Continuous measurement of cardiac output by the Fick principle: Clinical validation in intensive care

OBJECTIVETo compare continuous measurement of cardiac output by the Fick principle with the thermodilution cardiac output technique in hemodynamically unstable patients. DESIGNAn open comparison of two methods. SETTINGMultidisciplinary ICU in a university hospital. PATIENTSEight patients after coronary bypass surgery and 13 patients with hyperdynamic septic shock. All patients were mechanically ventilated. MEASUREMENTS AND MAIN RESULTSThe continuous Fick cardiac output technique was compared with the thermodilution cardiac output using both warm and cold injection in the coronary artery bypass surgery patients and using warm injection only in the patients with hyperdynamic septic shock. The mean difference between the continuous cardiac output technique and all thermodilution measurements (n = 201) was 0.6 ± 19%. There was a good correlation between the continuous cardiac output and the warm thermodilution technique (n = 125, r =.79; p