Abstract:
This disclosure describes systems and methods for managing the ventilation of a patient being ventilated by a medical ventilator. The disclosure describes a novel approach of displaying ventilator information integrated with oximeter information. The disclosure further describes a novel approach of alarming based on the integration of ventilator information with oximeter information.

Description:
BACKGROUND 
       [0001]    Medical ventilator systems have been long used to provide supplemental oxygen support to patients. These ventilators typically comprise a source of pressurized oxygen which is fluidly connected to the patient through a conduit. Some ventilator systems monitor the patient during ventilation. In some systems, the pulse arterial oxygen saturation (SpO 2 ) is monitored via a pulse oximeter attached to the patient. 
         [0002]    A pulse oximeter includes a light sensor that is placed at a site on a patient, usually a. fingertip, toe, forehead or earlobe, or in the case of a neonate, across a foot. Light, which may be produced by alight source integrated into the pulse oximeter, containing both red and infrared wavelengths is directed onto the skin of the patient and the light that passes through the skin is detected. by the sensor. The intensity of light in each wavelength is measured by the sensor over time. The graph of light intensity versus time is referred to as the photoplethysmogram (PPG) or, more commonly, simply as the “pleth.” From the waveform of the PPG, it is possible to identify the pulse rate of the patient and when each individual pulse occurs. In addition, by comparing the intensities of two wavelengths when a pulse occurs, it is possible to determine blood oxygen saturation of hemoglobin in arterial blood. This relies on the observation that highly oxygenated blood will relatively absorb more red light and less infrared light than blood with a lower oxygen saturation. 
         [0003]    Some of previously known medical ventilators attempt to automate the adjustment of fractional inspired oxygen (FiO 2 ) as a function of the patient&#39;s SpO 2 . While these previously known automated ventilation systems utilize the oximeter readings for improving ventilation, patient care could be improved by further coordinating the operation of the two devices, particularly by integrating the analysis, storage and display of particular aspects of oximeter data and respiratory data. 
       SUMMARY 
       [0004]    This disclosure describes systems and methods for managing the ventilation of a patient being ventilated by a medical ventilator. The disclosure describes a novel approach of displaying ventilator information integrated with oximeter information. The disclosure further describes a novel approach of alarming based on the integration of ventilator information with oximeter information. 
         [0005]    In part, this disclosure describes a method for managing the ventilation of a patient being ventilated by a medical ventilator. The method includes:
       a) monitoring a patient during ventilation with an oximeter;   b) monitoring an oxygen saturation level of blood in the patient during ventilation;   c) monitoring a PEEP level of the patient;   d) graphing the oxygen saturation level of the blood in the patient as a function of the PEEP level versus time; and.   e) displaying a graph of the function versus time.       
 
         [0011]    The disclosure also describes another method for managing the ventilation of a patient being ventilated by a medical. ventilator. The method includes:
       a) monitoring a patient during ventilation with an oximeter;   b) monitoring an oxygen saturation level of blood in the patient during ventilation based on readings from the oximeter;   c) monitoring a PEEP level of the patient;   d) graphing the oxygen saturation level of the blood in the patient versus time;   e) graphing the PEEP level of the patient versus time; and   f) displaying both the oxygen saturation level of the blood in the patient versus time and the PEEP level of the patient versus time on one graph.       
 
         [0018]    The disclosure further describes another method for managing c ventilation of a patient being ventilated by a medical ventilator. The method includes:
       a) monitoring a patient during ventilation with an oximeter;   b) monitoring an oxygen saturation level of blood in the patient during ventilation based on readings from the oximeter;   c) monitoring the PEEP of the patient;   d) monitoring the fractional inspired oxygen level of the patient;   e) graphing the oxygen saturation level of the blood in the patient versus time;   f) graphing the PEEP level of the patient versus time;   e) graphing the fractional inspired oxygen level of the patient versus time; and   f) displaying the oxygen saturation level of the blood in the patient versus time, the fractional inspired oxygen level of the patient versus time, and the PEEP level of the patient versus time on one graph.       
 
         [0027]    Additionally, the disclosure also describes a computer-readable medium having computer-executable instructions for performing a method for managing the ventilation of a patient being ventilated by a medical ventilator. The method includes:
       a) repeatedly monitoring a patient with an oximeter during ventilation;   b) repeatedly monitoring an oxygen saturation level of blood in the patient during ventilation;   c) repeatedly monitoring a PEEP level of the patient;   d) repeatedly graphing the oxygen saturation level of le blood in the patient in a mathematical relation to the PEEP level versus time; and   e) repeatedly displaying a graph of the mathematical relationship versus time.       
 
         [0033]    Further, the disclosure also describes a medical ventilator system. The medical ventilator system includes means for repeatedly monitoring a patient during ventilation with an oximeter, means for repeatedly monitoring an oxygen saturation level of blood in the patient during, ventilation, means for repeatedly monitoring a PEEP level of the patient, means for repeatedly graphing the oxygen saturation level of the blood in the patient in a mathematical relation to the PEEP level versus time, and means for repeatedly displaying a graph of the mathematical relationship versus time. 
         [0034]    These and various other features as well as advantages which characterize the systems and methods described herein will be apparent from a reading of the following detailed description and a review of the associated drawings. Additional features are set forth in the description which follows, and in part will be apparent from the description, or may he learned by practice of the technology. The benefits and features of the technology will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
         [0035]    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 invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0036]    The following drawing figures, which form a part of this application, are illustrative of embodiment systems and methods described below and arc not meant to limit the scope of the invention in any manner, which scope shall be based on the claims appended hereto. 
           [0037]      FIG. 1  illustrates an embodiment of a ventilator and oximeter connected to a human patient. 
