Pancreatic duct ligation reduces lung injury following trauma and hemorrhagic shock

OBJECTIVE: To determine whether pancreatic digestive enzymes released into the ischemic gut during an episode of T/HS are involved in the generation of distant organ injury. This hypothesis was tested by examining the effect of PDL on T/HS-induced intestinal injury, lung injury, and RBC deformability. SUMMARY BACKGROUND DATA: The effect of pancreatic duct ligation (PDL) on distant organ injury following trauma/hemorrhagic shock (T/HS) was examined. PDL before T/HS decreases lung and red blood cell (RBC) injury and exerts a limited protective effect on the gut. Pancreatic proteases in the ischemic gut appear to be involved in gut-induced lung and RBC injury. Based on recent work, it appears that proinflammatory and/or toxic factors, which are generated by the ischemic intestine, play an important role in the pathogenesis of multiple organ failure. The process by which these toxic factors are generated remains unknown. Previous experimental work has clearly documented that intraluminal inhibition of pancreatic proteases decreases the degree of T/HS-induced lung injury and neutrophil activation. One possible explanation for this observation is that the toxic factors present in intestinal lymph are byproducts of interactions between pancreatic proteases and the ischemic gut. METHODS: Male Sprague-Dawley rats were subjected to a laparotomy (trauma) and 90 minutes of sham (T/SS) or T/HS with or without PDL. At 3 and 24 hours following resuscitation, animals were killed and samples of gut, lung, and blood were collected for analysis. Lung permeability, pulmonary myeloperoxidase levels, and bronchoalveolar fluid protein content were used to quantitate lung injury. Intestinal injury was determined by histologic analysis of terminal ileum (% villi injured). To assess RBC injury, RBC deformability was measured, as the RBC elongation index (RBC-EI), using a LORCA device. RESULTS: At 3 and 24 hours following resuscitation, PDL prevented shock-induced increases in lung permeability to both Evans blue dye and protein in addition to preventing an increase in pulmonary myeloperoxidase levels. T/HS-induced impairments in RBC deformability were significantly reduced at both time points in the PDL + T/HS group, but deformability did not return to T/SS levels. PDL did reduce the magnitude of ileal injury at 3 hours after T/HS, but the protective effect was lost at 24 hours after T/HS. CONCLUSIONS: PDL prior to T/HS decreases lung injury and improves RBC deformability but exerts a limited protective effect on the gut. Thus, the presence of pancreatic digestive enzymes in the ischemic gut appears to be involved in gut-induced lung and RBC injury.     

失血性休克后肠黏膜损伤与急性肺损伤相关性研究进展

背景 失血性休克后急性肺损伤(acute lung injury,ALI)的发生机制尚不完全明了,但是休克后机体失控性全身炎症反应综合征(systemic inflammatory response syndrome,SIRS)在ALI的发生发展过程中起着关键性作用,而休克后肠道黏膜损伤被认为是SIRS的始动因素. 目的 就失血性休克对肠道血供、肠黏膜屏障结构与功能的影响及失血性休克期间肠源性炎性因子的产生及其在ALI发生中的作用作一综述. 内容 讨论失血性休克后机体肠黏膜损伤对SIRS的影响及导致ALI的相关机制. 趋向 阐明失血性休克后ALI的发生机制,为失血性休克的救治提供依据.     

Leukotriene biosynthesis inhibition ameliorates acute lung injury following hemorrhagic shock in rats

Background

In cardiopulmonary bypass (CPB) patients, fibrinolysis may enhance postoperative inflammatory response. We aimed to determine whether an additional postoperative dose of antifibrinolytic tranexamic acid (TA) reduced CPB-mediated inflammatory response (IR).

Methods

We performed a randomized, double-blind, dose-dependent, parallel-groups study of elective CPB patients receiving TA. Patients were randomly assigned to either the single-dose group (40 mg/Kg TA before CPB and placebo after CPB) or the double-dose group (40 mg/Kg TA before and after CPB).

Results

160 patients were included, 80 in each group. The incident rate of IR was significantly lower in the double-dose-group TA2 (7.5% vs. 18.8% in the single-dose group TA1; P = 0.030). After adjusting for hypertension, total protamine dose and temperature after CPB, TA2 showed a lower risk of IR compared with TA1 [OR: 0.29 (95% CI: 0.10-0.83), (P = 0.013)]. Relative risk for IR was 2.5 for TA1 (95% CI: 1.02 to 6.12). The double-dose group had significantly lower chest tube bleeding at 24 hours [671 (95% CI 549-793 vs. 826 (95% CI 704-949) mL; P = 0.01 corrected-P significant] and lower D-dimer levels at 24 hours [489 (95% CI 437-540) vs. 621(95% CI: 563-679) ng/mL; P = 0.01 corrected-P significant]. TA2 required lower levels of norepinephrine at 24 h [0.06 (95% CI: 0.03-0.09) vs. 0.20(95 CI: 0.05-0.35) after adjusting for dobutamine [F = 6.6; P = 0.014 corrected-P significant]. We found a significant direct relationship between IL-6 and temperature (rho = 0.26; P < 0.01), D-dimer (rho = 0.24; P < 0.01), norepinephrine (rho = 0.33; P < 0.01), troponin I (rho = 0.37; P < 0.01), Creatine-Kinase (rho = 0.37; P < 0.01), Creatine Kinase-MB (rho = 0.33; P < 0.01) and lactic acid (rho = 0.46; P < 0.01) at ICU arrival. Two patients (1.3%) had seizure, 3 patients (1.9%) had stroke, 14 (8.8%) had acute kidney failure, 7 (4.4%) needed dialysis, 3 (1.9%) suffered myocardial infarction and 9 (5.6%) patients died. We found no significant differences between groups regarding these events.

