Abstract:
Intubation is a potentially dangerous invasive procedure with many plausible errors, such as over-inflation of a cuff and insertion of an intubation tube in the wrong lumen, potentially resulting in a patient&#39;s internal bleeding, suffocation, or even death. An intubation aide according to example embodiments of the present invention allows intubation of a patient, while eliminating potential injury to the patient, increasing accuracy and reliability of the placement of the intubation tube, and drastically decreasing procedural time. Within moments of insertion of the device into a patient, the medical caregiver knows, with complete certainty, the location of the intubation device without applying traditional time-consuming tasks. Embodiments also provide patient safety, if intubated for a prolonged periods, by regulating an inflation pressure of the cuff. The intubation aide can also be used for training purposes and is ideal for intubation in hospital and field settings.

Description:
RELATED APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Application No. 61/141,746, filed on Dec. 31, 2008. The entire teachings of the above application are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Intubation is the placement of an intubation tube of an intubation device into a lumen (i.e., trachea or esophagus) of the body of a subject in order to provide ventilation by mechanical or artificial means via the intubation tube. Intubation can be in the form of tracheal intubation, which is the placement of a tube into the trachea of a subject, as well as esophageal intubation, which is the placement of a tube into the esophagus of a subject. 
     Intubation is a potentially dangerous invasive procedure with many plausible errors when performed improperly. An example of an intubation error is over-inflation of a cuff, where the cuff is an inflatable bulb coupled to an exterior wall of the intubation tube and used to maintain a position of the intubation tube in the lumen. Over-inflation of the cuff can result in a patient&#39;s internal bleeding or, potentially, death. Another example of a common intubation error is the insertion of the intubation tube in the wrong lumen, potentially suffocating the patient. Even with proper training, medical caregivers cannot visually inspect which lumen the intubation tube was inserted into, and, under stress of emergency response, the medical caregiver can make an insertion error and injure the subject, sometimes fatally.  FIGS. 1 and 2  illustrate the foregoing examples. 
       FIG. 1  illustrates a first subject  101  requiring an intubation tube to assist in the subject&#39;s breathing, e.g., due to a health problem that impairs or stops normal breathing. To aid the subject, a medical caregiver may employ an intubation device  100 . The procedure for using a traditional intubation device begins by the medical caregiver&#39;s clearing the subject&#39;s mouth and airway, if needed, then inserting an intubation tube  105  of the intubation device  100  into the subject&#39;s trachea or esophagus, depending of the type of intubation device being used. During insertion, the cuff(s)  110  on the intubation tube  105  are in a deflated state. Once the intubation tube  105  is in an inserted position, the medical caregiver can stabilize a position of the intubation tube  105  by inflating the cuff(s)  110  through use of a pilot cuff  120  by a syringe filled with either air or a liquid. The pilot cuff  120  is connected to the cuff(s)  110  via tubing  125  for manual inflation of the cuff(s)  110 . Once the cuff(s)  110  are inflated and have stabilized the position of the intubation tube  105 , ventilation via the intubation tube through use of a ventilator  102  can begin. As mentioned above, over-inflation of the cuff(s) may result in complications, and the complications may manifest themselves as mucosal bleeding and ischemia, esophageal or tracheal bleeding, or death. 
       FIG. 2  illustrates a second subject  201  also requiring intubation, in which an intubation tube  205  of an intubation device  200  has been inserted into a lumen. In this example scenario, the intubation tube  205  has been inserted into the incorrect lumen  220 , which can result in suffocation of the patient, as well as other complications, including death (see von Goedecke et al. (2007) Anesth Analg, 104:481-483; and ACLS: Principles and Practice. pp. 135-180. Dallas: American Heart Association, 2003) as the resuscitation provided to the patient through use of a ventilator  202  would enter the epigastrium rather than the lungs of the subject. 
     Current methods and devices used for confirming correct tube placement of the intubation device include: visualization of chest movement during ventilation, sound detection of auscultation of chest and epigastrium, checking for fogging of the intubation device, absence of stomach contents in the device, colorimetric end tidal CO 2  detection, waveform capnography, self-inflating esophageal bulb, and pulse oximetry. Verification of cuff inflation level is generally not checked, as the maximal volume of the cuff is generally used and presumed to be accurate. 
     In addition to unaided visual verification, image sensor systems that employ fiber optic cameras can be used to verify cuff inflation and proper tube placement. Such image systems are not generally used because they are cost prohibitive and, in most cases, unnecessary. Moreover, medical caregivers would have to carry both intubation devices and image sensor systems whenever responding to an emergency, which would complicate or delay response time. 
     Unfortunately, each method by itself is neither efficient nor reliable for confirming correct tube placement. Thus, the use of multiple methods to confirm correct tube placement is currently the standard of care, which delays a medical caregiver from providing treatment to the subject, possibly leading to unintended injury to the subject. 
     SUMMARY OF THE INVENTION 
     An embodiment of the present invention assists medical caregivers by indicating which lumen, esophagus or trachea, an intubation tube has been inserted. Another embodiment assists medical caregivers by controlling a level of inflation of a cuff while the medical caregiver is securing the intubation tube in a lumen. Another embodiment includes a combination of each. The term “medical caregiver” as used herein refers to doctors, emergency responders trained in medical procedures, or persons untrained in medical procedures but who are acting in that capacity with regard to intubation of a subject requiring same, as described herein. 
     The embodiments may employ an intubation aide that optionally can be attachable to the intubation tube. The combination, including other standard intubation tube components (e.g., cuffs) may be referred to herein as an intubation device. The intubation aide may include a chassis with display elements (e.g., pressure meters, light emitting diodes (LEDs), and audio speakers), pump, pressure valve, sensor, and circuitry to perform configured functions, such as to indicate which lumen the intubation tube has been inserted and control a level of inflation of the cuff. The aide may also include memory and data networking elements to store or report states of the intubation device or accept remote commands to control states of the intubation device. 
     For purposes of explanation herein, pressure and force measurements, sensors, and related elements or techniques are used interchangeably, both in terms of the pressure or forces inside and outside the cuffs. 
     The pump, tubing, and cuff form an air-tight (i.e., closed) inflation system that accurately maintains pressure in the cuff once the cuff is inflated. The sensor can include a pressure sensor located anywhere within the air-tight inflation system and report the pressure in a human- or machine-readable form, optionally as “go” or “no go” discrete states or as an actual pressure reading. Alternatively, the pressure sensor may be located on the surface of the cuff (external from the air-tight inflation system) and report the force exerted by the cuff against a wall of the lumen. The pressure sensor may also be sealed in a medical grade sealant when located on the surface of the cuff to prevent direct contact with the lumen. A processor or circuitry may be employed to use the pressure reading to control the pump to inflate the cuff to a level that secures the intubation tube but does not injure the patient. 
