SMALL-VOLUME FLUID RESUSCITATION WITH HYPERTONIC SALINE PREVENTS INFLAMMATION BUT NOT MORTALITY IN A RAT MODEL OF HEMORRHAGIC SHOCK

Effect of Hypertonic Saline Solution on the Ventilatory Mechanics of Lungs Donated After Brain Death

INTRODUCTION

Brain death (BD) compromises the viability of the lung for donation. Hypertonic saline solution (HSS) induces rapid intravascular volume expansion and immunomodulatory action. We investigated its role in ventilatory mechanics (VMs) and in the inflammatory activity of the lungs of rats subjected to BD.

METHODS

Wistar rats were divided into four groups: control, n = 10: intact rats subjected to extraction of the heart-lung block; BD, n = 8 (BD): rats treated with isotonic saline solution (4 mL/kg) immediately after BD; hypertonic saline 0 h, n = 9 (Hip.0'): rats treated with HSS (4 mL/kg) immediately after BD; and hypertonic saline 1 h, n = 9 (Hip.60'), rats treated with HSS (4 mL/kg) 60 min after BD. The hemodynamic characteristics, gas exchange, VMs, inflammatory mediators, and histopathological evaluation of the lung were evaluated over 240 min of BD.

RESULTS

In VMs, we observed increased airway resistance, tissue resistance, tissue elastance, and respiratory system compliance in the BD group (P < 0.037), while the treated groups showed no impairment over time (P > 0.05). In the histological analysis, the BD group showed a greater area of perivascular edema and a higher neutrophil count than the control group and the Hip.60' group (P < 0.05).

CONCLUSIONS

Treatment with HSS was effective in preventing changes in the elastic and resistive pulmonary components, keeping them at baseline levels. Late treatment reduced perivascular and neutrophilic edema in lung tissue.

Effects of nebulized hypertonic saline on inflammatory mediators in patients with severe COVID-19 pneumonia: A double-blinded randomized controlled trial

INTRODUCTION

An exaggerated immune response is considered the most important aspect of COVID-19 pathogenesis. Hypertonic saline (HS) has shown promise in combating inflammation in several respiratory diseases. We investigated the effects of nebulized HS on clinical symptoms and inflammatory status in patients with severe novel coronavirus infection (COVID-19) pneumonia.

MATERIALS AND METHODS

We randomly assigned 60 adults admitted to the intensive care unit (ICU) due to severe COVID-19 pneumonia to the experimental (received nebulized 5% saline) and control (received nebulized distilled water) groups. All interventions were applied 4 times daily for 5 days. The levels of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and other clinical factors from venous blood were evaluated before and after intervention application. Mortality rate, intubation rate, and durations of ICU and hospital stay were also compared between groups.

RESULTS

The levels of TNF-α (MD: -21.35 [-32.29, -10.40], P  =  0.000) and IL-6 (-9.94 [-18.86, -1.02], P  =  0.003) were lower in the experimental group compared to the control group after applying the interventions. The levels of white blood cell count, PO2, and serum sodium were also statistically significant differences between groups. However, we did not observe significant differences in terms of hospitalization durations and mortality rates.

CONCLUSION

Nebulization of HS in patients with severe COVID-19 pneumonia appears to be effective in reducing inflammation, but does not appear to affect intubation rates, mortality, hospitalization, or length of stay in ICU.

Articles on hemorrhagic shock published between 2000 and 2021: A CiteSpace-Based bibliometric analysis

Objective

To conduct a bibliometric analysis of literature on hemorrhagic shock published between 2000 and 2021 with the help of Citespace to explore the current status, hotspots and research trends in this regard, with the results presented in a visualized manner.

Methods

The data over the past 22 years were retrieved from the Web of Science (WOS) Core Collection database and downloaded as the "Full Record and Cited References". Cooperative analysis, cluster analysis, co-citation analysis, and burst analysis were performed based on the data on countries/regions, institutions, journals, authors, and keywords through Citespace.

