沙漠干热环境创伤失血性休克猪模型的氧代谢特点

The Characteristics of Oxygen Metabolism in Swine Model with Traumatic Hemorrhagic Shock in Dry-heat Environment of Desert

目的:探讨沙漠干热环境创伤失血性休克猪的氧代谢特点。方法:选择长白仔猪40头,随机分为四组:常温假手术组(NS)、常温创伤失血性休克组(NTHS)、干热假手术组(DS)、干热创伤失血性休克组(DTHS),分别置于相应的环境暴露3小时后,进行麻醉,动静脉置管,NTHS组和DTHS组分别自剖腹术后,行左下叶1/4肝脏切除及脾切除术后,再快速放血至平均动脉压(MAP)降至45±5mmHg;NS组和DS组仅行腹中线剖腹术。持续检测计算动脉、混合静脉氧饱和度、氧含量及氧输送(DO_2)、氧耗(VO_2)、氧摄取率(O_2ER)和动脉血乳酸(Lac)。结果:整个病程中,各组动脉氧饱和度均无显著变化。DTHS组混合静脉氧饱和度和氧含量均较相同时间点的其他各组低,DO_2、VO_2、O_2ER均显著高于常温环境组(P<0.05)。模型成功后,NTHS组和DTHS组DO_2均经历"下降-代偿-稳定"的过程,但DTHS组短暂稳定后立即呈进行性快速下降至到动物死亡。在实验过程中,DTHS组各时间点氧摄取率(O_2ER)均高于相同时间点的其他组,差异具有统计学意义(P<0.05)。NTHS组和DTHS组氧O_2ER均在休克后0 h出现明显变化,而动脉血乳酸(Lac)在休克后1.5 h才出现明显变化,但DTHS组动脉Lac增高较NTHS组升高更加明显(P<0.05),且进展迅速。结论:(1)沙漠干热环境创伤失血性休克较高的氧代谢,是机体代偿能力弱、病程变化快的重要原因之一;(2)VO_2、O_2ER等直接氧代谢指标可作为早期评估监测机体氧代谢的敏感指标;(3)血Lac浓度可能是反映干热环境创伤失血性休克严重程度的重要指标。

Objective： To establish investigate the characteristics of oxygen metabolism were compared and analyzed. Methods： 40 cases of Landrace piglets were randomly and equally divided into the normal temperature sham operation （NS） group, normal temperature traumatic hemorrhagic shock （NTHS） group, dry-heat environment sham operation （DS） group, dry-heat environment traumatic hemorrhagic shock （DTHS） group. After being exposured to each envionment for 3h respectively, the swine were anaesthetized and catheterized, and then laparotomy were performed, after laparotomy, NTHS group and DTHS group underwent left lower lobe 1/4 liver resection and splenectomy, further rapid bleeding to mean arterial pressure （MAP） was approached 45±5 mmHg to establish the trau- matic hemorrhagic shock model, NS group and DS group underwent laparotomy alone. The arterial, mixed venous oxygen saturation and oxygen content, oxygen delivery （DO2）, oxygen consumption （VO2）, oxygen uptake rate （O2ER） and arterial blood lactate （Lac） were continuously measured. Results： There was no significant change in the arterial oxygen saturation during the whole course of the disease. The mixed venous oxygen saturation and oxygen content of the DTHS group were lower than the other three groups at the same time point. After being exposured for 3 h in dry-heat environment, DO2 and VO2 were significantly higher than those in the normal temperature enviroument group （P〈0.05）. After the traumatic hemorrhagic shock model were successfully established, the DO2 of NTHS and DTHS groups underwent the process of＂falling-compensatory-stabilization＂ in each group, but in the DTHS group, after shorter stable stage, the DO2 was falling quikly to the death. O2ER was significantly higher in the DTHS group than other three groups at the same time point （P〈0.05）. In theNTHS and DTHS group, the O2ER had significant changed early in the just establishment of the shock model （0 h）. How-ever, the level of arterial blood lactate had significant changes until 1.5 hatter the establishment of shock model. And the level of lactate was higher in the DTHS group than that of the NTHS group at the same time point. Conclusion： （1） The traumatic hemorrhagic shock in desert dry-heat environment could induce higher oxygen metabolism, which is one important reasons for the weak compensatory ability and rapid deterioration of the course of disease; （2） Direct oxygen metabolism （such as VO2, O2ER） can be use as a sensitive index for early assessment of oxygen metabolism monitoring; （3） Blood Lac concentration can be used as an important index to assess the serious degree of shock of traumatic hemorrhagic shock in the dry heat environment of desert.