The Impact of Intra-aortic Balloon Pumping on Cardiac Output Determination by Pulmonary Arterial and Transpulmonary Thermodilution in Pigs

Objective: The aim of this study was to evaluate the impact of intra-aortic balloon pumping (IABP) on the comparison of simultaneous measurements of cardiac output via pulmonary arterial and transpulmonary thermodilution (PiCCO; Pulsion Medical Systems, Munich, Germany).Design: Prospective.Settings: University research laboratory.Participants: The data were derived from 9 anesthetized (fentanyl, propofol, flunitrazepam, rocuronium) and ventilated pigs.Interventions: A thermodilution catheter was inserted into the pulmonary artery, a PiCCO catheter into the abdominal aorta through the right femoral artery, epicardial atrial pacing wires through a thoracotomy, and a balloon catheter for counterpulsation into the descending thoracic aorta through the left femoral artery. Cardiac output was varied over a wide range by cardiac pacing between 80 and 150/min in steps of 10/min and was measured without and during IABP at an assist frequency of 1:1.Measurements and Main Results: A total of 236 paired cardiac output measurements were carried out in a range of cardiac output between 1.4 to 4.9 L/min. A close correlation was found between transpulmonary and pulmonary arterial thermodilution both without and during IABP (r = 0.94 and 0.93, respectively) and a good agreement of both methods (bias of 0.30 and 0.26 L/min, respectively; precision 0.47 and 0.52 L/min, respectively).Conclusions: Transpulmonary thermodilution is suitable for cardiac output measurement during IABP. Hence, in critically ill patients with cardiac pump failure, blood flow may be determined as accurately with the less-invasive transpulmonary method as with the traditional pulmonary arterial thermodilution one.