Protective Effect of Crocin on Liver Function and Survival in Rats With Traumatic Hemorrhagic Shock.

BACKGROUND: This study investigated the underlying mechanism of crocin in protecting rats with traumatic hemorrhagic shock (THS) from liver injury. MATERIALS AND METHODS: Eighty Sprague Dawley rats were randomly divided into four groups (n = 20), namely, Sham group, THS group, crocin group, and Sodium Acetate Ringer group. A rat model of THS was induced by hemorrhage from the left femur fracture. The effects of crocin on hemodynamics, cardiac output, blood gas, animal survival rate, and liver function in the rats with THS were determined, and its relationship with oxidative stress was also explored. RESULTS: Crocin significantly improved the survival rate, hemodynamic parameters, increased tissue blood flow, and promoted the liver function of the THS rats. Further results indicated that crocin significantly inhibited oxidative stress in serum and liver tissue of THS rats, with increased levels of superoxide dismutase, catalase, and glutathione, and also reduced levels of malondialdehyde and myeloperoxidase levels. In addition, crocin greatly increased nuclear factor erythroid 2-related factor 2/heme oxygenase-1 level in liver tissues of THS rats. CONCLUSIONS: The protective mechanism of crocin on the liver of THS rats may be attributed to its abilities to stabilize hemodynamics, improve cardiac output and blood gas, increase antioxidant enzyme activity, reduce serum liver enzyme levels, and promote nuclear factor erythroid 2-related factor 2/heme oxygenase-1 pathway, thereby reducing oxidative stress.

Forgot calcium? Admission ionized-calcium in two civilian randomized controlled trials of prehospital plasma for traumatic hemorrhagic shock.

BACKGROUND: Randomized clinical trials (RCTs) support the use of prehospital plasma in traumatic hemorrhagic shock, especially in long transports. The citrate added to plasma binds with calcium, yet most prehospital trauma protocols have no guidelines for calcium replacement. We reviewed the experience of two recent prehospital plasma RCTs regarding admission ionized-calcium (i-Ca) blood levels and its impact on survival. We hypothesized that prehospital plasma is associated with hypocalcemia, which in turn is associated with lower survival. METHODS: We studied patients enrolled in two institutions participating in prehospital plasma RCTs (control, standard of care; experimental, plasma), with i-Ca collected before calcium supplementation. Adults with traumatic hemorrhagic shock (systolic blood pressure ≤70 mm Hg or 71-90 mm Hg + heart rate ≥108 bpm) were eligible. We use generalized linear mixed models with random intercepts and Cox proportional hazards models with robust standard errors to account for clustered data by institution. Hypocalcemia was defined as i-Ca of 1.0 mmol/L or less. RESULTS: Of 160 subjects (76% men), 48% received prehospital plasma (median age, 40 years [interquartile range, 28-53 years]) and 71% suffered blunt trauma (median Injury Severity Score [ISS], 22 [interquartile range, 17-34]). Prehospital plasma and control patients were similar regarding age, sex, ISS, blunt mechanism, and brain injury. Prehospital plasma recipients had significantly higher rates of hypocalcemia compared with controls (53% vs. 36%; adjusted relative risk, 1.48; 95% confidence interval [CI], 1.03-2.12; p = 0.03). Severe hypocalcemia was significantly associated with decreased survival (adjusted hazard ratio, 1.07; 95% CI, 1.02-1.13; p = 0.01) and massive transfusion (adjusted relative risk, 2.70; 95% CI, 1.13-6.46; p = 0.03), after adjustment for confounders (randomization group, age, ISS, and shock index). CONCLUSION: Prehospital plasma in civilian trauma is associated with hypocalcemia, which in turn predicts lower survival and massive transfusion. These data underscore the need for explicit calcium supplementation guidelines in prehospital hemotherapy. LEVEL OF EVIDENCE: Therapeutic, level II.

Nicotinamide mononucleotide preserves mitochondrial function and increases survival in hemorrhagic shock.

