Method of continuously, non-invasively monitoring pulmonary capillary blood flow and cardiac output

US6217524A · kind A · utility

Assignee

• NTC Technology, Inc. · US

Inventors

• Joseph Orr · Park City, US
• Michael B. Jaffe · Cheshire, US
• Kai Kuck · Hamburg, DE
• Dinesh G. Haryadi · Bengaluru, IN

Key dates

• Filing date: Sep 9, 1998
• Grant date: Apr 17, 2001
• Expiry date: Sep 9, 2018

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61M2016/103
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

A method of continuously, non-invasively determining the cardiac output of a patient. The method includes intermittently measuring the cardiac output, the volume of carbon dioxide exhaled by the patient per breath, and determining the arterial-venous gradient of the patient or a similar substantially constant value by dividing the volume of carbon dioxide exhaled by the measured cardiac output. The arterial-venous gradient or similar substantially constant value may then be employed to determine the cardiac output of the patient on a breath-by-breath basis. The carbon dioxide elimination, which is non-invasively measured as the volume of carbon dioxide exhaled by the patient per breath, is divided by the arterial-venous gradient or the substantially constant value to determine the cardiac output. The method may also include generating a signal to compensate for any non-metabolic changes in the carbon dioxide elimination, arterial-venous gradient, or other respiratory or blood gas profile measurements that may be caused by a change in ventilation or breathing of the patient. The compensatory signal may be employed to modify one or more of the respiratory or blood gas profile measure…