Device for assessing perfusion failure in a patient by measurement of blood flow

Abstract

Methods and devices are provided for assessing impairment of blood circulation in a patient, such as that in perfusion failure, by measurement of blood flow in the gastrointestinal tract or upper respiratory/digestive tract of the patient. The method comprises introducing a blood-flow sensor into the gastrointestinal tract or the upper respiratory/digestive tract of a patient, placing the sensor adjacent a mucosal surface therein, and measuring blood flow in adjacent tissue to determine blood flow in that tissue. The method may also involve measurement of PCO 2 and/or pH in combination with the blood flow determination. The invention affords rapid measurement and detection of perfusion failure.

1 . A device for assessing perfusion failure in a patient, the device comprising: 
 a blood-flow sensor means, adapted to be positioned adjacent a mucosal surface within a patient's body and measuring blood flow in adjacent tissue, and    an indicating means operably connected to the sensor means, for indicating the measured blood flow whereby a degree of perfusion failure of the patient may be deduced.    
     
     
         2 . The device of    claim 1   , wherein the mucosal surface is in the gastrointestinal tract or in the upper respiratory/digestive tract.  
     
     
         3 . The device of    claim 1   , wherein the mucosal surface is in the gastrointestinal tract.  
     
     
         4 . The device of    claim 1   , wherein the mucosal surface is in the upper respiratory/digestive tract.  
     
     
         5 . The device of    claim 1   , wherein the mucosal surface is in the esophagus.  
     
     
         6 . The device of    claim 1   , wherein the mucosal surface is in the oral-nasal cavity.  
     
     
         7 . The device of    claim 6   , wherein the mucosal surface is in a nasal passage.  
     
     
         8 . The device of    claim 6   , wherein the mucosal surface is in the mouth.  
     
     
         9 . The device of    claim 8   , wherein the mucosal surface is a sublingual surface.  
     
     
         10 . The device of    claim 1   , wherein the device further comprises a positioning means for locating or maintaining the blood flow sensor means at a position in the upper respiratory/digestive tract.  
     
     
         11 . The device of    claim 10   , wherein the positioning means is a holder adapted to fit within the oral-nasal cavity of the patient and maintain the sensor in place adjacent the mucosal surface.  
     
     
         12 . The device of    claim 11   , wherein the positioning means is a holder adapted to fit within the mouth of the patient and hold the sensor in place adjacent the mucosal surface.  
     
     
         13 . The device of    claim 1     1 , wherein the holder is adapted to position the sensor adjacent a sublingual mucosal surface.  
     
     
         14 . The device of    claim 11   , wherein the holder is constructed to fit between the inside of a lip and gum of the patient, wherein during detecting the sensor means is positioned within the holder and adjacent a mucosal surface isolated by the holder.  
     
     
         15 . The device of    claim 11   , wherein the positioning means is a holder adapted to fit within a nares of the patient and hold the sensor in place adjacent the mucosal surface.  
     
     
         16 . The device of    claim 1   , wherein the sensor is a laser-Doppler blood-flow sensor.  
     
     
         17 . The device of    claim 16   , further comprising a pH sensor, or a PCO 2  sensor, or both.  
     
     
         18 . The device of    claim 1   , wherein the sensor is an ultrasound-Doppler blood-flow sensor.  
     
     
         19 . The device of    claim 18   , further comprising a pH sensor, or a PCO 2  sensor, or both.  
     
     
         20 . The device of    claim 1   , further including a means for determining the rate of change of blood flow.  
     
     
         21 . The device of    claim 20    wherein the determining means comprises a circuit for generating a signal representing rate-of-change of blood flow.  
     
     
         22 . A device for use with a blood-flow sensor assembly for assessing perfusion failure of a patient, comprising: 
 a sensor holder with an inner portion and an outer portion, said inner portion shaped to fit in the mouth of a patient under the patient's tongue, said holder forming at least one holder passage extending from said outer portion to said inner portion.    
     
