Abstract:
The present disclosure relates to a leak detection system and method for tube or catheter placement. The system and method includes acoustically sensing a leak in the seal between a tube or catheter within a body and the body cavity against which it is sealed, assisting the user in adjusting the system until the leak has been substantially sealed, and establishing system parameters to be used thereafter to maintain the system in an operating state that will substantially prevent leakage, all using a noninvasive acoustic technique.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/606,679 filed Mar. 5, 2012. The disclosure of the provisional application is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure is generally related to a leak detection system and method for tube or catheter placement. 
       DESCRIPTION OF RELATED ART 
       [0003]    Endotracheal tubes (hereinafter “ETTs”), often referred to as breathing tubes, are used to provide a conduit for mechanical ventilation of patients with respiratory or related problems. An ETT is inserted through the mouth or nose and into the trachea of a patient for several reasons: (1) to establish and maintain an open airway; (2) to permit positive pressure ventilation which cannot be done effectively by mask for more than brief periods; (3) to seal off the digestive tract from the trachea thereby preventing inspiration of forced air into the stomach; and (4) as an anesthesia delivery system. 
         [0004]    ETTs are used extensively in the field, emergency rooms, surgical suites, and intensive care units for patients that require ventilatory assistance. During intubation, an ETT is typically inserted into the mouth, past the vocal cords, and into the trachea. The proper location of the ETT tip is roughly in the mid-trachea. However, there are at least three possible undesired placement positions that can result, either during intubation or due to a subsequent dislodgment. One of these positions is in the esophagus. Another undesired position occurs from over-advancement of the ETT past the bifurcation of the trachea (carina) and into one of the mainstem bronchi. A third is above the vocal cords in the vocal tract. 
         [0005]    The structure of the human airways is extremely complex. At the upper end of the trachea is the larynx containing the vocal folds, and at the lower end is the first bifurcation, known as the carina. The adult trachea is approximately 1.4 to 1.6 cm in diameter and 9 to 15 cm long. The newborn trachea averages about 0.5 cm in diameter and 4 cm in length. The airways that are formed by the carina are the right primary bronchus and the left primary bronchus. The right primary bronchus is shorter, wider, and more vertical than the left primary bronchus. For this reason a majority of erroneous ETT insertions past the carina tend to follow the right primary bronchus. Continuing farther down the airways, the bronchi branch into smaller and smaller tubes. They finally terminate into alveoli, small airfilled sacs where oxygen-carbon dioxide gas exchange takes place. 
         [0006]    Providing a correctly positioned and unobstructed endotracheal tube is a major clinical concern. Any misplacement or obstruction of an ETT can pose a threat to the patient&#39;s health. Misdirecting the ETT into the esophagus or locating the tip where there is a significant obstruction of its lumen can result in poor ventilation of the patient and eventually lead to cardiac arrest, brain damage or even death. Further, if the ETT is misplaced into a mainstem bronchus, lung rupture can occur. 
         [0007]    In an attempt to avoid possible complications with Err use, several techniques have been developed to aid clinicians in the proper placement/location of ETTs. Guidelines for the ideal technique are as follows: (1) the technique should work as well for difficult intubations as it does for those not so difficult; (2) the technique should indicate a proper ETT tip location unequivocally; (3) esophageal intubation must always be detected; and (4) clinicians must understand the technique and how to use it. The known techniques for clinical evaluation of ETT location include direct visualization of the ETT placement, chest radiography, observation of symmetric chest movements, auscultation of breath sounds, reservoir bag compliance, the use of a video stethoscope, fiberoptic bronchoscopy, pulse oximetry, and capnometry. However, none of the listed techniques allow a health care provider to constantly monitor the precise location of an ETT within the trachea, or the degree of obstruction of its lumen. 
         [0008]    Another challenge with placing the ETT in the trachea for ventilation is an undesirable backflow of air around the ETT, since such backflow reduces the amount of positive ventilation pressure that can be maintained in the lungs. To address this challenge, a cuff can be adapted to seal against the inner diameter of the trachea. However, as the tracheal walls move, leaks can still occur. In addition, post-placement movement of the ETT within the trachea can also cause leaks around the ETT. In some embodiments, the cuff may be inflated with a fluid (such as air) in order to form the seal. A cuff pressure that is too high can collapse the blood capillaries in the wall of the trachea and cause necrosis. A cuff pressure that is too low may provide an inadequate seal and result in both a reduction of positive ventilation pressure and an increased likelihood of fluid from the proximal side of the cuff (such as accumulated patient secretions) to leak into the lungs, raising the possibility of the patient contracting pneumonia. 