           [0038]      FIG. 2A  illustrates an embodiment of a method for managing the ventilation of a patient being ventilated by a medical ventilator. 
           [0039]      FIG. 2B  illustrates an embodiment of a method for managing the ventilation of a patient being ventilated by a medical ventilator. 
           [0040]      FIG. 3  illustrates an embodiment of a method for managing the ventilation of a patient being ventilated by a medical ventilator. 
           [0041]      FIG. 4  illustrates an embodiment of a method for managing the ventilation of a patient being ventilated by a medical ventilator. 
           [0042]      FIG. 5  illustrates an embodiment of a method for managing the ventilation of a patient being ventilated by a medical ventilator. 
           [0043]      FIG. 6  illustrates an embodiment of a graph of a function of SpO 2  and PEEP of a patient on a medical ventilator versus time as displayed on a display screen. 
           [0044]      FIG. 7  illustrates an embodiment of a graph of SpO 2  and PEEP of a patient on a medical ventilator versus time as displayed on a display screen. 
           [0045]      FIG. 8  illustrates an embodiment of a graph of SpO 2  and PEEP of a patient on a medical ventilator versus time as displayed on display screen. 
           [0046]      FIG. 9  illustrates an embodiment of a graph of a function of SpO 2  and PEEP of a patient on a medical ventilator versus time as displayed on a display screen. 
           [0047]      FIG. 10  illustrates an embodiment of a graph of a function of SpO 2  and PEEP of a patient on a medical ventilator versus time as displayed on a display screen. 
           [0048]      FIG. 11  illustrates an embodiment of a graph of a function of SpO 2  and PEEP of a patient on a medical ventilator versus time as displayed on a display screen. 
           [0049]      FIG. 12  illustrates an embodiment of a graph of a SpO 2 , FiO 2 , and PEEP of a patient on a medical ventilator versus time as displayed on a display screen. 
           [0050]      FIG. 13  illustrates an embodiment of a graph of a function of SpO 2 , FiO 2 , and PEEP of a patient on a medical ventilator versus time as displayed on a display screen. 
       
    
    
     DETAILED DESCRIPTION 
       [0051]    Although the techniques introduced above and discussed in detail below may be implemented for a variety of medical devices, the present disclosure will discuss the implementation of these techniques in the context of a medical ventilator and oximeter for use in providing ventilation support to a human patient, The reader will understand that the technology described, in the context of a medical ventilator and oximeter for human patients could be adapted for use with other systems and purposes, such as treating non-human patients. 
         [0052]    Medical ventilators are used to provide a breathing gas to a patient who may otherwise be unable to breathe sufficiently, In modem medical facilities, pressurized air and oxygen sources are often available from wall outlets. However, ventilators may also provide pressure regulating valves (or regulators) connected to localized sources of pressurized air and pressurized oxygen. Internal to the ventilator are regulating valves that function to regulate flow so that respiratory gas having a desired concentration of oxygen is supplied to the patient at desired pressures and rates. Ventilators capable of operating independently of external sources of pressurized air are also available. 
         [0053]    While operating a ventilator, it is desirable to control the percentage of oxygen in the gas supplied by the ventilator to the patient. Further, it is desirable to monitor the oxygen saturation level of blood (SpO 2  level) of a patient. Accordingly, medical care facilities typically have oximeters for non-invasively determining the SpO 2  level of a patient. 
         [0054]    Although ventilators and oximeters are often used on the same patient, ventilators typically display data based solely on respiratory data monitored by the ventilator. Further, oximeters typically display data based solely on the oximeter readings. However, it is desirable to display information that incorporates oximeter data with ventilator data for the patient, ventilator operator, and/or medical caregiver, 
         [0055]    The present disclosure describes trended SpO 2  data that is graphically depicted on a display as a function of a Positive End-Expiratory Pressure (PEEP) and/or other respiratory parameters such as FiO 2 . PEEP is the pressure exerted at the end of expiration to oppose passive emptying of the lung and to keep the airway pressure above the atmospheric pressure, By displaying the combination of SpO 2  and PEEP, a significantly clearer picture of the time-based cause and effect of PEEP on SpO 2 . can be better inferred. This clearer picture allows a clinician to more appropriately adjust PEEP and/or oxygen levels. 
         [0056]    Those skilled in the art will recognize that the methods and systems of the present disclosure may be implemented in many ways and as such are not to be limited by the foregoing exemplary embodiments and examples. In other words, functional elements being performed by a single or multiple components, in various combinations of hardware and software or firmware, and individual functions, can be distributed among software applications at either the client or server level or both. In this regard, any number of the features of the different embodiments described herein may be combined into single or multiple embodiments, and alternate embodiments having fewer than or more than all of the features herein described are possible. Functionality may also be, in whole or in part, distributed among multiple components, in manners now known or to become known. Thus, myriad software/hardware/firmware combinations are possible in achieving the functions, features, interfaces and preferences described herein. Moreover, the scope of the present disclosure covers conventionally known ways for carrying out the described features and functions and interfaces. and those variations and modifications that may be made to the hardware or software or firmware components described herein as would be understood by those skilled in the art now and hereafter. 
