Coagulation challenges after severe injury with hemorrhagic shock

During the past 50 years, there have been huge changes in the approach to coagulopathic bleeding following the treatment of traumatic hemorrhagic shock (HS). Treatment during the 1960s consisted primarily of physiologic saline (balanced electrolyte solution [BES]) and whole blood supported with sodium bicarbonate for acidosis. Subsequent coagulopathy was assumed to be caused by lack of the labile factors (FV and FVIII) which were then replaced by fresh whole blood. The decade of 1970s saw the implementation of component therapy by the American Blood Banking Association so that HS was treated with BES and packed red blood cells (RBC). A new paradigm had to be learned to determine when and how much fresh frozen plasma (FFP) was needed to restore all coagulation factors. By the end of 1970s, most trauma centers were supplementing BES and RBC with FFP in patients with severe injuries requiring massive transfusion of more than one circulating blood volume. By the 1980s, the use of FFP skyrocketed, creating a crisis for the American Blood Banking Association. This led to a National Institute of Health Consensus Development Conference which concluded that FFP should be given to only those patients who had a documented coagulopathy as evidenced by a prolongation of the prothrombin time and the partial thromboplastin time. Restriction of FFP replacement to patients with proven coagulopathy after treatment for HS led to postoperative bleeding which was sometimes fatal. During the 1990s, uncontrolled clinical studies and rigorously controlled animal studies showed that FFP should be administered before the onset of proven coagulopathy with prolongation of the prothrombin time and partial thromboplastin time. Later during the 1990s, recombinant-activated factor VII (FVIIa) was purported to provide quicker hemostasis in patients treated with HS. The efficacy of FVIIa supplementation is still being assessed. During the 2010s, the military surgeons promoted the use of a hemostatic regimen which consists of platelets, RBC, and FFP in a 1:1:1 ratio. This recommendation is still being assessed with different authors reporting benefits and detriments. Throughout these years, an unusual entity of disseminated intravascular coagulation (DIC) was known to complicate the resuscitation of seriously injured patients with HS. This syndrome was typically seen after treatment of HS and was associated with abnormal bleeding plus respiratory failure and renal failure thought to be caused by a combination of micro- and macrothromboses. The early studies suggested that the best therapy for breaking this viscous cycle of bleeding and intravascular coagulation was by infusing fresh whole blood. The theoretical benefits of administering heparin to prevent the thrombosis and epsilon-aminocaproic acid to enhance lysis have not proven beneficial. DIC is also seen in association with toxic exposures, including snake bites. Epsilon-aminocaproic acid may be beneficial in that setting. Many of the intricate understandings of DIC remain elusive and are still being studied.     

Low-volume resuscitation cocktail extends survival after severe hemorrhagic shock

After severe hemorrhage, low-volume resuscitation with hypertonic fluids is increasingly preferred to more aggressive resuscitation strategies. Oxygen delivery to the tissues may be improved by augmentation with hemoglobin [Hb]-based oxygen-carrying compounds (HBOCs); however, previous studies have reported negative outcomes presumably related to extravasation of tetrameric Hb. The purpose of this study was to evaluate a novel large molecular weight polymer of cross-linked bovine Hb (OxyVita; OXYVITA Inc, New Windsor, NY) in a cocktail of hypertonic saline and Hextend (HX; HBOC-C) as an alternative to standard small-volume resuscitation using Hextend (HX) only. Outcomes were survival to 3 h and duration of MAP support more than 60 mmHg without additional fluid support. Conscious male Long-Evans rats were hemorrhaged to 60% total blood volume over 40 min. There were 4 groups: HBOC-C administered in a pressure-titrated infusion, HX titration, HBOC-C administered as a bolus, and HX bolus. Cardiovascular parameters, arterial gases, acid-base status, metabolites, electrolytes, Hb level, and oxygen saturation were measured at baseline, during each 20% hemorrhage increment, and 1, 2, and 3 h after the initiation of hemorrhage. Small-volume resuscitation with HBOC-C significantly improved survival to 3 h and improved MAP support times regardless of method of administration. However, physiological status at the end of hemorrhage significantly influenced survival regardless of resuscitation treatment. These results suggest that HBOC-augmented hypertonic cocktails are of promise in improving survival and providing target MAP support during small-volume resuscitation. Experimental evaluation of any resuscitation therapy should account for the degree of preexisting physiological compromise before therapy is initiated.     

