Bacher A, Mayer N, Mittlboeck M, Zadrobilek E
Department of Anaesthesiology and General Intensive Care, University of Vienna, Austria.
Acta Anaesthesiol Scand. 1996 Sep;40(8 Pt 1):869-75. doi: 10.1111/j.1399-6576.1996.tb04552.x.
Anaesthesia induction and deep anaesthesia may be accompanied by a considerable haemodynamic depression, especially in patients suffering from cardiovascular diseases. A decrease in cardiac index (CI) leads to a concomitant decrease in oxygen transport (DO2I). We examined whether these changes in haemodynamic performance and oxygenation can cause an oxygen debt and anaerobic metabolism.
DO2I, oxygen uptake (VO2I), oxygen extraction ratio (O2ER) and plasma lactate were analysed at 9 pre-defined study stages during anesthesia induction, deep anaesthesia prior to surgery and during surgery in 65 patients (ASA 3) undergoing elective vascular surgery. Polynomials of increasing order were fitted to the data for the determination of the critical value of oxygen transport from the inflection point of the regression curve.
CI, heart rate, mean arterial pressure and DO2I decreased significantly after anaesthesia induction and during deep anaesthesia. VO2I showed an almost parallel change during the study period so that O2ER remained nearly constant. Plasma lactate did not exceed the physiological range in any patient and a critical value of DO2I could not be detected because a linear regression always provided the best fit for the data.
We conclude that in patients suffering from a substantial cardiovascular disease systemic oxygenation is not impaired by considerable haemodynamic changes induced by general anaesthesia. This fact can be explained by the parallel decrease in oxygen demand, expressed by the decrease in VO2I.
麻醉诱导和深度麻醉可能伴有显著的血流动力学抑制，尤其是在患有心血管疾病的患者中。心脏指数（CI）降低会导致氧输送（DO2I）随之下降。我们研究了这些血流动力学表现和氧合的变化是否会导致氧债和无氧代谢。
对65例接受择期血管手术的患者（ASA 3级）在麻醉诱导、手术前深度麻醉和手术期间的9个预定义研究阶段分析DO2I、氧摄取（VO2I）、氧摄取率（O2ER）和血浆乳酸。将递增阶数的多项式拟合到数据中，以从回归曲线的拐点确定氧输送的临界值。
麻醉诱导后和深度麻醉期间，CI、心率、平均动脉压和DO2I显著下降。VO2I在研究期间显示出几乎平行的变化，因此O2ER几乎保持恒定。在任何患者中，血浆乳酸均未超过生理范围，且由于线性回归始终能为数据提供最佳拟合，因此未检测到DO2I的临界值。
我们得出结论，在患有严重心血管疾病的患者中，全身氧合不会因全身麻醉引起的显著血流动力学变化而受损。这一事实可以通过VO2I下降所表示的氧需求平行下降来解释。