     With regard to indicating which lumen the intubation tube has been inserted, embodiments of the present invention measure an amount of force exerted on the fore of a cuff, an amount of force exerted on the aft of the cuff, or both, while the cuff is inflated or being inflated. In embodiments with fore and aft force measurements of the cuffs, which approximately corresponds to forces also being applied to the anterior and posterior walls of the trachea or esophagus for purposes of explanation herein are being used interchangeably, a differential between the fore and aft forces may be calculated (i.e., anterior minus posterior force measurements), where a positive differential indicates that the intubation tube is located in the trachea and a negative differential indicates that the intubation tube is located in the esophagus. The lumen in which the intubation tube corresponding to the differential calculated may be identified to the responder in an audible, visual, or other human-recognizable format. In an alternative embodiment, a single anterior, posterior, or internal cuff pressure measurement can be made with a comparison of the measurement against an absolute (rather than differential) threshold being used to determine in which lumen the intubation tube has been inserted. 
     At least one pressure sensor transducer, such as a piezoelectric transducer which generates a voltage as a function of pressure, may be used to measure the amount of pressure exerted on the fore of the cuff, the aft of the cuff, or both. A placement analyzer may be used to measure and analyze the pressures and report a result to a medical caregiver. It should be understood that force sensors may be employed to measure force at specific locations and that the force is a function of the pressure. 
     Additional methods and apparatuses relate to controlling inflation of cuff(s) coupled to an intubation tube of an intubation device. Responsive to an activation signal, such as an electrical boolean TRUE signal generated by a medical caregiver&#39;s pressing of a “start” button, inflation of the cuff(s) may commence. A pump inflates the cuff(s) via a pilot cuff tubing. In this embodiment, the pressure indication inflation of the cuff(s) is monitored, and a deactivation signal is generated as a function of a level of the inflation, where the pressure measured is compared against a threshold, range, or other parameter and the deactivation signal is generated once the proper pressure has been reached. Responsive to the state of the deactivation signal, the inflation of the cuff(s) is either continued or discontinued. The amount of inflation is set such that injury to the subject undergoing intubation does not occur, while adequately securing the cuff(s). Redundant sensing, such as force sensing as described above, may also be employed. It should be understood that the activation and deactivation signals, which may be analog or digital, or electrical or optical, may be the same signal or different signals. 
     Generation of the deactivation signal, such as due to cuff overpressure or incorrect insertion of the intubation tube, may be based on the pressure exerted on at least one pressure sensor transducer coupled to the cuff(s) while the intubation tube of the intubation device is within the oropharynx, esophagus or trachea of a subject. Other parameters may be used to deactivate pumping of the cuff(s), such as a time limit being exceeded (e.g., representing a leaky cuff, faulty pump, or overheating of the pump). 
     Further, the placement analyzer may cause the pump to drive out air if placement of the intubation tube has been detected, thereby rapidly deflating the cuff(s) and allowing the medical caregiver to reinsert the intubation tube but into the correct lumen. For example, if the intubation tube is designed for esophageal intubation and the measured forces indicate that the intubation tube is located in the trachea, the placement analyzer generates a characterization signal (e.g., sound or light) to alert an medical caregiver to remove and reinsert the intubation tube until the location of the intubation tube is characterized as being in the esophagus, which may be indicated to the medical caregiver by a different characterization signal. Alternatively, if the intubation tube is designed for tracheal intubation and the measured forces indicate that the intubation tube is located in the esophagus, the placement analyzer generates characterization signals to alert a medical caregiver to remove and reinsert the intubation tube until the location of the intubation tube is characterized as being in the trachea. 
     Following notice by the placement analyzer that the intubation tube is in the correct lumen, the medical caregiver may connect a positive pressure ventilator, which is separate from the pump used to inflate the cuff(s) in some embodiments, to the intubation tube and activate the positive pressure ventilator to provide oxygen to the lungs of the subject. 
     It should be understood that the foregoing example embodiments, or aspects thereof, may be combined in systems, devices, methods, etc. to form various combinations of same. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention. 
         FIG. 1  is a diagram of a prior art intubation tube illustrating over-inflation of a cuff, coupled to an intubation tube, located in the proper lumen of a body, appropriate for the intubation device; 
         FIG. 2  is a diagram of a prior art intubation device illustrating insertion of an intubation tube into an incorrect lumen (e.g., esophagus instead of trachea); 
         FIG. 3A-1  is a diagram illustrating an intubation device having a Vital DCDP design inserted into the esophagus of a patient with a positive pressure ventilator attached; 
         FIG. 3A-2  is a mechanical diagram of an intubation device using a dual-cuff dual-port (DCDP) design (hereinafter Vital DCDP design) having an intubation aide to perform functions according to an embodiment of the present invention; 
         FIG. 3B  is a mechanical diagram of an intubation device using a dual-cuff single-port (DCSP) design (hereinafter Vital DCSP design) having an intubation aide to perform functions according to an embodiment of the present invention; 
         FIG. 3C  is a mechanical diagram of an intubation device using a single-cuff single-port (SCSP) design (hereinafter Vital SCSP design) having an intubation aide with apparatus therein to perform functions according to an embodiment of the present invention; 
         FIG. 4A  is a schematic diagram of an intubation aide for an intubation device having a Vital DCDP design; 
         FIG. 4B  is a schematic diagram of an intubation aide, including a pump controller and placement analyzer, for an intubation device having either a Vital DCSP or Vital SCSP design, as the device is applicable to all intubation designs with a single port; 
         FIG. 4C  is a schematic diagram of an intubation aide, including a pump controller, for an intubation device having either a Vital DCSP or Vital SCSP design, as the device is applicable to all intubation designs with a single port; 
         FIG. 5A  is a schematic flow diagram of a placement analyzer according to an example embodiment of the present invention; 
         FIG. 5B-1  is a block diagram of example circuitry employed by a pump controller/regulator according to an example embodiment of the present invention; 
         FIG. 5B-2  is a schematic flow diagram of a pump controller according to an example embodiment of the present invention; 
         FIG. 5C  is a schematic flow diagram of a pump controller connected to a placement analyzer according to an example embodiment of the present invention; 
         FIG. 5D  is a schematic flow diagram illustrating a pump controller and a force analyzer independently operable according to an example embodiment of the present invention; 
         FIGS. 6A and 6B  are graphs illustrating measured force as units of conductance used to distinguish an anterior and posterior of an esophagus and trachea, respectively, in pigs; 
         FIG. 7  is a graph illustrating pressure within a cuff as a function of inflation of the cuff and an optimal pressure within the cuff that provides an adequate seal within a lumen of the body for mechanical ventilation; 
         FIG. 8  is a diagram illustrating remote control of an intubation device in accordance with example embodiments of the present invention; and 
         FIG. 9  is a diagram illustrating an intubation device holder with a compartment positioned at each cuff that includes compartment walls designed to biomimic anterior and posterior walls of a trachea or esophagus. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A description of example embodiments of the invention follows. The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety. 