         [0057]      FIG. 1  illustrates an embodiment of a ventilator  20  connected to a human patient  24 . Ventilator  20  includes a pneumatic system  22  (also referred to as a pressure generating system  22 ) for circulating breathing gases to and from patient  24  via the ventilation tubing system  26 , which couples the patient  24  to the pneumatic system  22  via physical patient interface  28  and ventilator circuit  30 . Ventilator  20  also includes an oximeter  62  for determining the SpO 2  of patient  24 , which is operatively coupled to the ventilator  20  during ventilation, 
         [0058]    Ventilator circuit  30  could be a two-limb or one-limb circuit  30  for carrying gas to and from the patient  24 . In a two-limb embodiment as shown, a wye fitting  36  may be provided as shown to couple the patient interface  28  to the inspiratory limb  32  and the expiratory limb  34  of the circuit  30 , 
         [0059]    The present description contemplates that the patient interface  28  may be invasive or non-invasive, and of any configuration suitable for communicating a flow of breathing gas from the patient circuit  30  to an airway of the patient  24 . Examples of suitable patient interface  28  devices include a nasal mask, nasal/oral mask (which is shown in  FIG. 1 ), nasal prong, full-face mask, tracheal tube, endotracheal tube, nasal pillow, etc. 
         [0060]    Pneumatic system  22  may be configured in a variety of ways. In the present example, system  22  includes an expiratory module  40  coupled with an expiratory limb  34  and an inspiratory module  42  coupled with an inspiratory limb  32 . Compressor  44  or another source or sources of pressurized gas (e.g., pressured air and/or oxygen) is controlled through the use of one or more gas regulators. The pneumatic system  22  may include a variety of other components, including sources for pressurized air and/or oxygen, mixing modules, valves, sensors, tubing, filters, etc. 
         [0061]    The oximeter  62  is connected to a patient oximeter sensor  64 . As illustrated, in an embodiment, the oximeter  62  is a completely separate and independent component from the ventilator  20 . In an alternative embodiment, the oximeter  62  is part of the ventilator system or the pneumatic system  22 . 
         [0062]    The oximeter  62  determines an oxygen gas saturation level of blood in the patient based on the patient readings taken by the pulse oximeter sensor  64  during ventilation of patient  24  by the ventilator  20 . The oximeter sends the measured oxygen saturation level of the blood of patient  24  to a controller  50 . The controller  50  may be any individual controller or combination of controllers within ventilator  20  or operatively coupled to ventilator  20 . In one embodiment, the controller  50  includes a SpO 2  controller, PEEP controller and/or FiO 2  controller, Controller  50  monitors the PEEP of patient  24 , In one embodiment, controller  50  sends a graph plotting the SpO 2  and PEEP of patient  24  in two separate lines versus time on the same graph to display  59 . In another embodiment, controller  50  sends the necessary data to the display  59  for displaying a graph plotting a function of SpO 2  and PEEP versus time. 
         [0063]    In an additional embodiment, controller  50  monitors the fractional inspired oxygen (FiO 2 ) delivered to patient  24 . In one embodiment, controller  50  sends the necessary data to display  59  for displaying a graph plotting SpO 2 , FiO 2  and PEEP of patient  24  in three separate lines versus time on the same graph. In another embodiment, controller  50  sends the necessary data to display  59  for displaying a graph plotting a function of FiO 2 , SpO 2  and PEEP versus time on a graph. 
         [0064]    In this embodiment, the function of SpO 2  and PEEP or FiO 2 , SpO 2 and PEEP may be the multiplication, addition, subtraction, ratio and/or any other mathematical relationship between the separate readings. This function is then plotted on a graph versus time. In an embodiment, controller  50  sends the necessary data to the display  59  for displaying a graph plotting the blood gas oxygen saturation level along with the fractional inspired oxygen concentration and PEEP to graphically depict the relationship between FiO 2 , SpO 2  and PEEP. 
         [0065]    In one embodiment, the graph is displayed on an oximeter display, In another embodiment, the graph is displayed on a ventilator display  59 . 
         [0066]    In another embodiment, the graph may display upper and/or lower preset thresholds for the plotted line or lines. As used herein, the term “preset” refers to any parameter that is calculated by the operator, entered by the operator, set during configuration, or selected by the operator. In this embodiment, the graph may designate with lines, colors, and/or shapes a preset threshold for the plotted line or lines, The preset threshold marker provides the patient, ventilator operator, and/or medical caregiver with a. quick and easy way to check the status of the patient. Further, the patient, ventilator operator, and/or medical caregiver can determine with one glance the severity of a preset threshold breach. The severity of the breach is determined by the amount by which the parameter exceeds the preset threshold, the magnitude of the breach and the duration of the breach, which are fully visible in this embodiment to the patient. ventilator operator, and/or medical caregiver on the displayed graph. Further, the graph illustrates the relationship between SpO 2  and PEEP or SpO 2  and FiO 2  at a glance providing the operator with additional useful information for operating the ventilator. In another embodiment, the graph illustrates the relationship between SpO 2 , FiO 2 , and PEEP at a glance providing the operator with additional useful information for managing the ventilator. 
         [0067]    In one embodiment, as illustrated in  FIG. 1 , the plotting of the data is performed by a graph module  57  in controller  50 . The graph module  57  interprets the SpO 2 , and PEEP data. and/or FiO 2  data and converts this information into the form necessary for graphing the SpO 2  and PEEP and/or FiO 2  or a function of SpO 7  and PEEP versus time and/or a function of SpO 2 , FiO 2 , and PEEP versus time and for displaying the determined graph on a display screen. In an alternative embodiment, the graph module  57  is part of the oximeter  62 . In another embodiment, the graph module  57  includes a processor and is a separate and independent component from the controller  50 . 
