Cardiac output measurements using the bioreactance technique in critically ill patients.

Measurement of cardiac output (CO) using minimally invasive devices has gained popularity. In 11 patients we compared CO values obtained using the bioreactance technique--a new continuous, totally non-invasive CO monitor--with those obtained by semi-continuous thermodilution using a pulmonary artery catheter. We obtained CO measurements at study inclusion and after any relevant change in hemodynamic status (spontaneous or during fluid challenge, inotrope or vasopressor infusions). There was a poor correlation between the two techniques (r = 0.145). These data suggest that caution should be applied when using bioreactance devices in critically ill patients.