Measurement of systemic perfusion

• US 5,579,763 A
• Filed: 07/06/1995
• Issued: 12/03/1996
• Est. Priority Date: 07/06/1995
• Status: Expired due to Term

• Current Assignee: Weil Institute Of Critical Care Medicine
• Original Assignee: Institute of Critical Care Medicine, Nihon Kohden Corporation
• Inventors: Weil, Max H., Tang, Wanchun, Bisera, Jose
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): ROBINSON, HERMAN
• Application Number:
  US08/498,932
• Time in Patent Office: 516 Days
• Field of Search: 128/630-635, 128/668, 128/673, 128/669, 128/642, 128/636
• US Class Current: 600/363
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/42 Detecting, measuring or recording for evaluating the gastrointestinal, the endocrine or the exocrine systems A61B1/00, A61B5/4857, A61B5/486, A61B5/4866, A61B5/4869 take precedence
• CPC Class Codes: A61B 5/4233 oesophagus
• CPC Class Codes: A61B 5/6853 with a balloon

Abstract

A method is described for assessing perfusion failure of a patient by measurement pCO₂ (partial pressure of carbon dioxide) in the digestive system of the patient. The method includes introducing a catheter (10, FIG. 1) through the nasal passage until a sensor (12) on the catheter lies in the esophagus, and taking measurements of CO₂ in the esophagus. The measurements can be taken at the wall of the esophagus without inflating a balloon, by instead allowing the walls of the esophagus to contract about the catheter and the sensor thereof. The measurement involves minimal invasion while avoiding false readings such as those arising from CO₂ produced in the stomach during digestion.

Claims

1. A method for assessing perfusion failure of a patient, comprising:

introducing a catheter with a carbon dioxide sensor, through the oral or nasal passage and at least partially through the esophagus of the patient, until the carbon dioxide sensor lies in the esophagus at a location on a side of the lower esophageal sphincter opposite the stomach;

taking measurements of carbon dioxide in the esophagus of the patient to assess perfusion failure of the patient.

2. The method described in claim 1 wherein:

said step of taking measurements includes avoiding expansion of the esophagus while allowing contraction of the esophagus around the carbon dioxide sensor.

3. A minimally invasive method for detecting a chemical characteristic in the gastrointestinal system of a patient who is in critical condition and whose critical condition is assessed as likely due to perfusion failure, but whose critical condition is not assessed as likely due to gastric acid reflux, where said chemical characteristic is the partial pressure of carbon dioxide, comprising:

introducing a catheter with a proximal end through an oral or nasal passage of a person, with a sensor at a location along said catheter, where said sensor is sensitive to said chemical characteristic, and with at least one signal conductor extending from said sensor to said proximal end, including moving said catheter location through a throat and into an esophagus of the person without first passing down through a lower esophageal sphincter of the person, and leaving said sensor in the esophagus while measuring an output of said at least one signal conductor;

assessing said output of said at least one signal conductor to determine the extent of perfusion failure.

4. The method described in claim 3 wherein:

said step of leaving said sensor in the esophagus includes avoiding expansion of said catheter location, but allowing the esophagus to contract thereagainst.