Hemorrhagic shock and resuscitation-mediated tissue water distribution is normalized by adjunctive peritoneal resuscitation

BACKGROUND: Adjunctive direct peritoneal resuscitation (DPR) from hemorrhagic shock (HS) improves intestinal blood flow and abrogates postresuscitation edema. HS causes water shifts as a result of sodium redistribution and changes in transcapillary Starling forces. Conventional resuscitation (CR) with crystalloid aggravates water sequestration. We examined the compartment pattern of organ tissue water after HS and CR, and modulation of tissue edema by adjunctive DPR. STUDY DESIGN: Rats were hemorrhaged (40% mean arterial pressure for 60 minutes) and assigned to four groups (n = 7): sham, no HS; HS no resuscitation; HS+CR (shed blood plus 2 volumes Ringer's lactate); and HS+CR+DPR (20 mL clinical intraperitoneal (IP) dialysis fluid). Isotopic markers determined equilibrium distribution volumes [V(D)] in gut, liver, lung, and muscle by quantitative autoradiography (2-hour postresuscitation). Total tissue water (TTW) was determined by wet-dry weights. Extracellular water was measured from (14)C-mannitol V(D), and intravascular volume (IVV) from (131)I-labeled IgG V(D). Cellular and interstitial water volumes were calculated. RESULTS: HS alone decreased IVV in all tissues and TTW in gut, lung, and muscle, but not liver, compared with shams. IVV remained decreased with all resuscitations despite restoration of central hemodynamics. CR caused interstitial edema in gut, liver, and muscle, and cellular edema in lung. DPR reduced (liver, muscle) or prevented (gut, lung) these volume shifts. CONCLUSIONS: HS decreases IVV. HS-induced water shifts are organ-specific and prominent in gut, lung, and muscle. CR restores central hemodynamics, does not restore IVV, and alters organ-specific TTW distribution. Adjunctive DPR with IP dialysis fluid normalizes TTW and water compartment distribution and prevents edema. Combined effect of DPR and intravascular fluid replacement appears to prevent global tissue edema and improve outcomes from HS.     

Peritoneal resuscitation

BACKGROUND: After resuscitation from hemorrhagic shock, intestinal microvessels constrict leading to impaired mucosal blood flow. This occurs despite restoration of central hemodynamics. We review studies on the use of peritoneal dialysis fluid as an adjunct treatment in amelioration of this gut hypoperfusion. METHODS: Using in vivo microscopy of the intestinal microcirculation, the effects of topically applied dextrose-based peritoneal dialysis fluid was measured. In other words, animal experiments, the survival benefits, the morbidity, blood flow distribution, and the postresuscitation inflammatory response to direct peritoneal resuscitation (DPR) were determined. RESULTS: Simulated DPR caused a dramatic vasodilation compared with a progressive vasoconstriction when used during conventional resuscitation (CR) from hemorrhagic shock. It also reversed established vasoconstriction 2 and 4 hours after CR. In CR animals, there was a 40% mortality compared with 100% survival in DPR animals. DPR resulted in a downregulation of the gut-associated proinflammatory response noted after CR and similarly prevented edema formation. CONCLUSION: DPR enhances organ blood flow to organs incited in the pathogenesis of multiple organ failure and improves survival after severe hemorrhage and CR.     

Direct peritoneal resuscitation as adjunct to conventional resuscitation from hemorrhagic shock: a better outcome

BACKGROUND: Conventional resuscitation (CR) from hemorrhagic shock often culminates in multisystem organ failure and death, commonly attributed to a progressive splanchnic vasoconstriction and hypoperfusion, a gut-derived systemic inflammatory response (SIR), and fluid sequestration. Direct peritoneal resuscitation (DPR) produces a sustained state of tissue hyperperfusion in splanchnic and distant organs. In this study we evaluated the therapeutic potential of DPR on the SIR and fluid sequestration as parameters of treatment outcome. METHODS: Anesthetized nonheparinized rats continuously monitored for hemodynamics were bled to 40% of mean arterial pressure for 60 minutes. Animals were randomized for CR or CR plus DPR under aseptic conditions. Sham nonhemorrhaged rats served as control. Qualitatively, animals were blindly observed for body weight, illness score, or death for 72 hours. Tissues were harvested from survivors, and SIR was measured by interleukin (IL)-6, IL-10, tumor necrosis factor-alpha, and enzyme-linked immunosorbent assay, and fluid sequestration was measured by dry weight/wet weight ratio (DW/WW). RESULTS: Adjunct DPR caused a marked increase (P >.01 by analysis of variance) in the immunoregulator IL-10 in the liver (10,990 +/- 1,470 pg/g) and gut (1815 +/- 640 pg/g), compared to CR rats (6450 +/- 1000 pg/g and 1555 +/- 590, respectively), which is associated with down-regulation of IL-6 and tumor necrosis factor-alpha in liver and gut, from 57 +/- 4 and 20 +/- 3 pg/g, respectively, to 42 +/- 4 and 9 +/- 2 pg/g in DPR-treated animals. CR animals had a lower DW/WW ratio in liver (-36%), spleen (-22%), and lung (-24%) compared to DPR (P <.05), where the DW/WW ratio did not differ from control animals. This fluid sequestration is consistent with a 12% and 5% gain in prehemorrhage body weight at 24 and 72 hours after treatment in the CR animals. Thirty percent of CR animals died within 24 hours, and survivors were squeaking, cold, and pale in eyes and ears and oliguric despite features of fluid overload. In comparison, DPR animals exhibited normal appearance by 24 hours and demonstrated a 100% survival at 72 hours. CONCLUSIONS: This study demonstrates that DPR as adjunct to CR has beneficial effects on the pathophysiology of resuscitated hemorrhagic shock. In addition to restoration of tissue perfusion, DPR has immunomodulation and anti-fluid sequestration effects. These modulations result in improved outcome.     