Results

A total of 2027 articles were retrieved. The number of annual publications fluctuated but was generally on an upward trend. The United States stands out as the most productive country (989 articles), the University of Pittsburgh the most productive publishing institution (109 articles), SHOCK the most cited journal (1486 articles), TAO LI the most productive author (40 articles), DEITCH EA the most cited author (261 times of citation), hemorrhagic shock the most frequent keyword (725 times of occurrence), and "traumatic brain injury" the most covered article in keyword clustering (29 articles). The burst analysis revealed Harvard University as the institution with the highest strength value and the Journal of Trauma and Acute Care Surgery the most important journal. It was also concluded that HASAN B ALAM, AARON M WILLIAMS, and LIMIN ZHANG may continue to publish high-quality articles in the future. In the meanwhile, both "protect" and "transfusion" were considered the hotspots and trends in current research.

Conclusions

The United States has been a major contributor to the publication of the articles over the past 22 years, with the most productive publishing institution, the most cited journal, and the most cited author all coming from the US. Hemorrhagic shock, injury, resuscitation, trauma, models, activation, expression, fluid resuscitation, rats, and nitric oxide are hot topics in relevant research. According to the keyword burst analysis, the areas related to "protect" and "transfusion" may rise as the research directions in the future. However, since the hotspots in the research of hemorrhagic shock are short-lived and fast-changing, the researchers should pay more attention to the development trend in this field.

Terlipressin combined with conservative fluid management attenuates hemorrhagic shock-induced acute kidney injury in rats

Hemorrhagic shock (HS), a major cause of trauma-related mortality, is mainly treated by crystalloid fluid administration, typically with lactated Ringer's (LR). Despite beneficial hemodynamic effects, such as the restoration of mean arterial pressure (MAP), LR administration has major side effects, including organ damage due to edema. One strategy to avoid such effects is pre-hospitalization intravenous administration of the potent vasoconstrictor terlipressin, which can restore hemodynamic stability/homeostasis and has anti-inflammatory effects. Wistar rats were subjected to HS for 60 min, at a target MAP of 30-40 mmHg, thereafter being allocated to receive LR infusion at 3 times the volume of the blood withdrawn (liberal fluid management); at 2 times the volume (conservative fluid management), plus terlipressin (10 µg/100 g body weight); and at an equal volume (conservative fluid management), plus terlipressin (10 µg/100 g body weight). A control group comprised rats not subjected to HS and receiving no fluid resuscitation or treatment. At 15 min after fluid resuscitation/treatment, the blood previously withdrawn was reinfused. At 24 h after HS, MAP was higher among the terlipressin-treated animals. Terlipressin also improved post-HS survival and provided significant improvements in glomerular/tubular function (creatinine clearance), neutrophil gelatinase-associated lipocalin expression, fractional excretion of sodium, aquaporin 2 expression, tubular injury, macrophage infiltration, interleukin 6 levels, interleukin 18 levels, and nuclear factor kappa B expression. In terlipressin-treated animals, there was also significantly higher angiotensin II type 1 receptor expression and normalization of arginine vasopressin 1a receptor expression. Terlipressin associated with conservative fluid management could be a viable therapy for HS-induced acute kidney injury, likely attenuating such injury by modulating the inflammatory response via the arginine vasopressin 1a receptor.

Divergent Effects of Hypertonic Fluid Resuscitation on Renal Pathophysiological and Structural Parameters in Rat Model of Lower Body Ischemia/Reperfusion-Induced Sterile Inflammation