Conclusions

Prolonged inhibition of fibrinolysis, using an additional postoperative dose of tranexamic acid reduces inflammatory response and postoperative bleeding (but not transfusion requirements) in CPB patients. A question which remains unanswered is whether the dose used was ideal in terms of safety, but not in terms of effectiveness.

Current Controlled Trials number

ISRCTN: ISRCTN84413719     

失血性休克后液体复苏的研究进展

背景 失血性休克是外伤死亡的主要原因.在重危病例的急救和围手术期的处理中,液体复苏起着关键性的治疗作用. 目的 就重度失血性休克后液体治疗方案的研究进展作一综述. 内容 除了传统的晶体液,近年来开发了诸多新品种的液体用于复苏,如丙酮酸钠溶液等.复苏方式的研究也在静脉复苏的基础上拓展到了腹腔复苏. 趋向 丙酮酸钠溶液以及腹腔复苏是近年来研究提出的新的复苏液体和复苏方案,通过已有的研究已经证实其积极的治疗作用.其应用于失血性休克的方法、时间、疗效等仍需更进一步研究.     

Advances in fluid resuscitation of hemorrhagic shock.

The optimal fluid for resuscitation in hemorrhagic shock would combine the volume expansion and oxygen-carrying capacity of blood without the need for cross-matching or the risk of disease transmission. Although the ideal fluid has yet to be discovered, current options are discussed in this review, including crystalloids, colloids, blood and blood substitutes. The future role of blood substitutes is not yet defined, but the potential advantages in trauma or elective surgery may prove to be enormous.     

Changes in lung ultrastructure following heterologous and homologous serum albumin infusion in the treatment of hemorrhagic shock.

The object of this study was to compare the ultrastructure pulmonary effects of the infusion of homologous and heterologous serum albumin solution in the treatment of hemorrhagic shock in baboons. Adult baboons subjected to hemorrhagic shock were resuscitated with either baboon serum albumin, human serum albumin, or Ringer's lactate solution. The lungs were fixed in vivo with potassium pyroantimony, a solution which produces electron dense interstitial precipitation of sodium. The lungs from animals resuscitated with baboon serum albumin showed evidence of interstitial edema, including dispersion of collagen fibers, interstitial smudging and increased interstital sodium concentrations. Similar changes were seen following human serum albumin infusions. Lung tissue from animals treated with Ringer's lactate solution showed minimal changes from normal. These results suggest that interstitial pulmonary edema develops after either homologous or heterologous serum albumin infusion in the treatment of hemorrhagic shock in baboons.     

失血性休克液体复苏实验研究进展

失血性休克的液体复苏研究虽为时较长,但至今对其研究仍非常活跃,其研究结果对临床治疗有积极的参考意义。现就近几年来关于不同复苏液对机体影响的研究、常用复苏液的种类及一些复苏方法作一介绍。     

高原失血性休克大鼠相关急性肺损伤病变及发病机制

目的探讨高原失血性休克相关急性肺损伤(acute lung injury,ALI)病变及发病机制。方法雄性Wistar大鼠72只,体重280~320g,随机分为六组:假手术组(Sham组)、休克15min组(HS15组)、休克30min组(HS30组)、休克45min组(HS45组)、休克60min组(HS60组)和休克90min组(HS90组),每组12只。建立高原大鼠失血性休克模型后,Sham组麻醉置管后不予失血,仅观察90min即刻处死,其余五组分别按照15、30、45、60和90min观察终止时间窗维持于休克状态。光镜下观察肺组织病理变化,测定肺湿/干重比(W/D)、计算肺通透指数,同时测定肺组织髓过氧化物酶(MPO)、总超氧化物歧化酶(T-SOD)的活性和丙二醛(MDA)的浓度,采用ELISA法检测肺组织中TNF-α和IL-10的浓度。采用免疫组化法检测肺组织中claudin-3和claudin-4的表达和分布。结果与Sham组比较,休克造成不同程度的肺损伤,且与休克维持时间成正比。在休克15~30min,大鼠肺组织W/D、肺通透指数、MPO、MDA、TNF-α、T-SOD和IL-10的变化甚微,在此之后,随着时间的延长,肺W/D、肺通透指数、MPO活性、MDA浓度和TNF-α浓度明显升高,同时伴随SOD活性和IL-10浓度的明显下降(P0.05)。claudin-3和claudin-4在肺上皮细胞和内皮细胞处的表达明显错位并减少(P0.05)。结论高原环境下,遭受失血性休克的大鼠血流动力学在短时间代偿后,病变呈现螺旋式恶化。且随着休克的延续,大鼠体内炎性/抗炎、氧化/抗氧化稳态失衡,导致肺上皮细胞内claudin-3和claudin-4流失,呈现出急性肺损伤的表现。     

