Englehart Michael S, Allison Carrie E, Tieu Brandon H, Kiraly Laszlo N, Underwood Samantha A, Muller Patrick J, Differding Jerome A, Sawai Rebecca S, Karahan Ayhan, Schreiber Martin A
Section of Trauma and Surgical Critical Care, Department of Surgery, Oregon Health & Science University, Portland, Oregon 97239, USA.
J Trauma. 2008 Oct;65(4):901-8; discussion 908-9. doi: 10.1097/TA.0b013e318184ba72.
Inhalational anesthetics can cause profound hemodynamic effects including decreases in systemic vascular resistance and cardiac inotropy. Although widely used in uncontrolled hemorrhagic shock (UHS), their consequences compared with other anesthetic regimens are not well-studied. Ketamine-based total intravenous anesthesia (TIVA) may produce less profound cardiovascular depression, and has been used during elective surgery but rarely during traumatic shock. The purpose of this study was to compare the effects of isoflurane (ISO) and TIVA regimens in a swine grade V liver injury model. We hypothesized that TIVA would result in less hypotension and dysfunctional inflammation than ISO.
Twenty swine were randomized blindly to receive either 1% to 3% ISO, or intravenous ketamine, midazolam, and buprenorphine for maintenance anesthesia. Six animals acted as controls. After sedation and intubation, randomized anesthesia was initiated and monitored by an independent animal technician. Invasive lines were placed followed by celiotomy and splenectomy. Baseline mean arterial pressure (MAP) was documented and a grade V liver injury created. After 30 minutes of UHS, animals were resuscitated with 8 mL of Ringer's lactate per milliliter blood loss at 165 mL/min. MAP and tissue oxygen saturation (StO2) were continuously recorded. The animals were sacrificed 120 minutes after injury and lung tissue was harvested. Serum cytokines (interleukin-6 [IL-6], IL-8, and tumor necrosis factor-alpha [TNF-alpha]) were quantified with enzyme-linked immunosorbent assay. Lung cytokine mRNA levels were quantified with real time reverse transcriptase polymerase chain reaction.
Animal weight, liver injury pattern, and blood loss were similar (p > 0.1). The ISO group had a lower MAP at baseline (p = 0.02), at injury (p = 0.004), and study completion (p = 0.001). After resuscitation, MAP decreased in the ISO group but remained stable in the TIVA group. StO2 was significantly higher in the TIVA group immediately after injury (p = 0.004), but similar between groups throughout the remainder of the study. Animals who received TIVA trended toward higher levels of lactate and lower pH throughout the study, reaching significance at 30 minutes postinjury (p = 0.037 and 0.043). Inflammatory cytokine (IL-6, IL-8, and TNF-alpha) production did not differ between groups, however TNF-alpha mRNA production was significantly lower in the TIVA group (p = 0.04).
Although a TIVA regimen produced less pronounced hypotension in a swine model of UHS than did ISO, end-organ perfusion with TIVA appeared to be equivalent or inferior to ISO. In circumstances of limited resources, such as those experienced by forward Army surgical teams, a ketamine-based TIVA regimen may be an option for use in UHS.
吸入性麻醉剂可引起显著的血流动力学效应，包括全身血管阻力降低和心肌收缩力下降。尽管其在失血性休克（UHS）中广泛应用，但与其他麻醉方案相比，其后果尚未得到充分研究。氯胺酮全静脉麻醉（TIVA）可能产生较轻微的心血管抑制，已用于择期手术，但在创伤性休克中很少使用。本研究的目的是比较异氟烷（ISO）和TIVA方案在猪V级肝损伤模型中的效果。我们假设TIVA导致的低血压和炎症功能障碍比ISO少。
20头猪被随机分为两组，一组接受1%至3%的ISO，另一组接受静脉注射氯胺酮、咪达唑仑和丁丙诺啡进行维持麻醉。6只动物作为对照。在镇静和插管后，由独立的动物技术员开始并监测随机麻醉。放置有创监测线，随后进行剖腹术和脾切除术。记录基线平均动脉压（MAP），并造成V级肝损伤。在UHS 30分钟后，以每失血1毫升输注8毫升乳酸林格液的速度，以165毫升/分钟的速度对动物进行复苏。连续记录MAP和组织氧饱和度（StO2）。在损伤后120分钟处死动物，采集肺组织。用酶联免疫吸附测定法定量血清细胞因子（白细胞介素-6 [IL-6]、IL-8和肿瘤坏死因子-α [TNF-α]）。用实时逆转录聚合酶链反应法定量肺细胞因子mRNA水平。
动物体重、肝损伤模式和失血量相似（p>0.1）。ISO组在基线时（p = 0.02）、损伤时（p = 0.004）和研究结束时（p = 0.001）的MAP较低。复苏后，ISO组的MAP下降，而TIVA组保持稳定。损伤后立即，TIVA组的StO2显著更高（p = 0.004），但在研究的其余时间两组相似。在整个研究过程中，接受TIVA的动物乳酸水平有升高趋势，pH值有降低趋势，在损伤后30分钟达到显著差异（p = 0.037和0.043）。两组间炎症细胞因子（IL-6、IL-8和TNF-α）的产生没有差异，然而TIVA组的TNF-α mRNA产生显著较低（p = 0.04）。
尽管在UHS猪模型中，TIVA方案产生的低血压比ISO轻，但TIVA的终末器官灌注似乎与ISO相当或更差。在资源有限的情况下，如前方陆军外科医疗队所面临的情况，基于氯胺酮的TIVA方案可能是UHS中使用的一种选择。