Cellular edema regulates tissue capillary perfusion after hemorrhage resuscitation

BACKGROUND: Hemorrhage-induced activation of endothelial cell Na+/H+ -exchanger results in cellular swelling, which physically impedes capillary filling and compromises gut perfusion. We hypothesized that correction of the vascular volume deficit by conventional resuscitation does not improve capillary filling unless cellular swelling is prevented. Also, we hypothesized that adjunctive direct peritoneal resuscitation (DPR) with topical peritoneal dialysis solution (Delflex; Fresenius USA, Inc., Ogden, Ut) enhances capillary filling and gut perfusion by mechanisms that are independent of the Na+/H+ function. METHODS: In vivo intravital videomicroscopy and Doppler velocimeter were used by us to measure microvascular diameter and flow, capillary filling (index of functional capillary density, FCD), and endothelial cell function in the terminal ileum of anesthetized rats. Rats were bled to 50% mean arterial pressure for 60 min and resuscitated with the shed blood plus 2 volumes of saline (conventional resuscitation). Prevention of endothelial cell swelling was achieved with topical amiloride (specific Na+/H+ inhibitor) in the tissue bath before hemorrhage or simultaneously with conventional resuscitation. DPR was simulated by instillation of Delflex in the tissue bath as adjunctive to conventional resuscitation. Sham no hemorrhage group and a simulated DPR group that received topical amiloride treatment served as controls. RESULTS: Conventional resuscitation from hemorrhagic shock restored and maintained central hemodynamics but caused progressive and persistent intestinal vasoconstriction and hypoperfusion associated with low FCD and endothelial cell dysfunction. Prevention of endothelial cell swelling when combined with conventional resuscitation, preserved endothelial cell function, and restored local intestinal microvascular variables to near-prehemorrhage levels. Simulated adjunctive DPR produced rapid, sustained, and generalized vasodilation associated with restoration of endothelial cell function, and maximum recruitment of FCD independent of the Na+/H+ -exchanger function. CONCLUSIONS: Paradoxical endothelial cell swelling occurs early during hemorrhagic shock because of activation of the Na+/H+ exchanger. This cellular edema, which is not resolved by correction of the vascular volume deficit, explains the persistent postresuscitation endothelial cell dysfunction and gut hypoperfusion. Simulated adjunctive DPR in this study reversed endothelial cell swelling and enhanced gut perfusion by mechanisms that are independent of the Na+/H+ exchanger activity.     

不同液体腹腔复苏对失血性休克大鼠肠道炎性反应的影响

目的 探讨不同液体腹腔复苏对失血性休克大鼠肠道炎性反应的影响.方法 清洁级健康雄性SD大鼠50只,体重200～250 g,随机分为5组(n=10):假手术组(S组)仅行手术操作,不制备失血性休克模型;采用股动脉置管放血法制备大鼠失血性休克模型,常规静脉复苏组(CVR组)失血性休克1 h后,经左侧股静脉匀速回输自体血及相当于2倍失血量的生理盐水行常规静脉复苏;不同液体腹腔复苏组(DPR1～3组)行常规静脉复苏,同时分别腹腔输注生理盐水、6%羟乙基淀粉130/0.4、2.5%腹膜透析液20 ml行腹腔复苏.输注时间均为30 min.右颈总动脉连接多功能监测仪持续监测平均动脉压;于复苏后2 h时股动脉采血,测定乳酸浓度,取小肠组织检测髓过氧化物酶(MPO)活性,采用免疫组化法检测小肠组织肿瘤坏死因子α(TNF-α)表达水平,光镜下观察小肠黏膜组织形态,计算小肠黏膜上皮损伤指数.结果 与S组比较,其余各组大鼠复苏后平均动脉压差异无统计学意义(P>0.05),动脉血乳酸浓度、小肠组织MPO活性、TNF-α表达水平及小肠黏膜上皮损伤指数升高(P<0.05或0.01);与CVR组比较,DPR3组动脉血乳酸浓度、小肠组织MPO活性、TNF-α表达水平及小肠黏膜上皮损伤指数降低(P<0.05).结论 采用2.5%腹膜透析液20 ml行腹腔复苏可有效抑制肠道炎性反应,从而对失血性休克大鼠产生保护作用.     