     
         23 . The device of    claim 22   , wherein the sensor holder has an upper surface that supports the tongue of the patient.  
     
     
         24 . The device of    claim 22   , wherein the outer portion has a slot for receiving the patient's frenulum, and the holder passage has an inner end lying on one side of said slot.  
     
     
         25 . The device of    claim 22   , wherein at least a portion of the holder is comprised of an elastomeric material.  
     
     
         26 . A method for assessing perfusion failure of a patient, the method comprising: 
 placing a blood-flow sensor adjacent a mucosal surface within the body of a patient; and    measuring blood flow in adjacent tissue;    wherein a measured blood flow that is substantially lower than a normal blood flow is indicative of perfusion failure in the patient.    
     
     
         27 . The method of    claim 26   , wherein the mucosal surface is in the gastrointestinal tract or in the upper respiratory/digestive tract.  
     
     
         28 . The method of    claim 26   , wherein the mucosal surface is in the gastrointestinal tract.  
     
     
         29 . The method of    claim 26   , wherein the mucosal surface is in the upper respiratory/digestive tract.  
     
     
         30 . The method of    claim 26   , wherein the mucosal surface is in the esophagus.  
     
     
         31 . The method of    claim 26   , wherein the mucosal surface is in the oral-nasal cavity.  
     
     
         32 . The method of    claim 26   , wherein the mucosal surface is in the mouth.  
     
     
         33 . The method of    claim 26   , wherein the mucosal surface is a sublingual surface.  
     
     
         34 . The method of    claim 26   , wherein the mucosal surface is in a nasal passage.  
     
     
         35 . The method of    claim 26   , wherein the blood flow is measured using a laser-Doppler blood-flow sensor.  
     
     
         36 . The method of    claim 26   , wherein the blood flow is measured using an ultrasound-Doppler blood-flow sensor.  
     
     
         37 . The method of    claim 26   , wherein said measuring step comprises: 
 positioning a blood-flow sensor means adjacent the mucosal tissue; and    measuring a rate-of-change of blood flow in the mucosal tissue whereby the rate-of-change indicates whether blood flow is decreasing, and whereby a decreasing blood flow indicates a worsening condition in a patient.    
     
     
         38 . A method for assessing perfusion failure of a patient, the method comprising: 
 placing a blood-flow sensor adjacent a mucosal surface within the body of a patient;    placing a PCO 2  sensor adjacent a mucosal surface within the body of a patient;    measuring blood flow in adjacent tissue using the blood-flow sensor; and    measuring PCO 2  with the PCO 2  sensor,    wherein a measured blood flow that is substantially lower than a normal blood flow and a PCO 2  that is substantially higher than a normal PCO 2  are indicative of perfusion failure in the patient.    
     
     
         39 . A method for assessing perfusion failure of a patient, the method comprising: 
 placing a blood-flow sensor adjacent a mucosal surface within the body of a patient;    placing a pH sensor adjacent a mucosal surface within the body of a patient;    measuring blood flow in adjacent tissue using the blood-flow sensor; and    measuring pH with the pH sensor,    wherein a measured blood flow that is substantially lower than a normal blood flow and a pH that is substantially lower than a normal pH are indicative of perfusion failure in the patient.    
     
     
         40 . A method for assessing perfusion failure of a patient, the method comprising: 
 placing a blood-flow sensor adjacent a mucosal surface within the body of a patient;    placing a PCO 2  sensor adjacent a mucosal surface within the body of a patient;    measuring blood flow in adjacent tissue using the blood-flow sensor;    placing a pH sensor adjacent a mucosal surface within the body of a patient;    measuring PCO 2  with the PCO 2  sensor; and    measuring pH with the pH sensor,    wherein a measured blood flow that is substantially lower than a normal blood flow, a PCO 2  that is substantially higher than a normal PCO 2  and a pH that is substantially lower than a normal pH are indicative of perfusion failure in the patient.