Hemorrhagic shock depletes nicotinamide adenine dinucleotide (NAD) and causes metabolic derangements that, in severe cases, cannot be overcome, even after restoration of blood volume and pressure. However, current strategies to treat acute blood loss do not target cellular metabolism. We hypothesized that supplemental nicotinamide mononucleotide (NMN), the immediate biosynthetic precursor to NAD, would support cellular energetics and enhance physiologic resilience to hemorrhagic shock. In a rodent model of decompensated hemorrhagic shock, rats receiving NMN displayed significantly reduced lactic acidosis and serum IL-6 levels, two strong predictors of mortality in human patients. In both livers and kidneys, NMN increased NAD levels and prevented mitochondrial dysfunction. Moreover, NMN preserved mitochondrial function in isolated hepatocytes cocultured with proinflammatory cytokines, indicating a cell-autonomous protective effect that is independent from the reduction in circulating IL-6. In kidneys, but not in livers, NMN was sufficient to prevent ATP loss following shock and resuscitation. Overall, NMN increased the time animals could sustain severe shock before requiring resuscitation by nearly 25% and significantly improved survival after resuscitation (P = 0.018), whether NMN was given as a pretreatment or only as an adjunct during resuscitation. Thus, we demonstrate that NMN substantially mitigates inflammation, improves cellular metabolism, and promotes survival following hemorrhagic shock.

Hypotensive resuscitation combined with polydatin improve microcirculation and survival in a rabbit model of uncontrolled hemorrhagic shock in pregnancy.

BACKGROUND: Obstetric hemorrhage remains a leading cause of maternal death internationally. Polydatin is an effective drug in ameliorating microcirculatory insufficiency and increasing survival rate in non-pregnant animal model of controlled hemorrhagic shock. In the present study, we investigated the effects of hypotensive resuscitation combined with Polydatin administration on microcirculation and survival rate in a clinically relevant model of uncontrolled hemorrhagic shock in pregnancy. MATERIALS AND METHODS: Twenty anesthetized New Zealand white rabbits at mid and late gestation were anesthetized, and an ear chamber was prepared to examine microvessels by intravital microscopy. Shock was induced by transecting a small artery in mesometrium, followed by blood withdrawal via the femoral artery to a mean arterial pressure (MAP) of 40-45 mm Hg. Animals were randomly divided into two groups (n=10 per group): 30 min after hemorrhage induction, hypotensive resuscitation with Ringer's solution to MAP of 60 mm Hg, followed by a single volume infusion of 4 mL/Kg of normal saline or Polydatin at 60 min after hemorrhage induction (group NS, PD). Finally all the animals received hemorrhage control and resuscitated with half of the heparinized shed blood and Ringer's solution to MAP of 80 mm Hg. RESULTS: At the end of resuscitation, compared with group NS, group PD showed significantly improved capillary perfusion as indicated by increased arteriole diameter [0.95±0.02 of baseline (PD), 0.71±0.05 of baseline (NS); P=0.000] and higher functional capillary density[95.3% ± 2.6% (PD), 57.2% ± 4.1% (NS); P=0.000]. Median survival time was significantly longer in group PD than that in group NS [4 d (PD), 2 d (NS); P=0.000]. CONCLUSIONS: On the basis of hypotensive resuscitation, Polydatin administration improved microcirculation and prolonged survival time in pregnant rabbit model of uncontrolled hemorrhagic shock.

Polyphenols of Camellia sinenesis decrease mortality, hepatic injury and generation of cytokines and reactive oxygen and nitrogen species after hemorrhage/resuscitation in rats.