       FIGS. 3A-C  illustrate designs of intubation devices that may be employed with embodiments of the present invention. 
       FIG. 3A-1  is a diagram illustrating an intubation device  300  having a Vital DCDP design with at least one intubation tube  305   a ,  305   b  inserted into an esophagus  320  of a patient. The Vital DCDP is designed, as illustrated, to be placed into the esophagus  320  or trachea  315  of the patient. The Vital DCDP has side holes  304   a  aligned with the patients trachea  315  to direct airflow from the intubation tube  305   a  into the trachea  315 , when the intubation tube  305   a  is placed into the esophagus. Alternatively, the Vital DCDP directs airflow from the intubation tube  305   b  to the trachea  315  via hole  304   b , if the intubation tube  305   b  is placed in the trachea  315 . After the intubation device  300  is inserted, a medical caregiver may begin ventilation of the patient using a ventilator  302 . The ventilator  302  is attached to the intubation device  300  to transfer air into the trachea  315  of the patient. During ventilation, the proximal cuff  310   a  prevents back flow of air, ensuring that a maximal amount of air is transferred into the trachea  315  while also securing the location of the intubation tube  305   a.    
     In the past, the medical caregiver has only been able to confirm correct tube placement of the intubation device  300  after beginning ventilation. Examples of confirming correct tube placement using traditional methods include visualization of chest movement during ventilation and sound detection of auscultation of chest and epigastrium, among others. Embodiments of the present invention include an intubation aide  330 , which allows a medical caregiver to confirm tube placement of the intubation device prior to beginning ventilation of the patient. The intubation aide  330  is able to determine the placement of the intubation device by detecting forces exerted on a distal cuff  310   b  then alerting the medical caregiver of the location of the intubation device  300 . By determining placement of the intubation device prior to ventilation, a number of possible injuries to the patient can be avoided. Further, control of cuff inflation can be performed by the intubation aide  330 , thereby avoiding other possible injuries. 
     For purposes of discussion, the intubation aide  330  may refer to all or a subset of components or corresponding methods used to aide a medical caregiver in pre-ventilation activities, active resuscitation, or on-going ventilation activities. Examples of intubation aides  330  include pumps, electronics, sensors (including transducers), status indicators, and communications modules, which are described in more detail below. 
     Intubation devices, having a cuff, may have a single or double lumen design, along with a dual-cuff dual-port design, referred to as a Vital DCDP design herein (e.g., a resuscitation tube design), a dual-cuff single-port design, referred to as a Vital DCSP design herein (e.g., a transpharyngeal tube design, a laryngeal tube design), and a single-cuff single-port design, referred to as a Vital SCSP (e.g., a laryngeal mask airway, an endotracheal tube design). Regardless of the design, the intubation tube(s) are configured to be inserted into the trachea or esophagus to provide ventilation of a subject (e.g., an injured person or animal). The cuff is inflated through use of a pilot cuff and is used to maintain a position of the intubation tube in the trachea or esophagus of the subject. 
     Example embodiments of the present invention are directed to confirming proper placement of an intubation tube through monitoring force(s) between an inflatable cuff and an interior of a lumen. Alternative example embodiments of the present invention are directed to inflating a cuff to a desired pressure. Other example embodiments are related to recording, controlling, testing, or calibrating intubation devices. 
     Embodiments also monitor patient safety, as cuffs alter their pressure after prolonged placement in a patient, often injuring the patient. The intubation aide can also be used for training purposes and can be employed with intubation in hospital and emergency field settings. 
       FIG. 3A-2  illustrates a Vital DCDP intubation device  300  with a double lumen design. The Vital DCDP intubation device  300  with two intubation tubes  305   a ,  305   b  may include an intubation aide  330  with a chassis  332  attachable to the tubes  305   a ,  305   b , a proximal cuff  310   a , and a distal cuff  310   b . A first tube  305   a  allows resuscitation when placed in the esophagus by way of a side opening(s)  304   a , and a second tube  305   b  allows resuscitation when placed in the trachea or esophagus by way of an opening  304   b  at the distal end. In addition, at least one pressure or force transducer  335  is coupled to an external wall of the distal cuff  310   b  and in operative communications with electronics (not shown) of the intubation aide  330  in the intubation assistance chassis  332 . The term “transducer” as used herein refers to a specific element, such as a piezoelectric element, that generates an electrical signal, such as a voltage, as a function of forces or pressure, and the term “sensor” includes a transducer and electronics that performs functions on the electrical signal generated by the transducer. Details of how the electronics and transducer operate together are described below beginning in reference to  FIG. 4A . 
       FIG. 3B  illustrates an intubation device  300  having a Vital DCSP design. The Vital DCSP intubation device  300  with intubation tube  305  may include an intubation aide  330  attachable to the tube  305 , a proximal cuff  310   a , and a distal cuff  310   b . The tube  305  allows resuscitation when placed in the esophagus or trachea by way of a side hole or holes  304   a . In addition, at least one pressure or force transducer  335  is coupled to an external wall of the distal cuff  310   b  and in operative communications with electronics (not shown) in the intubation aide  330 . 
       FIG. 3C  illustrates an intubation device  300  having a “Vital SCSP design.” The intubation device  300  with intubation tube  305  may include an intubation aide  330  attachable to the tube  305  and single cuff  310 . The tube  305  allows resuscitation when placed in the trachea by way of a distal opening  304   b . In addition, at least one pressure or force transducer  335  is coupled to an external wall of the cuff  310  and in operative communications with electronics (not shown) in the intubation aide  330 . 