Alteration in Kupffer cell function after mild hemorrhagic shock

Functional changes in Kupffer cells occur after profound hemorrhagic shock. This study was performed to demonstrate if Kupffer cell changes also occur after mild hemorrhagic shock. Sprague-Dawley rats were bled to a systolic blood pressure of 60 to 70 mmHg and resuscitated with Lactated Ringers solution (twice the shed blood volume) after 30 min. Resuscitation produced immediate recovery of blood pressure and allowed long-term recovery of the animals. Sham animals received anesthesia and monitoring only. Thirty minutes after resuscitation, Kupffer cells were isolated by centrifugal elutriation and cultured for 48 h. In Kupffer cells isolated from shocked animals, phorbol ester-stimulated superoxide production increased 7-fold and lipopolysaccharide- (LPS) stimulated prostaglandin E2 (PGE2) production increased 4-fold. Tumor necrosis factor-alpha (TNFalpha) production, on the other hand, was decreased by 50%. A non-significant trend toward increased phagocytosis was also observed, whereas LPS-stimulated nitric oxide production was unchanged. In conclusion, mild hemorrhagic shock produced increases in superoxide and PGE2 production, and decreases in TNFalpha production by Kupffer cells, changes that may be appropriate to defend against the infectious challenges that often follows trauma and hemorrhage.     

Acadesine and intestinal barrier function after hemorrhagic shock and resuscitation

OBJECTIVE: To determine actions of the prototype adenosine-regulating agent, acadesine (5-amino-1-[beta-D-ribofuranosyl]imidazole-4-carboxamideriboside; AICAR), on intestinal barrier function after hemorrhagic shock and fluid resuscitation, three series of experiments were performed to measure functional (series 1: intestinal permeability and intramural blood flow), structural (series 2: histology), and biochemical (series 3: tissue concentrations of adenine nucleotides and metabolites) changes. DESIGN: Prospective, controlled animal study. SETTING/SUBJECTS: University laboratory; juvenile crossbred pigs of either gender. INTERVENTIONS: Either AICAR or its saline vehicle were intravenously administered 30 mins before 40% hemorrhage. After 1 hr shock, shed blood plus crystalloid was administered for resuscitation. Data were collected for 1 hr thereafter. MEASUREMENTS AND MAIN RESULTS: In series 1, permeability of the ileum was measured by assaying the portal venous concentration of fluorescein-labeled dextran after placement of this tracer in the lumen. In addition, serosal and mucosal blood flow were monitored with laser-Doppler probes. With vehicle, hemorrhage and resuscitation increased the dextran concentration three-fold and decreased blood flow 50% of the baseline values (both p < .05). AICAR attenuated the permeability increase (p < .05) and attenuated mucosa, but not serosal, ischemia (p < .05). Similar effects were observed with a structurally dissimilar compound-- 4-amino-1-(5-amino-5-deoxy-1-beta-D-ribofuranosyl)-3-bromo-pyrazolo [3,4-d] pyrimidine, a specific adenosine kinase inhibitor-as well as continuous intra-arterial infusion of adenosine. In series 2, AICAR ameliorated the mucosal damage caused by shock/resuscitation (p < .05). In series 3, AICAR increased ileal tissue adenine nucleotides and metabolites during the shock period (p < .05). CONCLUSIONS: AICAR attenuated gut permeability changes, increased mucosal perfusion, and increased tissue adenine nucleotides, which is consistent with preserved intestinal barrier function after hemorrhage and fluid resuscitation. In context with previous studies from this laboratory, these results provide further evidence for a role for adenosine as an endogenous anti-inflammatory autacoid after shock and trauma. Further study is needed to determine the therapeutic potential of adenosine-regulating agents in resuscitation fluids.     