         [0068]    In a further embodiment, controller  50  issues an alarm based on the graphed information to notify the operator, patient, and/or medical caregiver that the patient requires assistance or a change in ventilator parameters and/or features is desirable. For example, if the function of SpO 2  and PEEP and/or FiO 2  falls below or above a preset threshold in a patient, the controller  50  may execute an alarm. The alarm may be any visual and/or audio cue supplemental to the graphed information that notifies the patient, operator, and/or medical care giver of a preset threshold breach. In another example, controller  50  determines if the PEEP of patient  24  drops before a drop in SpO 2 , such as could occur in response to a clinician lowering PEEP. In this embodiment, if controller  50  determines that PEEP dropped before a drop in SpO 2 , controller  50  executes a 2 nd  type SpO 2  alarm, As used herein, a “2 nd  type SpO 2  alarm” is any suitable audio and/or visual warning supplemental to the graph information that notifies the patient, operator, and/or medical care giver of a preset threshold breach with a drop in PEEP prior to a drop in SpO 2 . As used herein, a “3 rd  type SpO 2  alarm” is any suitable audio and/or visual warning supplemental to the graph information that notifies the patient, operator, and/or medical care giver of a preset threshold breach with a drop in FiO 2  prior to a drop in SpO 2 . In yet another example. the controller  50  determines if SpO 2  drops independently of a change in PEEP and/or FiO 2 . If controller  50  determines a drop in SpO 2  independent of a change in PEEP and/or FiO 2 , the controller  50  executes a first type oxygen saturation or 1 st  type SpO 2  alarm. As used herein, a “1 st  type SpO 2  alarm” is any suitable audio and/or visual warning supplemental to the graph information that notifies the patient, operator, and/or medical care giver of a preset threshold breach with a drop in SpO 2  independent of a change in PEEP and/or FiO 2 . 
         [0069]    In another embodiment, the ventilator may alarm if the plotted parameter exceeds the preset threshold. The alarm may include a visual cue and/or an audio cue. Further, the alarm may offer different levels or degrees of visual cues and/or audio cues depending upon the severity of the preset threshold breach. 
         [0070]    Controller  50  is operatively coupled with pneumatic system  22 , signal measurement and acquisition systems, and an operator interface  52 , which may be provided to enable an operator to interact with the ventilator  20  (e.g., change ventilator settings, select operational modes, view monitored parameters, e(c.). In one embodiment, controller  50  is operatively coupled with a SpO 2  controller, PEEP controller, and/or FiO 2  controller. Controller  50  may include memory  54 , one or more processors  56 , storage  58 , and/or other components of the type commonly found in command and control computing devices. 
         [0071]    The memory  54  is non-transitory computer-readable storage media that stores software that is executed by the processor  56  and which controls the operation of the ventilator  20 . In an embodiment, the memory  54  comprises one or more solid-state storage devices such as flash memory chips. In an alternative embodiment, the memory  54  may be mass storage connected to the processor  56  through a mass storage controller (not shown) and a communications bus (not shown). Although the description of non-transitory computer-readable media contained herein refers to a solid-state storage, it should be appreciated by those skilled in the art that non-transitory computer-readable storage media can be any available media that can be accessed by the processor  56 . Non-transitory computer-readable storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or other data. Non-transitory computer-readable storage media includes, but is not limited to, RAM, ROM, EPROM, EEPROM, flash memory or other solid state memory technology, CD-ROM, DVD, or other optical storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by the processor  56 . 
         [0072]    The controller  50  issues commands to pneumatic system  22  in order to control the breathing assistance provided to the patient  24  by the ventilator  20 . The specific commands may be based on inputs received from patient  24 , pneumatic system  22  and sensors, operator interface  52  and/or other components of the ventilator  20 . 
         [0073]    In the depicted example, operator interface  52  includes a display  59  that is touch-sensitive, enabling the display  59  to serve both as an input user interface and an output device. The display  59  can display any type of ventilation information, such as sensor readings, parameters, commands, alarms, warnings, and smart prompts (i.e., ventilator determined operator suggestions). In this embodiment, display  59  further displays oximeter and ventilator information, such as a graph of SpO 2  in relation to PEEP versus time. In an alternative embodiment, an oximeter display or monitor displays oximeter and ventilator information, such as a graph of SpO 2  in relation to PEEP versus time. 
         [0074]    In another embodiment, display  59  further displays oximeter and ventilator information, such as a graph of SpO 2  in relation to PEEP and FiO 2  versus time. In an alternative embodiment, an oximeter display or monitor displays oximeter and ventilator information, such as a graph of SpO 2  in relation to PEEP and FiO 2  versus time. 
         [0075]    As illustrated in  FIGS. 2A and 2B , an embodiment of a method  200  for managing the ventilation of a patient being ventilated by a medical ventilator is shown. Method  200  performs a patient monitoring operation  202 , The patient monitoring operation  202  utilizes an oximeter to monitor the status of a patient during ventilation, The oximeter is operatively coupled to the controller of the ventilation system. 
         [0076]    Next, method  200  performs a SpO 2  monitoring operation  204 . The SpO 2  monitoring operation  204  determines the SpO 2  of the patient from patient data gathered by patient monitoring operation  202 . The SpO 2  monitoring operation  204  can be performed by the oximeter and/or the ventilator by utilizing oximeter sensor readings to monitor the SpO 2  of the patient. 
         [0077]    Further, method  200  performs a PEEP monitoring operation  206 . The PEEP monitoring operation  206  monitors the PEEP of the patient during ventilation. The PEEP monitoring operation  206  may monitor the PEEP of the patient with one or more flow and/or pressure sensors depending on the configuration of the ventilator. The reading from the flow and/or pressure sensors may be utilized, to monitor the PEEP of the patient. 
         [0078]    Method  200  performs a graphing operation  208 . The graphing operation  208  graphs SpO 2  and PEEP versus time. In one embodiment, graphing operation  208  graphs PEEP and SpO 2  as separate lines on one graph, In an alternative embodiment, graphing operation  208  calculates a function of PEEP and SpO 2  and graphs this number as one line verse time. The function of SpO 2  and PEEP may be the multiplication, addition, subtraction, ratio and/or any other mathematical relationship between of the separate readings. 
