Comparison between methods for measuring oxygen consumption in patients after cardiac surgery: the reverse Fick method versus indirect calorimetry / 中华麻醉学杂志

ABSTRACT

Objective The purpose of this study was to compare the whole body oxygen consumption determined by reverse Pick method and indirect calorimetry in mechanically ventilated patients after cardiac surgery. Methods Eight NYHA II-III patients (2 male, 6 female ) aged 43-68 yr, undergoing aortic valve replacement, mitral valve replacement or coronary artery bypass grafting(CABG) under CPB. Swan-Ganz catheter was placed via right internal jugular vein. Anesthesia and operation were carried out uneventfully. The patients were placed in ICU after operation and mechanical ventilation was continued (IPPV, FiO2 40%-50% , PEEP 5 cm H2O) . PaCO2 was maintained at 35-45 mm Hg by adjustment of VT and RR. T was maintained at 37.0 1C+0.5C .Total body oxygen consumption was measured by the reverse Fick method and indirect calorimetry simultaneously at 2h and 6h after operation. Results The mean oxygen consumption (VO2 ) value determined by indirect calorimetry( 162 + 30 mlmin-1m-2) was significantly higher than that determined by reverse Fick method (127+23 ml min-1m-2)(P