A monoclonal antibody against cytokine-induced neutrophil chemoattractant attenuates injury in the small intestine in a model of ruptured abdominal aortic aneurysm

PURPOSE: Ruptured abdominal aortic aneurysm (RAAA) continues to be a major source of aneurysm-related morbidity and mortality. Neutrophils have been implicated in RAAA repair-induced organ injury; however, the agents responsible for neutrophil activation and organ sequestration have not been identified. This study investigated the role of cytokine-induced neutrophil chemoattractant (CINC) in organ injury in an RAAA model. METHODS: Rats were subjected to 1 hour of hemorrhagic shock with resuscitation, followed by 45 minutes of lower torso ischemia and 2 hours of reperfusion, and randomly were selected to receive saline solution or anti-rat CINC monoclonal antibody at the start of hemorrhagic shock. Another group of animals underwent sham operation, and served as a control group. Intestinal and lung permeability, intestinal and lung myeloperoxidase (MPO) activity, intestinal and lung CINC, and tumor necrosis factor-alpha (TNF-alpha) levels, resuscitation fluid requirements, and histologic mucosal injury were evaluated in all groups. RESULTS: The RAAA model resulted in increased lung and intestinal permeability to radiolabeled albumin and lung MPO activity (P <.01), with increases in intestinal TNF-alpha (P <.001) and CINC (P <.01) levels, when compared with sham-operated animals. Treatment with anti-rat CINC monoclonal antibody attenuated the increases in intestinal permeability and histologic mucosal injury (P <.01), gut TNF-alpha level (P <.001), and resuscitation fluid volume required (P <.05), without significantly affecting lung and intestinal MPO activity, lung permeability, and intestinal CINC level (P = NS), compared with animals given saline solution. CONCLUSION: Neutralization of CINC by the anti-rat CINC monoclonal antibody attenuated intestinal injury and induction of intestinal TNF-alpha, but failed to significantly attenuate remote pulmonary injury in this model of RAAA.     

Mesenteric lymph is responsible for post-hemorrhagic shock systemic neutrophil priming.

BACKGROUND: Hemorrhagic shock-induced splanchnic hypoperfusion has been implicated as a priming event in the two event model of multiple organ failure (MOF). We have previously shown that early postinjury neutrophil (PMN) priming identifies the injured patient at risk for MOF. Recent in vitro studies have demonstrated that postshock mesenteric lymph primes isolated human neutrophils. We hypothesize that lymphatic diversion before hemorrhagic shock abrogates systemic PMN priming and subsequent lung injury. METHODS: Sprague-Dawley rats (n >or= 5 per group) underwent hemorrhagic shock (MAP 40 mm Hg x 30 min) and resuscitation (shed blood + 2x crystalloid) with and without mesenteric lymphatic duct diversion. Sham animals underwent anesthesia and laparotomy. Whole blood was taken 2 hours after resuscitation, heparinized, and incubated for 5 min at 37 degrees C. Surface expression of CD11b (a marker for PMN priming) was determined by flow-cytometry compared with isotype controls. In addition, lung myeloperoxidase (MPO) was measured for PMN sequestration, and Evans blue lung leak was assessed in the bronchoalveolar lavage fluid in sham, and shock +/- lymph diversion animals. RESULTS: Hemorrhagic shock resulted in increased surface expression of PMN CD11b relative to sham (23.8 +/- 6.7 vs. 9.9 +/- 0.6). Mesenteric lymphatic diversion before hemorrhagic shock abrogated this effect (8.0 +/- 2.6). Lung PMN accumulation, as assessed by MPO, was greater in the lungs of nondiverted (113 +/- 14 MPO/mg lung) versus sham (55 +/- 4 MPO/mg lung, p < 0.05); lymph diversion reduced lung PMNs to control levels (71 +/- 6.5 MPO/mg lung, p < 0.05). Evans blue lung leak was 1.6 times sham in the hemorrhagic shock group; this was returned to sham levels after lymph diversion (p < 0.05). CONCLUSION: Post-hemorrhagic shock mesenteric lymph primes circulating PMNs, promotes lung PMN accumulation, and provokes acute lung injury. Lymphatic diversion abrogates these pathologic events. These observations further implicate the central role of mesenteric lymph in hemorrhagic shock-induced lung injury. Characterizing the PMN priming agents could provide insight into the pathogenesis of postinjury MOF and ultimately new therapeutic strategies.     

