The present disclosure relates, in some embodiments, to devices, systems, and / or methods for collecting,
processing, and / or displaying
stroke volume and / or
cardiac output data. For example, a device for assessing changes in
cardiac output and / or
stroke volume of a subject receiving
airway support may comprise 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. A method of assessing changes in cardiac output or stroke volume of a subject receiving airway support from a
breathing assistance
system may comprise sensing pressure in the subject's airway as a function of time, sensing pulsatile volume of blood in a tissue of the subject as a function of time, producing a
photoplethysmogram from the sensed pulsatile volume, determining the ratio of the amplitude of the photoplethysmogram during
inhalation to the amplitude of the photoplethysmogram during
exhalation, and determining the change in cardiac output or stroke volume of the subject using the determined ratio.