         [0079]    In one embodiment, the graphing operation  208  is performed by a controller, Further, the controller may include a graphing module for receiving and interpreting the PEEP and SpO 2  data to correctly graph this data verse time. The graphing operation  208  converts the PEEP and SpO 2  data into graphable information and displayable information. 
         [0080]    Method  200  also performs a display operation  210 . Display operation  210  displays the graph created by graphing operation  208 . The displaying operation  210  may display the graph on a display in the oximeter. and/or ventilator. As illustrated in FIGS,  6  through  11 , an embodiment of a graph of a function of SpO 2  and PEEP or separate SpO 2  and PEEP readings of a patient on a medical ventilator versus time as displayed on a display screen is shown. 
         [0081]    In one embodiment, as illustrated in  FIG. 2B , method  200  further performs a preset threshold display operation  212 . The preset threshold display operation  212  displays at least one preset threshold on the graph displayed by display operation  210 . The preset threshold provides the patient, operator, and/or medical care giver with a quick reference point to determine the status of the patient during ventilation. In an embodiment, preset threshold display operation  212  displays an upper and a lower preset threshold limit on the graphed function of SpO 2  and PEEP or each reading individually. Preset threshold display operation  212  may depict a preset threshold with color, symbols, lines, light, and/or text. The preset threshold may be preset by the operator, configured into the ventilator based on the ventilator settings, and/or selected by the operator. 
         [0082]    As illustrated in  FIG. 2B , method  200  may further perform a preset threshold determination operation  214 . The preset threshold. determination operation  214  determines if PEEP, SpO 2 , and/or a function of PEEP and SpO 2  exceeds a preset threshold. If preset threshold determination operation  214  determines that PEEP, SpO 2 , and/or a function of PEEP and SpO 2  exceeds a preset threshold, preset threshold determination operation  214  has method  200  perform PEEP determination operation  216 . If preset threshold determination operation  214  determines that PEEP, SpO 2 , and/or a function of PEEP and SpO 2  do not exceed a preset threshold, preset threshold determination operation  214  has method  200  perform patient monitoring operation  202  again. 
         [0083]    As illustrated in  FIG. 2B , method  200  may further perform a PEEP determination operation  216 , The PEEP determination operation  216  determines if PEEP changes prior to a SpO 2  drop after preset threshold determination operation  214  determines that a preset threshold had been exceeded. If PEEP determination operation  216  determines that PEEP changed prior to a SpO 2  drop, PEEP determination operation  216  has method  200  perform a 2 nd  type SpO 2  alarm operation  218 . If PEEP determination operation  216  determines that SpO 2  dropped independently of a change in PEEP, PEEP determination operation  216  has method  200  perform a 1 st  type SpO 2  alarm operation  220 . 
         [0084]    As illustrated in  FIG. 2B , method.  200  may perform a 2 nd  type SpO 2  alarm operation  218 . Second type SpO 2  alarm operation  218  executes a specific alarm that notifies the operator that a preset threshold was exceeded during which PEEP change(prior to a drop in SpO 2 . The  2   nd  type SpO 2  alarm may be any visual and/or audio cue. 
         [0085]    As illustrated in  FIG. 2B , method  200  may perform 1 st  type SpO 2  alarm operation  220 . First type SpO 2  alarm operation  220  executes a specific alarm that notifies the operator that a preset threshold was exceeded during which PEEP did not change prior to a drop in SpO 2 . The 1 st  type SpO 2  alarm may be any visual and/or audio cue. 
         [0086]    After performing the 2 nd  type SpO 2  alarm operation  218  or the 1 st  type SpO 2  alarm operation  220 , method  200  performs patient monitoring operation  202  again. 
         [0087]    In an additional embodiment, method  200  further monitors a FiO 2  level of the patient, graphs the oxygen saturation level of the blood in the patient as a function of the FiO 2  level and PEEP versus time, and then displays in the graph the oxygen saturation level of the blood in the patient as a function of the FiO 2  level and PEEP versus time, Accordingly, method  200  may further determine that the either function is outside a preset threshold. If method  200  determines that the FiO 2  of the patient dropped prior to a drop in the oxygen saturation level of the blood in the patient, method  200  executes a 3 rd  type SpO 2  alarm. Alternatively, if method  200  determines that the PEEP of the patient dropped prior to a drop in the oxygen saturation level of the blood in the patient, method  200  executes a 2 rd  type SpO 2  alarm. In an another embodiment, if method  200  determines that the oxygen saturation level of the blood in the patient dropped independently of a drop in PEEP and/or FiO 2 , then method  200  executes a first type oxygen saturation alarm. Further, the step of graphing the oxygen saturation level of the blood in the patient as a function of the FiO 2  level and PEEP versus time performed by method  200  can include converting PEEP data, oxygen saturation level data, and FiO 2  data into plotted graph and into displayable information. 
         [0088]    As illustrated in  FIG. 3 , an embodiment of a method  300  for managing the ventilation of a patient being ventilated by a medical ventilator is shown. Method  300  performs a patient monitoring operation  302 . The patient monitoring operation  302  utilizes an oximeter to monitor the status of a patient during ventilation. The oximeter is operatively coupled to the controller of the ventilation system. 
         [0089]    Next, method  300  performs a SpO 2  monitoring operation  304 . The SpO 2  monitoring operation  304  determines the SpO 2  of the patient based on the results of the patient monitoring operation  302 , The SpO 2  monitoring operation  304  can be performed by the oximeter or the ventilator, The oximeter or the ventilator utilizes oximeter sensor readings to monitor the SpO 2  of the patient. 