The pathogenesis of acute kidney injury (AKI) is characterized by the deterioration of tissue perfusion and oxygenation and enhanced inflammation. The purpose of this study was to investigate whether or not the hemodynamic and inflammatory effects of hypertonic saline (HS) protect the kidney by promoting renal microcirculatory oxygenation and possible deleterious effects of HS due to its high sodium content on renal functional and structural injury following ischemia/reperfusion. Mechanically ventilated and anesthetized rats were randomly divided into four groups (n = 6 per group): a sham-operated control group; a group subjected to renal ischemia for 45 min by supra-aortic occlusion followed by 2 h of reperfusion (I/R); and I/R group treated with a continuous i.v. infusion (5 mL/kg/h) of either % 0.9 NaCl (IR+NS) or %10 NaCl (I/R+HS) after releasing the clamp. Systemic and renal hemodynamic, renal cortical (CμPO2), and medullar microcirculatory pO2 (MμPO2) are measured by the oxygen-dependent quenching of the phosphorescence lifetime technique. Renal functional, inflammatory, and tissues damage parameters were also assessed. HS, but not NS, treatment restored I/R-induced reduced mean arterial pressure, CμPO2, renal oxygen deliver (DO2ren), and consumption (VO2ren). HS caused a decrease in tubular sodium reabsorption (TNa) that correlated with an elevation of fractional sodium excretion (EFNa) and urine output. HS had an anti-inflammatory effect by reducing the levels TNF-α, IL-6, and hyaluronic acid in the renal tissue samples as compared with the I/R and I/R+NS groups (P < 0.05). HS treatment was also associated with mild acidosis and an increased renal tubular damage. Despite HS resuscitation improving the systemic hemodynamics, microcirculatory oxygenation, and renal oxygen consumption as well as inflammation, it should be limited or strictly controlled for long-term use because of provoking widespread renal structural damage.

Secretome Conveys the Protective Effects of ASCs: Therapeutic Potential Following Hemorrhagic Shock?

OBJECTIVES

We tested whether resuscitation supplemented with rat adipose-derived stem cells (ASCs) or secretome (conditioned media) of ASCs can ameliorate inflammation, cell/organ injury, and/or improve outcome after hemorrhagic traumatic shock (HTS).

INTERVENTIONS

Rats were subjected to HTS and a resuscitation protocol that mimics prehospital restrictive reperfusion followed by an adequate reperfusion phase. Twenty minutes into the restrictive reperfusion, animals received an intravenous bolus of 2 × 10 cells (ASC group) or the secretome produced by 2 × 10 ASCs/24 h (ASC-Secretome group). Controls received the vehicle (Vehicle group). All rats were observed for 28-day survival.

MEASUREMENTS AND MAIN RESULTS

HTS-induced inflammation represented by IL-6 was inhibited in the ASC (80%, P < 0.001) and in ASC-Secretome (59%, P < 0.01) group at 48 h compared with Vehicle group. At 24 h, HTS-induced liver injury reflected in plasma alanine aminotransferase was ameliorated by 36% (P < 0.001) in both the ASC and ASC-Secretome groups when compared with the Vehicle. There was no effect on kidney function and/or general cell injury markers. HTS induced a moderate 28-day mortality (18%) that was prevented (P = 0.08) in the ASC but not in the ASC-Secretome group (12%).

CONCLUSIONS

Our data suggest that the ASC-secretome supplemented resuscitation following HTS, in the absence of the stem cells, exerts anti-inflammatory and liver protective effects. Given its ease of preparation, storage, availability, and application (in contrast to the stem cells) we believe that the cell-free secretome has a better therapeutic potential in the early phase of an acute hemorrhagic shock scenario.

Experimental Models of Endotheliopathy: Impact of Shock Severity

BACKGROUND

Hemorrhagic shock (HS) followed by resuscitation is often associated with sympathoadrenal activation (SAA) and endothelial damage (ED).

OBJECTIVE

We aimed to evaluate the impact of HS alone on the magnitude of SAA and consecutive ED, and to characterize potential targets for a standardized and reproducible model of HS-induced endotheliopathy in rats.

METHODS

Rats were subjected either to a volume-controlled HS (40% of total blood volume: v-HS group) or to a laboratory-guided HS (l-HS) targeting base deficit (BD) more than 5.5 mmol/L and/or lactate more than 2.2 mmol/L using a pressure-controlled volume loss.