Hemorrhage-Induced Hepatic Injury and Hypoperfusion can be Prevented by Direct Peritoneal Resuscitation

Background  Crystalloid fluid resuscitation after hemorrhagic shock (HS) that restores/maintains central hemodynamics often culminates in multi-system organ failure and death due to persistent/progressive splanchnic hypoperfusion and end-organ damage. Adjunctive direct peritoneal resuscitation (DPR) using peritoneal dialysis solution reverses HS-induced splanchnic hypoperfusion and improves survival. We examined HS-mediated hepatic perfusion (galactose clearance), tissue injury (histopathology), and dysfunction (liver enzymes). Methods  Anesthetized rats were randomly assigned (n = 8/group): (1) sham (no HS); (2) HS (40% mean arterial pressure for 60 min) plus conventional i.v. fluid resuscitation (CR; shed blood + 2 volumes saline); (3) HS + CR + 30 mL intraperitoneal (IP) DPR; or (4) HS + CR + 30 mL IP saline. Hemodynamics and hepatic blood flow were measured for 2 h after CR completion. In duplicate animals, liver and splanchnic tissues were harvested for histopathology (blinded, graded), hepatocellular function (liver enzymes), and tissue edema (wet–dry ratio). Results  Group 2 decreased liver blood flow, caused liver injuries (focal to submassive necrosis, zones 2 and 3) and tissue edema, and elevated liver enzymes (alanine aminotransferase (ALT), 149 ± 28 μg/mL and aspartate aminotransferase (AST), 234 ± 24 μg/mL; p < 0.05) compared to group 1 (73 ± 9 and 119 ± 10 μg/mL, respectively). Minimal/no injuries were observed in group 3; enzymes were normalized (ALT 89 ± 9 μg/mL and AST 150 ± 17 μg/mL), and tissue edema was similar to sham. Conclusions  CR from HS restored and maintained central hemodynamics but did not restore or maintain liver perfusion and was associated with significant hepatocellular injury and dysfunction. DPR added to conventional resuscitation (blood and crystalloid) restored and maintained liver perfusion, prevented hepatocellular injury and edema, and preserved liver function. Presented at the Digestive Disease Week, American Association for the Study of Liver Diseases, Los Angeles, CA, USA, May 2006. No conflicts of interest exist. Grant support: This project was supported by a VA Merit Review grant and by NIH research Grant # 5R01 HL076160-03, funded by the National Heart, Lung, and Blood Institute and the United States Army Medical Resources and Material Command.     

Clinical peritoneal dialysis solutions modulate white blood cell-intestinal vascular endothelium interaction

BACKGROUND: Hemorrhagic shock (HS) with conventional resuscitation (CR) (HSCR) primes neutrophils and modulates leukocyte (WBC)-endothelium interaction as part of an exaggerated systemic inflammatory response. We hypothesize that topical application of clinical peritoneal dialysis solutions (PD) modulates such interaction. METHODS: Intestinal intravital microscopy was used to measure WBC rolling in terminal ileum post capillary venules (V2 and V3) in sham-operated animals, and in animals that underwent fixed pressure hemorrhage (50% mean arterial pressure for 60 minutes), followed by conventional resuscitation with the return of the shed blood and 2 vol of saline. Number of rolling WBCs per thirty seconds in selected V2 and V3, bathed in either Kreb's solution or a 2.5% clinical peritoneal dialysis solution (PD) was quantified. Diameters were measured for the in-flow arterioles (A1), and out-flow venules (V1), for calculation of local blood flow with optical Doppler velocimetry. RESULTS: The PD solution significantly (P < .05, n = 11) attenuated WBC-endothelium interaction in sham-operated animals while no significant difference was elicited in HSCR (P > .05, n = 9 Kreb's, n = 7 PD). In addition, the PD solution produced an instantaneous dilation at all levels of the intestinal arterioles in both sham and HSCR. While intestinal venular blood outflow was increased by the PD solution, venular diameters changed very little. CONCLUSION: Superfusion of the gut with glucose-based peritoneal dialysis solutions decreases the concentration of rolling leukocytes along the venular vascular endothelium by a vasodilation-mediated increase in arteriolar inflow and venous outflow mechanism. Hemorrhagic shock and conventional resuscitation enhance the concentration of rolling leukocytes presumably by mechanisms related to upregulation of the adhesion molecules and the low-flow state. Hemorrhage and resuscitation-enhanced leukocytes rolling was not reversed by adjunctive DPR despite the associated marked increase in arterial inflow and venous outflow. The status of the endothelium and the level of leukocyte priming in low-flow states are stronger predictors of leukocyte-endothelium interaction than rheology factors.     

