Acoustic reflectometry device in catheters

Abstract

A device and method for verifying the proper position of catheters in the body by means of acoustic reflectometry, the device including a sound source, one or more sound receivers, a tube with compliant walls and open distal end to be introduced through an entrance to a body cavity, the sound source and receiver(s) coupled to the proximal end of the tube, a processor for causing the sound source to generate an acoustic excitation signal, the processor processing the acoustic signals sensed by the sound receiver(s) and generating an approximation of the acoustic impulse response of the tube, and the processor analyzing the acoustic impulse response to determine the position of the tube in the body cavity.

1 - 18 . (canceled) 
     
     
         19 . A method for detecting nasogastric device positioning through acoustic reflectometry, the method comprising:
 emitting sound waves, from a sound generator, into a proximal end of a nasogastric enteral access device having a distal end inserted through a naris of a body;   detecting, by a sound receiver at the proximal end, an acoustic reflection of one or more of the sound waves from a deformation in a wall of the nasogastric enteral access device; and   analyzing a timing of the detected acoustic reflection to determine a distance the distal end of the nasogastric enteral access device is inserted into the body.   
     
     
         20 . The method of  claim 19 , further comprising:
 determining a length of the nasogastric enteral access device; and   wherein determining the distance the distal end of the nasogastric enteral access device is inserted into the body is further based on the determined length.   
     
     
         21 . The method of  claim 19 , wherein the deformation in the wall is caused by an esophageal sphincter. 
     
     
         22 . The method of  claim 21 , wherein the esophageal sphincter is a lower esophageal sphincter. 
     
     
         23 . The method of  claim 21 , wherein the esophageal sphincter is an upper esophageal sphincter. 
     
     
         24 . The method of  claim 19 , further comprising providing positive pressure into the nasogastric enteral access device to push fluids out the distal end of the nasogastric enteral access device. 
     
     
         25 . The method of  claim 19 , wherein the sound generator and sound receiver are included in an acoustic reflectometry device that includes a wave tube coupled to the proximal end of the nasogastric enteral access device. 
     
     
         26 . A method for detecting nasogastric device positioning through acoustic reflectometry, the method comprising:
 emitting sound waves, from a sound generator, into a proximal end of a nasogastric enteral access device having a distal end inserted through a naris of a body;   detecting, by a sound receiver at the proximal end, an acoustic reflection of one or more of the sound waves from the distal end of the nasogastric enteral access device; and   based on the acoustic reflection, indicating that the distal end of the nasogastric enteral access device is above or below the lower esophageal sphincter.   
     
     
         27 . The method of  claim 26 , wherein the acoustic reflection is a positive amplitude deflection and the indication indicates that the nasogastric enteral access device is above the lower esophageal sphincter. 
     
     
         28 . The method of  claim 26 , wherein the acoustic reflection is a negative amplitude deflection and the indication indicates that the nasogastric enteral access device is below the lower esophageal sphincter. 
     
     
         29 . The method of  claim 26 , wherein the sound waves are emitted and detected as the distal end of the nasogastric enteral access device is advancing in the body. 
     
     
         30 . The method of  claim 26 , wherein the sound waves are emitted and detected as the distal end of the nasogastric enteral access device is stationary in the body. 
     
     
         31 . The method of  claim 26 , further comprising providing positive pressure into the nasogastric enteral access device to push fluids out the distal end of the nasogastric enteral access device. 
     
     
         32 . The method of  claim 26 , wherein the sound generator and sound receiver are included in an acoustic reflectometry device that includes a wave tube coupled to the proximal end of the nasogastric enteral access device. 
     
     
         33 . A system for detecting nasogastric device positioning through acoustic reflectometry, the system comprising:
 a sound generator to emit sound into a nasogastric enteral access device;   a sound receiver to detect an acoustic reflection of one or more of the sound waves from a deformation in a wall of the nasogastric enteral access device; and   at least one processor and a memory, that is accessible to the processor, the processor configured to analyze a timing of the detected acoustic reflection to determine a distance a distal end of the nasogastric enteral access device is inserted into a body.   
     
     
         34 . The system of  claim 33 , wherein the processor is further configured to determine a length of the nasogastric enteral access device and determine the distance the distal end of the nasogastric enteral access device is inserted into the body is further based on the determined length. 
     
     
         35 . The system of  claim 33 , wherein the deformation in the wall is caused by an esophageal sphincter. 
     
     
         36 . The system of  claim 35 , wherein the esophageal sphincter is a lower esophageal sphincter. 
     
     
         37 . The system of  claim 35 , wherein the esophageal sphincter is a upper esophageal sphincter. 
     
     
         38 . The system of  claim 33 , wherein the sound generator and sound receiver are included in an acoustic reflectometry device that includes a wave tube coupled to a proximal end of the nasogastric enteral access device.