RESULTS

At the end of shock, mean arterial pressure was significantly higher in the v-HS than the l-HS group (36 ± 5.6 vs. 30 ± 3.0 mmHg; P < 0.01). Base deficit and lactate were higher in l-HS than the v-HS group (BD: 9.5 ± 2.5 vs. 3.0 ± 1.0 mmol/L; P < 0.001; lactate: 4.1 ± 1.3 vs. 1.6 ± 0.6 mmol/L; P < 0.001). sVEGFR-1 and syndecan-1 were approximately 50% higher in the l-HS than the v-HS group (% changes vs. baseline: 160 ± 10 vs. 116 ± 36; P < 0.01; 170 ± 37 vs. 113 ± 27; P < 0.001). Adrenaline was 2-fold higher in l-HS than the v-HS group (1964 ± 961% vs. 855 ± 451%; P < 0.02, respectively). Moreover, linear regression analysis revealed an independent association of shock severity BD with syndecan-1 (rho = 0.55, P = 0.0005), sVEGFR1 (rho = 0.25, P < 0.05), and adrenaline (rho = 0.31, P = 0.021).

CONCLUSIONS

Our findings indicate that ED has already occurred during HS without reperfusion; intensity is strongly related to the severity of HS and consecutive SAA; and severity may appropriately be targeted and standardized in a HS model controlled by biological endpoints such as BD and/or lactate.

Organ-Specific Oxidative Events under Restrictive Versus Full Reperfusion Following Hemorrhagic Traumatic Shock in Rats

Background aim: Reperfusion after hemorrhagic traumatic shock (HTS) is often associated with complications that are partly ascribed to the formation of reactive oxygen species (ROS). The aim of our study was to compare the effects of restrictive reperfusion (RR) to rapid full reperfusion (FR) on ROS formation and/or oxidative events.

MATERIALS AND METHODS

Anesthetized male rats were randomly subjected to HTS followed by FR (75 mL/kg/h) or RR (30 mL/kg/h for 40 min, followed by 75 mL/kg/h) with Ringer's solution (n = 8/group). Compartment-specific ROS formation was determined by infusion of ROS scavenger 1-hydroxy-3-carboxy-2,2,5,5-tetramethyl-pyrrolidine hydrochloride (CP-H) during resuscitation, followed by electron paramagnetic resonance spectroscopy. Sham-operated animals (n = 8) served as controls. The experiment was terminated 100 min post-shock.

RESULTS

Mean arterial pressure was significantly higher in the FR compared to the RR group during early reperfusion. Only RR animals, not FR animals, showed significantly higher ROS concentrations in erythrocytes (1951 ± 420 vs. 724 ± 75 AU) and in liver (474 ± 57 vs. 261 ± 21 AU) compared to sham controls. This was accompanied by elevated alanine aminotransferase and creatinine levels in RR animals compared to both shams and FR animals, while lipid peroxidation products (thiobarbituric acid reactive substances) were significantly increased only in the kidney in the FR group (p < 0.05). RR animals showed significantly higher plasma peroxiredoxin-4 values when compared to the FR group (20 ± 2 vs. 14 ± 0.5 RLU).

CONCLUSION

Restrictive reperfusion after HTS is associated with increased ROS formation in erythrocytes and liver compared to sham controls. Moreover, the restrictive reperfusion is associated with a more pronounced injury to the liver and kidney, which is likely mediated by other than lipid peroxidation process and/or oxidative stress reactions.

Ringer's lactate solution enhances the inflammatory response during fluid resuscitation of experimentally induced haemorrhagic shock in rats

INTRODUCTION

Hemorrhagic shock leads to systemic oxygen deficit (hypoxaemia) that results in systemic inflammatory response syndrome (SIRS), a recognised cause of late mortality in this case. The aim of this study was to analyse the impact of fluid resuscitation, using two Ringer solutions, on the microcirculation changes that take place during experimentally induced haemorrhagic shock.

MATERIAL AND METHODS

A model of the rat cremaster muscle was used to assess microcirculation in vivo. The experimental groups (n = 10 each) included: control (CTRL); shock (HSG); Ringer's acetate (RAG); and Ringer's lactate (RLG). Microhaemodynamic parameters were measured during the experiment.

RESULTS

A statistically significantly higher level of leukocytes, both those attached to the endothelium and those located in the extravascular space (p < 0.05), was reported in the lactate Ringer (LR) group compared with the AR group. There were significant differences in the activity of A3 arterioles compared with A1 and A2 arterioles. Ringer's lactate solution seemed to the inflammation response during fluid resuscitation from haemorrhagic shock. A3 arterioles are likely to play a role as a pre-capillary sphincter in the skeletal muscle.