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补液是治疗各类休克的主要手段 ,是综合治疗休克的重要组成部分。因休克发生与发展的各环节均不同程度地伴有容量的丧失。　　输入等渗溶液作为抗休克的标准疗法 ,一直沿用至今[1] 。等渗溶液即为按正常人体渗透压而配制的等渗性溶液 (或生理性溶液 ) [2 ] ,而用生理性溶液 (包括血液 )来拮抗已发生明显病理生理改变的状态 ,这是值得探讨的。按正常人配制的生理性溶液 ,理应给予正常人似乎更为合理 ,但正常人又不需要这些液体。因而 ,在对发生轻度病理生理变化时作为补充替代或作为载体 (如溶入维生素及抗生素等 )是可行的。而对已发生明显…     

Delayed immune dysfunction following hemorrhagic shock and resuscitation

Immune system function is thought to be depressed after hemorrhagic shock. We evaluated the delayed effect of hemorrhagic shock on the immune system in rats with and without spleens and investigated the effect of the colloid hetastarch on reticuloendothelial system (RES) function. There were six groups: controls (N = 30, no shock), two groups of shocked animals resuscitated with either hetastarch (HES, N = 13) or lactated Ringer's (LR, N = 13); the remaining three groups were identical except that splenectomy had been performed (N = 16, N = 14, and N = 16, respectively). One week after shock and resuscitation, all groups were challenged with intravenous Streptococcus pneumoniae; quantitative blood and tissue (liver, lung, and spleen) cultures were then obtained. There were no differences between the HES and LR groups. In nonsplenectomized animals, colony counts in the blood, liver, lung, and spleen were significantly higher in shocked animals when compared with controls. Splenectomized rats had no significant differences between shocked groups and controls. These data demonstrate that delayed immune function is depressed in nonsplenectomized rats. Splenectomy causes more severe immune dysfunction than does shock. Also, in similar animals without splenectomy, hetastarch does not appear to alter delayed RES function.     

Effect of acute hemorrhagic shock on pulmonary microvascular fluid filtration and protein permeability in sheep.

In an attempt to further delineate the pathophysiology of the shock-lung syndrome, we studied the effect of hemorrhagic shock on the pulmonary microcirculation in the adult sheep with lung lymph flow and lymph protein transport as indices of fluid filtration and vascular permeability to protein. We noted that lymph flow remained at baseline levels during shock, despite significant decreases in pulmonary artery and left atrial pressures. This suggests that microvascular pressure is maintained by an increase in pulmonary venous resistance. We demonstrated that lymph protein transport does not increase during shock, which indicates that a change in pulmonary vascular permeability to protein does not occur.     

Coronary vasomotor dysfunction following hemorrhagic shock.

Myocardial dysfunction and subendocardial ischemia have been described during hemorrhagic shock, but technical limitations have precluded the in vitro examination of coronary reactivity following hemorrhage. We tested the hypothesis that in vitro coronary artery contraction and relaxation are impaired by hemorrhagic shock (HS). HS was produced in awake rats (n = 6) 24 hr after surgery for arterial cannulation, by bleeding to a mean arterial pressure of 50 mm Hg for 2 hr followed by reinfusion of shed blood. Using a small vessel myograph, reactivity of coronary arterial ring segments from three groups of rats not undergoing HS were compared to coronaries harvested from rats after HS (Group 4). The three nonshock treatments included normal rats without pretreatment (Group 1), rats undergoing prior surgical cannulation alone (Group 2), and rats undergoing prior surgical cannulation followed by nonhypotensive hemorrhage (Group 3). Responses to 125 mM potassium (KCl) and to 10(-6) M serotonin (STN) determined smooth muscle contraction. Acetylcholine administration determined endothelium-mediated smooth muscle relaxation, whereas acetylcholine plus nitroprusside combined determined maximum smooth muscle relaxation. Rats following HS demonstrated impaired coronary arterial smooth muscle contraction to KCl when compared to normal rats, but the response to STN did not differ among groups. Maximum smooth muscle relaxation was significantly lower in rats following HS as compared to rats in Groups 1 and 2. Endothelium-dependent relaxation was significantly impaired when compared to each of the three nonshock groups. Thus, in coronary arteries isolated from neurohumoral influences, HS was associated with diminished smooth muscle contraction and relaxation as well as impaired endothelium-mediated relaxation.(ABSTRACT TRUNCATED AT 250 WORDS)