Melatonin pretreatment improves liver function and hepatic perfusion after hemorrhagic shock

Exogenous administration of pineal hormone melatonin (MEL) has been demonstrated to attenuate organ damage in models of I/R and inflammation by antioxidative effects. However, specific organ-protective effects of MEL with respect to hemorrhagic shock have not been investigated yet. In the present study, we evaluated the role of MEL pretreatment for hepatic perfusion, redox state, and function after hemorrhage and resuscitation, with emphasis on MEL receptor activation. In a model of hemorrhagic shock (MAP 35 +/- 5 mmHg for 90 min) and reperfusion (2 h), we measured nicotinamide adenine dinucleotide phosphate (reduced form; NADPH) autofluorescence, hepatic microcirculation, and hepatocellular injury by intravital microscopy, as well as plasma disappearance rate of indocyanine green (PDRICG) as a sensitive maker of liver function in rat. Pretreatment with 10 mg kg(-1) MEL (i.v.) 15 min before induction of hemorrhage resulted in a significantly improved PDR(ICG) compared with controls (MEL/shock, 15.02% min(-1) +/- 2.9 SD vs. vehicle/shock, 6.18 +/- 4.6 SD; P = 0.001). Intravital microscopy after reperfusion revealed an improved hepatic perfusion index, redox state, and reduced hepatocellular injury in pretreated animals compared with the vehicle group. Melatonin receptor antagonist luzindole (LZN; 2.5 mg kg(-1)) almost completely abolished the protective effects of MEL pretreatment with respect to liver function (MEL + LZN/shock PDR(ICG), 7.31% min(-1) +/- 3.4 SD). Beneficial effects regarding hepatic perfusion, redox state, and cellular injury were not influenced by LZN, indicating that they may depend on antioxidative effects of MEL. However, liver function after hemorrhage is effectively maintained by MEL pretreatment via receptor-dependent pathways.     

Intrinsic myocardial function in hemorrhagic shock

Hemorrhage is a stress on the cardiovascular system that results in decreased loading of the heart but also decreased blood pressure and thus decreased perfusion pressure for tissue blood flow. The heart's response to hemorrhage is governed by both an increase in sympathetic nervous system activation of the heart and decreased preload and afterload for the heart. Whether the heart can maintain normal contractile function and reserves under conditions of prolonged hemorrhagic shock is not clear. To assess the effects of hemorrhagic shock of different lengths on intrinsic cardiac contractile function, guinea pigs were surgically prepared for the measurement of blood pressure, heart rate, and cardiac output and blood samples were taken for the measurement of metabolic indices of cardiovascular stress. Fifty percent of the animals' blood volume was removed and then animals were followed for 1, 2, or 3 h of hemorrhagic shock. Hearts were then removed for measurement of intrinsic contractile function. Hearts from animals exposed to 1 or 2 h of shock exhibited normal ventricular function although hearts removed after 3 h exhibited changes in ventricular function. Maintenance of normal cardiac function through at least 2 h of shock must represent adequate physiologic modulation of coronary blood flow to deliver adequate oxygen to match the myocardial oxygen demands under conditions of severe blood loss. This balance may be disrupted by 3 h of shock thus resulting in loss of contractile reserve.     

甲泼尼龙对失血性休克后肠屏障功能的影响

目的探讨应用甲泼尼龙对失血性休克后肠黏膜屏障功能的影响。方法新西兰大白兔30只,随机分为失血性休克组、甲泼尼龙组、对照组。失血性休克采用股动脉放血制做模型,休克持续2h后回输失血及等量林格氏液复苏;甲泼尼龙组在复苏时静注甲泼尼龙50mg/kg一次;对照组不行放血处理。复苏后2h,留取血浆检测D-乳酸水平;取小肠组织行常规病理学检查,并制备肠组织匀浆测定其肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)和丙二醛(malondialdehyde,MDA)水平。结果失血性休克组肠黏膜结构破坏,血浆D-乳酸显著升高,肠组织匀浆中TNF-α和MDA水平增加。甲泼尼龙组上述指标均低于失血性休克组,差异具有统计学意义(P<0.05)。结论早期大剂量使用甲泼尼龙对失血性休克后的肠屏障功能有保护作用。     

Glucosamine administration improves survival rate after severe hemorrhagic shock combined with trauma in rats

