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

Objective: The authors compared four clinical techniques of measuring cardi ac 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 pul monary 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 wa s 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-oximetr y. 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 betwee n CO(AORTA) and CO(PA) (r = 0.98), whereas agreement between these two tech niques and CCO was lower (r = 0.92 and r = 0.93). All three techniques corr elated 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 sim ilar, with CO(PA) and CO(AORTA) techniques showing the highest agreement. B ecause 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 j ustified, unless continuous CO measurements are needed. Copyright (C) 2000 by W.B. Saunders Company.