丙酮酸腹膜透析液对大鼠失血性休克静脉液体复苏后腹腔脏器的保护作用

目的：研究丙酮酸腹腔透析液对大鼠失血性休克静脉液体复苏后腹腔脏器的保护作用。方法：雄性SD大鼠40只,随机分为4组（n=10）。大鼠按全身血容量的45％经股动脉放血制作失血性休克模型。单纯静脉复苏组（VR组）于休克1h后回输失血及2倍失血量的乳酸钠林格液行静脉复苏,其余3组在上述静脉复苏基础上,分别腹腔注射生理盐水（DPR组）、乳酸钠透析液（L组）、丙酮酸钠透析液（P组）20ml行腹腔复苏,时间30min。分别于休克前（O时）及休克后60（静脉复苏前）、180（腹腔复苏后1h）、360rain（腹腔复苏后4h）用PICCO心肺容量监测仪监测大鼠平均动脉压（MAP）;激光多普勒血流仪测定休克后180min和360min肝、肾和小肠黏膜血流量;生化法测定休克前及休克后180、360min血丙氨酸转氨酶（ALT）、二胺氧化酶（DAO）活性和肌酐（cr）水平;干／湿比重法测定休克后180、360min肝、肾、肠各组织含水率。结果：失血性休克后各组MAP骤降至（35±5）mmHg;休克后60min时,各组大鼠MAP无明显差异（P〉0．05）。腹腔复苏后,与VR组比较,L和P组均能显著提高失血性休克大鼠MAP（P〈0．05）,降低血ALT、Cr和DAO水平,减轻肝、肾、肠组织含水率,提高腹腔脏器血流量（P〈0．05或P〈0．01）,在失血后360min时,P组的上述变化较其余复苏组更为显著。结论：丙酮酸腹腔透析液对大鼠失血性休克静脉液体复苏后腹腔脏器具有保护作用。     

Alpha1-acid-glycoprotein protects against trauma-hemorrhagic shock

BACKGROUND: Recent studies have shown that the acute phase protein alpha(1)-acid-glycoprotein (AAG) directly modifies endothelial cell responsiveness and is a crucial factor for maintaining endothelial barrier function. We hypothesized that the addition of AAG to the resuscitation fluid will prevent edema formation, increases circulating blood volume, and reduces tissue inflammation following soft tissue trauma and hemorrhagic shock. MATERIALS AND METHODS: Male Sprague-Dawley rats (338 +/- 28 g) underwent a 5-cm midline laparotomy (i.e., induction of soft tissue trauma) and were bled to and maintained at a mean arterial pressure of 35 mm Hg for 90 min. The rats were then resuscitated with four times the shed blood volume with Ringer's lactate containing 200 mg/kg AAG or the same amount of albumin. At 6 h after resuscitation, organ wet-to-dry weight ratios and circulating blood volume (Evans blue dilution) were determined. Neutrophil accumulation (myeloperoxidase activity, MPO) and tissue lipid peroxidation (thiobarbituric acid reactive substances) were also measured in the lungs, liver, and intestine. RESULTS: Administration of AAG during the resuscitation significantly increased circulating blood volume and reduced edema formation, neutrophil accumulation, and lipid peroxidation. Interestingly, concomitant plasma IL-6 levels increased while TNF-alpha levels were not significantly affected. CONCLUSIONS: Since addition of AAG to the resuscitation fluid increased circulating blood volume, reduced edema formation, and neutrophil accumulation following trauma and hemorrhagic shock, supplementation of this acute phase protein appears to be a potential adjunct to prevent capillary leakage in patients undergoing major traumatic injury.     

A novel method of peritoneal resuscitation improves organ perfusion after hemorrhagic shock

BACKGROUND: After resuscitation from hemorrhagic shock, intestinal microvessels constrict leading to impairment of blood flow. This occurs despite restoration and maintenance of central hemodynamics. Our recent studies have demonstrated that topical and continuous exposure of the gut microvasculature to a clinical solution (Delflex; Fresenius Medical Care), as a technique of direct peritoneal resuscitation (DPR), reverses the postresuscitation vasoconstriction and hypoperfusion to a sustained dilation and hyperperfusion. We hypothesize that initiation of DPR simultaneously with resuscitation from hemorrhagic shock enhance organ blood flow to all tissues surrounding the peritoneal cavity as well as distant organs. METHODS: Male Sprague-Dawley rats were anesthetized, intubated and cannulated for monitoring of hemodynamics and for withdrawal of blood. Rats were hemorrhaged to 50% of mean blood pressure for 60 minutes prior to resuscitation with shed blood plus 2 volumes of saline. Animals were randomized for intraperitoneal therapy with 30 mL saline (group 1, n = 9), or Delflex (group 2, n = 9). Whole organ blood flow was measured by colorimetric microsphere technique with phantom organ at baseline, after completion of resuscitation, and at 120 minutes postresuscitation. Replenishment of the dwelling intraperitoneal saline or Delflex was performed in (group 3, n = 8), and (group 4, n = 8), respectively at 90 minutes postresuscitation, and a single whole organ blood flow was performed at 120 minutes postresuscitation. RESULTS: Direct peritoneal resuscitation caused a significant increase in blood flow to the jejunum (35%), ileum (33%), spleen (48%), and pancreas (57%), whereas a marked increase in blood flow was detected in the lung (111%), psoas major muscle (115%), and diaphragm (132%), as compared with the saline treated animals in group 1. At 120 minutes postresuscitation, organ blood flow returned to the prehemorrhagic shock baseline level in all organs irrespective of peritoneal therapy. Replenishment of the intraperitoneal solution in group 3 and 4, enhanced blood flow to the liver, kidneys, and diaphragm. CONCLUSIONS: Direct peritoneal resuscitation enhanced blood flow to organs incited in the pathogenesis of multiple organ failure that follows hemorrhagic shock.     