     The intubation devices  300  of  FIGS. 3A-C  also include cuff inflation port(s) or pilot cuff port(s) (not shown) used to inflate the cuff(s). The pilot cuff port(s) may be located within the intubation aide  330 . Further, the number of ports does not always correspond to the number of cuffs; for example, one port can be used for more than one cuff, as illustrated by the Vital DCSP design. 
       FIGS. 4A-4C  are schematic diagrams of intubation aide designed for intubation devices having a Vital DCDP, Vital DCSP, or Vital SCSP designs, respectively. As illustrated in  FIGS. 4A-4C , each intubation device may have its own respective intubation aide with associated front panel to provide for the intubation device&#39;s proper functionality. 
       FIG. 4A  is a schematic diagram illustrating an intubation aide (“apparatus”)  430  configured for a dual-port intubation device (i.e., Vital DCDP design). The apparatus  430  includes a front panel  445  and internal functional elements (e.g., pumps  460   a ,  460   b , power source  465 ) controlled or activated by human-to-machine interface elements on the front panel  445 . 
     In this example embodiment, the apparatus  430  includes a placement analyzer  450  and pump controller  455  used to perform functions as described below. The apparatus  430  further includes pumps  460   a  and  460   b  with respective output tubes and cuff ports  462   a ,  462   b . The pilot cuff ports  462   a ,  462   b  are configured to connect to their corresponding cuffs (not shown) and to the pumps to allow the cuffs to be inflated. The apparatus  430  further houses a power source  465 , which may be any form of portable power, such as a battery. 
     The front panel  445  also includes an on/off switch  403  to power on/off the intubation device, such as by electrically activating the placement analyzer  450  and pump controller  454 , and arming the pumps  460   a ,  460   b , which are manually triggered in some embodiments by a medical caregiver by way of pushbutton trigger switches  404   a ,  404   b  configured to activate the placement analyzer  450  and pump controller  455 , which, in turn, activates the pumps  460   a ,  460   b  for each cuff. The front panel  445  may also include knobs  405   a  and  405   b  configured to enable the medical caregiver to set user-adjustable pressure for each cuff. Alternatively, the knobs  405   a ,  405   b  may not be provided to prevent medical caregivers from accidentally over-inflating the cuffs; instead, a factory setting or calibration may be employed with the pump controller being configured to perform field adjustments. The front panel  445  may further include a pressure level display  406   a ,  406   b , configured to indicate a fully-inflated pressure level, and a placement display  407  configured to indicate placement of an intubation tube of the intubation device. Each pump-cuff port connection  462   a ,  462   b  may be connected to pressure relief valves  408   a  and  408   b  configured to prevent maximal over-inflation of the cuffs. 
     The front panel  445  and internal electronics, such as the placement analyzer  450  or pump controller  455 , may be configured to support additional sensors that are configured to sense correct insertion in a lumen of an intubation tube. An example of sensors that may be used are “body insertion” sensors, such as moisture sensors, body chemistry sensors, temperature sensors, CO 2  sensors, and acidity sensors, and also acceleration or other motion detection sensors (e.g., an accelerometer), where the body insertion sensor can be located either on the inside or outside wall of a cuff to detect when the intubation tube has been deployed in a subject&#39;s lumen and the motion detection sensor indicates when the intubation tube has reached a state of rest, optionally for a given duration of time (e.g., 10 seconds), indicating that the tube and cuff(s) have been set in place and are ready to be inflated. Because, in some embodiments, the placement analyzer  450  and pump controller  455  are there to protect against incorrect deployment, the medical caregiver has intelligent failsafe protection in case a fully autonomous activation mode incorrectly activates. Moreover, an emergency override button (not shown) may also be provided to deflate the cuff(s) and deactivate all circuitry. Manual access to the pilot cuffs for manual inflation of the cuffs may also be provided for full manual override. The pump controller(s) and/or placement analyzer(s) may also be controlled via a console that remotely (not shown) views the outputs of the Vital design. Examples of remote access or control are described below in reference to  FIG. 8 . 
       FIG. 4B-C  are a schematic diagrams illustrating an intubation aide  430  configured for a single-port intubation device design (i.e., a Vital SCSP or Vital DCSP). More specifically,  FIG. 4B  illustrates the aide  430  for a single-port intubation device design that includes both the placement analyzer  450  and pump controller  455 .  FIG. 4C  illustrates the apparatus  430  with only the pump controller  455 . The basic operation of the components of the apparatus  430  of  FIGS. 4B and 4C  is the same as that described in reference to  FIG. 4A . 
     Placement Analyzer 
     In operation, embodiments of the present invention may measure forces exerted by walls of a lumen (e.g., trachea or esophagus) of a subject on an anterior side and posterior side of cuff(s) during inflation. The measured forces exerted on the cuff(s) may then be used to determine whether the intubation tube of the intubation device is located in the trachea or esophagus. The reason for force differences between the fore and aft of a cuff is due to human and animal anatomy. Specifically, the trachea is bounded on the anterior side by cartilaginous rings but only bound by soft tissue on the posterior side. The esophagus is bounded by soft tissue on the anterior side but adjacent to hard vertebrae along the posterior side. Thus, force differences can be measured anterior and posterior in both lumens during cuff inflation. 
     As described above in reference to  FIG. 3A , pressure or force transducer(s) are coupled to an external wall of a cuff and are in operative communications with electronics (e.g., placement analyzer as illustrated in  FIG. 4A ) in the intubation aide. The transducer(s) measure forces exerted to the external walls of the cuff and, in some embodiments, communicate the measurements to the placement analyzer. The measurements may also be directed to the pump controller as redundancy to measurements by the pressure sensors that sense pressure within the cuffs, in which case appropriate conversion of force external on the cuffs to pressure internal to the cuffs is performed through hardware, firmware, or software. 
     According to an embodiment of the present invention, the placement analyzer is used to detect if a force exerted by a wall of the lumen on the fore of the cuff is greater than a force exerted on the aft of the cuff and also to determine the location of the cuff. If the force on the fore of the cuff is greater than the force on the aft of the cuff, the placement analyzer determines that the cuff is located in the trachea of a subject. If, however, the force exerted on the aft side of the cuff is greater than the force exerted on the fore side of the cuff then the placement analyzer determines that the cuff is located in the esophagus of the subject. Upon determination of the location of the cuff, the placement analyzer may indicate the location to a medical caregiver via any human- (or machine-)observable signal, e.g., a digital readout, light, sound, or to an external device. The observable signal indicates the location of the intubation tube of the intubation device, such as whether the intubation tube is located in the trachea or esophagus of the subject. 
