EVALUATION OF THE ACCURACY AND RESPONSE-TIME OF STAT-MODE CONTINUOUS CARDIAC-OUTPUT

Objectives: This study was conducted to compare continuous cardiac out put (CCO) with bolus thermodilution cardiac output (BTD) at steady sta te, and to compare the response time of STAT CCO with that of trend CC O, mean arterial pressure, and mixed venous oxygen saturation (SvO(2)) during an acute hemodynamic change. Design: Prospective study. Settin g: University hospital. Participants: Twenty-nine patients undergoing cardiac surgery or liver transplantation. Interventions: STAT and tren d CCO were compared with BTD cardiac output during steady state intrao peratively and postoperatively in the intensive care unit. Ten patient s, who required epicardial pacing after cardiac surgery, were studied to compare the response time of STAT CCO with that of trend CCO, mean arterial pressure, and SvO(2) after a 10% to 20% increase in pacing ra te. Measurements and Main Results: A total of 108 cardiac output data sets were analyzed at steady state. Steady state was defined as stable heart rate and mean arterial pressure (+/-5%) and stable central veno us pressure (+/-2 mmHg) measured immediately before and after each dat a set. Cardiac output ranged from 2.3 to 8.5 L/min. The correlation be tween STAT CCO and BID was r = 0.94, and for trend CCO and BTD was r = 0.94. The bias and precision for STAT CCO versus BTD were 0.06 L/min (Cl 95%: -0.06 to 0.18) and 0.61 L/min. The bias and precision for tre nd CCO versus BTD were 0.06 L/min (Cl 95%: -0.04 to 0.16) and 0.49 L/m in. Eleven data sets were analyzed to study response time of STAT CCO, which was defined as the first time the percent change of the mean of each variable was significantly increased from baseline. Significant increases in mean arterial pressure and SvO(2) were detected after 30 seconds (2.5%, p = 0.01) and 90 seconds (2.0%, p = 0.04), respectively . A significant increase in STAT CCO was reached at 270 seconds (4.4%, p = 0.006), Trend CCO tended to increase but did not reach statistica l significance within 6 minutes. Conclusions: STAT and trend CCO are a ccurate and precise and show close agreement with BTD cardiac output a t steady state. The faster algorithm of STAT CCO offers some advantage over trend CCO during an acute hemodynamic change. However, because o f the averaging process for determining CCO, the response time of STAT CCO is slower than that of mean arterial pressure and SvO(2). Copyrig ht (C) 1997 by W.B. Saunders Company.