Cardiac output measurement by transpulmonary versus conventional thermodilution technique in intensive care patients after coronary artery bypass grafting

Abstract

Objective: The aim of the present study was to evaluate the correlation, accuracy, and precision of transpulmonary thermodilution cardiac output (CO) measurement. For this purpose, this technique was compared with the clinical gold standard, the CO measurement by pulmonary artery catheter in patients after coronary artery bypass grafting (CABG).

Design: A prospective clinical study.

Setting: A university medical center.

Participants: Seventy-five patients in an intensive care unit (ICU) after CABG.

Interventions: Standard (SCO) and transpulmonary thermodilution CO measurement (TPCO) measurements were simultaneously performed in triplicate by central venous injection of cooled saline solution. All variables were recorded at five different time points of measurement during weaning from mechanical ventilation.

Measurements and main results: CO measurements yielded 375 data pairs. SCO ranged from 2.0 to 10.2 L/min, and TPCO from 1.3 to 10.6 L/min. During the entire observation period, TPCO measurements tended to yield relatively high values, whereas SCO measurements resulted in lower values. Correlation between TPCO and SCO measurements was significant (r = 0.73; p < 0.05), accompanied by an accuracy with a bias of 0.456 L/min (7.3%) and a precision of 1.156 L/min (18.5%).

Conclusion: In most patients, TPCO measurement will not replace the conventional technique by pulmonary artery catheter, but in some patients it offers an attractive, reliable, and safe method to determine CO.