         [0090]    Further, method  300  performs a PEEP monitoring operation  306 . The PEEP monitoring operation  306  monitors the PEEP of the patient during ventilation. The PEEP monitoring operation  306  may monitor the PEEP of the patient with a flow and/or pressure sensor. The reading from the flow and/or pressure sensor may be utilized to monitor the PEEP of the patient. 
         [0091]    Method  300  performs a graphing operation  308 , The graphing operation  308  graphs SpO 2  and PEEP versus time. In one embodiment, graphing operation  308  graphs PEEP and SpO 2  as separate lines on one graph. In an alternative embodiment, graphing operation  308  calculates a function of PEEP and SpO 2  and graphs this number in one line verse time. The function of SpO 2  and PEEP may be the multiplication, addition, subtraction, ratio and/or any other mathematical relationship between the separate readings. 
         [0092]    In one embodiment, the graphing operation  308  is performed by a controller. Further, the controller may include a graphing module for receiving and interpreting the PEEP and SpO 2  data to correctly graph this data verse time. The graphing operation  308  converts the PEEP and SpO 2  data into graphable information and displayable information. 
         [0093]    Method  300  also performs :display operation  310 . Display operation  310  displays the graph created by graphing step  308 . The displaying operation  310  may display the graph on a display in the oximeter and/or ventilator. As illustrated in  FIGS. 6 through 11 , an embodiment of a graph of a function of SpO 2  and PEEP or separate SpO 2  and PEEP readings of a patient on a medical ventilator versus time as displayed on a display screen is shown. 
         [0094]    Next, method  300  performs a preset threshold. display operation  312 . The preset threshold display operation  312  displays at least one preset threshold on the graph displayed by display operation  310 , The preset threshold provides the patient, operator, and/or medical care giver with a quick reference point to determine the status of the patient during ventilation, In an embodiment, preset threshold display operation  312  displays an upper and a lower preset threshold limit on the graph. Preset threshold display operation  312  may depict a preset threshold with color, symbols, lines, light, and/or text. The preset threshold may be preset by the operator, configured into the ventilator based on the ventilator settings, and/or selected by the Operator. 
         [0095]    Further. method  300  performs a preset threshold determination operation  314 . The preset threshold determination operation  314  determines if PEEP, SpO 2 , and/or a function of PEEP and SpO 2  preset threshold was exceeded. If preset threshold determination operation  314  determines that a preset threshold was exceeded, preset threshold determination operation  314  has method.  300  perform an alarm operation  316 . If preset threshold determination operation  314  determines that preset threshold was not exceeded, preset threshold determination operation  314  has method  300  perform patient monitoring, operation  302  again. 
         [0096]    Method  300  performs an alarm operation  316 , The alarm operation  316  executes an alarm to notify the operator that a preset threshold has been exceeded. The alarm may be any visual and/or audio cue. After performing alarm operation  316 , method  300  performs patient monitoring operation  302  again. 
         [0097]    As illustrated in  FIG. 4 , an embodiment of a method  400  for managing the ventilation of a patient being ventilated by a medical ventilator is shown, Method  400  performs a patient monitoring operation  402 . The patient monitoring operation  402  utilizes an oximeter to monitor the status of a patient during ventilation. The oximeter is operatively coupled to the controller of the ventilation system. 
         [0098]    Next, method  400  performs a SpO 2  monitoring operation  404 . The SpO 2  monitoring operation  404  determines the SpO 2  of the patient based. on the results of the patient monitoring operation  402 . The SpO 2  monitoring operation  404  can be performed by the oximeter and/or the ventilator. The oximeter and/or the ventilator utilize oximeter sensor readings to monitor the SpO 2  of the patient. 
         [0099]    Further, method  400  performs a PEEP monitoring operation  406 . The PEEP monitoring operation  406  monitors the PEEP of the patient during ventilation. The PEEP monitoring operation  406  may monitor the PEEP of the patient with a flow and/or pressure sensor. The reading from the flow and/or pressure sensor may be utilized to monitor the PEEP of the patient. 
         [0100]    Further, method  400  performs a FiO 2  monitoring operation  407 . The FiO 2 . monitoring operation  402  monitors the FiO 2  of the patient during ventilation. The FiO 2  monitoring operation  402  may monitor the FiO 2  of the patient with a gas sensor and/or a flow and/or. pressure sensor. The reading from the gas sensor may be utilized to monitor the FiO 2  of the patient. 
         [0101]    Method  400  performs a graphing operation  408 , The graphing operation  408  graphs SpO 2 , FiO 2 , and PEEP versus time. In one embodiment, graphing operation  408  graphs PEEP, FiO 2 , and SpO 2  as separate lines on one graph. In an alternative embodiment, graphing operation  408  calculates a function of PEEP, FiO 2 , and SpO 2  and graphs this number in one line verse time. The function of FiO 2 , SpO 2 and PEEP may be the multiplication, addition, subtraction, ratio and/or any other mathematical relationship between the separate readings. 
         [0102]    In one embodiment, the graphing operation  408  is performed by a controller. The controller may be located in the oximeter and/or the ventilator. Further, the controller may include a graphing module for receiving and interpreting the PEEP, FiO 2 , and SpO 2  data to correctly graph this data verse time. The graphing operation  408  converts the PEEP, FiO 2 , and SpO 2  data into graphable information and displayable information. 
         [0103]    Method  400  also performs a display operation  410 . Display operation  410  displays the graph created by graphing step  408 . The displaying operation  410  may display the graph on a display in the oximeter and/or ventilator, As illustrated in  FIGS. 12 and 13 , an embodiment of a graph of a function of FiO 2 , SpO 2  and PEEP or separate SpO 2 , FiO 2 , and PEEP readings of a patient on a medical ventilator versus time as displayed on a display screen is shown. 
