 - 1  on both sides of support structure  1230 - 1  (e.g., +/− terminals). 
     In some embodiments, the support structures  1230 - 1 ,  1230 - 2 , can have a proximal portion coupled to the electronics board  300  and a distal portion transverse to a plane defined by the top of the electronics board  300 . When the electronics board is positioned within the housing, the distal portion of the support structures  1230 - 1 ,  1230 - 2  can extend into respective nasal flow passages. In some embodiments, the support structure  1230 - 3  can have a proximal portion coupled to the electronics board  300  and a distal portion that is normal with or substantially parallel to a plane defined by the top of the electronics board  300 . 
       FIG. 32  illustrates a detailed view of a bottom portion of an electronics board  300  of a respiration sensor  100   a ,  100   b  including a thermistor  500 - 1  to measure skin temperature, and a capacitive plate or sensor  1401  to measure sensor location in the upper lip, according to some embodiments. A respiration sensor including electronics board may be turned on/off based on the signal. Additionally, in some embodiments, the electronics board  300  includes an accelerometer  1150 . 
       FIG. 33  illustrates a detailed view of an electronics board  300  coupled with a frame  320  and a battery  1110 , according to some embodiments. Support structures  1130 - 1  and  1130 - 2  extend away from the electronics board, and include thermistors  400 - 1  and  400 - 2 , respectively. A thermistor  500 - 1  sensitive to skin temperature may be located on the bottom side of the board as close to skin as possible. In some embodiments, the thermistor is placed close to one of the two ridges above the upper lip to ensure closest distance to skin. The frame  320  most advantageously contains a perforation adjacent to thermistor that enables better thermal contact to upper lip skin. Perforation can also be filled with thermally conductive material to increase conductivity to skin. 
     The electronics board  300  includes a battery contact tab  1111  that extends toward the battery  1110 . A portion of the spacer  2019  is positioned between the battery contact tab  1111  and the battery  1110  such that the contact tab  1111  is spaced apart from the battery  1110 . When the spacer  2019  is coupled with the respiration sensor  100   b , the battery  1110  the battery does not provide power to the respiration sensor  100   b.    
     In some embodiments, the board  300  includes an LED  2013 , which can be visible from an outer surface of the respiration sensor  100   b  when the respiration sensor  100   b  is assembled. In some embodiments, the board  300  includes a microphone  2020 . The microphone  2020  can detect ambient sounds or a patient speaking. The sound detected by the microphone  2020  can be used to during processing of signals. For example, the sound detected by the microphone  2020  can filtered out to reduce or remove noise in the signals from the other sensors. 
     In some embodiments, any respiration sensor  100   a ,  100   b  is an affordable, disposable, wireless sensor configured to detect breath flow in real time. Accordingly, the sensor  100   a ,  100   b  includes a battery  1110 , which may provide several days (e.g., five days, or more) of continuous, real time, fast response operation with a high signal quality. In some embodiments, the respiration sensor  100   a ,  100   b  is configured to measure a respiration rate (RR) and magnitude, and to provide real time respiration waveforms, in digital and/or analog form. Furthermore, a processor circuit in the respiration sensor may be configured to determine trends and projections based on the real-time data (e.g., via moving averages, Kalman filtering, and the like). The respiration sensor  100   a ,  100   b  may also provide skin temperature, body position, movement, fall detection (e.g., through an accelerometer  1150 ), sensor placement, and the like. 
     V. Processing of Readings for Indications 
       FIG. 34  illustrates a block diagram  1410  of components, which are utilized on the electronics board  300  of the respiration sensor  100   a ,  100   b  according to some embodiments. In such embodiments, the electronics board  300  includes a temperature-to-voltage converter  1412 , an analog-to-digital (AD) converter  1414 , a central processing unit (CPU)  1416 , and a communications module or radio transceiver  1418  for providing a two-way data communication coupling to a network link that is connected to a local network. Such communication may occur, for example, through a radio-frequency transceiver. In addition, short-range communication may occur, such as using a Bluetooth, Wi-Fi, or other such transceiver. In some embodiments, the CPU  1416  includes the Bluetooth low energy processor  1160  (shown in  FIG. 33 ). 
     In some embodiments, the temperature-to-voltage converter  1412  includes any of the thermistor  500 - 1 , the thermistor  500 - 2 , the thermistor  400 - 1 , the thermistor  400 - 2 , and the thermistor  400 - 3 . In some embodiments, any of the thermistors  400 - 1 ,  400 - 2 ,  400 - 3 ,  500 - 1 ,  500 - 2  are negative temperature coefficient (NTC) type thermistors, such that the thermistor&#39;s electrical resistance decreases when the temperature increases. In some other embodiments, any of the thermistors are positive temperature coefficient (PTC) type thermistors, such that the thermistor&#39;s electrical resistance increases when the temperature increases. The respiration sensor  100   a ,  100   b  can include any combination of NTC type thermistors and PTC type thermistors. The temperature-to-voltage converter  1412  converts or transforms the temperature resistance value detected at any of the thermistors to a voltage at Vout  1420 . The AD converter  1414  then converts the Vout  1420  into digital form, which is received by the CPU  1416  for further processing and calculations. In some embodiments, the CPU  1416  can transmit the digital signal to the host monitor or other client device. The CPU  1416  can transmit the digital signal via the Bluetooth low energy processor  1160 . In some other embodiments, the CPU  1416  transmits the digital signal to the communications module or radio transceiver  1418  for wireless transmission to the host monitor or other client device. 
     In addition to the respiration sensor  100   a ,  100   b  measuring or detecting temperature differences between inspiratory and expiratory gas flows via the thermistors  400 - 1 ,  400 - 2 ,  400 - 3 , the respiration sensor  100   a ,  100   b  also measures or detects ambient air temperature via the thermistor  500 - 1  and conductive temperature from the patient&#39;s skin via the thermistor  500 - 2 . 
     In some instances, the thermistor  500 - 1  and the thermistor  500 - 2  include a wide operating temperature range and can be adjusted to include a lowest and a highest temperature of operating range. The respiration sensor  100   a ,  100   b  is configured to measure or detect the electrical signal voltages proportional to the ambient air temperature via the thermistor  500 - 1  and the skin temperature via the thermistor  500 - 2  and compensate the signal offset, gain, and the peak to peak amplitude errors from the inspiratory and expiratory gas flow signal amplitude. 
     In some embodiments, any of the thermistors  400 - 1 ,  400 - 2 ,  400 - 3 ,  500 - 1 ,  500 - 2  can measure any of an inspiratory gas flow, an expiratory gas flow, an ambient air temperature, and a conductive temperature. For example, when the respiration sensor  100   a ,  100   b  is turned on, but is not yet placed on or attached to the patient&#39;s face, the thermistor  400 - 1 ,  400 - 2 ,  400 - 3 ,  500 - 1 ,  500 - 2  detect ambient air temperature. When the respiration sensor  100   a ,  100   b  is placed on or attached to the patient&#39;s face, the thermistor  500 - 2  begins detecting the temperature of skin on the patient&#39;s upper lip. Meanwhile, the thermistor  500 - 1  remains detecting the ambient air temperature and the thermistors  400 - 1 ,  400 - 2 ,  400 - 3  begin detecting the temperature differences between the inspiratory and the expiratory gas flows (e.g., inspired ambient air and expired warm gas coming out from the lungs). 
     During normal, stable ambient conditions, after the respiration sensor  100   a ,  100   b  is placed on or attached to the patient&#39;s face, the electrical voltage signals from the thermistor  500 - 2  (e.g., detecting ambient air temperature) are stable and change slowly, whereas the electrical voltage signal from at least one of the thermistors  400 - 1 ,  400 - 2 ,  400 - 3  changes its amplitude relatively faster. In some embodiments where the thermistors are NTC type and the temperature-to-voltage converter  1412  includes negative feedback amplifiers, the electrical voltage signal changes between maximum voltage proportional to ambient air temperature and minimum voltage proportional to temperature of exhaled warm, moister gas coming out of the patient&#39;s lungs. 
     In other embodiments where the thermistors  400 - 1 ,  400 - 2 ,  400 - 3 ,  500 - 1 ,  500 - 2  are PTC type and the temperature-to-voltage converter  1412  include positive feedback amplifiers, the electrical voltage signal changes between maximum voltage proportional to temperature of exhaled warm, moister gas coming out of the patient&#39;s lungs and minimum voltage proportional to ambient air temperature. In both NTC type and PTC type scenarios, the frequency of electrical signal may vary between 0 to 3 Hz ( 0 - 180  RR/min) depending on how fast the patient is inhaling and exhaling. Smaller patients tend to breathe relatively faster than relatively larger patients, such as adults. 
