Method and apparatus for measuring pulmonary blood flow by pulmonary exchange of oxygen and an inert gas with the blood

• US 6,659,961 B2
• Filed: 05/01/2002
• Issued: 12/09/2003
• Est. Priority Date: 10/25/1996
• Status: Expired due to Fees

• Current Assignee: Gavin J.B. Robinson
• Original Assignee: Gavin J.B. Robinson
• Inventors: Robinson, Gavin J. B.
• Primary Examiner(s): Hindenburg, Max F.
• Assistant Examiner(s): Natnithithadha, Navin
• Application Number:
  US10/137,204
• Publication Number:
  US 20030040678A1
• Time in Patent Office: 587 Days
• Field of Search: 600/531, 600/529, 600/532, 600/533, 600/538, 600/504, 600/481, 600/484, 128/204.18, 128/204.21
• US Class Current: 600/531
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/0813 Measurement of pulmonary parameters by tracers, e.g. radioactive tracers
• CPC Class Codes: A61M 16/04 Tracheal tubes catheters in general A61M25/00
• CPC Class Codes: A61M 16/0404 with means for selective or partial lung respiration
• CPC Class Codes: A61M 16/0459 one cuff behind another
• CPC Class Codes: A61M 16/0484 at the distal end
• CPC Class Codes: A61M 16/0486 Multi-lumen tracheal tubes
• CPC Class Codes: A61M 2016/003 with a flowmeter
• CPC Class Codes: A61M 2202/0225 Carbon oxides, e.g. Carbon dioxide

Abstract

A method and apparatus for measuring pulmonary blood flow in a subject by pulmonary exchange of oxygen and an inert gas with the blood using a divided respiratory system. One method of isolating two or more divisions of the respiratory system uses a multi-lumen cuffed endobronchial catheter. In one embodiment, a triple-lumen cuffed endobronchial catheter is provided. In another embodiment, gas mixtures are supplied to each lumen using a bag-in-a-box type ventilator for each breathing system for synchronizing the rate and pressure of mixed gas supplied to the lumens.

Claims

1. A method for measuring the pulmonary blood flow in a subject including:

isolating two or more divisions of the respiratory system, said divisions comprising the complete gas exchanging part of said respiratory system;

ventilating each said division with a separate gas mixture, at least one of said gas mixtures including an inert soluble gas;

determining uptake of inert soluble gas in at least two of said divisions;

determining relative pulmonary blood flow of said divisions;

determining end tidal concentration of inert soluble gas in at least two of said divisions; and

calculating pulmonary blood flow from determined values of uptake and end tidal concentration of inert soluble gas, and relative pulmonary blood flow.

2. A method according to claim 1 wherein two divisions of the respiratory system are isolated.

3. A method according to claim 2 wherein said two divisions comprise the left and right lungs respectively.

4. A method according to any one of claims 1 to 3 wherein said inert soluble gas comprises nitrous oxide.

5. A method according to any one of claims 1 to 3 wherein at least one of said gas mixtures comprises two or more inert soluble gases.