Abstract:
A method for identifying an occlusion in a breathing tube of a ventilator system is disclosed herein. The method includes obtaining data related to a respiratory signal, transferring the data to a processor, and implementing the processor to evaluate the data in a manner adapted to automatically identify the presence of an occlusion in the breathing tube. A corresponding ventilator system is also disclosed.

Description:
FIELD OF THE INVENTION 
       [0001]    This disclosure relates generally to a method and system for detecting a breathing tube occlusion. 
       BACKGROUND OF THE INVENTION 
       [0002]    Medical ventilators are used to provide respiratory support to patients undergoing anesthesia and respiratory treatment whenever the patient&#39;s ability to breath is compromised. The primary function of the medical ventilator is to maintain suitable pressure and flow of gases inspired and expired by the patient. The medical ventilator is commonly coupled with a patient via a breathing tube such as, for example, a tracheal tube or an endotracheal tube. The problem is that the breathing tube can become occluded with a mucus plug and/or other debris thereby posing a health risk to the patient and diminishing the effectiveness of the ventilator. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0003]    The above-mentioned shortcomings, disadvantages and problems are addressed herein which will be understood by reading and understanding the following specification. 
         [0004]    In an embodiment, a method for identifying an occlusion in a breathing tube of a ventilator system includes obtaining data related to a respiratory signal, transferring the data to a processor, and implementing the processor to evaluate the data in a manner adapted to automatically identify the presence of an occlusion in the breathing tube. 
         [0005]    In another embodiment, a method for identifying an occlusion in a breathing tube of a ventilator system includes providing a sensor, implementing the sensor to measure a respiratory signal, transferring measurement data from the sensor to a processor, implementing the processor to generate a measurement data plot, and implementing the processor to evaluate the measurement data plot in a manner adapted to automatically identify the presence of an occlusion in the breathing tube. 
         [0006]    In another embodiment, a ventilator system includes a ventilator, a breathing tube connected to the ventilator, and a sensor connected to either the ventilator or the breathing tube. The sensor is configured to measure a respiratory signal. The ventilator system also includes a processor connected to the sensor. The processor is configured to evaluate data from the sensor in a manner adapted to automatically identify the presence of an occlusion in the breathing tube. 
         [0007]    Various other features, objects, and advantages of the invention will be made apparent to those skilled in the art from the accompanying drawings and detailed description thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a schematic diagram illustrating a ventilator system connected to a patient; 
           [0009]      FIG. 2   a  is graph of pressure versus time as measured with both an unobstructed breathing tube and an occluded breathing tube; and 
           [0010]      FIG. 2   b  is graph of flow versus time as measured with both an unobstructed breathing tube and an occluded breathing tube. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments that may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is, therefore, not to be taken as limiting the scope of the invention. 
         [0012]    Referring to  FIG. 1 , a schematically illustrated ventilator system  10  is shown connected to a patient  12  in accordance with an exemplary embodiment. The ventilator system  10  includes a ventilator  14 , a breathing tube or circuit  16 , one or more sensors  18 , and a processor  20 . The ventilator system  10  may also optionally include an alarm  22  and a catheter  24 . 
         [0013]    The ventilator  14  provides breathing gasses to the patient  12  via the breathing circuit  16 . The ventilator  14  includes a plurality of connectors  26 ,  28  configured to respectively receive an inspiratory branch  30  and an expiratory branch  32  of the breathing circuit  16 . The breathing circuit  16  includes the inspiratory branch  30 , the expiratory branch  32 , a Y-connector  34 , a patient branch  36 , and an interface  38 . The interface  38  is the portion of the breathing circuit  16  that is directly coupled with the patient  12 . According to the embodiment depicted and described hereinafter, the interface  38  is an endotracheal tube, however it should be appreciated that other known devices may also be implemented for the interface  38 . 
         [0014]    The endotracheal tube  38  is generally inserted through the patient&#39;s mouth and advanced into the patient&#39;s airway until the distal end  40  of the endotracheal tube  38  passes through the patient&#39;s larynx (not shown). As is known to those skilled in the art, the endotracheal tube  38  can become occluded or blocked by an occlusion  42  that may, for example, comprise a mucus plug and/or other debris. The occlusion  42  can pose a health risk to the patient  12  and can diminish the effectiveness of the ventilator system  10 . As will be described in detail hereinafter, the ventilator system  10  is adapted to automatically identify the presence of an occlusion so that steps may be taken to clear the endotracheal tube  38 . 
         [0015]    The sensors  18  may be operatively connected to or disposed within the breathing circuit  16  as shown in  FIG. 1  and described in detail hereinafter. Alternatively, the sensors  18  may be incorporated into the ventilator  14 . The sensors  18  may be configured to monitor respiratory signals such as, for example, flow rate and pressure level, and may therefore include a flow sensor  18   a  and pressure sensor  18   b . The flow sensor  18   a  and the pressure sensor  18   b  are known devices and will therefore not be described in detail. According to one embodiment the flow sensor  18   a  is configured to measure the flow rate of expiratory gasses passing through the breathing circuit  16 , and the pressure sensor  18   b  is configured to measure the pressure within the breathing circuit  16  on the ventilator side of the occlusion  42 . 