         [0104]    Next, method  400  performs a preset threshold display operation  412 , The preset threshold display operation  412  displays at least one preset threshold on the graph displayed by display operation  408 , The preset threshold provides the patient, operator, and/or medical care giver with a quick reference point to determine the status of the patient during ventilation. In an embodiment, preset threshold display operation  412  displays an upper and a lower preset threshold limit on the graph, Preset threshold display operation  412  may depict a preset threshold with color, symbols, lines, light, and/or text. The preset threshold may be preset by the operator, configured into the ventilator based on the ventilator settings, and/or selected by the operator. 
         [0105]    Further, method  400  performs a preset threshold determination operation  414 . The preset threshold determination operation  414  determines if a PEEP, FiO 2 , SpO 2 , and/or a function of PEEP, FiO 2 , and SpO 2  preset threshold was exceeded. If preset threshold determination operation  414  determines that a preset threshold was exceeded, preset threshold determination operation  414  has method  400  perform an alarm operation  416 . If preset threshold determination operation  414  determines that a preset threshold was not exceeded, preset threshold determination operation  414  has method  400  perform patient monitoring operation  402  again, 
         [0106]    Method  400  performs an alarm operation  416 , The alarm operation  416  executes an alarm to notify the operator that a preset threshold has been exceeded. The alarm may be any visual and/or audio cue. After performing alarm operation  416 , method  400  performs patient monitoring operation  402  again. 
         [0107]    As illustrated in  FIG. 5 , an embodiment of a method  500  for managing the ventilation of a patient being ventilated by a medical ventilator is shown, Method  500  performs a patient monitoring operation  502 . The patient monitoring operation  502  utilizes an oximeter to monitor the status of a patient during ventilation. The oximeter is operatively coupled to the controller of the ventilation system. 
         [0108]    Next, method  500  performs a SpO 2  monitoring operation  504 , The SpO 2  monitoring operation  504  determines the SpO 2  of the patient based on the data gathered by the patient monitoring operation  502 . The SpO 2  monitoring operation  504  can be performed by the oximeter or the ventilator, The oximeter or the ventilation utilizes oximeter sensor readings to monitor the SpO 2  of the patient. 
         [0109]    Further, method  500  performs a FiO 2  monitoring operation  506 . The FiO 2  monitoring operation  506  monitors the FiO 2  of the patient during ventilation. The FiO 2  monitoring operation  506  may monitor the FiO 2  of the patient with a gas sensor and/or a flow and/or pressure sensor. The reading from the gas sensor may be utilized to monitor the FiO 2  of the patient. 
         [0110]    Method  500  performs a graphing operation  508 . The graphing operation  508  graphs SpO 2  and FiO 2  versus time. In one embodiment, graphing operation  508  graphs FiO 2  and SpO 2  as separate lines on one graph. In an alternative embodiment, graphing operation  508  calculates a function of FiO 2  and SpO 2  and graphs this number in one line verse time, The function of SpO 2  and FiO 2  may be the multiplication, addition, subtraction, and/or ratio of the separate readings, 
         [0111]    In one embodiment, the graphing operation  508  is performed by a controller. The controller may be located in the oximeter and/or the ventilator. Further, the controller may include a graphing module for receiving and interpreting the raw FiO 2  and SpO 2  data to correctly graph this data verse time. The graphing operation  508  converts the raw FiO 2  and SpO 2  data into graphable information and displayable information. 
         [0112]    Method  500  also performs a display operation  510 . Display operation  510  displays the graph created by graphing step  508 . The displaying operation  510  may display the graph on a display in the oximeter, and/or ventilator. 
         [0113]    Next, method  500  performs a preset threshold display operation  512 . The preset threshold display operation  512  displays at least one preset threshold on the graph displayed by display operation  508 , The preset threshold provides the patient, operator, and/or medical care giver with a quick reference point to determine the status of the patient during ventilation. In an embodiment, preset threshold display operation  512  displays an upper and a lower preset threshold limit on the graph, Preset threshold display operation  512  may depict a preset threshold with color, symbols, lines, light, and/or text. The preset threshold may be preset by the operator, configured into the ventilator based on the ventilator settings, and/or selected by the Operator. 
         [0114]    Further, method  500  performs a preset threshold determination operation  514 . The preset threshold determination operation  514  determines if a FiO 2 , SpO 2 , and/or a function of FiO 2  and SpO 2  preset threshold was exceeded. If preset threshold determination operation  514  determines that a preset threshold was exceeded, preset threshold determination operation  514  has method.  500  perform an alarm operation  516 . If preset threshold determination operation  514  determines that preset threshold was not exceeded, preset threshold determination operation  514  has method  500  perform patient monitoring, operation  502  again. 
         [0115]    Method  500  performs an alarm operation  516 . The alarm operation  516  executes an alarm to notify the operator that a preset threshold has been exceeded. The alarm may be any visual and/or audio cue. After performing alarm operation  516 , method  500  performs patient monitoring operation  502  again. 
         [0116]    In alternative embodiment, a computer-readable medium having computer-executable instructions for performing a method for managing the ventilation of a patient being ventilated by a medical ventilator is disclosed. The method includes repeatedly performing the steps disclosed in method  200 , method  300 , method  400 , or method  500 . 
