缺氧复合氰化钠中毒对家兔动脉血气成分的影响

Effects of combined hypoxia and NaCN intoxication on the arterial blood gases in rabbits

目的探讨缺氧复合氰化钠(NaCN)中毒对家兔动脉血气成分的影响。方法以人工低压氧舱模拟4 000m高原缺氧环境。20只家兔随机均分为4组:高原高剂量组(2mg/kg),高原低剂量组(1.5mg/kg),平原高剂量组(2mg/kg),平原低剂量组(1.5mg/kg)。高原组动物在低压氧舱内预处理72h后进行实验。以戊巴比妥钠(30mg/kg)麻醉动物后进行股动脉插管,腹腔注射NaCN毒剂(2mg/kg或1.5mg/kg)。分别于NaCN中毒前10min(-10min),中毒后5、10、15、20、30、60、120和180min采血测定动脉血气变化。结果高原缺氧72h后动物的动脉血氧分压(PaO2)和二氧化碳分压(PaCO2)明显降低,与平原组中毒前比较差异有统计学意义(P<0.01),而pH值和碳酸氢根(HCO-3)浓度与平原组中毒前比较,差异无统计学意义(P>0.05)。各组NaCN中毒后动脉血pH值先升高后降低,PaO2显著升高,PaCO2和HCO-3浓度显著降低。结论NaCN中毒后酸碱平衡紊乱,早期表现为呼吸性碱中毒,后期表现为代谢性酸中毒。

Objective To investigate the effects of combined hypoxia and sodium cyanide （NaCN） intoxication on arterial blood gases in rabbits. Methods An artificial hypobaric hypoxia chamber was employed to simulate the environment of 4 000m altitude. Twenty rabbits were randomly divided into 4 groups： hypoxia high dose group （2mg/kg）, hypoxia low dose group （1.5mg/kg）, normoxia high dose group （2mg/kg） and normoxia low dose group （1. 5mg/kg）. Animals in the frontal two groups were pretreated for 72h in the chamber. The rabbits in each group were anesthetized with pentobarbital sodium （30mg/kg） and a femoral arterial cannulation was operated for the later sampling. The animals in each group were randomly administrated intra peritoncously with NaCN at the dosages of 2mg/kg or 1.5mg/kg, respectively. Arterial blood gas was determined before poisoning and at the time points of 5, 10, 15, 20, 30, 60, 120 and 180min after NaCN injection. Results The values of PaO2 and PaCO2 in the arterial blood were significantly decreased by 72h hypoxia. There existed a significant difference between the hypoxia groups and the normoxia groups （P〈0. 01）, while the arterial blood pH and the concentration of HCO^-3 showed no statistically significant changes. After NaCN poisoning, arterial blood pH was increased immediately. It was then decreased gradually. At the same time, arterial blood PaO2 rose significantly while PaCOz and the concentration of HCO^-3 dedined significantly. Conclusion After poisoning, respiratory alkalosis appears immediately, and then metabolic acidosis appears gradually.