     The placement analyzer may include a combination of electrical components, such as operational amplifiers (op-amps), microcontrollers, transistors, logic gates, capacitors, and/or resistors, which are operably linked to provide the observable result. 
     Embodiments of the present invention may employ one or more sensors with transducers operably linked to anterior and posterior sides of the cuff where the forces are to be detected and measured. The forces may be detected or measured by pressure sensor transducers, such as piezoelectric sensors, which provide electric outputs that are proportional to the mechanical force exerted thereon. Piezoelectricity is used in many kinds of sensors, such as piezoresistivity in force sensors, piezoelectric crystals in load cells, piezoelectric and piezoresistive transducers in pressure sensors, and the like. The forces may also be detected or measured by fiber optic pressure measurements, pressure transducers, contact sensing, and strain measurements, all of which provide or affect an electric output (e.g., voltage or current) as a function of force. The forces may be detected or measured simultaneously (i.e., in parallel) or consecutively (e.g., multiplexed). 
       FIG. 5A  is a schematic diagram illustrating a placement analyzer  550 . The placement analyzer  500  may employ a single force sensor or multiple force sensors  505  for measuring pressure(s) exerted on at least one sensing area or a pressure sensor measuring the force on the cuff. The placement analyzer  550  receives measurements of forces from the force sensor(s)  505  exerted on an anterior and posterior of a cuff coupled to an intubation tube of an intubation device. The placement analyzer may then calculate a difference between of the forces exerted on the anterior force sensor from the amount of forces exerted on the posterior force sensor. If the result is a positive amount, then the cuff is located in the esophagus of the subject. If the result is a negative amount, then the cuff is located in the trachea of the subject. In alternative embodiments, the force sensors and force analyzer may be implemented such that a positive amount indicates that the cuff is located in the trachea of the subject and a negative amount indicates that the cuff is located in the esophagus of the subject by setting the anterior force sensor to be positive, and the posterior force sensor to be negative. In alternative embodiments, the pump can inflate the cuff for a given duration of time (e.g., 5 seconds), and, if the pressure or force, either inside the cuff or exerted on the cuff, reaches a certain threshold, then the intubation device is determined to be located in the trachea; otherwise the intubation device is determined to be located in the esophagus. Logical changes to polarity of analog signals or corresponding digital signals can be performed, if needed, in analog or digital electronics, or by a programmed processor. 
     In example embodiments in which the intubation device has a cuff designed to be located in the esophagus, the positive amount may provide a light, such as a green light or another positive signal as an observable result to a medical caregiver. In another example embodiment in which the intubation device has a cuff that is designed to be placed in the trachea, the negative amount may provide a positive signal indicating the cuff is located in the trachea. Alternatively or in combination with the positive signal, a red light or negative signal may be provided to indicate that the cuff is located in the incorrect lumen of the subject for which the intubation device was designed. For example, if the intubation device has a cuff that is designed to be located in the esophagus, a negative signal may be provided as the observable result if the cuff is erroneously located in the trachea of a subject. 
     Alternatively, a single force sensor can be placed on either the anterior or posterior side of the at least one cuff. The differences between the differential measurements and single measurement is in calculations and having to pre-characterize or quantify forces expected to be observed, which will be different for soft tissue between the trachea and esophagus, ribbing at the anterior of the trachea, and vertebrae at the posterior of the esophagus. 
     Pump Controller 
     As described above in reference  FIG. 4A , a pump controller may be employed to control inflation of a cuff to a desired pressure, force, or volume. Similarly, the pump controller may be employed to regulate and/or change the pressure, force, and/or volume of the cuff. The desired pressure, force, or volume may be one that provides a seal between the cuff and walls of a lumen (e.g., trachea or esophagus) of a subject without excess pressure or force being applied to the walls of the lumen such that a suitable airway for ventilation via the intubation tube may be maintained. The desired volume may be a preset volume that the cuff is set to not exceed. A pressure relief valve may be connected to the cuff to prevent over-inflation by allowing the release of air if the pressure the cuff exceeds a maximal pressure. 
     The pump controller may accept inputs from a pressure sensor, timer, force sensors or corresponding placement analyzer, and pump optionally configured with a pressure relief valve(s). It should be understood that combinations thereof, including fewer or more elements providing inputs to the pump controller, may be employed in various embodiments. 
     The timer may be used to provide a fail-safe against over-inflation of the cuff by providing counts or other metrics, which if exceeded indicate a fault (e.g., leak) in the cuff or tubing associated with the cuff. For example, the pump controller may control and regulate the volume per unit of time (i.e., rate) at which the pump(s) associated with the cuff pumps a gas or liquid into the cuff. Based on the rate and maximal volume of the cuff, the timer may reach a value that causes the pump to stop inflating the cuff and indicate a fault in the cuff or pump. 
       FIG. 5B-1  is a block diagram of an example circuit employed by a pump controller  555  according to an example embodiment of the present invention. Upon insertion of the intubation tube into a lumen of a subject, a medical caregiver begins inflation of the cuff  525  by depressing an “inflate cuff” button  501 . Contemporaneously, the depression of the “inflate cuff” button  501  may signal a timer  515  to begin monitoring time elapsed from the time the “inflate cuff” button  501  is depressed. In one embodiment of the fully self-activating system, the “inflate cuff” button  501  may not be present, as the “body insertion” sensor and motion detection sensors indicate insertion and readiness (i.e., tube-is-in-position) states, which can be used to automatically trigger activation of pump(s) to inflate (and deflate) the cuffs, accordingly. 
     While the cuff  525  is being inflated, pressure transducer(s)  505  measure pressure exerted in the interior of the cuff  525 . Based on an amount of pressure measured, the pressure transducer(s)  505  produce an electrical output of voltage V in  that is output to a voltage amplifier  530  having a voltage gain, A. The voltage amplifier  530  increases the input voltage V in  by effectively multiplying V in  by the gain A. The result is an electrical output of voltage A*V in  that is output to threshold comparator  535 . The threshold comparator  535  determines from the voltage A*V in  whether the cuff  525  is over-inflated or under-inflated and produces a digital output of ‘0’ indicating over-pressure, or ‘1’ indicating under-pressure, to an ‘AND’ gate  540 . Contemporaneously, the timer  515  determines whether the “inflate cuff” button  501  is activated and whether the time elapsed since activation is over or under a time threshold. If the “inflate cuff” button  501  is not activated or the timer  515  has exceeded an expected length of time, the timer  515  produces a digital output of ‘0.’ If the “inflate cuff” button  501  is activated and the timer  515  is under-time, the timer  515  produces a digital output of ‘1’ that is output to the ‘AND’ gate  540 . 