         [0009]    Apparatuses and methods for acoustically guiding, positioning, and monitoring tubes within a body are known in the art. See, for example, U.S. Pat. Nos. 5,445,144 and 6,705,319 to Wodicka et al., incorporated herein by reference, which disclose an apparatus and method for acoustically monitoring the position of a tube within an anatomical conduit. In various embodiments, a sound pulse is introduced into a wave guide and is recorded as it passes by one or more microphones located in the wave guide wall. After propagating down the ETT, the sound pulse is emitted through the distal tip of the ETT into the airway (or wherever in the body the tip of the ETT is located) and an acoustic reflection propagates back up the BIT to the wave guide for measurement by the same microphone(s). The amplitude and the polarity of the incident and reflected sound pulse are used to estimate the characteristics of the airway and the ETT, and thereby guide the MT placement or monitor the ETT for patency. 
         [0010]    As disclosed by Wodicka, et al., the acoustical properties of the airways of a respiratory system change dramatically over the audible frequency range. At very low frequencies, the large airway walls are yielding and significant wall motion occurs in response to intra-airway sound. In this frequency range, the airways cannot be represented accurately as rigid conduits and their overall response to sonic pulses is predictably complex. At very high audible frequencies, the large airway walls are effectively more rigid due to their inherent mass. However, one-dimensional sound propagation down each airway segment cannot be ensured as the sonic wavelengths approach in size the diameter of the segment, and effects of airway branching are thought to increase in importance. There appears to be a finite range of frequencies between roughly 500 and 6,000 Hz where the large airways behave as nearly rigid conduits and the acoustical effects of the individual branching segments are not dominant. It is over this limited frequency range where the complicated branching network can be approximately represented as a flanged “horn” and where its composite acoustical properties reflect the total cross-sectional area of the airways. 
         [0011]    Accordingly, there is a need for an improved method and system for acoustically sensing a leak in the seal between a tube or catheter within a body and the body cavity against which it is sealed and to assist the user in adjusting the system until the leak has been substantially sealed. In addition, there is a need for establishing system parameters to be used thereafter to maintain the system in an operating state that will substantially prevent leakage, all using a noninvasive acoustic technique. However, in view of the prior art at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled. 
       SUMMARY 
       [0012]    A leak detection system and method for tube or catheter placement is disclosed. The system and method of the present disclosure conveniently utilize the microphone in the waveguide connected to the ETT to detect sounds indicative of leakage past the ETT cuff. Alternatively, another microphone independent of the microphone used to guide placement of the ETT may be used. The noninvasive system and method of the present disclosure are therefore able to assist the user in creating an adequate seal between the ETT and the trachea (or between any other tube or catheter and a body cavity into which it has been inserted) and assist in maintaining the seal once it has been established. Furthermore, the system has no moving parts, and can be easily understood and operated by skilled clinicians. 
         [0013]    According to one aspect of the present disclosure, the system may be configured for acoustically detecting the sounds caused by fluids (such as air or other gases) leaking past a cuff sealing a tube or catheter against the walls of an anatomical conduit. Detection of these sounds, either by a human operator or by an automated system employing a processing device, can be used to warn a user of the system that a leak is occurring, and in other embodiments can automatically initiate adjustment of the system in order to stop the leak. For example, the system may include a microphone for detecting sounds in or near the tube and for generating a first signal corresponding to the detected sound, a speaker for creating an audible version of the first signal, where a user can listen to the audible version and determine if adjustments to the leakage prevention cuff are needed. 
         [0014]    In another particular embodiment, the system may include the microphone for detecting sounds in or near the tube and for generating a first signal corresponding to the detected sound, and a processor configured to receive the first signal and to discriminate between an expected baseline representing normal sounds in or near the tube and unexpected sounds representative of leakage past the cuff, where the processor using the first signal to report that a leak has been detected. The processor may be further configured to detect that a leak is present and to then control an inflation device to automatically increase the pressure in the leak prevention cuff. In addition, the tube may be adapted to be coupled to a medical device, such as a mechanical ventilator, a breathing bag, an anesthesia machine, or an infusion pump. Further, a display may be provided in electronic communication with the processor. 