       FIG. 35  illustrates a block diagram  1436  of components, which are utilized on the electronics board  300  of the respiration sensor  100   a ,  100   b  according to some embodiments. In such embodiments, the electronics board  300  includes a temperature-to-voltage converter  1438 , a filter  1440 , an analog-to-digital (AD) converter  1442 , a central processing unit (CPU)  1444 , and a communications module  1446  for providing a two-way data communication coupling to a network link that is connected to a local network. Such communication may occur, for example, through a radio-frequency transceiver. In addition, short-range communication may occur, such as using a Bluetooth, Wi-Fi, or other such transceiver. In some embodiments, the CPU  1444  includes the Bluetooth low energy processor  1160  (shown in  FIG. 33 ). 
     In some embodiments, the temperature-to-voltage converter  1438  includes any of the thermistors  400 - 1 ,  400 - 2 ,  400 - 3 ,  500 - 1 ,  500 - 2 . In some embodiments, any of the thermistors are negative temperature coefficient (NTC) type thermistors, such that the thermistor&#39;s electrical resistance decreases when the temperature increases. In other embodiments, any of the thermistors are positive temperature coefficient (PTC) type thermistors, such that the thermistor&#39;s electrical resistance increases when the temperature increases. The respiration sensor  100   a ,  100   b  can include any combination of NTC type thermistors and PTC type thermistors. The temperature-to-voltage converter  1438  converts or transforms the temperature resistance value detected at one of the thermistors  400 - 1 ,  400 - 2 ,  400 - 3 ,  500 - 1 ,  500 - 2  to a voltage at Vout  1448 . In some embodiments, the temperature-to-voltage converter  1438  also includes an amplifier  1451 , which increases the voltage at Vout  1448  for increased accuracy and resolution of the breathing gas flow signal. 
     The filter  1440  eliminates or subtracts any of the ambient air and the conducting skin temperature change from the breathing gas flow signal. The AD converter  1442  then converts the signal from the filter  1440  into digital form, which is received by the CPU  1444  for further processing and calculations. In some embodiments, the CPU  1444  can transmit the digital signal to the host monitor or other client device via the Bluetooth low energy processor  1160 . In some other embodiments, the CPU  1444  transmits the digital signal to the communications module  1446  for wireless transmission to the host monitor or other client device. In some embodiments, the filter  1440  is configured to subtract the electrical signal detected by the thermistor  500 - 2  from the electrical signal detected by the thermistor  500 - 1 . In some embodiments, the filter  1440  is configured to subtract the electrical signal detected by the thermistor  500 - 2  and the electrical signal detected by any of the nasal thermistor  400 - 1 , the nasal thermistor  400 - 2 , and the oral thermistor  400 - 3  from the electrical signal detected by the thermistor  500 - 1 . 
       FIG. 36  illustrates a respiration sensor detection state table  1458  for determining the respiration sensor placement and function. For example, an operation logic is derived from the electrical signals from the thermistor  500 - 1 , the thermistor  500 - 2 , and the thermistor  400 - 1 ,  400 - 2 ,  400 - 3  to detect different states of the respiration sensor  100   a ,  100   b . The different states of the respiration sensor  100   a ,  100   b  are utilized to identify sensor placement with respect to the patient and function of the sensor for monitoring and notifying of these states. The respiration sensor  100   a ,  100   b  is capable of identifying, for example, early signs of respiratory depression, spasms, obstructions, and other symptoms, and notifying of these identifications. In addition to notifying of such identifications, the respiration sensor  100   a ,  100   b  is also capable of notifying when an improper placement of the sensor is identified or detected to alert a caregiver to check on the patient and make sure that the sensor is not obstructing the patient&#39;s airways or otherwise disturbing the patient. 
     The respiration sensor  100   a ,  100   b  includes various detection states including, but not limited to: a not-yet-placed state (Not Yet Placed state  1460 ); a correctly-placed and measuring state (Correctly Placed &amp; Measuring state  1462 ); a correctly-placed, but no breath state (Correctly Placed, No Breath state  1464 ); a loose device state (Loose state  1466 ); a detached or no breath state (Detached or No Breath state  1468 ), and an operating-temperature exceeded state (Operating Temperature Exceeded state  1470 ). 
     In the Not Yet Placed state  1460 , the respiration sensor  100   a ,  100   b  is not yet placed on the patient. For example, when the respiration sensor  100   a ,  100   b  is turned on, but not yet placed on or attached to the upper lip of the patient, the thermistor  500 - 2 , the thermistor  500 - 1 , and the thermistor  400 - 3  all detect a similar signal corresponding to temperature proportional to ambient temperature and the breath indicator  1453   a  (shown in  FIG. 35 ) detects no breaths. Under these detected conditions, the respiration sensor  100   a ,  100   b  determines that it is in the Not Yet Placed state  1460  and will not transmit an alert notification. 
     After the respiration sensor  100   a ,  100   b  is placed on or attached to the upper lip of the patient, the thermistor  500 - 2  detects and adapts to a temperature close to skin temperature of the upper lip while the thermistor  500 - 1  remains detecting the ambient air temperature. In some embodiments, the temperature offset error in the thermistor  500 - 2 , which is caused by, for example, a mustache, may be ignored since the temperature detection is enough to monitor the temperature change during the time it takes to detect or determine whether the sensor is in proper placement or not (e.g., not the absolute value). When the location of the sensor between the nasal and the oral passages of the patient is proper and the patient is breathing the thermistor  400 - 3  start to adapt to and detect the temperature of the sequentially changing gas flow (e.g., Breath). At this point, the breath indicator  1453   a  determines that the thermistor  400 - 3  detected a breath. Under these conditions, the respiration sensor  100   a ,  100   b  determines that it is in the Correctly Placed &amp; Measuring state  1462  and will not transmit an alert notification. 
     The respiration sensor  100   a ,  100   b  determines that it is in the Correctly Placed, No Breath state  1464  when the thermistor  500 - 2  remains detecting and adapting to the skin temperature and the thermistor  500 - 1  remains detecting the ambient air temperature, but the thermistor  400 - 3  no longer sufficiently adapts or detects the gas flow temperature (e.g., detects ambient air temperature instead) even though the breath indicator  1453   a  detects breaths. In the Correctly Placed, No Breath state  1464 , the location of the respiration sensor  100   a ,  100   b  between the nasal and/or oral cavities may be unsatisfactory and the gas flow through the sensor cavities may be insufficient and the respiration sensor  100   a ,  100   b  will transmit an alert notification indicating that “No Breath” is detected. It is also possible that, in the Correctly Placed, No Breath state  1464 , the patient is not breathing sufficiently enough and needs immediate attention from clinical personnel. 
     The respiration sensor  100   a ,  100   b  determines that it is in the Loose state  1466  when the thermistor  500 - 2  does not detect the skin temperature and detects, instead, a similar value as the thermistor  500 - 1  (e.g., ambient air temperature) while the thermistor  500 - 1  remains detecting the ambient air temperature, the thermistor  400 - 3  detects the gas flow temperature, and the breath indicator  1453   a  detects breaths. In the Loose state  1466 , the respiration sensor  100   a ,  100   b  may be positioned askew with respect to the upper lip of the patient, such that breathing gas flow is not properly detected or monitored, and the respiration sensor  100   a ,  100   b  will transmit an alert notification indicating that a “Loose Sensor” is detected so that care personnel may adjust the respiration sensor  100   a ,  100   b  with respect to the patient&#39;s upper lip. 
     The respiration sensor  100   a ,  100   b  determines that it is in the Detached or No Breath state  1468  when the thermistor  500 - 2 , the thermistor  500 - 1 , and the thermistor  400 - 3  all detect ambient air temperature and the breath indicator  1453   a  detects no breaths. In the Detached or No Breath state  1468 , the respiration sensor  100   a ,  100   b  is detached from the patient and it will transmit an alert notification indicating “Sensor Detached.” In some embodiments, in the Detached or No Breath state  1468 , in addition to or alternatively, the respiration sensor  100   a ,  100   b  will transmit an alert notification indicating that “No Breath” is detected. 
     The respiration sensor  100   a ,  100   b  determines that it is in the Operating Temperature Exceeded state  1470  when temperature detected by the thermistor  500 - 1  equals or exceeds the temperature detected by the thermistor  500 - 2 . This means that the ambient temperature is too close to the breathing gas temperature to give sufficient differential temperature readings, which is proportional to the respiration signal amplitude. Such a situation may occur when the patient is lying face downward against a surface (e.g., bed or pillow). In the Operating Temperature Exceeded state  1470 , the respiration sensor  100   a ,  100   b  will transmit an alert notification indicating an “Operating Error.” 
