Patent ID: 8551006
Filing Date: 2013-10-08
Classification: A61B

Abstract:
1. A device for assessing changes in cardiac output and/or stroke volume of a subject receiving airway support from a breathing assistance system, the device comprising: a processor; an airway sensor in communication with the processor, wherein the airway sensor is configured and arranged to sense pressure in the subject's airway, lungs, and/or intrapleural space over time; a blood volume sensor in communication with the processor, wherein the blood volume sensor is configured and arranged to sense pulsatile volume of blood in a tissue of the subject over time; and a display configured and arranged to display a representative of an airway pressure, a pulsatile blood volume, a photoplethysmogram, a photoplethysmogram ratio, the determined cardiac output and/or stroke volume, or combinations thereof, wherein the processor is configured and arranged to (a) produce a photoplethysmogram, (b) determine a photoplethysmogram ratio of the amplitude of the photoplethysmogram during inhalation to the amplitude of the photoplethysmogram during exhalation, and (c) determine the change in cardiac output and/or stroke volume of the subject using the ratio of the amplitude of the photoplethysmogram during inhalation to the amplitude of the photoplethysmogram during exhalation.