Noninvasive determination of cardiac output using single breath CO sub 2 analysis

Abstract

Our data indicate that analysis of the CO2 expirogram can yield accurate information about the cardiovascular system. Specifically, two variables derived from a plot of expired CO2 concentration vs. expired volume predict changes in cardiac output in healthy adult sheep with an adjusted coefficient of determination of .94. Prospective application of this technology in the setting of lung injury and rapidly changing physiology will be essential in determining the clinical usefulness of the technique.

Can Quantitative Capnometry Differentiate Between Cardiac and Obstructive Causes of Respiratory Distress?

“…6 We had hypothesized that quantitative capnometry would be able to differentiate between cardiac and obstructive causes of respiratory distress. We had hoped to find an ETC0 2 level that, either alone or in conjunction with PEFR, could reliably differentiate between cardiac and obstructive causes of respiratory distress.…”

Monitoring cardiac function in intensive care

“…The equation may also be modified using CO 2 production and content, which has been adapted to provide non-invasive estimation. 25 Traditional techniques for measuring oxygen consumption, namely the Douglas bag, spirometry, and more recently mass spectrometry, have limited the clinical utility of this technique in the ICU. However, with the advent of portable metabolic monitors adapted for paediatric use, this technique is now possible in children and infants.…”

Role of lung function testing in the management of mechanically ventilated infants

“…An increase in PETCO 2 is usually associated with hypoventilation in relation to CO 2 production, but may rarely be caused by a sudden change in cardiac output. 6 A decrease in PETCO 2 may reflect an improvement in ventilation distribution, sudden pulmonary hypoperfusion, or an obstruction or disconnection of the ETT/ventilator. When the PETCO 2 is displayed against time (capnogram), the shape of the curve provides important information on physiological dead space.…”