Vrettos T, Poimenidi E, Athanasopoulos P, Balasis S, Karagiorgos N, Siklis T, Gatzounis G, Fligkou F
Department of Anesthesiology and Critical Care Medicine, University Hospital of Patras, Patras, Greece.
Eur Rev Med Pharmacol Sci. 2016;20(4):620-30.
Optimal hemodynamic resuscitation strategy of the trauma patient with uncontrolled hemorrhage and severe head injury in the pre-hospital setting remains a special challenge. Permissive hypotension prior to definite surgical haemostasis promotes coagulation, decreases blood loss and favors survival. However, hypotension is associated with poor outcome in severe head injury. The purpose of this experimental animal study was to assess the impact of permissive hypotension on survival, hemodynamic profile and brain oxygenation parameters before and/or after definite surgical haemostasis.
Six-week-old pigs (n=12) underwent general anesthesia and brain injury was produced by the fluid percussion model. Animals were instrumented to measure hemodynamic parameters and cerebral blood flow. All animals (n=12) were subjected to laparotomy and a surgical knot was placed through the abdominal aorta wall. Uncontrolled hemorrhage was simulated by pulling out the intentionally left protruding free ends of the suture (goal MAP=30 mmHg). Animals were randomly divided into two groups; group A (n=6) was subjected to aggressive fluid resuscitation (goal SAP >80 mmHg) and group B (n=6) was left hypotensive (permissive hypotension). Animals who survived one hour of hypotensive shock underwent definite surgical haemostasis and were resuscitated for one hour. We measured survival, hemodynamic and brain oxygenation parameters at different time points before and after surgical haemostasis.
All animals from Group A and 50% from Group B died before surgical haemostasis. In surviving animals (Group B, 50%, p=0.033), MAP, CO, rCBF, SjO2 and AVDO2 were restored to pre-procedural levels.
Permissive hypotension by delaying fluid resuscitation up to definite surgical haemostasis improves survival, hemodynamics and allows restoration of cerebral oxygenation in severe head injury.
在院前环境中，针对伴有无法控制的出血和严重颅脑损伤的创伤患者，最佳的血流动力学复苏策略仍然是一项特殊挑战。在确定性手术止血前采用允许性低血压可促进凝血、减少失血并有利于存活。然而，低血压与严重颅脑损伤的不良预后相关。本实验性动物研究的目的是评估允许性低血压对确定性手术止血前后的存活、血流动力学特征和脑氧合参数的影响。
六周龄猪（n = 12）接受全身麻醉，采用液压冲击模型造成脑损伤。对动物进行仪器安装以测量血流动力学参数和脑血流量。所有动物（n = 12）均接受剖腹手术，并通过腹主动脉壁放置一个手术结。通过拉出故意留在外面的缝线自由端模拟无法控制的出血（目标平均动脉压 = 30 mmHg）。动物被随机分为两组；A组（n = 6）接受积极的液体复苏（目标收缩压>80 mmHg），B组（n = 6）维持低血压状态（允许性低血压）。在经历一小时低血压休克后存活的动物接受确定性手术止血，并复苏一小时。我们在手术止血前后的不同时间点测量存活、血流动力学和脑氧合参数。
A组所有动物和B组50%的动物在手术止血前死亡。在存活的动物中（B组，50%，p = 0.033），平均动脉压、心输出量、相对脑血流量、颈静脉血氧饱和度和动静脉氧含量差恢复到术前水平。
通过延迟液体复苏直至确定性手术止血来实施允许性低血压，可提高严重颅脑损伤患者的存活率、改善血流动力学，并使脑氧合得以恢复。