         [0015]    In yet another illustrative embodiment, a method of acoustically detecting a leak past a cuff sealing a tube to a body is disclosed. The method includes detecting a sound in or near the tube, and audibly presenting the detected sound to a user of the tube for determination of whether a leak is present. In one aspect of this embodiment, the method further includes applying the detected sound signal to a processor that is configured to analyze the sound and detect the sound of a leak over a baseline expected sound profile. The method may also include causing the processor to operate an inflation device to renew the seal between the tube and the anatomical conduit if the processor detects a leak. In yet another aspect of this method, the detected sound may be used as a feedback mechanism when pressurizing the cuff, such that when the detected sound indicates that the leakage has stopped, the pressure of the cuff can be recorded and thereafter adjusted to maintain the pressure at that level. 
         [0016]    Additional objects, features, and advantages of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the teachings of the present disclosure as presently perceived. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a diagrammatical view of a prior art system for determining characteristics of an unknown system; 
           [0018]      FIG. 2  is a diagrammatical view of a prior art two-microphone system for determining characteristics of an unknown system; 
           [0019]      FIG. 3  is a diagrammatical view illustrating proper insertion of an endotracheal tube (ETT) into a trachea of a human body; 
           [0020]      FIG. 4  is a diagrammatical view illustrating improper placement of the ETT into an esophagus; 
           [0021]      FIG. 5  is a diagrammatical view illustrating improper placement of an ETT past a carina and into a right main bronchus; 
           [0022]      FIG. 6  is a cross-sectional diagrammatical view of one embodiment leak detection system; 
           [0023]      FIG. 7  is a diagrammatical view of a particular illustrative embodiment of a leak detection method for tube or catheter placement; and 
           [0024]      FIG. 8  is a flow diagram of a particular embodiment of a leak detection method for placement of a tube or catheter. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    For purposes of promoting an understanding of the principles of the method and system, reference will now be made to the embodiment illustrated in the drawings, and specific language will be used to describe that embodiment. It will nevertheless be understood that no limitation of the scope of the method and system is intended. Alterations and modifications, and further applications of the principles of the method and system as illustrated therein, as would normally occur to one skilled in the art to which the method and system relates are contemplated, are desired to be protected. Such alternative embodiments require certain adaptations to the embodiments discussed herein that would be obvious to those skilled in the art. 
         [0026]    When it is desired to direct an object (such as a tube, catheter, or other medical device) into an unknown system, it is known to generate a sound pulse within the tube or medical device and to receive the reflections of the pulse as they return from the unknown system, similar to the process used in sonar imaging. In the case of a system as shown in  FIG. 1 , a speaker transmits an incident sound pulse, P i  that travels toward the unknown system. As the incident sound pulse, P i , enters the unknown system, a sound pulse is reflected back, P r , which can be received by the microphone. The reflected sound pulse, P r , can be analyzed to determine various qualities of the unknown system, including the cross sectional area of the system. Furthermore, as the incident sound pulse P i  continues to propagate through the unknown system, additional reflections may occur. These subsequent reflected sound pulses can indicate additional qualities of the unknown system, such as the depth of the system, and whether the cross sectional area changes at all throughout that depth. 
         [0027]    A two-microphone system is shown in  FIG. 2 , where the two microphones are separated by a distance d. In the two-microphone system, determination can be made as to the direction of travel of a sound pulse, P i  or P r , by analyzing the difference between the instant in which the sound pulse is detected by the first microphone M 1 , and the instant in which the sound pulse is detected by the second microphone, M 2 . For example, if a sound pulse is first detected by M 1  and then by M 2 , the pulse is determined to be traveling away from the unknown system, and is thus a reflected pulse P r . In contrast, if a sound pulse is first detected by M 2  and then M 1 , the pulse is determined to be traveling toward the unknown system. 
         [0028]    The directional determination of the traveling sound pulse prevents the misreading of incident sound pulses that are reflected from the speaker end, SE, of the tube, such as P ir . For various reasons, an incident sound pulse, P i , may be reflected from the speaker end, SE, of the tube, including the presence of a blockage in the tube, a wall at the end of the tube, or the attachment of another device (i.e. a mechanical ventilator) to the end of the tube. False readings can occur when reflected sound pulse, P ir , travels past a single microphone, such as that shown in  FIG. 1 . However, when two microphones are used, such as in the system illustrated in  FIG. 2 , a determination of the direction of travel of the reflected sound pulse, P ir , can eliminate the possibility of a misreading. 
