Device for the measurement of oxygen consumption

• US 7,621,271 B2
• Filed: 06/30/2005
• Issued: 11/24/2009
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Cosmed Engineering S.r.l.
• Original Assignee: Cosmed Engineering S.r.l.
• Inventors: Brugnoli, Paolo
• Primary Examiner(s): Douglas; Steven O
• Application Number:
  US11/172,305
• Publication Number:
  US 20060005836A1
• Time in Patent Office: 1,608 Days
• Field of Search: 128/205.11, 128/205.12, 128/204.22, 128/204.23, 128/203.22, 128/203.25, 128/204.18, 600/531
• US Class Current: 128/205.11
• CPC Class Codes: A61M 16/085 Gas sampling
• CPC Class Codes: A61M 16/10 Preparation of respiratory gases or vapours
• CPC Class Codes: A61M 2016/1025 the O2 concentration
• CPC Class Codes: A61M 2230/435 partial O2 pressure (P-O2)

Abstract

Device for the measurement of oxygen consumption which, by use of a mixing chamber of small dimensions, allows compensation of the time delay between the measurement of the ventilation V_E and that of average oxygen concentration of the exhaled air volume FeO₂. The time delay between measurement of V_E and FeO₂ maintains a constant value under all ventilations, thanks to a dynamic control of the air quantity collected and introduced in the microchamber and to a dynamic update of proportion factor K, performed by a control system. This enables a precise measurement of oxygen consumption also with rapid ventilation changes.

Claims

1. A device for measurement of oxygen consumption incorporating a flowmeter adapted to measure the exhaled gas flow of a person whose breathed flow is monitored, a mixing chamber, a duct adapted to convey a portion of the exhaled air into the mixing chamber, detectors for detecting percentage of O₂ in the exhaled gas within the mixing chamber, an electronic control system adapted to process parameters associated with the breathed flow, a constant flow rate aspirating pump connected to the mixing chamber, a three-way valve positioned between and outside of the constant flow rate aspirating pump and the mixing chamber and adapted to open communication passage between said pump and said mixing chamber and close another communication passage between the pump and an outside environment when the flowmeter detects an exhalation by the person, and adapted to open the another communication passage between the pump and an outside environment and close communication passage between said pump and said mixing chamber when the flowmeter detects an interruption in the exhalation by the person.

2. A device according to claim 1 wherein the mixing chamber has a volume lower than 100 ml.

3. A method for the measurement of oxygen consumption of a subject whose breathed flow is monitored, comprising:

detecting and measuring an exhaled air of the subject with a flowmeter and transferring a relative measurement to a control system;

supplying a portion of the exhaled air to a mixing chamber (4) through a communication passage;

activating a three-way valve to connect the mixing chamber with a constant flow rate aspirating pump during an exhalation by the subject, and to connect the pump to an environment when the exhalation stops;

detecting a percentage of O2 inside the mixing chamber and communicating the percentage of O2 to the control system, and

processing the detected percentage of O2 by the control system so as to calculate data on oxygen consumption of the subject.

4. The method of claim 3, wherein the detecting of percentage of O2 is measured from the portion of the exhaled air entering the mixing chamber, calculated as a ratio between a total exhaled flow F(t) and a proportional factor K continuously changing to the following equation:

5. A device for measurement of oxygen consumption comprising:

a flowmeter that monitors and measures a breathed flow of exhaled air of a person;

a mixing chamber;

a duct that conveys a portion of the exhaled air into the mixing chamber;

detectors for detecting percentage of O2 of the exhaled air within the mixing chamber; and

electronic control system that measures the percentage of O2 from the portion of the exhaled air entering the mixing chamber, calculated as a ratio between total exhaled flow F(t) and a proportional factor K continuously changing to the following equation;

6. The device according to claim 5 wherein the mixing chamber has a volume lower than 100 ml.