BACKGROUND: Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced during hemorrhagic shock and resuscitation (H/R), which may contribute to multiple organ failure. The Aim of this study was to test the hypothesis that green tea (Camellia sinenesis) extract containing 85% polyphenols decreases injury after H/R in rats by scavenging ROS and RNS. METHODS: Female Sprague Dawley rats were given 100 mg polyphenol extract/kg body weight or vehicle 2 h prior to hemorrhagic shock. H/R was induced by two protocols: 1) withdrawal of blood to a mean arterial pressure of 40 mm Hg followed by further withdrawals to decrease blood pressure progressively to 28 mm Hg over 1 h (severe), and 2) withdrawal of blood to a sustained hypotension of 40 mm Hg for 1 h (moderate). Rats were then resuscitated over 1 h with 60% of the shed blood volume plus twice the shed blood volume of lactated Ringer's solution. Serum samples were collected at 10 min and 2 h after resuscitation. At 2 or 18 h, livers were harvested for cytokine and 3-nitrotyrosine quantification, immunohistochemical detection of 4-hydroxynonenol (4-HNE) and inducible nitric oxide synthase (iNOS) protein expression. RESULTS: After severe H/R, 18-h survival increased from 20% after vehicle to 70% after polyphenols (p < 0.05). After moderate H/R, survival was greater (80%) and not different between vehicle and polyphenols. In moderate H/R, serum alanine aminotransferase (ALT) increased at 10 min and 2 h postresuscitation to 345 and 545 IU/L, respectively. Polyphenol treatment blunted this increase to 153 and 252 IU/L at 10 min and 2 h (p < 0.01). Polyphenols also blunted increases in liver homogenates of TNFalpha (7.0 pg/mg with vehicle vs. 4.9 pg/mg with polyphenols, p < 0.05), IL-1beta (0.80 vs. 0.37 pg/mg, p < 0.05), IL-6 (6.9 vs. 5.1 pg/mg, p < 0.05) and nitrotyrosine (1.9 pg/mg vs. 0.6 pg/mg, p < 0.05) measured 18 h after H/R. Hepatic 4-HNE immunostaining indicative of lipid peroxidation also decreased from 4.8% after vehicle to 1.5% after polyphenols (p < 0.05). By contrast, polyphenols did not block increased iNOS expression at 2 h after H/R. CONCLUSION: Polyphenols decrease ROS/RNS formation and are beneficial after hemorrhagic shock and resuscitation.

Inhibition of intraluminal pancreatic enzymes with nafamostat mesilate improves clinical outcomes after hemorrhagic shock in swine.

BACKGROUND: Recent studies suggest that intraluminal pancreatic enzymes play a major role in the initiation of the inflammatory cascade by the gut after hemorrhagic shock. Previous animal models have shown that the inhibition of enteral pancreatic enzymes with a serine protease inhibitor, nafamostat mesilate (NM), decreases leukocyte activation and transfusion requirements after hemorrhagic shock. The objective of this study was to determine whether enteroclysis with NM would improve the clinical outcomes in swine after hemorrhagic shock and intestinal hypoperfusion. METHODS: Thirty-three male Yucatan minipigs weighing 25 kg to 30 kg underwent a controlled hemorrhage of 25 mL/kg with mesenteric clamp for further gut ischemia. Animals were allocated to three groups: (1) shock only (n = 15), (2) shock + enteroclysis with 100 mL/kg GoLYTELY (GL) as a carrier (n = 11), and (3) shock + enteroclysis with GL + 0.37 mmol/L NM (GL+NM, n = 7). Animals were resuscitated, recovered from anesthesia, observed for 3 days, and graded on a daily 4-point clinical scoring system. A score of 0 indicated a moribund state or early death, and a score of 4 indicated normal behavior. RESULTS: Pigs treated with GL + NM had significantly higher mean postoperative recovery scores (3.8 +/- 0.4, essentially normal behavior with no early deaths) compared with animals within the shock only and shock + GL groups (2.1 +/- 1 with one early death and 2.2 +/- 1.2 with two early deaths, respectively, analysis of variance p < 0.003). CONCLUSION: The inhibition of intraluminal pancreatic enzymes using enteroclysis with the serine protease inhibitor, NM, after hemorrhagic shock significantly improves the clinical outcome.

Does the type of resuscitative fluid affect healing of colonic anastomosis in experimentally induced hemorrhagic shock in rats?

OBJECTIVE: The aim of the study was to investigate the effects of different resuscitative fluids on the healing of intestinal anastomosis in a hemorrhagic-shock rat model. MATERIALS AND METHODS: Closed-colony Wistar male rats (n = 40; 8 rats per group) were subjected to volume-controlled hemorrhagic shock, followed by a 30-min shock phase. The animals were then resuscitated with one of the following fluids (which also corresponds to their respective groups): lactated Ringer's solution (LR), hydroxyethyl starch (HES), 7.5% hypertonic saline (HS) and autologous blood (AB). There was also a control group (CL), which did not experience hemorrhagic shock or receive any resuscitative fluids. All rats underwent laparotomy, segmental resection and anastomosis of the left colon. Five days later, a 2nd laparotomy was performed and the anastomotic bursting pressure was measured in vivo. Thereafter, the anastomosed segment was resected to measure the tissue hydroxyproline level and the grade of anastomotic fibrosis. RESULTS: All experimental groups (LR, HES, HS and AB) exhibited lower anastomotic bursting pressures than the CL group; however, no intergroup differences achieved statistical significance. The mean tissue hydroxyproline level and fibrosis grade also were similar across all 5 groups. CONCLUSION: In traumatic hemorrhagic shock, anastomosis safety does not appear to be affected by the type of fluid used for resuscitation. Moreover, LR, HES and HS all seemed to reinforce healing as effectively as transfused blood.