         [0029]    Although the method and system described below relate to maintaining a seal between an endotracheal tube (ETT) and a portion of a respiratory system of a body, it should be understood that the system and methods of the present disclosure may be used to maintain a seal between gas or liquid filled tubes or catheters and other anatomical conduits or cavities. 
         [0030]    As mentioned above, a method and system for guiding the positioning of an 
         [0031]    ETT is known in the art. For a description of a single microphone system for guiding the insertion of the ETT, and a more detailed description of the analysis and theory involved in determining the position of the ETT, reference can be made to U.S. Pat. No. 5,455,144 to Wodicka, et al., previously incorporated by reference. For a description of a two-microphone system for guiding the insertion of the ETT, and a more detailed description of the analysis and theory involved in determining the position of the ETT, reference can be made to U.S. Pat. No. 6,705,319 to Wodicka, et al., previously incorporated by reference. 
         [0032]    Referring now to the drawings,  FIGS. 3-5  illustrate insertion of an ETT  10  into a human body  12 . ETT  10  includes a hollow tube having a distal end  14  for insertion into body  12  and a connector  16  located outside body  12 . Illustratively, ETT  10  is inserted into a mouth  18  of the patient. A respiratory system  20  includes a trachea  22  which extends between vocal folds  24  of a larynx and a first bifurcation known as a carina  26 . Airways formed by carina  26  include a right primary bronchus  28  and a left primary bronchus  30 . Continuing farther down the airway, bronchial tubes branch into smaller and smaller tubes. 
         [0033]      FIG. 3  illustrates proper insertion of ETT  10  into trachea  22  between vocal folds  24  and carina  26 . For proper mechanical ventilation of the patient, it is important that distal end  14  of ETT  10  is positioned properly within trachea  22  between vocal folds  24  and carina  26  to provide adequate ventilation to both lungs  32  and  34 . An inflatable cuff  35  provides a seal between the ETT  10  and the airway, as described in greater detail hereinbelow. 
         [0034]    Insertion of ETT  10  into the trachea  22  is sometimes a difficult procedure. As illustrated in  FIG. 4 , it is possible for distal end  14  of ETT  10  to miss the entrance to trachea  22  and enter an esophagus  36  leading to the stomach (not shown). Improper placement of ETT  10  into the esophagus is most evident in a pre-hospital or emergency room setting which is characterized by high stress and limited time. Improper placement of open distal end  14  of ETT  10  into the esophagus  36  prevents ventilation of lungs  32  and  34 . 
         [0035]    Improper insertion of distal end  14  of ETT  10  past carina  26  will result in ventilation of only right lung  32  or left lung  34 .  FIG. 5  illustrates improper insertion of distal end  14  of ETT  10  past carina  26  and into right main bronchus  28 . Because right primary bronchus  28  is shorter, wider, and more vertical than left primary bronchus  30 , the majority of ETT insertions past carina  26  tend to follow the right primary bronchus  28 . The speaker/microphone guidance systems disclosed in U.S. Pat. Nos. 5,455,144 and 6,705,319 to Wodicka, et at, detect if ETT  10  is improperly inserted into esophagus  36 , right primary bronchus  28 , or left primary bronchus  30  and alert a user to the improper placement. The apparatus can then be used to guide movement of UT  10  back into its proper position within trachea  22 . 
         [0036]    According to some embodiments of the present disclosure, the Err  10  may be equipped with a cuff  35  as shown in  FIG. 6 . The cuff  35 , known to a person having ordinary skill in the art, is coupled to a tubular portion  204  of the ETT  10  near the distal end  14 . In  FIG. 6 , the ETT  10  is shown inserted into a body cavity, such as a trachea  22 . The cuff  35  is configured to be a flexible member. In one form, the cuff  35  is formed in a substantially toroidal form, having any desired cross-sectional shape such as circular, oval, square or rectangular, to name just a few non-limiting examples. Pressurizing the interior of the cuff  35  with a gas or fluid can adjust an outer diameter (identified by reference numeral  210 ) of the cuff  35  with respect to an inner diameter (identified by reference numeral  208 ), thereby determining the pressure with which the cuff  35  presses against both the tubular portion  204  of the ETT  10  and the walls of the trachea  22 . The inner portion of the cuff  35  is coupled to the outer surface of the tubular portion  204 . The cuff  35  can be permanently coupled to the tubular portion  204 , e.g., by being molded to or glued to the tubular portion  204 , or in other manners that will be apparent to those skilled in the art in view of the present disclosure. 