We have previously shown that glucosamine administration resulted in higher cardiac output and improved tissue perfusion after trauma-hemorrhage with resuscitation in rats, which was associated with the increased levels of protein O-linked-N-acetylglucosamine (O-GlcNAc). The purpose of the study was to evaluate the effect of glucosamine on the survival, without resuscitation, in rats. Adult male rats underwent midline laparotomy and 55% of total blood volume was withdrawn for 25 min under isoflurane anesthesia. At the end of the hemorrhage period, 2.5 mL of 150 mM glucosamine or equivalent osmolarity of mannitol solution was injected intravenously for 10 min. The survival time, mean blood pressure, heart rate, and central body temperature were monitored continuously; then, the O-GlcNAc levels in heart, brain, liver, and muscle were measured by means of Western blot analysis. Glucosamine administration significantly increased the survival rate in comparison with mannitol administration (percentage of survival after 2 h, 47% vs. 20%; P < 0.05). The mean arterial pressure was significantly higher in the glucosamine group for 18 min after treatment. The protein O-GlcNAc levels, assessed 30 min after glucosamine treatment, were significantly increased in the heart, brain, and liver. These data demonstrate that i.v. glucosamine administration improves the survival rate after trauma-hemorrhage without resuscitation; this effect may be related to the glucosamine-induced increase in protein O-glycosylation. Furthermore, the increase in mean arterial pressure may suggest a vasoactive and/or positive inotropic effect of glucosamine in hypovolemic shock.     

Hypercarbic arterial acidemia following resuscitation from severe hemorrhagic shock

Arteriovenous pH and PCO2 gradients can develop during low cardiac output states. We have seen a transient rise in arterial PCO2 and a fall in arterial pH in humans receiving closed-chest cardiopulmonary resuscitation immediately following restoration of spontaneous circulation. Using a hemorrhagic shock model in sheep, serial arterial and mixed venous blood gases were sampled and CO2 elimination was measured. When cardiac output was less than 30% of the baseline value and the arteriovenous PCO2 difference was greater than 20 mmHg, the animals were rapidly resuscitated with intravenous 0.9% NaCl and dopamine. Following resuscitation, there was a transient arterial acidosis and hypercarbia due to passage of venous blood with a high CO2 content into arterial blood. The clinical implications in the setting of hemorrhagic shock are that (1) arterial blood gases are poor indicators of the systemic acid-base state, (2) arterial blood gases drawn immediately following volume resuscitation may be misinterpreted and should probably not be used to guide therapy and (3) there is a transient hypercarbic arterial acidosis following volume resuscitation that may have deleterious effects on cardiac and cerebral function in the early post-resuscitative period.     

Lactate improves cardiac efficiency after hemorrhagic shock

This study was undertaken to examine the role of lactate on cardiac function and metabolism after severe acute hemorrhagic shock. Anesthetized, nonheparinized rats were bled to a mean arterial pressure of 25-30 mm Hg for 1 h; controls were not bled. Their hearts were removed, and cardiac work and efficiency (work/oxygen consumption) were measured in the isolated working heart mode for 60 min. The hearts were perfused with one of five substrate combinations: 1) glucose (11 mM), 2) glucose + 0.4 mM palmitate, 3) glucose + 0.4 mM palmitate + 8.0 mM lactate, 4) glucose + 1.2 mM palmitate, or 5) glucose + 1.2 mM palmitate + 8.0 mM lactate. After perfusion, hearts were freeze-clamped, and tissue contents of free coenzyme-A (CoA), acetyl CoA, and succinyl CoA were measured, as was myocardial pyruvate dehydrogenase (PDH) activity. The addition of 8.0 mM lactate significantly improved cardiac work in shocked hearts perfused with 0.4 mM palmitate and increased cardiac efficiency in the presence of either 0.4 mM or 1.2 mM palmitate. Compared to control hearts, shocked hearts exhibited a 20-30% decrease in PDH activity. Shocked hearts perfused with lactate demonstrated no increase in acetyl CoA content but did have a significant increase in tissue succinyl CoA compared to control hearts perfused with lactate or shocked hearts perfused without lactate. In the heart recovering from severe hemorrhagic shock, lactate improves cardiac efficiency in the presence of free fatty acids, possibly by a anaplerosis of the tricarboxylic acid cycle.     