Vasoactivity of bovine polymerized hemoglobin (HBOC-201) in swine with traumatic hemorrhagic shock with and without brain injury.

BACKGROUND: We previously reported that bovine polymerized hemoglobin (HBOC- 201) improved outcome in swine with hemorrhagic shock (HS) with and without traumatic brain injury (TBI). Herein, we add analyses of blood pressure (BP) responses, associated physiologic data, and HS fluid infusion guidelines. METHODS: HBOC-201 versus standard fluid resuscitation was compared in four anesthetized invasively monitored swine models: moderate controlled HS, severe controlled HS, severe uncontrolled HS (liver injury), and severe uncontrolled HS/TBI (liver/parietal brain injuries). Pigs received fluid for hypotension and tachycardia, and were followed up to 6 (HS alone) or 72 hours (HS/TBI). The change in mean arterial pressure (DeltaMAP) response severity was stratified and analyzed based on infusion number and HS severity, using Student's t and Fisher's exact tests. RESULTS: HBOC-201 vasoactivity resulted in higher MAP in all studies. Among HBOC-201 pigs, DeltaMAP responses were significant for the first two infusions and inversely related to HS severity. Among controls, DeltaMAP responses remained significant through the fourth infusion in controlled HS models, and through the first in severe uncontrolled HS/TBI; none were significant in severe uncontrolled HS. DeltaMAP was higher with HBOC-201 through the first infusion in moderate controlled HS, the fifth in severe uncontrolled HS, and the second in severe uncontrolled HS/TBI; there were no group differences in severe controlled HS. No severe MAP responses occurred. Higher DeltaMAP severity did not impact outcome. Hypotension satisfied fluid reinfusion criteria less consistently than tachycardia. Overall, HBOC-201 improved physiologic parameters and survival without causing hypoperfusion; in severe HS, perfusion improved. CONCLUSIONS: In swine with HS +/- TBI, HBOC-201 had mild to moderate vasoactivity, resulting in significant DeltaMAP responses mainly after initial infusions, no severe/adverse responses, and improved outcome. Our data suggest that use of physiologic parameters (e.g., tachycardia), in addition to hypotension to guide fluid reinfusion during HS resuscitation with HBOC-201, will minimize hypoperfusion risk and maximize potential benefit.

Survival in a rat model of lethal hemorrhagic shock is prolonged following resuscitation with a small volume of a solution containing a drag-reducing polymer derived from aloe vera.

Drag-reducing polymers (DRP) increase tissue perfusion at constant driving pressure. We sought to evaluate the effects of small-volume resuscitation with a solution containing a DRP in a rat model of hemorrhage. Anesthetized rats were hemorrhaged at a constant rate over 25 min. In protocol A, total blood loss was 2.45 mL/100 g, whereas in protocol B, total blood loss was 3.15 mL/100 g. Five minutes after hemorrhage, the animals were resuscitated with 7 mL/kg of either normal saline (NS) or NS containing 50 microg/mL of an aloe vera-derived DRP. In protocol B, a third group (CON) was not resuscitated. Whole-body O2 consumption (Vo2) and CO2 production (Vco2) were measured using indirect calorimetry. In protocol A, 5/10 rats in the NS group and 8/10 rats in the DRP group survived for 4 h (P = 0.14). Mean arterial pressure was higher in the DRP-treated group than in the NS-treated group 45 min after resuscitation (89 +/- 8 vs. 68 +/- 5 mmHg, respectively; P < 0.05). In protocol B, survival rates over 2 h in the DRP, NS, and CON groups were 5/15, 1/14, and 0/7, respectively (P < 0.05). Compared with NS-treated rats, those resuscitated with DRP achieved a higher peak Vo2 (9.0 +/- 1.0 vs. 6,3+/- 1.0 mL/kg/min) and Vco2 (9.0 +/- 1.1 vs. 6.0 +/- 1.0 mL/kg/min) after resuscitation. We conclude that resuscitation with a small volume of DRP prolongs survival in rats with lethal hemorrhagic shock.