     In some embodiments, signals from the nasal thermistors  400 - 1 ,  400 - 2  are compared to determine a state of the patient or the respiration sensor  100   a ,  100   b . The signal from the nasal thermistors  400 - 1 ,  400 - 2  can be compared relative to each other to determine if the respiration sensor  100   a ,  100   b  is correctly placed on the patient. For example, a normal signal from thermistor  400 - 1  or  400 - 2 , and a low or non-existent signal from the other of thermistor  400 - 1  or  400 - 2 , can indicate that the respiration sensor  100   a ,  100   b  is not positioned correctly relative to the patient&#39;s nostrils. 
     The capacitive sensor  1401  can also be used to activate and/or turn on the respiration sensor  100   b . In some embodiments, the processor can be set into a low power or sleep mode when the respiration sensor  100   b  is in storage or not in use. When in the sleep mode, the respiration sensor  100   b  can process a measured value from the capacitive sensor  1401  and compare the measured value to a previous value stored into the memory. The previous value stored into the memory can correspond to a respiration sensor  100   b  that is not engaged against a patient&#39;s face. When the respiration sensor  100   b  is placed on a patient&#39;s upper lip, the capacitive value measured by the capacitive sensor  1401  can change. The change of capacitive value can be caused by the capacitive sensor  1401  engaged against the patient&#39;s lip or tissue, which can have a different permeability relative to another material such as the capacitive sensor  1401  packaging or ambient air. 
     When a change in measured value from the capacitive sensor  1401  is detected, the processor can change the sensor from the low power or sleep mode to a normal operating mode. In some embodiments, the processor can activate other electrical circuits on the electronics board when a change in measured value from the capacitive sensor  1401  is detected. In some embodiments, when the respiration sensor  100   b  is separated from the face of a patient, and a measured value from the capacitive sensor  1401  corresponds to a respiration sensor that is not engaged against a patient&#39;s face, the respiration sensor  100   b  can turn off. In some embodiments, the respiration sensor  100   b  can turn off when the capacitive sensor  1401  detects a change back to the permeability of, for example, air and/or no breathes are detected. In some embodiments, the respiration sensor  100   b  can wait for a predetermined safety time limit, e.g., 5 minutes, and then turn off or enter a low power mode. 
     In some embodiments, the respiration sensor  100   a ,  100   b  can begin measurement automatically when the processor counts one or more breaths from any of the nasal and oral thermistors. For example, measurement can start automatically when the processor counts three different successful breaths from the nasal and/or oral thermistors. 
     To determine the respiration sensor placement and function, the electronics board  300  can include, for example, any of a Bluetooth low energy processor  1160 , the temperature-to-voltage converter  1438 , the filter  1440 , the AD converter  1442 , the CPU  1444 , the communications module  1446 , and the breath indicator  1453   a  stored in the memory  1453   b.    
     The amplitude of the alternating electrical voltage signal from the thermistors  400 - 1 ,  400 - 2 ,  400 - 3 ,  500 - 1 ,  500 - 2  can be converted proportional to a real temperature, for example into degrees of Celsius. In principle, when the patient breathes normally, the minimum amplitude of electrical signal from the NTC type thermistors is proportional to the maximum temperature of exhaled air and the maximum amplitude of electrical signal from the NTC type thermistors is proportional to the minimum temperature of inhaled ambient air. For the PTC type thermistors, the maximum amplitude of electrical signal is proportional to the maximum temperature of exhaled air and the minimum amplitude of electrical signal is proportional to the minimum temperature of inhaled ambient air. The conversion from electrical voltage signal to temperature is negative with NTC type thermistor, whereas the conversion from electrical voltage signal to temperature it is positive with PTC type thermistor. Accordingly, both NTC and PTC type thermistors can provide the same temperature value. 
       FIG. 37  illustrates the temperature of breathing (respiratory flows) during changes in ambient air temperature. The amplitude of the alternating breathing signal  1422  indicates a temperature difference between inhaled ambient air and exhaled gas from the lungs in degrees of Celsius [C° ], and can be proportional to a strength of breathing or volume and flow of breathing. The peak-to-peak amplitude of alternating breathing signal  1422 , presented in degrees of Celsius [C° ], depends mostly on the flow rate of gas and ambient air temperature  1424 . As can been seen in  FIG. 37  the peak-to-peak amplitude of the breathing signal  1422  decreases when the ambient air temperature  1424  increases. 
     In some instances, if exhaled breathing gas flow and volume decreases, the measured signal amplitude decreases proportionally. Due to lower gas volume there is less thermal energy, and due to lower gas flow speed, exhaled gas has more time to release thermal energy to surrounding air and sensor housing (e.g., housing  2001 ) before reaching the thermistor  400 - 1 ,  400 - 2 ,  400 - 3 . Additionally, the exhaled gas can have less thermal energy to warm up the thermistor  400 - 1 ,  400 - 2 ,  400 - 3 . 
     In some instances, if ambient air temperature decreases, the exhaled gas releases even more energy due to higher energy difference between two gas mediums. On the other hand, the maximum breathing signal is proportional to ambient temperature, and is sensitive to ambient air temperature changes, thus the peak-to-peak signal amplitude proportional to sequentially changing inhaled and exhaled gas is also dependent on ambient air temperature. In some instances, if ambient air temperature increases, the breathing signal amplitude between inspirations and expirations decreases and, vice versa, the breathing signal amplitude between inspirations and expirations increase when ambient air temperature decreases. 
     In some embodiments, energy in the form of heat from a patient&#39;s upper lip can be conducted through the respiration sensor housing to thermistors. In some instances, energy directed from or toward a gas flowing through the respiration sensor  100   a ,  100   b  can cause a similar effect as ambient air change.  FIG. 38  illustrates breathing (respiratory flows) during a change in thermal energy conducting temperature, for example when the respiration sensor  100   a ,  100   b  is coupled to a patient&#39;s face. The sensor housing (e.g., housing  2001 ) that guides gas flow through the respiration sensor  100   a ,  100   b  is preferably made of plastic, silicon, or similar material with low thermal coefficient to minimize its ability to absorb, store, and conduct thermal energy. However, the housing may conduct some thermal energy from patient&#39;s upper lip and elevate the sensor temperature, similar to ambient temperature change. The change in temperate generates a small offset, represented by offset curves  1426 , to the temperature signal  1428  proportional to inhaled ambient air temperature decreasing the breathing signal peak-to-peak amplitude. The thermistor  400 - 1 ,  400 - 2 ,  400 - 3  senses when thermal energy, stored during expiration, is released during inspiration, and senses when thermal energy is released during the expiration phase, thus decreasing the breathing signal peak-to-peak amplitude between inspired and expired phases. This offset, represented by the offset curves  1426 , can dependent on any of the ambient air temperature and the thermal coefficient of the sensor housing&#39;s material, which is a constant based on laboratory measurement and can be taken into account. The thermal energy conducting from a patient&#39;s upper lip through the sensor housing is strongly dependent on the thermal connection between the respiration sensor  100   a ,  100   b  and the patient&#39;s face, which in turn is proportional to temperature and the electrical signal from the thermistor  500 - 2 . 
     When the respiration sensor has been placed on patient&#39;s face, each of the inlets to the nasal flow passage cavities can be separated from the corresponding nasal outlet of the patient, and the inlet to the oral flow passage cavity can be separated from the corresponding oral outlet of the patient (i.e., mouth). When the patient breathes, warm and moist breathing gas flows through any of the nasal and oral flow passages. Warm and moister exhaled breathing gas releases thermal energy into the ambient air if the ambient air temperature is lower than the exhaled air temperature. The temperature of exhaled air decreases as shown in  FIG. 38  represented by the offset curves  1426 , which decreases the breathing signal amplitude. To get maximal breathing signal amplitude during exhalation, the sensor housing or respiration sensor cavities are positioned as close as possible to patient&#39;s nasal and oral passage cavities. 
     It can be important to have accurate breathing signal peak to peak amplitude proportional to patient&#39;s actual inspired and expired breathing efforts at any time and during any condition to be able to detect situations, such as, for example, opiates deteriorating patient&#39;s breathing, obstructions, bronchospasms, etc. Changes in ambient air temperature and in conducting thermal energy may cause a decrease in the peak-to-peak signal amplitude, which resembles a similar decrease, for example, as when opiates deteriorate the patient&#39;s breathing. In order to correctly identify or detect the cause of the decrease and to avoid a misidentification, such error signals can be compensated and eliminated to prevent any false notifications of these error signals. Ambient air temperature changes that decrease the breathing gas signal can be compensated and eliminated based on the temperature signal proportional to the thermistor  500 - 1  sensitive to the ambient temperature. Compensation to the breathing gas signal is inversely proportional to increases in the ambient air temperature, thus if the ambient air temperature increases, then the gain of the breathing gas signal is increased, and vice versa. Similarly, changes in skin temperature, which is proportional to the conducting temperature through the sensor housing  2001 , also decrease the breathing gas signal and is compensated and eliminated based on the temperature signal proportional to the thermistor  500 - 2  sensitive to the skin temperature. Compensation to the breathing gas signal is inversely proportional to increases in the skin temperature, thus if the skin temperature increases, then the gain of the breathing gas signal is increased, and vice versa. 
