The Evaluation of Hypoxic and Hypercapnic Ventilatory Depression Induced by Narcotic and Non-narcotic Analgesics

循环和呼吸对低氧或高碳酸血症的反应被认为是维持生命的简单反应。但有时，低氧或高碳酸血症会导致一些患者出现严重的呼吸抑制。因此，我们评估了麻醉性和非麻醉性镇痛剂对低氧或高碳酸血症呼吸性抑制的影响。实验在5只体重2.2~2.7 kg的兔身上进行。兔静脉注射戊巴比妥钠50 mg/kg麻醉。气管切开后，用50%氧气、50%氮气和1~2%氟烷对动物进行插管和机械通气。将激光血流仪和组织氧饱和度监测仪两个小传感器安装在动物小腹侧切开后的横隔肌表面。分别在自主呼吸、控制呼吸和吸气阻力负荷条件下测定膈血流量和膈肌组织氧饱和度。测量后计算隔膜耗氧量(Vo_2di)。自主呼吸2.08ml/min/100g，控制通气量1.98ml/min/100g，吸气阻力负荷2.87ml/min/100g。因此，吸气阻力负荷下的Vo_2di高于其他三种负荷。以上结果表明，我们通过测量组织氧饱和度和组织血流量来评价组织氧代谢的方法对于分析镇痛剂或止痛方法对低氧和高碳酸血症的呼吸和循环反应的影响是有用的。

Circulatory and respiratory responses to hypoxia or hypercapnia are thought to be compenstory responses to support life. But on occasion, hypoxia or hypercapnia induce severe respiratory depression in some patients. Therefore we evaluated the effect on hypoxic or hypercapnic ventilatory depression of narcotic and non-narcotic analgesics. Experiments was performed on 5 rabbits weighing 2.2kg to 2.7kg. Rabbits were anesthetized with pentobarbital 50mg/kg intravenously. After tracheostomy, animals were intubated and mechanically ventilated with 50% oxygen, 50% nitrogen, and 1-2% halothane. Two small sensors of laser flow meter and tissue oxygen saturation monitor were attached on diaphragma muscle surface of the animals after lateral small laparotomy. Diaphragmatic blood flow and diaphragmatic tissue oxygen saturation were measured under spontaneous respiration, controlled ventilation and inspiratory resistive loading. After the measurement was performed diaphragmatic oxygen consumption (Vo_2di) were computed. Obtained Vo_2di were followed ; spontaneous respiration : 2.08 ml/min/100g, controlled ventilation : 1.98 ml/min/100g, inspiratory resistive loading : 2.87 ml/min/100g. Consequently, Vo_2di under inspiratory resistive loading showed higher than the others. Above them, we concluded that our method evaluating the tissue oxygen metabolism by measuring both the tissue oxygen saturation and tissue blood flow was useful to analyze the effect of the analgesics or the analgesic method on hypoxic and hypercapnic ventilatory and circulatory responses.