Pharyngeal end-tidal carbon dioxide measuring catheter

• US 5,555,890 A
• Filed: 02/25/1994
• Issued: 09/17/1996
• Est. Priority Date: 06/08/1992
• Status: Expired due to Fees

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Schaller, Douglas A.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US08/202,859
• Time in Patent Office: 935 Days
• Field of Search: 128/716, 128/719, 128/730, 128/205.27, 128/205.28, 128/206.11, 128/207.14, 128/207.18, 128/205.12, 600/156, 600/138
• US Class Current: 600/532
• CPC Class Codes: A61B 5/0836 Measuring rate of CO2 production

Abstract

A catheter for measuring a fluid in a patient, such as end-tidal CO₂, having a proximal end, a proximal portion adjacent the proximal end, a distal end, a distal portion adjacent the distal end and a lumen therethrough. The distal end is adapted to terminate in the pharynx of the patient when the catheter is inserted through the patient'"'"'s nasal passage. The proximal end is attached to a device for measuring the fluid. Fluid is measured as it passes from the pharynx, through the catheter and then into the measuring means.

Claims

1. A catheter for use in measuring gas concentrations in a patient, said catheter having a lumen therethrough, a proximal end, a distal end including a plurality of gas intake ports, a proximal portion including a suction trap, and a rigid distal portion adjacent the distal end dimensioned to be received in and substantially conform to a patient'"'"'s nasal passage and to terminate at a location away from the patient'"'"'s posterior pharyngeal wall.

2. A catheter in accordance with claim 1, wherein the distal portion is integrally attached to a nasogastric tube, and the proximal portion diverges away from the nasogastric tube.

3. A catheter in accordance with claim 2, wherein the nasogastric tube is coaxial with the distal protin.

4. A catheter in accordance with claim 1, wherein the gas intake ports have a diameter of from about 1 m to about 3 mm.