     In some embodiments, thermal transients can be eliminated and signal amplitude relative to ambient and thermal energy conducting temperatures can be compensated to produce a respiratory flow signal. For example, after removing the thermal effects as discussed above with reference to  FIG. 35 , the breathing gas flow signal may be displayed at the host monitor or other client device. The accuracy and resolution of the breathing gas flow signal is enhanced due to the elimination of the thermal transients and compensating the signal amplitude relative to the ambient and conducting temperatures. 
     In some embodiments, a temperature is detected via the thermistor  500 - 2  when the respiration sensor  100   a ,  100   b  is initially placed on a patient&#39;s upper lip. Small sensors placed on the patient&#39;s airways or close to airways may block the airways if the sensor detaches or the attachment is loose. Some conventional approaches to mitigate the possibility of the sensor from detaching or becoming loose are to increase the size of the sensor and increase the adhesive area stuck to the skin. Larger sized sensors, however, may be uncomfortable for a patient and the increase in adhesive may irritate the skin of the patient, such that the patient may intentionally or unintentionally remove or detach the sensor. Some other conventional approaches may utilize a notification system when the sensor becomes detached. In such approaches, however, care personnel may experience “alarm fatigue” caused by false alarms. The disclosed respiration sensor  100   a ,  100   b  determines different suitable measurement parameters that are used to specify different situations to generate appropriate notifications. 
     For example, when the respiration sensor  100   a ,  100   b  is turned on, but is not yet placed on or attached to the patient&#39;s face, the thermistor  500 - 1 , the thermistor  500 - 2 , and the thermistor  400 - 3  detects ambient air temperature. Additionally, data for a breath indicator  1453   a  can be stored in a memory  1453   b  associated with the CPU  1444 , and can indicate that no breaths have been detected yet by the thermistors  400 . While the memory  1453   b  is illustrated to be included in the CPU  1444 , it can be a separate element. When the respiration sensor  100   a ,  100   b  is placed on the patient&#39;s upper lip, the thermistor  500 - 2  comes into close contact with or makes contact with the skin of the upper lip and begins detecting the skin temperature on the patient&#39;s upper lip as represented by a skin temperature curve. For example, at zero seconds, the thermistor  500 - 2  detects the ambient air of approximately 23° C. and warms up after the respiration sensor  100   a ,  100   b  is placed on the upper lip of the patient, at approximately 8 seconds, to detect the skin temperature of approximately 35.5° C. at 55 seconds. Accordingly, when the respiration sensor  100   a ,  100   b  is removed or loosened from the skin on the patient&#39;s upper lip, the thermistor  500 - 2  adapts and begins detecting the ambient temperature. 
     In some embodiments, a temperature offset error may be induced to the thermistor  500 - 2  to compensate for any space between the thermistor  500 - 2  and the patient&#39;s upper lip, such as a mustache or similar medium. As a result, the temperature detected by the thermistor  500 - 2  may differ from the actual skin temperature. However, this compensation or adjustment may be tolerated as it may be important only to detect the temperature change. For example, when the respiration sensor  100   a ,  100   b  is placed on the patient&#39;s upper lip the thermistor  500 - 2  monitors or detects the temperature trend over time until detection of removal of the respiration sensor  100   a ,  100   b  rather than measuring or detecting the absolute skin temperature value. 
     In some embodiments, a temperature is detected via the thermistor  500 - 1  during ambient temperature change. The thermistor  500 - 1  monitors or detects the ambient temperature. For example, on an ambient temperature curve, the thermistor  500 - 1  detects an initial ambient temperature of approximately 23° C. at zero seconds and detects a new ambient temperature of approximately 25° C. at 55 seconds when, for example, the patient is transferred from an ambulance to a hospital environment. 
     In some embodiments, a temperature is detected via the thermistor  400 - 1 ,  400 - 2 ,  400 - 3  during respiratory flows. The thermistor  400 - 1 ,  400 - 2 ,  400 - 3  sequentially detects the temperature change of the breathing gas flow between exhaled breathing gas and inspired ambient air at a constant ambient temperature of 25° C., as represented by a respiration temperature curve. During expiration, exhaled humid and warm air flows out from the nasal and/or the oral passages of the patient into the cavity, such as, for example, the nasal flow passages  301  and the oral flow passage  302 , inside the sensor housing (e.g., housing  2001 ) causing temperature of the thermistor  400 - 1 ,  400 - 2 ,  400 - 3  located inside the cavity to adapt to the exhaled gas flowing past the thermistor  400 - 1 ,  400 - 2 ,  400 - 3 . During inspiration, the patient inhales causing the ambient air to flow through the cavity, such as, for example, the nasal flow passages  301  and the oral flow passage  302 , inside the sensor housing (e.g., housing  2001 ) towards the oral and/or nasal passages of the patient, at which point, the thermistor  400 - 1 ,  400 - 2 ,  400 - 3  adapts back to the temperature of inhaled ambient air flowing past the thermistor  400 . Thus, during expiration, the air flowing out from the lungs warms up the thermistor  400 - 1 ,  400 - 2 ,  400 - 3  and, during inspiration, the ambient air cools down the thermistor  400 - 1 ,  400 - 2 ,  400 - 3 . The temperature difference between the inhaled ambient air and the exhaled breathing gas decreases and approaches zero when the temperature of the ambient air approaches the temperature of the exhaled breathing gas. When the temperature of the inhaled ambient air exceeds the temperature of the exhaled breathing gas the temperature difference exceeds zero again, but changes its sign. 
     In some embodiments, continuous, real time measurements of respiratory flows is determined. Accordingly, a curve indicates a respiration real time waveform. Accordingly, the curve is a waveform including more than two breathing cycles, each cycle including an expiration phase (positive amplitude) and an inspiration phase (negative amplitude). A respiration rate (RR) curve is a curve indicating a value of breaths per minute [bpm]. It can be calculated from respiration waveform curve according to equation RR=60 seconds/breathing cycle time [seconds]. Each respiration cycle has respiration magnitude that may be calculated from a difference between maximum amplitude of expiration and minimum amplitude of inspiration (which is negative). In some embodiments, respiration magnitude is proportional to a breathing flow rate. When a patient exhales, the warm, moist breathing gas from the lungs warm up thermistors  400 - 1 ,  400 - 2 ,  400 - 3  causing respiration waveform signal curve to rise. During inspiration, ambient air cools down thermistors  400 - 1 ,  400 - 2 ,  400 - 3  to a temperature close to the ambient air temperature. Thus, the breathing cycle amplitude is proportional to breathing gas flow rate or respiration magnitude, which is proportional to a temperature change of thermistors caused by the cooling/warming effects of inspiratory and expiratory air flowing past the thermistors. In the particular case of curve, respiration magnitude is a value in percentages indicating the breathing flow magnitude or rate, relative to a maximum breathing flow magnitude or a maximum rate for a particular patient. 
     In some embodiments, a respiration rate over an extended period of time may be monitored and fit to a curve. The curve may indicate a respiration magnitude, corresponding to the depth of breath, over an extended period of time. In some embodiments, curves may reflect both respiration rates and magnitude values calculated on a breath to breath basis. In some embodiments, the curves may include average values to reduce large fluctuations in signals received from sensors. In some embodiments, respiration rate and variance may be desirable parameters for detecting an upcoming heart stroke. In some embodiments, a breathing signal variance may anticipate a stroke event approximately 6-8 hours before the actual stroke. Similarly, overdose of opioids, or pain (e.g., too little opioids) may cause changes in respiration variance that are detectable in a respiration sensor, leading to quicker response and treatment to mitigate or prevent the impending risk. 
     VI. Accelerometer Functions 
     Referring to  FIG. 39 , the respiration sensor  100   a ,  100   b  can provide, for example, body position, movement, and fall detection via the accelerometer  1150  (shown in  FIG. 33 ). The accelerometer  1150  measures or detects acceleration, position, angular rotation and other parameters derived from electrical signals proportional to at least x-, y-, and z-axes directions of accelerometer  1150  and can detect the patient&#39;s position and movement, the patient&#39;s head position and movement, acceleration caused by movement of the respiration sensor  100 ,  100   b ,  100   c , and movement of patient&#39;s upper lip while talking or movement of the patient&#39;s heart. For example, the electrical signals from the accelerometer  1150  can be sent or transmitted to a monitoring device, such as a host monitor or similar client device, via Bluetooth or other communication method to monitor mobile patients. In some embodiments, the accelerometer  1150  of the respiration sensor  100   a ,  100   b  is a three-dimensional accelerometer that measures acceleration and position of at least x-, y-, and z-axes directions of the accelerometer  1150  as well as rotation around at least these three axes. 
