Methods of measuring cardiac output using a non-invasively estimated intrapulmonary shunt fraction

US6241681A · kind A · utility

Assignee

• NTC Technology, Inc. · US

Inventors

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

Key dates

• Filing date: Dec 16, 1999
• Grant date: Jun 5, 2001
• Expiry date: Dec 16, 2019

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61B5/083
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

A method of non-invasively estimating the intrapulmonary shunt in a patient. The method includes non-invasively measuring respiratory flow, respiratory carbon dioxide content, and arterial blood oxygen content. A re-breathing process is employed to facilitate an estimate of the patient's pulmonary capillary blood flow. Any inaccuracies of the arterial blood oxygen content are corrected to provide a substantially accurate arterial blood oxygen content measurement. The respiratory flow, carbon dioxide content and arterial blood oxygen content measurements, and the pulmonary capillary blood flow estimate are employed to estimate an intrapulmonary shunt of the patient. The invention also includes a method of determining the total cardiac output of the patient which considers the estimated intrapulmonary shunt.