Puhakka K, Räsänen J, Leijala M, Peltola K
Department of Anesthesiology, University Children's Hospital, Helsinki, Finland.
J Cardiothorac Vasc Anesth. 1994 Dec;8(6):642-8. doi: 10.1016/1053-0770(94)90195-3.
Metabolic responses during recovery from cardiac operations for various congenital heart defects were studied in 30 mechanically ventilated pediatric patients in two groups: infants 1 year or less (group I) and children more than 1 year old (group II). Oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured using a pediatric metabolic monitor intermittently after induction of anesthesia, after skin closure, 2 to 4 hours postoperatively, and on the first postoperative morning in the pediatric intensive care unit. Energy expenditure and respiratory quotient were determined from respiratory gas measurements. Rectal and skin temperatures and hemodynamic variables were recorded at the same time. VO2 increased during rewarming 2 to 4 hours after the operation by 12 +/- 15% in group I and by 24 +/- 19% in group II, while rectal temperature increased by 2.0 +/- 1.2 degrees C and 1.8 +/- 1.4 degrees C, respectively. No further increase in VO2 occurred until the first postoperative morning. A hypermetabolic response was not seen in all cases despite marked thermal changes. High-dose fentanyl anesthesia partly explains the low responses. On the other hand, low cardiac output may also compromise oxygen supply. Sixty-three percent of infants were treated for cardiac failure before surgery and 75% needed inotropic support immediately after the operation. Low central venous oxyhemoglobin saturation values (ScvO2 < 60%) were observed during rewarming, indicating an increase in oxygen extraction secondary to an increased oxygen demand in the brain during recovery from anesthesia, and a low cardiac output or delayed restoration of cerebral blood flow after CPB and deep hypothermia.
对30例接受机械通气的儿科患者进行了研究，这些患者因各种先天性心脏缺陷接受心脏手术，分为两组：1岁及以下婴儿（I组）和1岁以上儿童（II组）。在麻醉诱导后、皮肤缝合后、术后2至4小时以及术后第一个早晨在儿科重症监护病房，使用儿科代谢监测仪间歇性测量氧耗量（VO2）和二氧化碳产生量（VCO2）。根据呼吸气体测量结果确定能量消耗和呼吸商。同时记录直肠温度、皮肤温度和血流动力学变量。术后2至4小时复温期间，I组VO2增加了12±15%，II组增加了24±19%，而直肠温度分别升高了2.0±1.2℃和1.8±1.4℃。直到术后第一个早晨VO2才进一步增加。尽管有明显的体温变化，但并非所有病例都出现高代谢反应。高剂量芬太尼麻醉部分解释了低反应。另一方面，低心输出量也可能影响氧供应。63%的婴儿在手术前接受过心力衰竭治疗，75%在术后立即需要使用正性肌力药物支持。复温期间观察到中心静脉氧合血红蛋白饱和度值较低（ScvO2<60%），表明在麻醉恢复过程中，由于大脑氧需求增加，氧摄取增加，以及体外循环和深度低温后心输出量低或脑血流恢复延迟。