         [0117]    In another embodiment, a medical ventilator system is disclosed. The medical ventilator includes means for repeatedly monitoring a patient during ventilation with an oximeter, means for repeatedly monitoring an oxygen saturation level of blood in the patient during ventilation, means for repeatedly monitoring a PEEP level of the patient, means for repeatedly graphing the oxygen saturation level of the blood in the patient as a function of the PEEP level versus time, and means for repeatedly displaying a graph of the function versus time. In one embodiment, the means for the medical ventilator system are all illustrated in  FIG. 1  and description above in the description of  FIG. 1 . However, the means described above for  FIG. 1  and illustrated in  FIG. 1  are exemplary only and are not meant to be limiting. 
       EXAMPLE  1   
       [0118]    The following are embodiments of graphs that can be displayed on a display screen of a medical ventilator or an oximeter that graphs PEEP and SpO 2  versus time. 
         [0119]    The following are embodiments of graphs that depict PEEP and SpO 2  as separate lines versus time that can be displayed on a display screen. A display may show a graph with an upper and lower preset threshold for two separate lines depicting the patient&#39;s SpO 2  and PEEP during ventilation versus time in seconds as illustrated in  FIGS. 7 ,  8 , and  11 . As shown in  FIG. 7 , both PEEP and SpO 2  remain within the upper and lower preset thresholds depicted by the shaded areas, FIG,  8  illustrates a preset threshold that was exceeded first by a drop in PEEP and followed by a drop in SpO 2 . The appropriate scales for PEEP and SpO 2  may be displayed in any conventional manner. 
         [0120]      FIG. 11  illustrates a preset threshold that was exceeded first by a drop in SpO 2  and then followed by a drop in PEEP.  FIG. 11  further illustrates a visual alarm icon that indicates that a preset threshold was exceeded first by a drop in SpO 2  followed by a drop in PEEP. As illustrated in  FIG. 11 , the visual alarm cue is a colored star that flashes in the corner of the graph. This alarm is exemplary only and does not limit the disclosure. 
         [0121]    The following are embodiments of graphs that depict a function of SpO 2  and PEEP versus time that can be displayed on display screen. The function of SpO 2 and PEEP may be the multiplication, addition, subtraction, ratio, and/or any other mathematical relationship between the parameters. For example, in an embodiment, PEEP and SpO 2  for any given period. (e.g., for each monitoring cycle of 5 ms or for a group of monitoring cycles) are multiplied resulting in a graph of P PEEP *O 2 % v. time. However, any function of PEEP and SpO 2  of clinical value may be used. A display may show a graph with an upper and lower preset threshold for the function of the patient&#39;s SpO 2  and PEEP during ventilation verse time in seconds. 
         [0122]    In an alternative example, a display may show a graph with only a lower preset threshold and one line depicting the function of the patient&#39;s SpO 2  and PEEP during ventilation verse time in seconds as illustrated in  FIGS. 9 and 10 . The lower preset threshold is the shaded. area in the graphs illustrated in  FIGS. 9 and 10 .  FIGS. 9 and 10  further illustrate visual alarm icons that indicate that a preset threshold was exceeded by a drop in SpO 2  independently of a change in PEEP or was exceeded first by a drop in PEEP followed by a drop in SpO 2 . As illustrated in  FIG. 11 , the visual alarm icon is a colored star that flashes in the corner of the graph when a preset threshold is exceeded by a drop in SpO 2  independently of a change in PEEP. As illustrated in  FIG. 9 , the visual alarm icon is a colored circle that flashes in the corner of the graph when the preset threshold was exceeded first by a drop in PEEP followed by a drop in SpO 2 . These alarms are exemplary only and do not limit the disclosure. 
         [0123]    The following are embodiments of graphs that can be displayed on a display screen of a medical ventilator or an oximeter that graphs PEEP, FiO 2  and SpO 2  versus time 
         [0124]    The following is an embodiment of a graph that depicts PEEP, FiO 2  and SpO 2  as separate lines versus time that can be displayed on a display screen. A display may show a graph with an upper and lower preset threshold for three separate lines depicting the patient&#39;s SpO 2 , FiO 2 , and PEEP during ventilation versus time in seconds as illustrated in FIG. As shown in  FIG. 12  a preset threshold that was exceeded first by a drop in PEEP and followed by a drop in SpO 2 . The appropriate scales for PEEP, FiO 2 , and SpO 2  may be displayed in any conventional manner. 
         [0125]    The following is an embodiment of a graph that depicts a function of SpO 2 , PEEP, and FiO 2  versus time that can be displayed on a display screen. The function of SpO 2 , PEEP and FiO 2  may be the multiplication, addition, subtraction, ratio, and/or any other mathematical relationship between the parameters. For example, in an embodiment, PEEP, FiO 2 , and SpO 2  for any given period (e.g., for each monitoring cycle of 5 ms or for a group of monitoring cycles) are multiplied resulting in a graph of P FiO2 *P PEEP *O 2 % v. time. However, any function of PEEP, FiO 2 , and SpO 2  of clinical value may he used. A display may show a graph with an upper and/or lower preset threshold for the function of the patient&#39;s SpO 2 , FiO 2 , and PEEP during ventilation versus time in seconds.  FIG. 13  illustrates a graph displaying a lower preset threshold for the function of the patient&#39;s SpO 2  , FiO 2 , and PEEP during ventilation versus time in seconds. As shown in  FIG. 4 , the function of PEEP and SpO 2  exceeds the lower preset threshold depicted by the shaded areas activating an alarm icon (i.e. a colored star icon). The displayed alarm is exemplary only and does not limit the disclosure. 
         [0126]    Numerous other changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the disclosure and as defined in the appended claims. For example, in the embodiments of the methods described herein various operations and steps could be combined into a single operation (e.g., a single monitoring operation) or the operations could be performed in a different order or as parallel operations. While various embodiments have been described for purposes of this disclosure, various changes and modifications may be made which are well within the scope of the present invention. Numerous other changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the disclosure and as defined in the appended claims.