Patient CO.sub.2 Measurement

• US 6,055,447 A
• Filed: 06/18/1998
• Issued: 04/25/2000
• 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
• Inventors: Tang, Wanchun, Weil, Max Harry, Bisera, Jose
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US09/099,293
• Time in Patent Office: 677 Days
• Field of Search: 600/345-350, 600/309, 600/300, 600/301, 600/587, 600/529, 600/353, 600/354
• US Class Current: 600/353
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• 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 5/682 Mouth, e.g., oral cavity; tongue; Lips; Teeth

Abstract

A method and apparatus are provided for assessing impairment of blood circulation of a patient by measurement of PCO₂ (partial pressure of carbon dioxide) in the upper digestive/respiratory tract of the patient. The method includes introducing a CO₂ sensor into the mouth-nose area and against a mucosal surface. In one example, the sensor is placed under the tongue, in the manner of an oral thermometer, and sublingual (under the tongue) measurements of CO₂ are taken. This allows for the triage of patients or victims in emergency of disaster settings. The measurement involves minimal invasion while avoiding false readings. For monitoring of more than about one or two minutes, holders are used to hold the CO₂ sensor instrument stabily in the mouth or nose, and to isolate the mucosal area immediately around the CO₂ sensor from air flow that could carry away CO₂, while maintaining high humidity.

Claims

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

introducing a carbon dioxide sensor into the upper digestive/respiratory tract of the patient without passing the sensor down beyond the epiglottis, and holding the sensor against a mucosal surface in the upper digestive/respiratory tract while taking measurements of carbon dioxide by the sensor to assess perfusion failure of the patient.

2. The method described in claim 1, wherein:

said step of holding the sensor comprises holding the sensor under the tongue of the patient.

3. The method described in claim 1, wherein:

said step of holding the sensor comprises holding the sensor between a lip and teeth of the patient.

4. The method described in claim 1, wherein:

said step of holding the sensor comprises holding the sensor in a naris of the patient'"'"'s nose while blocking the naris from the free flow of air therethrough.

5. The method described in claim 1, wherein:

said step of introducing includes placing a holder with inner and outer holder portions in the mouth of the patient, with said sensor mounted at said inner portion of the holder, and with said holder substantially sealing the area around said sensor to prevent the free flow of air thereby.

6. The method described in claim 1, including:

displaying the rate of change with time of carbon dioxide sensed by said sensor.