     As discussed above, the respiration sensor  100   a ,  100   b  detects movement and position to monitor, for example, that the respiration sensor  100   a ,  100   b  has not fallen out of place with respect to the patient, that the patient has not fallen, or that the orientation of the patient&#39;s head is not obstructing the nasal and oral breathing gas flows (e.g., patient&#39;s face is downward towards pillow or bed). For example, it is desirable to obtain information about how a patient&#39;s head is positioned when the patient is lying in bed for determining the measurement of respiratory cycles from patients. When the patient is lying down on his/her back with his/her face upwards the patient can, for example, turn his/her head from left to right. In such a position, the patient can breathe in a manner that allows gas to flow freely through the nasal and/or oral cavities of the respiration sensor  100   a ,  100   b . When the patient is lying sideways, his/her head can turn upward or downward. In this sideways position, it possible for the patient&#39;s head to face sideways or upward, such that the patient can breathe in a manner that allows gas to flow freely through the nasal and/or oral cavities of the respiration sensor  100   a ,  100   b . It is also possible, however, in this sideways position, for the patient to turn his/her head downwardly toward the bed or a pillow, such that the gas does not flow freely or is obstructed through the nasal and/or oral cavities of the respiration sensor  100   a ,  100   b . This uneven gas flow or obstruction of gas flow can disturb the measurement signal proportional to breathing or the patient&#39;s breathing may be prevented or deteriorated. A similar result may occur when the patient is laying on his/her stomach with his/her face downward into the bed or the pillow. 
     In such scenarios, the respiration sensor  100   a ,  100   b  may detect the direction in which the patient&#39;s face is pointing via the accelerometer  1150 , which can also measure or detect the axial and/or angular position. The position of the patient&#39;s head is determined or calculated from the electrical signals in the x-, y-, and z-directions detected via the accelerometer  1150 . In some embodiments, the respiration sensor  100   a ,  100   b  determines, via the signals proportional to the patient&#39;s position that are monitored by the accelerometer  1150 , the position of the patient&#39;s head relative to the respiration sensor  100   a ,  100   b . As a result, the respiration sensor  100   a ,  100   b , responsive to determining that the patient&#39;s head is in a position that inhibits or obstructs gas flow therethrough and/or causes the respiration sensor  100   a ,  100   b , to function improperly, can transmit a notification to inform of such positioning to the host monitor or other client device via Bluetooth or other communication method. 
       FIG. 39  illustrates the respiration sensor  100   a ,  100   b  in use on a patient to identify or detect any of a seated position  1166 , a moving position  1168 , and a fallen position  1170 . In some embodiments, the respiration sensor  100   a ,  100   b  can identify or detect transitioning of a patient between any of a seated position  1166 , a moving position  1168 , and a fallen position  1170 . In some scenarios, the patient may be mobile (e.g., getting up from the bed to use the restroom) and it may be desirable to monitor the patient&#39;s movement and position. For example, the patient may be recovering from a health issue and feel dizzy when getting up from a stationary position, such that the patient may pass out, fall down, or hurt himself/herself and require acute medical attention and care. In some embodiments, the respiration sensor  100   a ,  100   b  detects, via the signals proportional to the patient&#39;s position that are monitored by the accelerometer  1150 , such situations and indicates or transmits a notification to inform or alert the host monitor or other client device via Bluetooth or other communication method. 
     As an example, the patient may be in a seated position  1166  and stand up to an upright position  1168 , such that the accelerometer  1150  detects movement of the patient&#39;s head via the electrical signals in the x-, y-, and z-directions. Further, as the patient moves or walks in the upright position  1168 , the accelerometer  1150  detects each step or movement the patient may make, such as when the patient gets out of bed to go to the restroom. Each step generates acceleration pulses that are detected by the accelerometer  1150  via the electrical signals proportional to acceleration in the x-, y-, z-directions. If the patient happens to fall down to the fallen position  1170 , the accelerometer  1150  detects a high acceleration value proportional to a falling down magnitude. With the patient in the fallen position  1170  (e.g., lying on the floor) from the upright position  1168 , the respiration sensor  100   a ,  100   b  determines that the patient has fallen down due to the accelerometer  1150  detecting a high acceleration value and determining the difference in the patient&#39;s head position in the upright position  1168  and the fallen position  1170 . Responsive to the determination that the patient has fallen down, the respiration sensor  100   a ,  100   b , transmits a notification to inform or alert the host monitor or other client device, via Bluetooth or other communication method, that the patient has fallen down and may require immediate medical care. 
     Additional measurements can be made based on movement of a patient&#39;s upper lip when patient talks. Talking is vibration of air coming from vocal cords and it may disturb the breathing gas flow measurement and the calculation of respiration rate (RR). The movement of the upper lip may be detected and indicate that the patient is talking. In some embodiments, movement of a patient&#39;s upper lip is detected by the accelerometer  1150 . 
     Additional measurement can be made based on movement of a patient&#39;s heart. The measurements can be used to determine a heart rate of the patient.  FIG. 40  illustrates blood circulation through a heart  1172  as the heart  1172  pumps blood through the body  1174 , shown in  FIG. 41 . Blood from the systemic circulation enters the right atrium from the superior and inferior vena cava and passes to the right ventricle. From the right ventricle, blood is pumped into the pulmonary circulation, through the lungs. Blood then returns to the left atrium, passes through the left ventricle and is pumped out through the aorta back to the systemic circulation. Normally, with each heartbeat, the right ventricle pumps the same amount of blood into the lungs as the left ventricle pumps to the body. Arteries transport blood away from the heart. The heart  1172  contracts at a resting rate close to 72 beats per minute. 
     Due to a specific orientation of the myocardial fibers, in a heartbeat cycle, the heart  1172  makes a wringing or twisting motion along its long-axis. On the other hand, the heart&#39;s sequential contraction, which allows superior and inferior blood to enter the right atrium and ventricle as well as allows expansion to pump blood from the left ventricle and the atrium back to the systemic and pulmonary blood circulation, generate micro movement along heart&#39;s long-axis. This back and forth movement is slightly leaned to the right regarding the body&#39;s longitudinal axis  1176 , as illustrated in  FIG. 41 . 
     The heart&#39;s movement moves the whole body  1174  back and forth cyclically at the phase of a heartbeat close to the direction along body&#39;s longitudinal axis  1176 . This micro movement can be detected by the accelerometer  1150  of the respiration sensor  100   a ,  100   b . The most sensitive direction for the accelerometer  1150  to detect would be the z-axis. In some embodiments, the accelerometer  1150  contains an angular motion sensor or sensing elements, in addition or alternatively, such that it can be used to detect the heart&#39;s rotation along its long-axis, which also generates rotational force around body&#39;s longitudinal axis  1176  at a phase of the heartbeat. Either or both the body&#39;s longitudinal movement or rotational movement around the body&#39;s longitudinal axis  1176  can be transformed to a heartbeat or heartbeats per minute value from the electrical signals of accelerometer. This heart rate (HR) information can be used together with the respiration rate (RR) and flow information, by the respiration sensor  110   a ,  100   b , in early detection and prevention of respiratory depression and other symptoms. 
     In some embodiments, the accelerometer  1150  can also detect rise and fall of a patient&#39;s chest or other thoracic movement. This information can be coupled with at least one of HR, RR, and other breath indicators to aid in early detection and prevention of respiratory distress and other illnesses. 
     VII. EtCO2 Surfaces 
     In some embodiments of the present disclosure, the respiration sensor, such as, for example, the respiration sensor  100   a ,  100   b , can include end-tidal CO2 (EtCO2) sensing features. The EtCO2 sensing features can include one or more EtCO2 sensitive surface. The one or more EtCO2 sensitive surface can be positioned on an outer surface of the shroud  2012  and on a surface of the oral shroud  2017 .  FIG. 42  shows a first EtCO2 sensitive surface  402 - 1  positioned on an outer surface of the shroud  2012  and adjacent to the thermistor  400 - 1 , a second EtCO2 sensitive surface  402 - 2  positioned on an outer surface of the shroud  2012  and adjacent to the thermistor  400 - 2 , and a third EtCO2 sensitive surface  402 - 3  positioned on an inner surface of the oral shroud  2017  and adjacent to the thermistor  400 - 3 . 
     The EtCO2 sensitive surface can change color as a result of nasal and/or oral breath detection of CO2. For example, the EtCO2 sensitive surface can change color to indicate the presence of CO2. In some embodiments, the one or more EtCO2 sensitive surface is coupled with an electrode. As nasal and/or or oral breath moves over the EtCO2 sensitive surface, a change in resistance can occur. The change in resistance is used to determine the presence of CO2 or other breathing related conditions. 