     While receiving the digital output from the threshold comparator  535  and timer  515 , the ‘AND’ gate  540  sends its output to a pump  560  to trigger pumping of the cuff  525 . If the ‘AND’ gate  540  receives a digital ‘1’ from both the timer  515  (pump time not exceeded) and threshold comparator  535  (cuff pressure not exceeded), the pump  560  remains in an active (i.e., pumping) state. If the ‘AND’ gate  540  receives a digital ‘0’ from either the timer  515  (pump time exceeded (or not started)) or threshold comparator  535  (cuff pressure reached or exceeded), the pump  560  is set into an inactive (non-pumping) state. 
     It should be understood that all or portions of the example circuit can be implemented in hardware, firmware, or software. In appropriate cases, such as software executed on a processor (not shown), other circuit elements, such as analog-to-digital converters, may be required to allow the processor to process outputs of the sensors. 
       FIG. 5B-2  is a schematic diagram of a pump controller  555  in accordance with an example embodiment of the present invention. A timer  515  may provide a positive voltage to the pump controller  555  based on a desired time. The desired time may be chosen by a user of an intubation device as a time needed to fill a cuff to a given volume, according to an output of a pump  520 . The desired time, given volume, or both, may be selected or adjusted by the user. A pressure (or force) sensor  505  may provide a variable voltage which corresponds to a pressure of the cuff (or the force exerted on the cuff). The pressure (or force) sensor  505  and the timer  515  are analyzed in the analyzer  540  to determine whether or not the pump  520  should be activated. The pump controller  555  may function without the timer, having inflation of the cuff guided by only the pressure or force sensor(s)  505  to fill the cuff. A pressure relief valve (not shown) may function as an additional fail-safe by enabling expulsion of air to maintain a desired pressure level in the cuff in a case in which excess pressure is pumped into the cuff. 
     Further, the pump controller  555  may provide an electric output to drive the pump  520  based on inputs received from the sensor(s)  505  and timer  515 . The pump controller  555  may further include a combination of one or more operational amplifiers (op-amps), microcontroller(s), transistors, capacitors, and/or resistors, which are operably linked to provide an electric output based on inputs. Additionally, the pump controller  555  may also include a current amplifier  512  configured to ensure sufficient current to drive the pump  520 ; a typical pump that may be used operates at 100-400 mA of current. The pump  520 , when activated, may pump a gas, such as air, or a liquid, such as saline, into the cuff. It should be understood that two similar or the same pump controllers  555  may be employed for intubation devices with two cuffs. 
     Combination of Placement Analyzer and Pump Controller 
     Example embodiments of the present invention may employ a combination of at least one placement analyzer and at least one pump controller. For example,  FIG. 5C  illustrates a placement analyzer  550  and a pump controller  555 , which are simultaneously activated but functionally independent of each other. The pump controller  555  of an intubation device may be designed to turn a pump on or off based upon pressure within the pump. The placement analyzer  550  and pump controller  555  may be integrally connected. For example, a sensor employed in the pump controller  555  of the intubation device may be the same as one or both of the sensors employed in operative connection with the placement analyzer  550 . 
       FIG. 5D  illustrates an example embodiment where the placement analyzer  550  and pump controller  555  may be activated independently of each other, e.g., by way of separate ON switches or buttons. 
     Example embodiments of the present invention may employ an intubation device having a Vital DCDP design, placement analyzer, and pump controller. Pressure or force sensor(s) in a proximal cuff of the intubation device may detect increase in pressure or force of the proximal cuff once the proximal cuff reaches the inside of an aperture, such as the oropharynx, which may then cause a drastic increase in intracuff pressure or force (up to 30 cm H2O), thereby stopping a pump. If the pressure or force on the proximal cuff is not sufficient to stop the pump, a timer may then stop the pump after a desired time, e.g., 2.5 seconds. 
     Alternatively, force sensor(s) in a distal cuff of the intubation device may detect an increase in force on the distal cuff once the distal cuff reaches the inside of a trachea or esophagus of a subject, thereby stopping the pump and indicating a location of the distal cuff. 
     Increase in pressure or force may indicate that the cuff is located in the trachea. For example, an increase in force or pressure indicates that the cuff is located in the trachea if forces at the fore of the cuff increases at a rate of 20 cm H2O with each ml of air inserted into the cuff, while forces at the aft of the cuff only increases at a rate of 5 cm H2O. More specifically, after the cuff is filled with 5 ml of air, there may be a significant difference in forces exerted between the fore and aft sides of the cuff, as there may be a force of 100 cm H2O exerted on the fore of the cuff compared to a force of 25 cm H2O exerted on the aft of the cuff. 
     Another example embodiment may employ an intubation device with a Vital DCSP design that may include a placement analyzer and pump controller, as illustrated in  FIG. 5C . Pressure sensor(s) in at least one cuff coupled to an intubation tube of the intubation device may be configured to detect increase in pressure of the at least one cuff. A significant increase in pressure may occur once the at least cuff reaches the inside of a lumen. For example, the increase in pressure may be up to 60 cm H2O or 80 cm H2O (if nitrous oxide is used for sedation), as detected by the pressure sensor(s). If the pressure is not sufficient to stop a pump, a timer may be configured to stop the pump after a given time, e.g. 2.5 seconds. The force sensors may also be employed in this example embodiment. 
     Additional example embodiments may employ an intubation device with a Vital SCSP design that may include a pressure or force sensor(s) coupled to at least one cuff of the intubation device. The pressure or force sensor(s) may be configured to detect increase in pressure or force(s) exerted on the at least one cuff. For example, once the at least one cuff reaches the inside of a lumen (e.g., trachea or esophagus) pressure or force(s) exerted on the at least one cuff may increase (e.g., up to at least 34 cm H2O), thereby stopping a pump. If the pressure or force is insufficient to stop the pump, a timer may be configured to stop the pump after a given time, e.g. 0.5 seconds. As with the distal cuff of the Vital DCDP, in some embodiments, the Vital SCSP may have force sensor(s) in a distal cuff of the intubation device that may be configured to detect increase in force exerted on the distal cuff once it reaches the inside of the lumen. A significant increase in force to one side, fore or aft, of the cuff may cause the pump to stop, which itself may indicate a location of device placement (e.g., trachea or esophagus). 