Involvement of the renin-angiotensin system in endogenous central histamine-induced reversal of critical haemorrhagic hypotension in rats.

The study was undertaken to examine the involvement of the renin-angiotensin system in the reversal by endogenous central histamine of critical haemorrhagic hypotension in anaesthetised Wistar rats. Histamine N-methyltransferase inhibitor metoprine (20 microg) administered intracerebroventricularly at 5 min of critical hypotension 20-25 mmHg produced increases in histamine concentrations as measured 20 min after treatment in the hypothalamus (581.33 +/- 63.23 vs. 488.26 +/- 56.34 ng/g of wet tissue; P < 0.01) and medulla oblongata (53.42 +/- 14.65 vs. 34.68 +/- 13.52 ng/g of wet tissue; P < 0.05). That was accompanied by 34.7% higher plasma angiotensin II concentration in comparison to the control group. Metoprine produced dose-dependent (5-20 microg) rises in mean arterial pressure (MAP) and heart rate, which were significantly higher than those in normotensive animals. The resuscitating action of metoprine (20 microg) was associated with rises in renal, mesenteric and hindquarters blood flows, and a 100% survival at 2 h after treatment, while in the saline-treated group, all the animals died within 30 min. Angiotensin type 1 (AT(1)) receptor antagonist ZD 7155 (0.5 mg/kg; iv) decreased regional vascular resistance and inhibited metoprine-induced increase in MAP, whereas AT(2) receptor blocker PD 123319 (10 mg/kg; i.v.) had no effect. Angiotensin-converting enzyme inhibitor captopril (30 mg/kg; i.v.) reduced the increase in plasma angiotensin II level and the haemodynamic effects of metoprine. Neither capropril, nor angiotensin receptor antagonists influence the survival at 2 h after treatment. In conclusion, the renin-angiotensin system is involved in central histamine-induced resuscitating action in rats.

Blood soluble drag-reducing polymers prevent lethality from hemorrhagic shock in acute animal experiments.

Over the past several decades, blood-soluble drag reducing polymers (DRPs) have been shown to significantly enhance hemodynamics in various animal models when added to blood at nanomolar concentrations. In the present study, the effects of the DRPs on blood circulation were tested in anesthetized rats exposed to acute hemorrhagic shock. The animals were acutely resuscitated either with a 2.5% dextran solution (Control) or using the same solution containing 0.0005% or 5 parts per million (ppm) concentration of one of two blood soluble DRPs: high molecular weight (MW=3500 kDa) polyethylene glycol (PEG-3500) or a DRP extracted from Aloe vera (AVP). An additional group of animals was resuscitated with 0.0075% (75 ppm) polyethylene glycol of molecular weight of 200 kDa (PEG-200), which possesses no drag-reducing ability. All of the animals were observed for two hours following the initiation of fluid resuscitation or until they expired. We found that infusion of the DRP solutions significantly improved tissue perfusion, tissue oxygenation, and two-hour survival rate, the latter from 19% (Control) and 14% (PEG-200) to 100% (AVP) and 100% (PEG-3500). Furthermore, the Control and PEG-200 animals that survived required three times more fluid to maintain their blood pressure than the AVP and PEG-3500 animals. Several hypotheses regarding the mechanisms underlying these observed beneficial hemodynamic effects of DRPs are discussed. Our findings suggest that the drag-reducing polymers warrant further investigation as a potential clinical treatment for hemorrhagic shock and possibly other microcirculatory disorders.

Prehospital resuscitation with phenylephrine in uncontrolled hemorrhagic shock and brain injury.