     VIII. Interconnectivity 
     Referring to  FIG. 43 , a respiration monitoring system  1  is illustrated including a sensor  2 , such as respiration sensor  110   a ,  100   b , a hub  4 , and a monitor  6 . The sensor  2 , hub  4 , and monitor  6  can be in communication with each other with wires or wirelessly. In some embodiments, any of a sensor  2 , a hub  4 , and a monitor  6  can be in communication with each other and with a network  50 . The network can include, for example, any of a local area network (LAN), a wide area network (WAN), the Internet, a remote or cloud server, and the like. Further, network  50  can include, but is not limited to a network topologies, including any of a bus network, a star network, a ring network, a mesh network, a star-bus network, tree or hierarchical network, and the like. Although one sensor  2 , hub  4 , and monitor  6  are shown, it should be understood that the respiration monitoring system can include multiple sensors  2 , hubs  4 , and monitors  6 . 
     Some embodiments of the respiration monitoring system can include a patient inside a hospital, a patient at home (e.g., homecare), and other original equipment manufacturer (OEM) applications. Accordingly, in some embodiments OEM parameters can be added to monitoring system (i.e., SpO2, Temp, NiBP, ECG etc.) 
     Communication between the sensor  2  and any of a hub  4  and a monitor  6  can be established using low energy communication  8 , such as Bluetooth. A hub near the respiration sensor, for example, attached to or near a patient, can enable longer respiration sensor operation time by using low energy communication  8 . The low energy communication  8  can include any of a wireless personal area network technology or Bluetooth. The hub can also provide respiration sensor pairing with patient, which can help secure patient identification information. Further, the use of a hub  4  with the sensor  2  can permit patient mobility and continuous monitoring throughout the hospital. 
     A long distance communication  10  protocol (e.g., Wi-Fi, cellular or other communication) may provide data transfer between the hub  4  and a monitor  6 . In some embodiments, data can transfer between the hub  4  and a monitor  6  through the network  50 . In some embodiments, the sensor  2  communicates with a hub in the form of a smartphone. The smartphone communicates to internet through Wi-Fi or cellular systems. Data can be transferred and saved into a cloud in real time. Patient data can be viewed in a different physical location in real time with a smartphone, a tablet, a laptop or desktop computer, a smart TV, and the like. 
       FIG. 44  illustrates a sensor  2 , such as respiration sensor  110   a ,  100   b , coupled to a patient&#39;s  20  head, and a hub  4  positioned adjacent to the patient. The hub  4  provides a user interface to the clinician for bedside monitoring. The hub  4  can also provide connectivity and communication between the patient  20  and a network  50  of the hospital. 
       FIG. 45  illustrates a sensor  2 , such as respiration sensor  110   a ,  100   b , coupled to a patient&#39;s  20  head, and a hub  4 , in the form of a smartphone  14  connected via a band to the patient&#39;s  20  arm. The hub  4  provides a user interface to the clinician for bedside monitoring. The hub  4  can also provide connectivity and communication between the patient  20  and a network  50  of the hospital. In some embodiments of the present disclosure, the smartphone  14  can be placed on a holder adjacent to the patient. The holder can couple with the smartphone  14  to provide any of a communication interface of charging of the smartphone  14 . 
     The smartphone  14  may include a camera, which can be used for pairing with the sensor  2 ; Bluetooth to communicate with a low power consumption sensor  2 ; Wi-Fi to communicate with cloud &amp; hospital network; a user interface enabled for a patient and/or a caregiver; 4G, WCDMA, and GPS. In some embodiments, the smartphone  14  communication is disabled for in-hospital use, and enabled for out-of-hospital use. For example, in out-of-hospital use, when patient and user authentication may be less readily available, the smartphone  14  may perform a face recognition algorithm or other personal/visual/audible recognition algorithms to pair the patient  20  and the respiration sensor  2 , and authenticate that the pairing is correct and accurate. When any information is not authenticated, smartphone  14  may issue an alert, sound an alarm, or communicate a warning to a nurse in the centralized system. In some embodiments, the smartphone  14  is configured to integrate with hospital system to provide authentication of patient and/or user during in-hospital use. 
       FIG. 46  illustrates an interaction between, for example, the sensor  2  and the smartphone  14  in a respiration monitoring system, according to some embodiments. The interaction can be used to pair the sensor  2  and the hub  4 , and can be used to identify the patient with the sensor  2 . 
     In a first step  1800 A, a nurse or authorized healthcare personnel may read data from the sensor  2  in a proximity mode (e.g., a sensor identification value, such as a barcode and the like). In a second step  1800 B, the healthcare personnel may further read the patient&#39;s wristband  12  to log in the respiratory data in the appropriate patient record. In a third step  1800 C, the healthcare personnel may securely place the smartphone  4  in an arm belt  14  on the patient  20 . After connection of the hub  4  with a network  50  or a centralized server, for example, the sensor  2  can send and/or receive, in real-time, continuous respiratory data and other information to the network  50  or centralized server. 
       FIG. 47  illustrates a sensor  2 , such as respiration sensor  110   a ,  100   b , and a headdress  16  coupled to the head of a patient  20 . The headdress  16  provides an easy to wear, wireless monitoring structure for a mobile patient. The headdress includes a hub  4 , in the form of a pod  18  that can be coupled to the headdress  16  at a position adjacent the top of the patient&#39;s head. 
     The headdress  16  can contain sensors attached to, integrated into or in connection with headdress fabric. A sensor  2  (e.g., respiration sensor  100   a ,  100   b ) can measure respiration rate and flow. The pod  18  can include a pod sensor  22  to measure any of skin temperature, ambient temperature, or position, motion and acceleration of the patient. 
     A head sensor  24  can be configured to engage against the patient&#39;s head when the headdress is worn by the patient. In some embodiments, the head sensor  24  is positioned adjacent to the temple of the patient&#39;s head when the headdress is worn by the patient. In some embodiments, the head sensor  24  can extend across the patient&#39;s forehead. The head sensor can measure any of temperature, frontal EEG, frontal oxygen saturation, or movement of the patient. In some examples, the head sensor  24  includes electrodes positioned at different positions on the patient&#39;s head to measure full EEG. 
     An ear sensor  26  can be configured to engage against an ear lobe of the patient when the headdress is worn by the patient. The ear sensor  26  can measure oxygen saturation. The sensor  2  and headdress sensors  22 ,  24 ,  26  can transform physiological signals into electrical signals for measuring physiological parameters. For example, respiration sensor  110   a ,  100   b , and/or other headdress sensors  22 ,  24 ,  26 , can measure any of respiration rate (RR), breathing gas flow, nasal-SpO2, ear-SpO2, frontal-SpO2, pulse rate (PR), heart rate (HR), skin temperature, ambient temperature, core temperature, body position or movement, chest or thoracic motion, EtCO2, full-EEG, frontal EEG, or similar parameters. The sensors are located at suitable locations around the headdress, depending on the measured physical parameter, to enable optimized measurement of that parameter. 
     Each sensor may contain a battery to electrically power up the sensor and each sensor may also contain a transceiver to communicate with a host (e.g., network  50 ) or monitor further away. Preferably sensors are electrically powered through wires  28  integrated into headdress  16 , which connect the sensors with a battery located into one location on the headdress  16 . The sensors also communicate with the host through one transceiver located in the pod  18 . The data communication between the sensors and the transceiver can be via the wires  28  integrated into headdress. This simplifies the electronics and power management infrastructure, decreases radio frequency pollution, which improves communication quality, lowers the cost, weight and size, decreases the power consumption and improves usability and patient comfort. 
     The sensors attached to headdress  16  only contain a minimum amount of mechanics and electronics to simplify and minimize the sensors infrastructure. For example, to enable the measurement of a physiological signal, only the parameter specific electronics to enable to transform the physiological signal of that specific parameter into an electrical signal are located into each sensor. All the electronics that have commonalities between the sensors can be combined in the pod  18 , which can also include the battery, processing unit, transceiver and similar. This centralizing reduces complexity, makes size and weight smaller, increase patient comfort and usability and also reduces the cost of the sensors. 
     Sensors located on fixed or certain places on the headdress  16  also increase the usability and the quality of measurement as sensors locate and place optimally on patient&#39;s head regardless of patient&#39;s appearance or differences between users. Simpler, easy to dress wearable system also increases the adoption of a complex multi-parameter system. 
     The pod  18  can be removed for reuse, and the headdress  16  and sensors therein disposed. Disposability reduces cross contamination risk and decreases care personnel&#39;s working time needed for otherwise disinfecting products. 
     The pod  18  can include most of the electronics, radio transceiver, electrical power source such as a battery, processor etc. and software. The system hardware and mechanics are simplified by centralizing complex functions into a reusable pod, which also makes the system more efficient, easy to clean to prevent cross contamination between patients and low cost. Further, the top of the head is also one of the most comfortable places for the pod  18  when patient is lying, sitting or moving, but it also ensures easy device access and alarm visibility to care personnel. 