     Example Device Configurations 
     Intubation devices according to some embodiments of the present invention comprise at least one sensor such as a pressure sensor or a force sensor, at least one air pump, connectors, tubing, tubing connectors, air release valve(s), circuitry such as logic gates, microcontrollers, op-amps, transistors, resistors, and the like, a user interface, and a power source such as a battery pack, over-charged capacitor, or lithium, alkaline batteries, or the like. 
     In some embodiments, the intubation devices of the present invention are portable. In some embodiments, the intubation devices according to the present invention may further comprise operational indicators such as lights, sound speakers, or LCD screen, transmitter to transmit data to an external device, receiver to receive data or commands from an external device, and buttons or switches. 
     It should be understood that components and corresponding methods beyond basic intubation tube(s) with associated lumen(s) may be part of various embodiments of the intubation aides disclosed herein or equivalents thereof. 
     Alternative Embodiments 
     The intubation aide, such as the embodiment illustrated in  FIG. 4A , may also include circuitry comprising a breathing monitor, internal memory, use counter, battery monitor, or wireless interface and control unit according to example embodiments of the present invention. The intubation aide may, more generally, be used to track, record, react to, transmit, or take other functional action based on a state of the intubation device, subject being or about to be ventilated, or medical caregiver providing assistance to the subject. Alternatively, the intubation aide may perform actions as a function of a remotely delivered notice or control signal. 
     As an example, upon successful intubation of a subject and operation of an intubation device, the subject may regain an ability to breathe without the assistance of the intubation device. In such instances, the intubation device may impede the subject&#39;s ability to breathe autonomously. As such, the aide may include a breathing monitor configured to detect breathing of a subject and alert the medical caregiver to remove the intubation device. For example, the intubation tube may be internally fitted with a bi-directional flow meter (not shown). A “breathing” analyzer (not shown) can then monitor regularity of artificial breathing for an irregularity, which may indicate the subject is beginning self-breathing capability. The monitoring can be done in the time domain or frequency domain, and many forms of analysis can be employed to monitor for the subject&#39;s self-breathing restoration. 
     As another example, internal memory (not shown) may be configured to record use of the intubation device and any other relevant operational data or device parameters. The memory may record certain information, such as the identity of the medical caregiver that used the intubation device, number of times intubation placement was successful on a first try, not successful on the first try, and number of attempts needed for proper placement of the intubation device. Such information may be used to gather statistics to aid in training of medical caregivers. For example, if the data shows that multiple attempts are needed for correct placement of an intubation device, this may indicate that the medical caregiver needs additional training. Similarly, the data may useful in testing intubation tube designs with different curvatures to determine a curvature that statistically improves placement of an intubation tube in a correct lumen. 
     The battery monitor may indicate power levels of the battery and signal a need to recharge or replace the battery. The signal may be a local audio or visual signal or may be a wirelessly or wired transmitted signal. A transmitted signal (e.g., voice over IP packet) may include sufficient information for a recipient of the signal to identify the intubation tube and a request, such as a maintenance service request (e.g., battery charging or replacements) that is being notified. Optionally, data providing a location of the intubation device may also be transmitted in the signal. 
     In many emergency situations, a medical caregiver may arrive at a scene where multiple victims need emergency aid. Each of those parties may need the use of an intubation device. In addition, the number of victims may exceed the number of medical caregivers available at the scene. Therefore, a wireless interface and control unit as illustrated in  FIG. 8  may be employed to enable remote control of the intubation device by a central control unit or emergency operators at a central emergency operating facility, hospital, or ambulance. The intubation control unit  880  may be configured to allow remote medical caregivers (e.g., doctors) to monitor the intubation device and communicate states to a central control unit  890  via a wireless interface  870 . Based on the communication of the states of the intubation device, the central control unit  890  may send commands to the intubation control unit  880  via the wireless interface  870  to cause the intubation control unit to control the circuitry of the intubation aide  830  in a certain manner. For example, the central control unit  890  may command the intubation control unit  880  to shut down operation of the ventilator or cause a valve (not shown) to open to bypass the ventilator if the central control unit has received an indication that the subject has begun unassisted breathing. Conversely, the central control unit  890  may alert the intubation control unit  880  to activate the ventilator (and close the valve if applicable) to begin providing assisted breathing upon detecting no autonomous breathing from the subject. 
     A remote server (not shown) may also cause an intubation aide to run readiness checks (e.g., battery charge state, cuff integrity, etc.) or calibrations on a periodic, random, or event driven basis. For example, the remote server may activate an intubation aide to auto-inflate its cuff(s) a certain length of time and expect to have its pressure sensor report back a measured pressure. If the pressure is higher or lower than expected, the remote server may provide notice to the medical caregiver associated with the intubation device by causing the intubation aide to change a report output to a “fault notification” state, which may include sounding an audible notice, activating a red or blinking LED, or vibrating. Other forms of providing notice include sending a paging message, voice call, voice mail, text message, written notice, or other notice to the medical caregiver to provide notice of a faulty intubation device. Similarly, the remote server may activate the intubation aide to run calibration testing through use of a locally applied biomimicry calibration assembly that mimics a trachea or esophagus with predetermined parameters such that returned or locally stored measurements provide future calibration offsets for making future field uses more accurate and safe.  FIG. 9  describes an example calibration assembly. 
       FIG. 9  is a diagram illustrating an intubation device holder with a compartment positioned at each cuff that includes compartment walls that act as structures designed to biomimic anterior and posterior walls of a trachea or esophagus. The structures may be made of a solid material connected to springs configured with constant spring forces designed to mimic either the anterior or posterior forces of the trachea or esophagus that may be exerted on a cuff. The structures may alternatively be made of a material, such as a foam or rubber, configured to mimic the elasticity of either the anterior or posterior side of the trachea or esophagus. Other structures or materials may be employed to provide the biomimicry structure or function. 
     Remote (or local) testing or calibration of the intubation aide may also include activating the intubation aide to inflate the cuff(s)  910  while in a specially designed holder  970  with a compartment positioned at each cuff  910  that includes compartment walls  980 ,  990  designed to biomimic anterior and posterior walls of a trachea or esophagus to test pressure or force sensors configured to measure forces on the fore or aft (or both) of the cuff(s)  910 . Because the compartments  980 ,  990  have predetermined wall stiffnesses, the intubation aide or remote server can be configured to expect certain measurement levels from force or pressure sensors. By knowing the expected measurement levels, the intubation aide may be tested to determine if it accurately determines whether the cuff(s)  910  is located in a trachea or esophagus. Offsets from expected measurements may be stored locally (or remotely) and applied to the intubation aide in a manner making future uses of the intubation aide more accurate. Notifications of faults or downloading of calibration settings or offsets may be transmitted to the medical caregiver, intubation aide, or remote server. 
