Oudemans-van Straaten H M, Scheffer G J, Eysman L, Wildevuur C R
Department of Anaesthesiology, Academical Hospital, Free University, Amsterdam, The Netherlands.
Intensive Care Med. 1993;19(2):105-10. doi: 10.1007/BF01708371.
To determine whether intra-pulmonary oxygen consumption or whole body oxygen consumption is the main determinant of the hypermetabolic response after cardiopulmonary bypass. Secondly, which method of measuring oxygen consumption best quantifies this hyperdynamic response.
We measured oxygen consumption by analysing respiratory gas (VO2-gas), carbon dioxide excretion (VCO2), and respiratory exchange ratio (RER = VCO2/VO2), and calculated oxygen consumption using the Fick-method (VO2-Fick) and intra-pulmonary oxygen consumption (VO2-gas - VO2-Fick) in patients at fixed times before and after elective cardiac surgery. Next, comparisons were made between methods and also between measurements at different times before and after bypass.
University hospital.
10 elective cardiac surgical patients.
None.
VO2-gas, VCO2 and RER were measured with an open circuit indirect calorimeter. VO2-Fick was calculated: VO2-Fick = cardiac index x (arterial - mixed venous oxygen content). Intrapulmonary oxygen consumption was calculated as the difference between VO2-gas and VO2-Fick. Both VO2-gas and VO2-Fick were about 20% higher after bypass than after induction of anaesthesia. Absolute values of VO2-gas were about 30% higher than VO2-Fick. Intra-pulmonary oxygen consumption accounted for 32% of whole body oxygen consumption after induction of anaesthesia and did not increase after bypass.
Whole body oxygen consumption and not intra-pulmonary oxygen consumption is the main determinant of the hypermetabolic response after bypass. Increased intra-pulmonary oxygen consumption is not related to bypass. VO2-gas best quantifies this hypermetabolic response directly after bypass, and not VO2-Fick, VCO2 or intra-pulmonary oxygen consumption, since VO2-Fick excludes intra-pulmonary oxygen consumption and VCO2 does not reflect metabolism directly after bypass.
确定肺内氧消耗或全身氧消耗是否是体外循环后高代谢反应的主要决定因素。其次，哪种测量氧消耗的方法能最好地量化这种高动力反应。
我们通过分析呼吸气体（VO2-气体法）、二氧化碳排出量（VCO2）和呼吸交换率（RER = VCO2/VO2）来测量氧消耗，并在择期心脏手术前后的固定时间，使用Fick法（VO2-Fick）和肺内氧消耗（VO2-气体法 - VO2-Fick）计算患者的氧消耗。接下来，对不同方法之间以及体外循环前后不同时间的测量结果进行比较。
大学医院。
10例择期心脏手术患者。
无。
使用开路间接热量计测量VO2-气体法、VCO2和RER。计算VO2-Fick：VO2-Fick = 心脏指数×（动脉 - 混合静脉血氧含量）。肺内氧消耗计算为VO2-气体法与VO2-Fick之间的差值。体外循环后VO2-气体法和VO2-Fick均比麻醉诱导后高约20%。VO2-气体法的绝对值比VO2-Fick高约30%。麻醉诱导后肺内氧消耗占全身氧消耗的32%，体外循环后未增加。
全身氧消耗而非肺内氧消耗是体外循环后高代谢反应的主要决定因素。肺内氧消耗增加与体外循环无关。VO2-气体法能在体外循环后直接最好地量化这种高代谢反应，而非VO2-Fick、VCO2或肺内氧消耗，因为VO2-Fick排除了肺内氧消耗，而VCO2不能直接反映体外循环后的代谢情况。