Detrimental effects of rapid fluid resuscitation on hepatocellular function and survival after hemorrhagic shock

Because end-organ injury can occur with reperfusion following hemorrhage or ischemia, we hypothesized that aggressive intravenous fluid resuscitation would aggravate tissue injury in a fixed-volume model of hemorrhagic shock. Unanesthetized chronically prepared male rats were hemorrhaged 33-36 mL/kg for 2.5 h. Then Lactated Ringers Solution (3x hemorrhage volume) was infused over 5 min (FAST), 20 min (MEDIUM), 180 min (SLOW), or not at all (NO RESUS). Plasma ornithine carbamoyltransferase (OCT), lactate, and creatinine were measured as indices of hepatocellular injury, anaerobic metabolism, and renal function, respectively. At 1 h post-resuscitation (PR), MAP was greater after SLOW and MEDIUM treatment (tx) than after other txs (P < 0.05). OCT increased earliest after FAST tx to values greater than those after other txs from 30 min to 24 h PR (P < 0.01). Plasma lactate was elevated immediately before resuscitation in all groups (P < 0.01) and returned to baseline at 3 h PR after SLOW tx compared to 5 h PR after FAST tx (P < 0.05). Creatinine at 5 h PR was less in the groups treated with intravenous fluid compared to the NO RESUS group, P < 0.05. Survival at 72 h was reduced in the FAST (57%) and NO RESUS (58%) groups compared to the SLOW (87%) and MEDIUM (85%) groups (P < 0.05). Thus, overly aggressive fluid tx accelerates hepatocellular injury, is no better than lesser rates of resuscitation at correcting plasma lactate and preserving renal function, and provides no overall survival benefit.     

Evidence of transcellular albumin transport after hemorrhagic shock

Hemorrhagic shock-induced ischemia-reperfusion injury is characterized by an increase in microvascular permeability. This increase in permeability is thought to occur mainly via passive transport through interendothelial cell junctions. However, recent data have suggested that a transcellular (caveolae) transport mechanism(s) may also play a role after shock. The purpose of our study was to investigate the role of caveolae transport after hemorrhagic shock. After a control period, blood was withdrawn to reduce the mean arterial pressure to 40 mmHg for 1 h in urethane-anesthetized Sprague-Dawley rats. Mesenteric postcapillary venules in a transilluminated segment of small intestine were examined to determine changes in permeability. Rats received an intravenous injection of fluorescein isothiocyanate-bovine albumin during the control period. The fluorescent light intensity emitted from the fluorescein isothiocyanate-bovine albumin was recorded with digital microscopy within the lumen of the microvasculature and was compared with the intensity of light in the extravascular space. The images were downloaded to a computerized image analysis program that quantitates changes in light intensity. This change in light intensity represents albumin extravasation. Our results demonstrated a marked increase in albumin leak after hemorrhagic shock that was significantly attenuated with two different inhibitors of transcellular transport, N-ethylmaleimide and methyl-beta-cyclodextrin. These data suggest that caveolae transport plays a significant role in microvascular permeability after hemorrhagic shock.     

Pulmonary pressure-flow relation after trauma and hemorrhagic shock

The significance of pulmonary pressure-flow relation and its correlation to alveolar dead space and histological lesions of the lung were evaluated in ten mongrel dogs, which were subjected to standardized bone trauma and hemorrhagic hypotension at 40 mm Hg for 3h. These results were compared with those of 5 control dogs without trauma and shock. Two different pressure-flow curves were obtained by consecutive measurements of cardiac output and mean pulmonary artery pressure during stepwise arterial hemorrhage and reinfusion. In each experiment, the difference between the two curves at CO of 100 ml/kg min was obtained and represents an increase in pulmonary artery pressure (delta MPP). This increase in pulmonary artery pressure is flow-independent and, therefore, can be used as a quantitative indicator of pulmonary vasoconstriction or vascular obstruction. Severity of shock (uptake) as well as grade of early histological lesions of the lung (microthrombi, edema, hemorrhage) and increased alveolar dead space after reinfusion were associated with a more pronounced shift of the pulmonary pressure-flow curve. In severe experimental shock, therefore, a consistent pattern of pulmonary hemodynamics, lung histology, and respiratory function was demonstrated by the pulmonary pressure-flow relation. This approach permits estimation of the effects of therapeutic interventions and may be suitable for assessing postshock pulmonary impairment.     