Direct peritoneal resuscitation from hemorrhagic shock: effect of time delay in therapy initiation

BACKGROUND: After conventional resuscitation from hemorrhagic shock, splanchnic microvessels progressively constrict, leading to impairment of blood flow. This occurs despite restoration and maintenance of central hemodynamics. The authors' recent studies have demonstrated that topical and continuous ex vivo exposure of the gut microvasculature to a glucose-based clinical peritoneal dialysis solution (Delflex), as a technique of direct peritoneal resuscitation (DPR), can prevent these postresuscitation events when initiated simultaneously with conventional resuscitation. This study aimed to determine whether DPR applied after conventional resuscitation reverses the established postresuscitation intestinal vasoconstriction and hypoperfusion. METHODS: Male Sprague-Dawley rats were bled to 50% of baseline mean arterial pressure and resuscitated intravenously over 30 minutes with the shed blood returned plus two times the shed blood volume of saline. Initiation of ex vivo, topical DPR was delayed to 2 hours (group 1, n = 8), or to 4 hours (group 2, n = 8), respectively, after conventional resuscitation. Intravital microscopy and Doppler velocimetry were used to measure terminal ileal microvascular diameters of inflow A1 and premucosal A3 (proximal pA3, distal dA3) arterioles and blood flow in the A1 arteriole, respectively. Maximum arteriolar dilation capacity was obtained from the topical application, in the tissue bath, of the endothelium-independent nitric oxide-donor sodium nitroprusside (10M). RESULTS: Hemorrhagic shock caused a selective vasoconstriction of A1 (-24.1% +/- 2.15%) arterioles from baseline, which was not seen in A3 vessels. This caused A1 blood flow to drop by -68.6% of the prehemorrhage value. Conventional resuscitation restored and maintained hemodynamics in all the animals without additional fluid therapy. In contrast, there was a generalized and progressive postresuscitation vasoconstriction of A1 (-21.7%), pA3 (-18.5%), and dA3 (-18.7%) vessels. The average postresuscitation A1 blood flow was -49.5% of the prehemorrhage value, indicating a persistent postresuscitation hypoperfusion. Direct peritoneal resuscitation reversed the postresuscitation vasoconstriction by 40.9% and enhanced A1 blood flow by 112.9% of the respective postresuscitation values. CONCLUSIONS: Delayed DPR reverses the gut postresuscitation vasoconstriction and hypoperfusion regardless of the initiation time. This occurs without adverse effects on hemodynamics. Direct peritoneal resuscitation-mediated enhancement of tissue perfusion results from the local effects from the vasoactive components of the Delflex solution, which are hyperosmolality, lactate buffer anion, and, to a lesser extent, low pH. The molecular mechanism of this vasodilation effect needs further investigation.     

Pancreatic enzymes in the gut contributing to lung injury after trauma／hemorrhagic shock

Objective: To examine whether pancreatic proteolytic enzymes involve in lung injury induced by trauma/hemorrhagic shock (T/HS). Methods: Male Sprague-Dawley rats received intraluminal or intravenous pancreatic serine protease inhibitor, 6-amidino-2-naphthyl p-guanidinobenzoate dimethanesulfate (ANGD) during laparotomy (trauma), and were subjected to 90 minutes of T/HS or trauma-sham shock (T/SS). Degree of lung injury was assessed 3 hours after resuscitation with Ringer‘s lactate solution. Results: Lung permeability, pulmonary myeloperoxidase levels and the ratio of bronchoalveolar lavage fluid protein to plasma protein increased after T/HS, and significantly decreased in intraluminal-ANGD treated but not in intravenous-ANGD treated rats. Histological analysis demonstrated fewer injured villi in the intraluminal-ANGD treated rats compared with those in the control rats. Linear regression analysis revealed that the percentage of injured ileal mucosal villi directly related to pulmonary polymorphic neutrophil sequestration and lung permeability to Evans blue dye. Conclusions: Pancreatic proteolytic enzymes in the ischemic gut may be important toxic factors contributing to lnng injury after T/HS.     