BACKGROUND: Hypotension doubles the adverse outcome of severe brain injury (BI). This finding is thought to be due to secondary ischemia caused by cerebral hypoperfusion. Aggressive prehospital fluid resuscitation in BI is advocated to maintain mean arterial pressure (MAP). Increasing MAP by prehospital fluid resuscitation before control of hemorrhage is thought to increase blood loss and reduce survival. We hypothesized that vasoconstrictor treatment of uncontrolled hemorrhage would increase MAP, reduce hemorrhage volume, and decrease the extent of BI compared with delayed fluid resuscitation (DR) or resuscitation with Ringer's lactate (RL). METHODS: Swine were randomly assigned to a control group or an experimental group: splenic laceration (uncontrolled hemorrhage) and cryogenic BI. The experimental group received one of three prehospital resuscitation regimens: DR, RL, or phenylephrine (Phen) to maintain baseline MAP. Variables were measured at baseline and at 20, 50, and 120 minutes during the simulated "prehospital and early hospital" phases and at 2 and 8 hours after surgical control of the uncontrolled hemorrhage. After killing, biopsies of the brain, liver, kidney, and gut were evaluated for histologic evidence of ischemia and compared between groups. RESULTS: Hemorrhage volume was similar in the experimental groups. Mortality was lowest in the Phen group (11%) compared with DR (40%) and RL (33%) groups. Phen increased MAP and cerebral perfusion pressure. RL infusion increased cerebral blood flow and resulted in less secondary injury than either Phen or DR. CONCLUSION: Phen improves MAP and systemic and cerebral perfusion pressure in the prehospital phase but does not reduce secondary neuronal ischemia. RL restores cerebral blood flow earlier and is associated with less secondary ischemia than either Phen or DR in this model. These data suggest that prehospital infusion of RL in patients with BI and shock is warranted and decreases secondary ischemia.

[The mechanism of the action of opiate receptor antagonists in acute shock-induced blood loss]. / K mekhanizmu deistviia antagonistov opiatnykh retseptorov pri ostroi shokogennoi krovopotere.

Experiments on 81 rabbits showed that intravenous infusion of naloxone and nalorphine in different periods of hemorrhagic shock promoted the death of animals. It is concluded that in hypoxia only the antagonistic activity of the drugs is manifested as total inactivation of the endogenous opioid system depriving it of its protective functions. Nalorphine infused after blood reinfusion exhibits agonistic activity and additional activation of the endogenous opioid system promotes the use of the biological reserves by the organism, which saves some of the animals from death or essentially prolongs the survival of the others. Infusion of naloxone after blood transfusion has no effect on the outcome.

Significance of NO in hemorrhage-induced hemodynamic alterations, organ injury, and mortality in rats.

In an attempt to evaluate the role of nitric oxide (NO) in pathophysiological alterations and multiple organ damage caused by hemorrhagic shock, we employed NG-monomethyl-L-arginine (L-NMMA), an inhibitor of NO synthase, in anesthetized rats subjected to a prolonged hypovolemic insult (30-35 mmHg for 180 min). Infusion of 2.0 mg/kg L-NMMA at the end of resuscitation diminished the fall in mean arterial pressure (MAP) and significantly increased the cardiac index and stroke volume, together with remarkable protection from multiple organ damage compared with the controls. The 48-h survival rate was significantly improved from 26.7% in the control group to 68.8% in the treatment group (P < 0.05). In contrast, the high dose of 20.0 mg/kg L-NMMA resulted in a strong blood pressure response, but a marked reduction in cardiac index and stroke volume concomitant with an increased total peripheral resistance index within the observation period, and tended to increase damage to various organs at 2 h after treatment. In addition, marked elevation in both endotoxin and tumor necrosis factor levels were observed in animals subjected to shock insult. The results suggest that NO induced by hemorrhagic shock in rats is an important mediator for pathophysiological alterations associated with cardiovascular abnormalities, multiple organ dysfunction, and even lethality. Regulation of NO generation and use of NO inhibitors might provide new aspects in the treatment of hemorrhage-related disorders, whereas the administration of L-NMMA would be either deleterious or salutary in a dose-dependent manner.

Liver function and morphology after resuscitation from severe hemorrhagic shock with hemoglobin solutions or autologous blood.