     Electrical signals from any of the headdress sensors  22 ,  24 ,  26  and respiration sensor  2  can be transmitted from through the electrical wires  28  to the pod  18  where they are processed into suitable form to be transmitted wirelessly to the monitor. In some embodiments, the pod  18  can communicate with any of the sensors  2 ,  22 ,  24 ,  26 , headdress  16 , and the monitor via Low energy Bluetooth or similar communication method. Preferably the communication with the monitor is via WiFi, 3G, 4G communication or similar. This ensures that data from a mobile patient can be transferred to a monitor device and hospital from any place inside or outside hospital. 
     To ensure data is not lost during communication interruption the pod  18  can contain internal First in first out (FiFo) memory to record data for a time of interruption. The monitor shows the processed data in a suitable form, for example on the host&#39;s display in digits and waveforms and alarms the care personnel when needed. 
     The pod  18  can have electrical contacts on a surface, which are configured to engage against reciprocal electrical contacts  30  on a surface of a pod frame  32  coupled to the headdress  16 . In some embodiments, the electrical contacts  30  in connection with the headdress  16  are planar. When pod  18  is attached to pod frame  32  these electrical contacts  30  connect electrical power and electrical data lines to enable power and data transfer between the sensors  2 ,  22 ,  24 ,  26  and the pod  18  through the electrical wires integrated into to headdress  16 . The attachment between the pod  18  and pod frame  32  may be mechanical sliding or pressing into rails or it may be magnetic or similar. 
     A battery inside the pod  18  can be rechargeable. When charging is needed, the pod  18  can be separated from the pod frame  32  and coupled to a source of electricity. In some embodiments, the pod  18  can be placed on a wireless charging table or a docking station based on for example inductive charging. 
     The outer surfaces of pod  18  can be smooth to prevent injury, prevent catching on fabric, and permit easy cleaning and disinfecting. Power on/off and similar functions are implemented with for example capacitive buttons rather than mechanical buttons so that the user only touches the marked areas on the surfaces of pod  18 . The pod  18  can have any of an alarm light and an audible alarm. The alarm light or audible alarm can be integrated inside the pod  18 . The alarm light can become visible through a partially transparent housing made of material such as plastic. 
     The headdress can include straps  34   a ,  34   b  that extend around at least a portion of the patient&#39;s  20  head, as illustrated in  FIG. 47 . The headdress  16  can be configured so that, when the headdress  16  is worn by a patient  20 , a first strap  34   a  can extend over the top of the patient&#39;s head, and a second strap  34   b  can extend across the forehead of the patient. The headdress  16  can include a fastener to permit attachment of the straps  34   a ,  34   b  to each other and to adjust the headdress  16  to conform to a particular patient&#39;s head. The fastener can include any of a hook and loop fastener, button, snap, or adhesive. In some embodiments, the at least a portion of the straps  34   a ,  34   b  or headdress  16  is formed of an elastic material. 
       FIG. 48  illustrates an embodiment of a headdress  40 , which extends along a greater portion of the patient&#39;s  20  head relative to the headdress  16  illustrated in  FIG. 47 . When worn by a patient  20 , the headdress  40  can extend along any of the patient&#39;s head top, forehead, crown, and nape, as well as the upper lip. The additional area covered by the headdress  40  distributes pressure against the patient  20  over a greater area, thereby reducing discomfort. Further, the additional area covered by the headdress  40  can resist movement of the headdress  40  relative to the patient&#39;s head. The headdress  40  can be used for adults and/or children as well as infants. 
     Referring to  FIGS. 49 and 50 , examples of monitors are illustrated. The monitor can be any device or system where data is received from a hub  4  or respiration sensor  2 .  FIG. 49  illustrates a monitor in the form of a smartphone  14 . The smartphone  14  can be a patient&#39;s phone, a caregiver&#39;s phone, or the phone of another person monitoring the patient.  FIG. 50  illustrates a monitor in the form of a central station  42 . The central station  42  can be a television, computer station, display board, or another display that can be observed by a person monitoring the patient. 
     The monitor can graphically display information regarding the patient and/or data received from any of the sensor  2  and hub  4 . The displayed information can include a temperature value from at least one of two nasal flow passages, a temperature value from an oral flow passage, a temperature value of a patient&#39;s skin surface, and a temperature value of a patient&#39;s environment. In some embodiments, the displayed information includes an identification of the patient and/or their location (e.g., 1-1, 1-2, 2-1), SpO2 measurement, heart rate, and respiration rate. Additionally, displayed information can include an indication of a patient&#39;s orientation or position. The patient&#39;s orientation or position can be shown in text or as a symbol. For example, the text or symbol may represent whether the patient is lying on the bed, is standing upright, is sitting up, or is in some other position. 
     Illustration of Subject Technology as Clauses 
     Various examples of aspects of the disclosure are described as numbered clauses (1, 2, 3, etc.) for convenience. These are provided as examples, and do not limit the subject technology. Identifications of the figures and reference numbers are provided below merely as examples and for illustrative purposes, and the clauses are not limited by those identifications. 
     Clause 1. A respiration sensor comprising: a housing having a first nasal flow passage and a second nasal flow passage that extend therethrough, wherein the first and second nasal flow passages are disposed in parallel to one another with respect to a nasal respiratory flow direction; and an electronics board comprising a first nasal thermistor and a second nasal thermistor, the electronics board coupled to the housing such that the first and second nasal thermistors are positioned into each of the first and second nasal flow passages, respectively. 
     Clause 2. The respiration sensor of Clause 1, wherein the electronics board comprises a support structure, the support structure having a proximal portion coupled to the electronics board and a distal portion transverse to a plane defined by a top of the electronics board, wherein, when the electronics board is positioned within the housing, the distal portion of the support structure extends into at least one of the first and second nasal flow passages. 
     Clause 3. The respiration sensor of Clause 2, wherein any of the first or second nasal thermistors are coupled to the distal portion of the support structure. 
     Clause 4. The respiration sensor of any of Clauses 1 and 2, further comprising an oral flow passage and an oral thermistor, the oral flow passage disposed transverse to the first and second nasal flow passages, along an oral respiratory flow direction. 
     Clause 5. The respiration sensor of Clause 4, wherein the electronics board comprises a support structure having a proximal portion coupled to the electronics board and a distal portion extending along a plane defined by a top of the electronics board wherein, when the electronics board is positioned within the housing, the distal portion of the support structure extends into at least one of the first and second nasal flow passages. 
     Clause 6. The respiration sensor of Clause 5, wherein the oral thermistor is coupled to the distal portion of the support structure. 
     Clause 7. The respiration sensor of any of Clauses 4 to 6, further comprising at least one oral flow guide disposed in the oral flow passage. 
     Clause 8. The respiration sensor of Clause 7, wherein a first oral flow guide of the at least one oral flow guide is disposed proximate an oral inlet of the oral flow passage and a second oral flow guide of the at least one oral flow guide is disposed proximate an oral outlet of the oral flow passage. 
     Clause 9. The respiration sensor of Clause 8, wherein any of the oral inlet and the oral outlet is elliptical. 
     Clause 10. The respiration sensor of any of Clauses 8 and 9, wherein the oral flow passage tapers from the oral inlet toward the oral outlet. 
     Clause 11. The respiration sensor of any of Clause 1 to 10, further comprising a third thermistor and a fourth thermistor, wherein the third thermistor is an ambient thermistor and the fourth thermistor is a skin thermistor configured to determine whether the respiration sensor is properly positioned against a patient&#39;s physiognomy. 
     Clause 12. The respiration sensor of Clause 11, wherein the electronics board further comprises a filter configured to subtract a first electrical signal detected by the skin thermistor from a second electrical signal detected by the ambient thermistor. 
     Clause 13. The respiration sensor of any of Clauses 11 and 12, wherein the electronics board further comprises a filter configured to subtract a first electrical signal detected by the skin thermistor and a second electrical signal detected by any of the first and second nasal thermistors and an oral thermistor from a third electrical signal detected by the ambient thermistor. 
     Clause 14. The respiration sensor of any of Clauses 1 to 13, further comprising a shroud configured to protect the electronics board and to form at a least a portion of the first and second nasal flow passages. 
     Clause 15. The respiration sensor of any of Clauses 1 to 14, wherein the electronics board further comprises an accelerometer configured to detect movement of the respiration sensor. 
     Clause 16. The respiration sensor of Clause 15, wherein the accelerometer is configured to determine whether the respiration sensor has fallen from a face of a patient or the patient has fallen. 