         [0037]    The cuff  35  may be in communication with an inflation device  225 . In one embodiment, the inflation device  225  comprises a one-way valve  220  to which a syringe  221 (or other appropriate device) may be attached. The inflation device  225  can be configured to inflate the cuff  35  for an improved sealing against the anatomical conduit such as the trachea  22 . Syringe  221  contains a gas or fluid  222  that may be injected to, or withdrawn from, the cuff  35  through the tube  224  by actuation of the plunger  226 . Once inflated, the syringe  221  may be optionally disconnected from the one-way valve  220 . Other devices known in the art may be used as an inflation device  225 , such as a pump, for example. 
         [0038]    The cuff  35 , when properly pressurized, is configured to prevent backflow of air, or other fluids (e.g., blood, mucous, liquid and gaseous compounds, etc.), collectively referred to hereunder as air or other fluids, between the tubular portion  204  of the ETT  10  and the trachea  22 , or other anatomical structures, collectively referred to hereunder as anatomical conduits, with which the ETT  10  or other tubular device is used to transfer air or other fluids therein. Such a backflow is undesired in ventilation and other applications in which the air or other fluids are introduced through the ETT  10  to an anatomical conduit, as it is desired to maintain a positive pressure within the anatomical conduit. In the case of an ETT  10  positioned within a trachea  22 , the cuff  35  performs the further function of preventing the flow of accumulated fluids that may be proximal to the cuff  35  past the cuff  35  and into the lungs. Such unintended flow can cause pneumonia in the patient. 
         [0039]    The undesirable passage of the air or other fluids between the cuff  35  and the anatomical conduit generates vibrations. The vibrations can generate waves that can be sensed by a detection device that may include the first microphone  76  and/or the second microphone  78 . The microphone(s)  76 ,  78  may be coupled to an external speaker or headphones through an appropriate optional amplifier so that a user can listen for the sound made by the fluid leaking past the cuff  35 . In one embodiment, the inflation device  225  is operated to increase the pressure in the cuff  35  until the user detects that the sound generated by the leakage past the cuff  35  has stopped or substantially stopped. An appropriate pressure sensor of the cuff  35  (and/or the inflation device  225 ) may sense a cuff pressure and record the cuff pressure at this point in time and adjustment of the cuff pressure using the inflation device  225  may be made throughout the remaining time that the ETT  10  is inserted in order to maintain the cuff  35  at that pressure. Such monitoring and maintenance of the appropriate pressure may be done manually by the operator, or under the control of a computer or other processing device as will be appreciated by those skilled in the art in view of the present disclosure. For example, an automated system may be used to maintain the cuff  35  pressure at a set point, and that set point may be determined by acoustic feedback identifying the presence or absence of sound leaking past the cuff  35 . 
         [0040]    In some embodiments, two microphones (such as those illustrated in  FIGS. 2 and 6 ), may be used in order to help identify the sounds indicative of leakage past the cuff  35 . As described hereinabove, two microphones  76 ,  78  may be used to determine the direction of travel of a sound. Using such techniques, the system may differentiate between sounds that arise from the machine (e.g., ventilator) end from those that arise from the patient end. The system may use this information to verify that the sound identified as noise leaking past the cuff  35  is indeed propagating in a direction coming from the cuff  35  to the microphones  76 ,  78  using a temporal analysis or other appropriate analysis. 
         [0041]    In other embodiments, the cuff  35  can be initially filled to a predetermined pressure (such as a pressure recommended by the manufacturer of the ETT  10 ). Thereafter, the microphones  76 ,  78  can be used to monitor for a leak past the cuff  35  and, if detected, the inflation device  225  can be used to increase the pressure in the cuff  35  until the leakage is heard to cease or substantially cease. 
         [0042]    In other embodiments, the leak detection may also be automated, with a detection system configured to detect vibrations generated due to the backflow of the air or other fluids. In other embodiments, the processor may have direct control of the operation of the inflation device  225  and can automatically adjust the pressure in the cuff  202 . 