OBJECTIVE: To test the effects of three hemoglobin solutions on liver function and hepatic morphology after resuscitation from severe hemorrhagic shock. DESIGN: Prospective study. SETTING: Laboratory. SUBJECTS: Thirty-three beagle dogs. INTERVENTION: Hemorrhagic shock was induced in anesthetized dogs by removal of blood at a rate of 2 mL/kg/min until systolic blood pressure (BP) reached 50 mm Hg. BP was maintained at this level 2 hrs by further withdrawing 5 to 10 mL aliquots whenever BP increased > 50 mm Hg. Resuscitation was then initiated with autologous whole blood (n = 7), 4% pyridoxalated-hemoglobin-polyoxyethylene conjugate (4% PHP [n = 6]), 8% pyridoxalated-hemoglobin-polyoxyethylene conjugate (8% PHP [n = 9], or 8% stroma-free hemoglobin (n = 7). Four dogs were managed identically but were not resuscitated. Gross necropsy and histologic examination of the liver were performed on all dogs after 7 days, or earlier if death occurred. MEASUREMENTS AND MAIN RESULTS: In vitro interferences of PHP and stroma-free hemoglobin with liver function tests were determined and recommendations for interpretation of results from blood samples containing PHP and stroma-free hemoglobin were made. Blood was collected before, during, and after resuscitation from hemorrhagic shock. The dogs were then awakened and survivors were monitored daily with blood sampling until they were killed and necropsy was performed. After 7 days, the survival rate following hemorrhagic shock was 100% for whole blood and 4% PHP, 86% for stroma-free hemoglobin, and 33% for 8% PHP. Of the resuscitated dogs not surviving 7 days, all but one died within 27 hrs from coagulopathy. All dogs not resuscitated died within 1.75 hrs after 2 hrs of shock. Bilirubin, alkaline phosphatase, and lactic dehydrogenase concentrations could not be measured due to interferences of stroma-free hemoglobin and PHP. Aspartate (AST) and alanine (ALT) aminotransferase concentrations could be measured after dilution to overcome the interferences. Significant increases in AST and ALT values in all groups 24 hrs after resuscitation were attributed to hypoxic hepatocellular damage associated with the severity of the shock model rather than to the resuscitation fluid. Liver histology showed no changes attributed to toxic damage of hepatocytes in dogs resuscitated with stroma-free hemoglobin or PHP. However, changes, were less severe in dogs resuscitated with 4% PHP than in other groups. CONCLUSION: Morphologic studies at necropsy and liver function tests in dogs receiving hemoglobin solutions, compared with autologous blood, support the conclusion that the PHP and stroma-free hemoglobin solutions tested did not produce hepatic toxicity when used as resuscitation fluids in this model of severe shock.

Salutary consequences of oxygen therapy on the long-term outcome of hemorrhagic shock in awake, unrestrained rats.

Decreased oxygen delivery and cellular hypoxia are major factors in the pathophysiology of shock. We studied the effects of 100% O2 at 0.1 and 0.3 MPa (1 and 3 atm abs) in severe hemorrhagic shock in awake, unrestrained rats. Shock was induced by withdrawing 50% of the total blood volume within 120 min. Blood pressure, heart rate, and the electroencephalogram (EEG) were recorded during the first 6 h of the protocol. The animals were observed for 7 days. The shock protocol resulted in 60 and 90% mortality after 1 day and at the end of 7 days, respectively. A single 90-min exposure to O2 at 0.1 and 0.3 MPa, which was started 30 min after bleeding, maintained mean arterial blood pressure at significantly higher values compared to untreated controls throughout the exposure period (P < 0.05). Oxygen therapy at both doses also improved the long-term survival rate and survival time significantly (P < 0.01). No clinical or EEG sign of CNS O2 toxicity was detected in O2-treated animals. Our results indicate that O2 given alone after severe bleeding exerts a beneficial effect on the long-term outcome of hemorrhagic shock in awake, unrestrained rats.

Controversies in shock research: hypertonic resuscitation--pros and cons.

The proper fluid resuscitation of hemorrhagic shock is still controversial. Hypertonic saline has been suggested for prehospital resuscitation of hemorrhagic shock, because of its superior ability to expand blood volume and elevate systemic blood pressure and cardiac output in a small volume and during a short time period. We have defined two types of hemorrhagic shock: controlled hemorrhagic shock (CHS), where the bleeding source is immediately occluded following hemorrhage, and uncontrolled hemorrhagic shock (UCHS), where bleeding is induced by injury to blood vessels that are left unoccluded. It was observed that hypertonic saline (HTS) treatment of controlled hemorrhagic shock leads to an increase in blood pressure and cardiac output, while HTS treatment of UCHS leads to increased bleeding from injured blood vessels, hemodynamic deterioration, and increased mortality. Conversion of UCHS to CHS by tourniquet, military antishock trousers, or surgical hemostasis prevented excessive bleeding and mortality following HTS. Several clinical studies have used hypertonic saline dextran (HSD) or hypertonic saline (HS) for treatment of trauma casualties, but to date no significant improvement in mortality has been demonstrated by either HS or HSD. A more favorable effect but still not statistically significant effect has been demonstrated in patients with a Glasgow Coma Scale of 8 or less. The efficacy of HS has not clearly been established in clinical trials, in all of which HS was used in combination with conventional crystalloid therapy. Further human trials are required to better define the patient population that would benefit most from the prehospital administration of HS.