     The following examples are intended to illustrate, but not to limit, embodiments of the invention: 
     Experiment 1 
     Pump Controller 
     Step 1a Pressure Sensor calibration: A MPX5050 Integrated Silicone Pressure Sensors was tested with a manometer to verify that the voltage output correctly followed Voltage Output=Vcc*(0.018*Pressure+/−0.04). 
     Step 1b Force sensor calibration: Tekscan Flexiforce Piezoresistive Force Sensor(s) were calibrated using small weights, measured in increments of 5 grams, and an inverting amplifier, used to verify that it follows Voltage output=−Voltage Input (Fixed Resistance/Flexiforce variable resistance). 
     Step 2 Pump Controller Analyzer calibration: The pump controller analyzer, employing a comparator, was tested with an input voltage that matched the expected voltage from the pressure or force sensor(s). The analyzer gave an output voltage changing from +Vcc to 0 volts, once the expected voltage was inputted. 
     Step 3 Pressure or Force Sensors and Pump Controller&#39;s Analyzer: The pressure or force sensor(s) were tested together along with the pump controller&#39;s analyzer to ensure that there was a 0 voltage output reached at the threshold pressure or force, respectively. 
     Step 4 Timer circuit Calibration: The pump controller&#39;s timer circuit module was tested with an oscilloscope to give an output+Vcc voltage in accordance to the expected designated time. This was done by following the equation: Time=1.1*Resistor*Capacitor in the Monostable Timer Circuit. 
     Step 5 Pump Controller&#39;s Analyzer with the timer circuit and pressure or force sensor(s): The pressure or force sensor(s) along with the timer circuit modules were tested together to ensure that the pump controller analyzer was working correctly. The output voltage of this stage was +Vcc, which would accordingly drive the pump, as long as either the pressure or force sensor(s) are below its threshold voltage, and the timer circuit is within its expected time frame, which is dependent on the cuff size. (Otherwise, the output voltage of this stage was 0 volts.) 
     Placement Analyzer 
     Step 1 Force sensor calibration: The Tekscan Flexiforce Piezoresistive Force Sensor(s) were calibrated, using small weights of known value and the recommended drive circuit, to verify that it follows its appropriate transfer characteristics. The equation used was: Voltage output=−Voltage Input (Fixed Resistance/Flexiforce variable resistance). 
     Step 2 Analyzer: The two force sensors were placed in a differential amplifier, which subtracted the voltage output from one force sensor from the other force sensor. This gave a positive or negative voltage output, depending on which force sensor had a higher force against the cuff. 
     Step 3 Indication: The output voltage of the differential circuit went to two reverse-facing light emitting diodes (LEDs), which would indicate the placement; as one LED was active with a positive voltage input, the other was active (or inactive) with a negative voltage input. 
     Combination: Pump Controller and Placement Analyzer 
     The pump controller and placement analyzer were tested together to ensure that they were responsive to increases in pressure and/or force and time. The placement analyzer was tested to ensure that the tracheal and esophageal LED(s) illuminated if the cuff had a higher front force or higher back force, respectively. 
     Experiment 2 
     In order to determine the use of this technology in human beings, the following experiment was conducted in an animal model. Pigs were utilized, as they have similar respiratory system to other mammalian species. 
     Two pigs were utilized in each of the two experiments (Experiment 2A and Experiment 2B). The pigs were initially sedated with Telazol 4.4 mg/kg and Xylazine 2.2 mg/kg, and maintained sedation with 2.00% Isoflurane. 
     Experiment 2A—employed each of the designed tubes measuring the forces in the fore and aft sides of the cuff using the Flexiforce piezoresistive force sensors (with the output measured in resistance, but converted to conductance to illustrate force increase) in both the trachea and esophagus. All of the designed tubes were tested by filling their cuffs to their maximal volume; the respective maximum volumes values were as follows: 100 ml and 15 ml for the proximal and distal cuff of the resuscitation tube, 60 ml for the connected cuffs of the transpharyngeal tube, and 20 ml for the single cuff of the endotracheal tube. The results showed that, as volume in milliliters was added into the cuff, the force (recorded in conductance) was higher on the front side (fore) of the cuff in the trachea and the backside (aft) of the cuff in the esophagus (as illustrated in  FIG. 6A-6B ). In contrast, the force (also recorded in conductance) was lower in the backside of the cuff in the trachea and the front side of the cuff in the esophagus. The intracuff pressure was also measured using a MPX5050 silicon piezoresistive pressure sensor (with output measured in voltage), which increased when air was added to the cuff. The results showed that the recommended optimal pressure was exceeded, as the cuff was filled to maximal inflation (as illustrated in  FIG. 7 ). The optimal pressure under standard conditions (such as no nitrous oxide being used, as this would increase the pressure inside the cuff) is 30 cm H2O for the proximal cuff of the resuscitation tube, 60 cm H2O for the connected cuffs of the transpharyngeal tube, and 34 cm H2O, with the pressure measured at 60+/−15 cm H2O, 140+/−20 cm H2O ( FIG. 5B ), and 65+/−18 cm H2O, respectively. 
     Experiment 2B—During Experiment 2B, the electric circuit confirmed proper functioning of pump controller and placement analyzer by the use of output lights that indicate full inflation and placement of the device. 
     To the extent necessary to understand or complete the disclosure of the present invention, all publications, patents, and patent applications mentioned herein are expressly incorporated by reference therein to the same extent as though each were individually so incorporated. 
     It should be understood that the methods, as described in reference to or understood with respect to the mechanical, electrical, schematic, or network diagrams, may be implemented in the form of hardware, firmware, or software. In the case of software, the software may be any language capable of performing the example embodiments disclosed herein or equivalents thereof or example embodiments understood in the art at the present time or later developed, or equivalents thereof, as understood from the teachings herein. Moreover, it should be understood that the software may be stored in any form of computer-readable medium, such as Random Access Memory (RAM), Read-only Memory (ROM), Compact-Disk ROM (CD-ROM), optical or magnetic medium, as so forth. The software may be stored thereon as sequences of instructions and loaded and executed by processor(s), including general purpose or application specific processor(s) capable of executing the software in manner(s) disclosed herein or understood from the disclosed embodiments or equivalents thereof. 
     While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.