失血性休克延迟复苏对犬血流动力学和内脏灌流的影响

目的 研究延迟补液对失血性休克血流动力学和内脏灌流的影响.方法 Beagle犬14只,先期无菌手术行颈动脉、静脉置管,24 h后从颈动脉放血造成失血性休克,总失血量为全身血容量的42%.随机(随机数字法)分为延迟补液组(n=8)和立即补液组(n=6).失血后第1个24小时延迟补液组无治疗,立即补液组静脉输入3倍失血量的葡萄糖-电解质溶液.失血后24 h起2组犬均实施静脉补液.测定犬失血前和失血后2,4,8,24,48和72 h非麻醉状态下的循环血流动力学和肠道组织灌流指标,并记录失血后72 h病死率.结果 与失血前相比,两组犬平均动脉压、心排指数、全身血管阻力指数、左室内压最大变化速率、尿量以及肠黏膜血流量在失血后均大幅降低(P＜0.05),而全身血管阻力显著升高.从失血后4 h起,立即补液组上述指标逐渐恢复,失血后72 h除全身血管阻力和肠黏膜血流量外均恢复至失血前水平.延迟补液组上述指标则持续恶化,8例中有5例无尿,失血后4 h起各时间点平均动脉压、心输出量、尿量以及肠黏膜血流量均显著低于立即补液组(P＜0.05).失血后72 h病死率延迟补液组为5/8(62.5%),立即补液组为0.结论 延迟补液显著加重失血性休克犬血流动力学紊乱、延迟脏器组织灌流恢复,增加早期病死率.

The effects of delayed fluid resuscitation on hemodynamics and visceral perfusion in dogs with hemorrhagic shock

Objective To investigate the effects of delayed fluid resuscitation on hemodynamics and visceral perfusion in dogs with hemorrhagic shock. Methods Fourteen Beagle dogs were prepared for cannulation of carotid artery and jugular vein, and 24 hours later they were subjected to hemorrhagic shock with about 42% of total blood volume exsanguinated. Animals were divided into delayed resuscitation group ( DR group, n = 8) and immediate resuscitation group ( IR group, n = 6) . In the first 24 hours after hemorrhage, dogs in Dr group were given no fluid resuscitation, while those in IR group were immediately given resuscitation with intra-venous glucose-electrolyte solution, of which the volume was three times that of blood loss. In the second 24 hours, all animals had intra-venous fluid resuscitation. The variables of hemodynamics and visceral perfusion were determined before hemorrhage and 2, 4, 8, 24, 48 and 72 hours after hemorrhage under conscious state of dogs. Results After hemorrhage, the mean arterial pressure,cardiac output index, max of left ventricular contractility, blood flow of intestinal mucosa and urinary output greatly decreased and systemic vascular resistance obviously increased in each group compared with those before hemorrhage ( P ＜ 0.05 ) . From 4 hours after hemorrhage, the above measurements of dogs in IR group gradually resumed and reach Oh levels in 72 hours after hemorrhage except systemic vascular resistance index and intestinal blood flow. Whereas those measurements in dogs of DR group kept on worsening, and the levels of mean arterial pressure, cardiac output index, intestinal blood flow and urinary output were significantly lower than those in dogs of IR group ( P ＜ 0. 05 ) . Over 72 hours, five of eight dogs died with anuria in DR, and no animals died in IR group. Conclusion The findings indicate that delayed fluid resuscitation deteriorates hemodynamics, handicapping the restoration of visceral perfusion and increasing mortality in dogs with hemorrhagic shock.