Amrinone improves survival in hemorrhagic shock.

Amrinone is a noncatecholamine inotropic agent used clinically in the management of heart failure. The purpose of this study was to determine if intravenous (i.v.) infusion of amrinone has beneficial effects during resuscitation from experimental hemorrhagic shock. Effectiveness was defined as significantly improved survival rate. Mean arterial pressure (MAP) and tissue oxygen tension (pO2) were measured to assess the physiologic effects of amrinone. Two separate randomized and blinded survival trials were conducted. In each trial, rats were randomly assigned to either a control group (n = 10) or an experimental group (n = 10). All animals were bled 27 ml/kg over 2 minutes and maintained in shock for 45 minutes before resuscitation. Resuscitation in placebo (control) animals was with 54 ml/kg (2 times the hemorrhage volume) Lactated Ringer's solution over 1 hour, whereas resuscitation in drug-treated animals was with a 0.75 mg/kg bolus amrinone over 3 minutes followed by 54 ml/kg Lactated Ringer's solution and 5 ug/kg/min infusion over 1 hour. Results were that resuscitation with amrinone significantly increased MAP, tissue pO2, and survival over resuscitation with Lactated Ringer's alone (P < 0.05). In both trials, survival rates increased by more than 66 per cent in the amrinone groups.

Effects of poloxamer 188 in a rabbit model of hemorrhagic shock.

Poloxamer 188 is a synthetic surfactant that reduces the viscosity of whole blood without hemodilution. It is postulated that poloxamer 188 would improve outcome if administered during retransfusion following hemorrhage. Rabbits were anesthetized and instrumented for 3 hours of hemodynamic monitoring. After stabilization, blood was withdrawn over a 5 minute period to reduce mean arterial pressure to 35 mmHg (4.7 kPa). Following a 60 minute shock period, animals were randomly assigned to 1 of 5 experimental groups (n = 8 in each): (1) Shock (no retransfusion); (2) Transfusion (retransfusion of autologous shed blood); (3) Volume (retransfusion with autologous blood and infusion of an additional volume of normal saline equivalent to the volume of poloxamer 188 given in the next 2 experimental groups); (4) Low and (5) High drug (i.v. bolus of 200 mg/kg of poloxamer 188 over 5 minutes at retransfusion, followed by a continuous infusion of poloxamer 188 at 50 mg/kg/hr in the Low drug group and 200 mg/kg/hr in the High drug group). All animals in a surgery Control group (n = 6) remained stable during the 3 hour monitoring period. In contrast, none of the animals in the Shock group remained alive, confirming this to be a relevant model of trauma and severe hemorrhagic shock. There were significantly more animals surviving at the end of the monitoring period in the two groups that received poloxamer 188 (numbers of animals alive after 3 hours = 7 of 8 in the High group and 6 of 8 in the Low group) compared to the Transfusion (4 of 8) and Volume (2 of 8) groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[The reinfusion of blood and the administration of dalargin in experimental hemorrhagic shock]. / Reinfuziia krovi i vnutrivennoe vvedenie dalargina pri éksperimental'nom gemorragicheskom shoke.

In acute experiment on 95 adult rabbits it was determined that during the subdivided blood exfusion from femoral artery in the volume of (16 + 1) ml/kg the reversible hemorrhagic shock occurs and the animals survive without the hemorrhage compensation. The increase of hemorrhage volume up to (23 + 3) ml/kg leads to lethal hemorrhagic shock. The heparinized blood reinfusion in the early period promotes the survival of the whole of animals, in the late period it promotes trustworthy their life span increase. Under the influence of dalargin intravenous infusion in the dose of 0.1 mg/kg after the blood reinfusion in the late period of shock all the animals survived. Intravenous infusion of dalargin is expedient for the increase of the transfusion therapy effectiveness in the late period of hemorrhagic shock.