         [0016]    The sensors  18  transmit sensor data to the ventilator  14  and/or the processor  20 . As will be described in detail hereinafter, the processor  20  is configured to automatically analyze the sensor data in order to identify an occlusion within the endotracheal tube  38 . Advantageously, the automation of this identification process reduces personnel requirements and ensures that the occlusion is identified as quickly as possible. For purposes of this disclosure, “automatic processes” and “automated processes” are those that may be performed independently without direct human interaction. The processor  20  may optionally be connected to an alarm  22  in order to alert hospital personnel to the presence of an occlusion within the endotracheal tube  38 . 
         [0017]    According to one embodiment, the processor  20  includes an algorithm  21  configured to identify patterns in the sensor data that may be indicative of an occlusion within the endotracheal tube  38 . In a non-limiting manner, the following will describe several of these patterns. 
         [0018]    Referring to  FIG. 2   a , an unobstructed pressure plot or graph  50 , and an occluded pressure plot or graph  52  are shown. The unobstructed pressure plot  50  represents a pressure versus time plot of a single inhalation/exhalation cycle with an unobstructed endotracheal tube  38  (shown in  FIG. 1 ). Similarly, the occluded pressure plot  52  represents a single inhalation/exhalation cycle with an occluded endotracheal tube  38 . 
         [0019]    Points  59 - 66  distinguish the occluded pressure plot  52  from the unobstructed pressure plot  50  and can therefore be implemented to identify the presence of an occlusion within the endotracheal tube  38  (shown in  FIG. 1 ). More precisely, the portions of plot  52  labeled  59 ,  60 ,  64  and  65  represent relative minimum points and relative maximum points that are not present in the unobstructed pressure plot  50 . Additionally, the portion of the plot  52  labeled  62  is steeper than the corresponding portion of the unobstructed pressure plot  50 , and the portion of the plot  52  labeled  66  is less steep than the corresponding portion of the unobstructed pressure plot  50 . Therefore, the processor  20  (shown in  FIG. 1 ) may be configured to identify the relative minimum and maximum points  59 ,  60 ,  64  and  65 , and to evaluate the slope of a pressure plot at or near regions  62  and  66  in order to determine if the endotracheal tube  38  is occluded. 
         [0020]    Referring to  FIG. 2   b , an unobstructed flow plot or graph  70 , and an occluded flow plot or graph  72  are shown. The unobstructed flow plot  70  represents a flow versus time plot of a single inhalation/exhalation cycle with an unobstructed endotracheal tube  38  (shown in  FIG. 1 ). Similarly, the occluded flow plot  72  represents a single inhalation/exhalation cycle with an occluded endotracheal tube  38 . 
         [0021]    Points  73 - 76  distinguish the occluded flow plot  72  from the unobstructed flow plot  70  and can therefore be implemented to identify the presence of an occlusion within the endotracheal tube  38  (shown in  FIG. 1 ). More precisely, the portions of plot  72  labeled  73 ,  74 ,  75  and  76  represent relative minimum points and relative maximum points that are not present in the unobstructed flow plot  70 . Therefore, the processor  20  (shown in  FIG. 1 ) may be configured to identify the relative minimum and maximum points  73 ,  74 ,  75  and  76  in order to determine if the endotracheal tube  38  is occluded. 
         [0022]    Referring again to  FIG. 1 , the embodiment of the ventilator system  10  wherein the optional catheter  24  is implemented will now be described. The catheter  24  is inserted through the endotracheal tube  38  into the patient&#39;s airway such that a distal end  44  of the catheter  24  extends slightly beyond the distal end  40  of the endotracheal tube  38 . A pressure sensor  18   b  may be operatively connected to the catheter  24  in order to obtain a pressure reading at or near the distal end  44  which is on the lung side of the occlusion  42 . 
         [0023]    Referring to  FIG. 2   a , an unobstructed pressure plot or graph  80  and an occluded pressure plot or graph  82  measured using the catheter  24  (shown in  FIG. 1 ) are shown with dashed lines. It can be seen that the unobstructed pressure plot  50  measured on the ventilator side of the occlusion  42  (e.g., as measured in the breathing circuit  16 ) varies only slightly from the unobstructed pressure plot  80  measured on the lung side of the occlusion  42  (e.g., as measured with the catheter  24 ). Conversely, the occluded pressure plot  52  measured on the ventilator side of the occlusion  42  varies significantly from the occluded pressure plot  82  measured on the lung side of the occlusion  42 . Therefore, the processor  20  (shown in  FIG. 1 ) may be configured to compare a pressure measurement taken at a first location (e.g., within the breathing circuit  16 ) with a pressure measurement taken at a second location (e.g., at or near the distal end  44  of the catheter  24 ) as an indicator of endotracheal tube  38  occlusion. More precisely, if the processor  20  determines that the pressure measurement taken at the first location varies by more than a predetermined amount from a pressure measurement taken at the second location, the endotracheal tube  38  may be occluded. In addition, sudden increases in the difference between the pressure signals relative the same measurements in previous breaths may trigger an alarm condition. 
         [0024]    While the invention has been described with reference to preferred embodiments, those skilled in the art will appreciate that certain substitutions, alterations and omissions may be made to the embodiments without departing from the spirit of the invention. Accordingly, the foregoing description is meant to be exemplary only, and should not limit the scope of the invention as set forth in the following claims.