急救护理在严重创伤失血性休克患者中的应用体会

目的探讨急救护理在严重创伤失血性休克患者中的应用效果。方法选取2018年7月至2019年1月本院收治的20例严重创伤失血性休克患者为研究对象,回顾性分析其急救处理方法及效果。结果 20例严重创伤失血性休克患者经过有效急救护理后,好转18例、无变化1例、恶化1例,其中19例患者的失血性休克得到有效纠正,18例血压、心率恢复正常已康复出院,1例因创伤严重实质性脏器破裂性出血而死亡。本组患者的临床好转率为90.0%。结论对创伤失血性休克患者要采取迅速、及时、有效的急救措施,有助于提高临床救治成功率,降低死亡率。     

Therapeutic hypothermia limited to the resuscitation period does not prolong survival after severe hemorrhagic shock in rats

OBJECTIVE: Controlled hypothermia induced during hemorrhagic shock (HS) has been shown previously to improve survival in HS rat outcome models. We hypothesized that hypothermia (34 degrees C) induced immediately with reperfusion would also improve survival. METHODS: Twenty-four rats were lightly anesthetized with halothane and maintained spontaneous breathing. The rats underwent: an HS phase I of 75 min, with an initial blood withdrawal of 2.5 mL/100 g over 15 min, followed by either additional blood withdrawal or re-infusion in order to maintain a mean arterial pressure (MAP) of 30 mmHg over 60 min; a resuscitation phase II of 60 min with return of shed blood and infusion of lactated Ringer's solution to maintain a MAP of 75 mmHg; and an observation phase III without anesthesia for 72 h. Five minutes before the start of phase II, 12 rats were randomized into either a normothermia (38 degrees C) group or hypothermia (34 degrees C) group. The rectal temperature in each group was carefully maintained during the 60-min period of phase II. Survival at 72 h, as well as gut damage were assessed. RESULTS: All 24 rats survived beyond phases I and II. At 72 h, 8 of 12 rats survived in the hypothermia group, while and 6 of 12 survived in the normothermia group (p=0.64). Intestines of the 72 h survivors were macroscopically normal. In rats that died during phase III, total gut scores did not differ statistically between the groups (1.2+/-0.6 versus 1.0+/-0.9). CONCLUSION: Brief resuscitative hypothermia of 60 min duration induced immediately with reperfusion after HS did not improve survival in this model.     

Adverse effects of resuscitation with lactated ringer compared with ringer solution after severe hemorrhagic shock in rats

Lactated Ringer (LR) is a widely used resuscitation fluid that is known to mediate beneficial effects on acid-base balance when compared with normal saline. We here compared LR with the more physiological Ringer solution (RS) regarding acid-base status, hemodynamics, survival, and organ injury following fluid resuscitation subsequent to severe hemorrhagic shock. Anesthetized rats were hemorrhaged to a mean arterial blood pressure of 25 to 30 mmHg within 30 min. After 60 min, they were resuscitated with either RS or LR (three times the shed blood volume) or with RS or LR plus blood (shed blood plus twice its volume) within 30 min. Subsequently, the animals were observed for further 150 min. When the rats were resuscitated with pure LR or RS, all animals of the shock/LR group, but only three of eight shock/RS group rats were dead 100 min later (median survival, 50 ± 13.1 vs. 120 ± 14.1 min; P < 0.05). Coadministration of the shed blood with RS or LR increased the survival rates to 100%. In these blood-resuscitated groups, organ injury, especially of the kidney, was diminished by the use of RS compared with LR. Time-matched acid-base parameters were not different in all shock groups until death of the animals or euthanasia at the end of experimental time. We conclude that, in severe hemorrhagic shock, resuscitation with RS leads to an improved outcome compared with resuscitation with LR, regardless whether blood is coadministered or not.