     Clause 17. The respiration sensor of any of Clauses 1 to 16, wherein the electronics board further comprises a radio transceiver configured to communicate with an external device that is coupled with a network. 
     Clause 18. The respiration sensor of any of Clauses 2 to 17, wherein the electronics board comprises a capacitive sensor configured to detect a contact between the housing and a patient&#39;s face, when the respiration sensor is in condition for use. 
     Clause 19. The respiration sensor of any of Clauses 1 to 18, further comprising at least one nasal flow guide disposed in each of the first and second nasal flow passages. 
     Clause 20. The respiration sensor of Clause 19, wherein a first nasal flow guide of the at least one nasal flow guide is disposed proximate a nasal inlet of one of the first and second nasal flow passages, and a second nasal flow guide of the at least one nasal flow guide is disposed proximate a nasal outlet of the one of the first and second nasal flow passages. 
     Clause 21. The respiration sensor of any of Clauses 1 to 20, further comprising a battery. 
     Clause 22. A respiration sensor comprising: one or more thermistors configured to detect at least one of an inspiratory temperature, an expiratory temperature, an ambient temperature adjacent the respiratory sensor, or a temperature of a patient&#39;s skin engaged against the respiration sensor; an accelerometer configured to detect at least one of a movement of the patient, a position of the patient, a heart rate, or a respiration rate; and an electronics board coupled to the one or more thermistors and the one or more thermistors. 
     Clause 23. The respiration sensor of Clause 22, comprising a thermistor configured to detect a temperature of a patient&#39;s skin engaged against the respiration sensor. 
     Clause 24. The respiration sensor of Clause 22, comprising a EtCO2 sensitive surface configured to detect the presence of CO2. 
     Clause 25. A system, comprising: a server having a memory storing commands, and a processor configured to execute the commands to: receive, from a hub, a data indicative of a respiratory condition of a patient; transfer the data into a memory in a remote server; provide the data to a mobile computer device, upon request; and instruct the mobile computer device to graphically display the data, wherein the data comprises a temperature value from at least one of two nasal flow passages, a temperature value from an oral flow passage, a temperature value of a patient&#39;s skin surface, and a temperature value of a patient&#39;s environment. 
     Clause 26. The system of Clause 25, wherein the processor is configured to determine a respiration rate from the data indicative of the respiratory condition of a patient. 
     Clause 27. The system of any of Clauses 25 to 26, wherein the processor is configured to determine a respiration magnitude from the data indicative of the respiratory condition of a patient. 
     Clause 28. The system of any of Clauses 25 to 27, wherein the processor is configured to determine a probability of a patient having a stroke or the patient being under an opioid based on a variance of the data indicative of the respiratory condition of a patient. 
     Clause 29. A method, comprising: receiving, from a hub, a data indicative of a respiratory condition of a patient; transferring the data into a memory in a remote server; providing the data to a monitor, upon request; and instructing the monitor to graphically display the data, wherein the data comprises a temperature value from at least one of two nasal flow passages, a temperature value from an oral flow passage, a temperature value of a patient&#39;s skin surface, and a temperature value of a patient&#39;s environment. 
     Clause 30. The method of Clause 29, further comprising determining a respiration rate from the data indicative of the respiratory condition of a patient. 
     Clause 31. The method of any of Clauses 29 to 30, further comprising determining a respiration magnitude from the data indicative of the respiratory condition of a patient. 
     Clause 32. The method of any of Clauses 29 to 31, further comprising determining a probability of a patient having a stroke or the patient being under an opioid based on a variance of the data indicative of the respiratory condition of a patient. 
     Clause 33. The method of any of Clauses 29 to 32, further comprising associating, in the remote server, a patient record with the respiratory condition of the patient. 
     Clause 34. The method of any of Clauses 29 to 33, wherein the patient is one of a hospital patient or a home-care patient, the method further comprising alerting an emergency care unit when the respiratory condition of the patient indicates a catastrophic event. 
     Clause 35. A respiration sensor system comprising: a respiration sensor comprising a housing having a nasal flow passage that extends therethrough, wherein the nasal flow passage is aligned with a nasal respiratory flow direction, and an electronics board comprising a nasal thermistor, the electronics board coupled to the housing such that the nasal thermistor is positioned into the nasal flow passage; and a hub configured to move data between the respiration sensor and a network. 
     Clause 36. The respiration sensor system of Clause 35, wherein the hub is a smartphone. 
     Clause 37. The respiration sensor system of Clause 35, further comprising a monitor configured to receive data from an of the respiration sensor and the hub. 
     Clause 38. A method, comprising: monitoring data using a respiration sensor; receiving, by a hub separate from the respiration sensor, data from a respiration sensor; transmitting, from the hub to a network, the data from the respiration sensor; and transmitting, from the network to a monitor, the data from the respiration sensor. 
     Clause 39. The method of Clause 38, wherein the data monitored by the respiration sensor is monitored via at least one of a skin thermistor, an ambient thermistor, at least one nasal thermistor, an oral thermistor, an accelerometer, and a breath indicator. 
     Clause 40. The method of Clause 39, further comprising receiving, by the hub from the respiration sensor, a notification indicating a correctly-placed-no-breath state, wherein receiving the notification is in response to the respiration sensor determining that the skin thermistor is detecting a skin temperature, the ambient thermistor is detecting an ambient air temperature, one of the at least one nasal thermistor and the oral thermistor is detecting the ambient air temperature, and the breath indicator is detecting breaths. 
     Clause 41. The method of any of Clauses 39 to 40, further comprising receiving, by the hub from the respiration sensor, a notification indicating a loose state, wherein receiving the notification is in response to the respiration sensor determining that the skin thermistor is detecting an ambient air temperature, the ambient thermistor is detecting the ambient air temperature, one of the at least one nasal thermistor and the oral thermistor is detecting a gas flow temperature, and the breath indicator is detecting breaths. 
     Clause 42. The method of any of Clauses 39 to 41, further comprising receiving, by the hub from the respiration sensor, a notification indicating any of a detached or no breath state, wherein receiving the notification is in response to the respiration sensor determining that the skin thermistor is detecting an ambient air temperature, the ambient thermistor is detecting the ambient air temperature, one of the at least one nasal thermistor and the oral thermistor is detecting the ambient air temperature, and the breath indicator is detecting no breaths. 
     Clause 43. The method of any of Clauses 39 to 42, further comprising receiving, by the remote hub from the respiration sensor, a notification indicating an operating temperature exceeded state, wherein receiving the notification is in response to the respiration sensor determining that the skin thermistor is detecting a skin temperature and the ambient thermistor is detecting a temperature equal to or greater than the skin temperature. 
     FURTHER CONSIDERATION 
     In some embodiments, any of the clauses herein may depend from any one of the independent clauses or any one of the dependent clauses. In one aspect, any of the clauses (e.g., dependent or independent clauses) may be combined with any other one or more clauses (e.g., dependent or independent clauses). In one aspect, a claim may include some or all of the words (e.g., steps, operations, means or components) recited in a clause, a sentence, a phrase or a paragraph. In one aspect, a claim may include some or all of the words recited in one or more clauses, sentences, phrases or paragraphs. In one aspect, some of the words in each of the clauses, sentences, phrases or paragraphs may be removed. In one aspect, additional words or elements may be added to a clause, a sentence, a phrase or a paragraph. In one aspect, the subject technology may be implemented without utilizing some of the components, elements, functions or operations described herein. In one aspect, the subject technology may be implemented utilizing additional components, elements, functions or operations. 
     The foregoing description is provided to enable a person skilled in the art to practice the various configurations described herein. While the subject technology has been particularly described with reference to the various figures and configurations, it should be understood that these are for illustration purposes only and should not be taken as limiting the scope of the subject technology. 
     There may be many other ways to implement the subject technology. Various functions and elements described herein may be partitioned differently from those shown without departing from the scope of the subject technology. Various modifications to these configurations will be readily apparent to those skilled in the art, and generic principles defined herein may be applied to other configurations. Thus, many changes and modifications may be made to the subject technology, by one having ordinary skill in the art, without departing from the scope of the subject technology. 
     As used herein, the phrase “at least one of” preceding a series of items, with the term “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase “at least one of” does not require selection of at least one of each item listed; rather, the phrase allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C. 
     Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiments described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. 
     In one or more aspects, the terms “about,” “substantially,” and “approximately” may provide an industry-accepted tolerance for their corresponding terms and/or relativity between items. 
     A reference to an element in the singular is not intended to mean “one and only one” unless specifically stated, but rather “one or more.” The term “some” refers to one or more. All structural and functional equivalents to the elements of the various configurations described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and intended to be encompassed by the subject technology. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the above description. 
     While certain aspects and embodiments of the subject technology have been described, these have been presented by way of example only, and are not intended to limit the scope of the subject technology. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms without departing from the spirit thereof. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the subject technology.