         [0043]    Referring to  FIG. 7 , a particular illustrative embodiment of a leak detection system is depicted and generally designated  300 . As described above, the ETT  10  may be inserted into the anatomical conduit, such as a trachea  22  and equipped with a cuff  35 . The pressure of the cuff  35  can be increased and decreased to adjust to an outer diameter of the cuff  35  to press against the ETT  10  and the walls of the trachea  22 . The system  300  includes a processor  304  that is communication with a vibration detection device  80  configured to detect acoustic waves generated by vibrations caused by a leak of fluids between the cuff  35  and an anatomical conduit  22 . In addition, the tube  10  may be adapted to be coupled via connector  16  to a medical device  90 , such as a mechanical ventilator, a breathing bag, an anesthesia machine, or an infusion pump. A memory  306  of a computer  302  may be configured to store baseline expected sound profile(s)  308 . An analysis module  310  may be used to determine whether signals received from the microphones  76 ,  78  of the vibration detection device  80  indicate a leak around the cuff  35  when compared to the expected sound profiles  308 . In addition, an output device  312  may be in direct communication with the computer  302 , where the output device  312  is able to render an audio alert, visual alert, or any combination thereof. For example, a cathode ray tube (CRT) display, liquid crystal display (LCD), light emitting diode (LED) display, plasma display, or other display device that is accessible to the processor  304  to display a visual rendering of the expected sound profiles  308  and the signals received from the microphones  76 ,  78 . 
         [0044]    An inflation device  225  may be in communication with the cuff  35  via tube  224  and the computer  302 . The sound profile(s)  308  and analysis module  310  may be implemented in hardware, firmware, software, other programmable logic, or any combination thereof. The memory  306  includes media that is readable by the processor  304  and that stores data and program instructions that are executable by the processor  304 . 
         [0045]    In operation, the sound profile exhibited by air or other fluids leaking past the cuff  35  may be characterized, such as vibrations within a defined frequency range detected over a minimum window of time. The processor  302  of the detection system  300  is programmed to analyze the signals generated by one or more microphones  76 ,  78  of the vibration detection device  80 , and to detect a sound pattern matching the known leakage sound profile  308 . In an alternative embodiment, a baseline is established for normal passage of the air or other fluids, i.e., absence of a backflow of the air or other fluids caused by leakage past the cuff  35 , and a processor  304  of the detection system  300  is programmed to analyze signals generated by at least one the microphone  76  or  78 . The processor  304  can then be programmed to recognize vibrations caused due to the backflow of the air or other fluids, such vibrations being in addition to the expected baseline vibrations. When the processor  304  identifies the air or other fluids are leaking due to the backflow, the processor  304  can then provide an audio and/or visual alert to an operator to take corrective actions. 
         [0046]    A flow diagram of a particular embodiment of a leak detection method is described in  FIG. 8 . At  400 , a sound in or near a tube that is inserted in an anatomical conduit is detected using a microphone. The sound may be generated from a speaker within the tube or acoustic waves generated by vibrations caused by a leak of fluids between a cuff and an anatomical conduit. Moving to  402 , the detected sound may be audibly presented to an operator of the tube for determination of whether a leak around a cuff of the tube is present. In addition, or alternatively, the detected sound signal may be transmitted, at  404 , to a processor that is configured to analyze the sound and detect the sound of the leak over a baseline expected sound profile. The processor is configured to operate and cause an inflation device to renew a seal between the tube and the anatomical conduit if the processor detects the leak, at  406 . The detected sound may be used as a feedback mechanism when pressurizing the cuff, at  408 , such that when the detected sound indicates that the leakage has stopped, a level of pressure of the cuff is recorded and thereafter adjusted to maintain the pressure at the level. 
         [0047]    Although the system and method described is related to maintaining a seal around an ETT  10  within a respiratory system of a body, it is understood that the system and method of the present disclosure may be used to maintain seals around gas or liquid filled tubes or catheters into other body cavities or in various mechanical operations. The leak detection system and method can be applied to a wide variety of clinical tubes or catheters where maintenance of a seal therearound is required. 
         [0048]    Although the teachings of the present disclosure have been described in detail with reference to certain embodiments, variations and modifications exist within the scope and spirit of these teaching as described and defined in the following claims: