Is the placement of a pulmonary artery catheter still justified solely for the measurement of cardiac output?

Objective: The authors compared four clinical techniques of measuring cardiac output (CO) in critically ill patients: pulmonary artery thermodilution (CO[PA]), transpulmonary aortic thermodilution (CO[AORTA]), Fick principle-derived (CO[FICK]), and continuous pulmonary artery (CCO) measurements. Design: Prospective clinical study. Setting: Surgical intensive care unit of a university hospital. Participants: Twelve adult patients suffering from sepsis or septic shock. Interventions: All patients were deeply sedated and mechanically ventilated in a pressure-controlled mode. Each patient received a 7.5F five-lumen pulmonary artery catheter for the continuous measurement of cardiac output and a 4F aortic catheter with an integrated thermistor. The thermistors of the two different catheters were connected to one computer system (COLD-Z021, Pulsion Medical Systems, Munich, Germany). Whole-body oxygen consumption was measured by indirect calorimetry using a metabolic cart (Deltatrac, Datex-Engstroem, Helsinki, Finland) over a 5-minute period, at the end of which arterial and mixed venous blood gases were taken and measured by co-oximetry. During each measuring period, three bolus CO measurements were performed. A total number of 51 CO measurements was analyzed. Results: Linear regression analysis revealed the highest correlation between CO(AORTA) and CO(PA) (r = 0.98), whereas agreement between these two techniques and CCO was lower (r = 0.92 and r = 0.93). All three techniques correlated comparably with CO(FICK) (r = 0.85, r = 0.83, and r = 0.83). Conclusion: The correlations among the four CO techniques were high and similar, with CO(PA) and CO(AORTA) techniques showing the highest agreement. Because CO with similar accuracy can be obtained from transpulmonary aortic thermodilution in a less-invasive manner, it appears that the placement of a pulmonary artery catheter solely for the measurement of CO is no longer justified, unless continuous CO measurements are needed. Copyright (C) 2000 by W.B. Saunders Company.