Hypertonic saline resuscitation attenuates neutrophil lung sequestration and transmigration by diminishing leukocyte-endothelial interactions in a two-hit model of hemorrhagic shock and infection

BACKGROUND: Hypertonic saline (HTS) attenuates polymorphonuclear neutrophil (PMN)-mediated tissue injury after hemorrhagic shock. We hypothesized that HTS resuscitation reduces early in vivo endothelial cell (EC)-PMN interactions and late lung PMN sequestration in a two-hit model of hemorrhagic shock followed by mimicked infection. METHODS: Thirty-two mice were hemorrhaged (40 mm Hg) for 60 minutes and then given intratracheal lipopolysaccharide (10 microg) 1 hour after resuscitation with shed blood and either HTS (4 mL/kg 7.5% NaCl) or Ringer's lactate (RL) (twice shed blood volume). Eleven controls were not manipulated. Cremaster intravital microscopy quantified 5-hour EC-PMN adherence, myeloperoxidase assay assessed lung PMN content (2 1/2 and 24 hours), and lung histology determined 24-hour PMN transmigration. RESULTS: Compared with RL, HTS animals displayed 55% less 5-hour EC-PMN adherence (p = 0.01), 61% lower 24-hour lung myeloperoxidase ( p= 0.007), and 57% lower mean 24-hour lung histologic score ( p= 0.027). CONCLUSION: Compared with RL, HTS resuscitation attenuates early EC-PMN adhesion and late lung PMN accumulation in hemorrhagic shock followed by inflammation. HTS resuscitation may attenuate PMN-mediated organ damage.     

Effects of two fluid resuscitations on the bacterial translocation and inflammatory response of small intestine in rats with hemorrhagic shock

Objective： To investigate the effects of two fluid resuscitations on the bacterial translocation and the inflammatory factors of small intestine in rats with hemorrhagic shock. Methods： Fifty SD healthy male rats were randomly divided into 5 groups （ n = 10 per group） ： Group A （ Sham group）, Group B （ Ringer＇ s solution for 1 h ）, Group C （Ringer＇ s solution for 24 h ）, Group D （ hydroxyethyl starch for 1 h ） and Group E （（ hydroxyethyl starch for 24 h）. A model of rats with hemorrhagic shock was established. The bacterial translocation in liver, content of tumor necrosis factor-α （TNF-α） and changes of myeloperoxidase enzyme （MPO） activities in small intestine were pathologically investigated after these two fluid resuscitations, respectively. Results ： The bacterial translocation and the expression of TNF-α in the small intestine were detected at 1 h and 24 h after fluid resuscitation. There were significant increase in the number of translocated bacteria, TNF-α and MPO activities in Group C compared with Group B, significant decrease in Group E compared with Group D and in Group B compared with Group D. The number of translocated bacteria and TNF-α expression significantly decreased in Group E as compared with Group C. Conclusions： The bacterial translocation and the expression of TNF-α in the small intestine exist 24 h after fluid resuscitation. 6 % hydroxyethyl starch can improve the intestinal mucosa barrier function better than the Ringer＇ s solution.     

高渗氯化钠羟乙基淀粉复合液对失血性休克肺的保护作用

目的观察用高渗氯化钠羟乙基淀粉复合液(7.5%氯化钠 6%羟乙基淀粉200/0.5,HHS)小容量复苏对失血性休克后肺损伤的影响。方法雄性SD大鼠随机分为五组:正常对照组(CON组,n=6):不放血不补液;其他大鼠通过放血使MAP降至45mmHg并维持120min,然后分为:休克组(SH组,n=6),不补液复苏;HHS组(n=8),用HHS5ml/kg静脉滴注;7.5%氯化钠高渗溶液组(HTS组,n=6),用7.5%NaCl5ml/kg静脉滴注;复方乳酸钠组(LR组,n=7),用3倍失血量的复方乳酸钠静脉滴注。观察休克2h末、补液结束即刻、15、30、60、120、180min时MAP、CVP的变化,测定补液结束2、24h存活动物的氧合指数和肺水含量、肺髓过氧化物酶(MPO)水平、肺损伤评分。结果在补液结束120、180min,HTS组MAP、CVP低于HHS和LR组(P<0.05);在补液结束24h,HHS组氧合指数、肺水含量、肺MPO水平、肺损伤评分优于HTS和LR组(P<0.05)。结论用HHS小容量复苏失血性休克,维持血流动力学稳定时间更长;对肺组织的保护作用优于7.5%氯化钠高渗溶液或复方乳酸钠。     

L-selectin blockade and liver function in rats after uncontrolled hemorrhagic shock.

