VALIDATION OF A NEW METHOD TO MEASURE CARDIAC-OUTPUT DURING EXTRACORPOREAL DETOXIFICATION

Cardiac output was measured in 11 patients during extracorporeal detox ification after open heart surgery. All patients were mechanically ven tilated and had pulmonary artery catheters for cardiac output (COT) me asured by thermodilution. A sensor on the arterial side of the extraco rporeal circulation measured flow and sound velocity transients. Injec tions of 2-5 ml 0.9% saline at 37 degrees C into the arterial line ups tream of the sensor permitted its calibration; 10-20 ml of the same so lution was injected intravenously or into the venous dialysis injectio n port, and cardiac output (COUD) was calculated by the ultrasound vel ocity dilution technique. COT was measured within 5 min of the ultraso und dilution measurement. CO was in the range of 2-8 L/m. The regressi on equation was COUD = 1.09 X COT - 0.32 (r = 0.97, n = 31). These dat a suggest agreement between the ultrasound dilution technique and ther modilution. Ultrasound dilution is preferable in patients undergoing e xtracorporeal detoxification when pulmonary artery catheterization is not required or dangerous.