Hemorrhagic shock (HS) and resuscitation can be seen as a global body ischemia-reperfusion (I/R) injury characterized by neutrophil infiltration and organ damage. Liver dysfunction occurs early after HS. Adhesion molecules are needed for the first steps ofneutrophil migration. Thus, the purpose of this study was to investigate the role of L-selectin in the liver after uncontrolled HS and resuscitation. Forty-eight Sprague Dawley rats were subjected to uncontrolled HS and resuscitation. Animals were divided into three groups: sham, uncontrolled HS and resuscitation, and uncontrolled HS and resuscitation with anti-L-selectin treatment. At 6 we evaluated liver injury tests, liver tissue myeloperoxidase (MPO), and liver histology. Survival was followed for 3 days and compared between groups. Statistical analysis included Fisher's exact test and one-way analysis of variance. Survival significantly increased from 30% in the control group to 60% in the treated group (p < .05). Hepatocellular and structural injury as well as neutrophil infiltration was significantly decreased in treated animals (p < .05). Thus, blockade of L-selectin resulted in decreased hepatocellular injury and increased survival in our model of uncontrolled HS. Selectins may be important therapeutic targets for blockade in the treatment of HS.     

Inhibition of enteral enzymes by enteroclysis with nafamostat mesilate reduces neutrophil activation and transfusion requirements after hemorrhagic shock

BACKGROUND: The gut origin of the inflammatory response in trauma patients has been difficult to define. "In vivo" generation of neutrophil-activating factors by gut proteases may be a cause of multiorgan failure after hemorrhagic shock, and can be prevented with the serine protease inhibitor nafamostat mesilate (Futhan). The objective of this study was to determine the effect of nafamostat mesilate given by enteroclysis on enteric serine protease activity, neutrophil activation, and transfusion requirements during hemorrhagic shock. METHODS: Sixteen pigs weighing 21 to 26 kg were divided into control and treatment groups. A laparotomy was performed under anesthesia, and catheters were placed in the duodenum, midjejunum, and terminal ileum. Pigs were bled 30 mL/kg over 30 minutes and maintained at a mean arterial pressure of 30 mm Hg for 60 minutes. Shed blood was then used to maintain a mean arterial pressure of 45 mm Hg for another 3 hours. Treated animals received 100 mL/kg of 0.37 mmol/L nafamostat mesilate in GoLYTELY through the duodenal catheter at 1 L/h. Control animals received GoLYTELY only. Samples of enteral content and blood were taken at baseline, after shock, and at 30-minute intervals during resuscitation. Animals were killed after 3 hours of resuscitation. Enteral trypsin-like activity at the three gut sites was measured by spectrophotometry. Activation of naive human neutrophils by pig plasma was measured by the percentage of cells having pseudopods larger than 1 microm on microscopy. Lung, liver, and small bowel were analyzed by histology and myeloperoxidase assay. RESULTS: Both control and nafamostat mesilate-treated groups had significant reductions in protein and protease levels in the duodenum during enteroclysis; however, only nafamostat mesilate-treated animals had persistent suppression of protease activity throughout the experiment. Nafamostat mesilate-treated animals had a lower transfusion requirement of shed blood, 18.1 +/- 4.5 mL/kg versus 30 +/- 0.43 mL/kg (p = 0.002). Nafamostat mesilate-treated animals had significantly less neutrophil activation than controls at 150 minutes after resuscitation (33.7 +/- 6.48% vs. 42.4 +/- 4.57%,p = 0.01) and 180 minutes after resuscitation (31.1 +/- 3.31% vs. 46.9 +/- 4.53%, p = 0.0002). Lung myeloperoxidase activity was lower in nafamostat mesilate-treated animals (0.31 +/- 0.14) than in control animals (0.16 +/- 0.04, p = 0.04). Histology of liver and small intestine showed less injury in nafamostat mesilate-treated animals. CONCLUSION: Nafamostat mesilate given by means of enteroclysis with GoLYTELY significantly reduces enteral protease levels, leukocyte activation, and transfusion requirements during resuscitation from hemorrhagic shock. This strategy may have clinical promise.     

限制性液体复苏对失血性休克大鼠网状内皮系统的影响

目的探讨限制性液体复苏对失血性休克大鼠网状内皮系统的影响。方法60只SD大鼠制成未控制性重度失血性休克模型,随机分成对照组、NF组(无液体复苏组)、NS40组(限制性液体复苏组)和NS80组(常规大量液体复苏组),检测和比较休克复苏后各组存活大鼠肝脏枯否细胞和腹腔巨噬细胞的吞噬功能。结果重度失血性休克大鼠失血后150min存活率NF组、NS40组和NS80组比对照组明显提高,NS40组较NS80组显著改善(P0.05);NS40组大鼠肝脏枯否细胞和腹腔巨噬细胞的吞噬功能较NS80组明显改善(P0.05)。结论限制性液体复苏可以显著改善失血性休克大鼠的网状内皮系统的吞噬功能,提高大鼠的免疫功能,降低死亡率。