CONCLUSIONS

The present study revealed that fluid resuscitation with Ringer's lactate solution exacerbates inflammation in the skeletal muscle. It is worth noting that Ringer's acetate solution reduces local inflammation and could therefore be recommended as the "first line" crystalloid of the fluid resuscitation during haemorrhagic shock.

Hypertonic saline attenuates the cytokine-induced pro-inflammatory signature in primary human lung epithelia

Trauma/hemorrhagic shock is a complex physiological phenomenon that leads to dysregulation of many molecular pathways. For over a decade, hypertonic saline (HTS) has been used as an alternative resuscitation fluid in the setting of trauma/hemorrhagic shock. In addition to restoring circulating volume within the vascular space, studies have shown a positive immunomodulatory effect of HTS. Targeted studies have shown that HTS affects the transcription of several pro-inflammatory cytokines by inhibiting the NF-κB-IκB pathway in model cell lines and rats. However, few studies have been undertaken to assess the unbiased effects of HTS on the whole transcriptome. This study was designed to interrogate the global transcriptional responses induced by HTS and provides insight into the underlying molecular mechanisms and pathways affected by HTS. In this study, RNA sequencing was employed to explore early changes in transcriptional response, identify key mediators, signaling pathways, and transcriptional modules that are affected by HTS in the presence of a strong inflammatory stimulus. Our results suggest that primary human small airway lung epithelial cells (SAECS) exposed to HTS in the presence and absence of a strong pro-inflammatory stimulus exhibit very distinct effects on cellular response, where HTS is highly effective in attenuating cytokine-induced pro-inflammatory responses via mechanisms that involve transcriptional regulation of inflammation which is cell type and stimulus specific. HTS is a highly effective anti-inflammatory agent that inhibits the chemotaxis of leucocytes towards a pro-inflammatory gradient and may attenuate the progression of both the innate and adaptive immune response.

Hypertonic Saline in the Treatment of Hemorrhagic Shock

Context

The present review discusses different studies about the treatment of hemorrhagic shock (HS) with hypertonic saline (HTS).

Evidence acquisition

We have searched the title in the most popular databases containing recent meta-analysis or randomized clinical trials (RCTs).

Results

We introduce the hemodynamic effects and mechanisms of action of HTS in HS. Evidence in this field shows controversial results. There are some data supporting the potential benefits of HTS infusion in HS. The goal of research in this field is to identify the best therapy in HS with the least mortality.

Conclusion

Our conclusion shows that although HTS can decrease inflammatory response during HS, it can attenuate hypercoagulability and cause complications. There are no data supporting less mortality while treatment with HTS versus other fluids in HS.

TNF-α release capacity is suppressed immediately after hemorrhage and resuscitation

PURPOSE

It has been suggested that patients with traumatic insults are resuscitated into a state of an early systemic inflammatory response. We aimed to evaluate the influence of hemorrhagic shock and resuscitation (HSR) upon the inflammatory response capacity assessed by overall TNF-α secretion capacity of the host compared to its release from circulating leukocytes in peripheral circulation.

METHODS

Rats (8/group) subjected to HS (MAP of 30-35 mmHg for 90 min followed by resuscitation over 50 min) were challenged with Lipopolysaccharide (LPS), 1 μg/kg intravenously at the end of resuscitation (HSR-LPS group) or 24 h later (HSR-LPS24 group). Control animals were injected with LPS without bleeding (LPS group). Plasma TNF-α was measured at 90 min after the LPS challenge. In addition, whole blood (WB) was obtained either from healthy controls (CON) immediately after resuscitation (HSR), or at 24 h post-shock (HSR 24). WB was incubated with LPS (100 ng/mL) for 2 h at 37 °C. TNF-α concentration and LPS binding capacity (LBC) was determined.

RESULTS

Compared to LPS group, HSR followed by LPS challenge resulted in suppression of plasma TNF-α in HSR-LPS and HSR-LPS24 groups (1835 ± 478, 273 ± 77, 498 ± 200 pg/mL, respectively). Compared to CON the LPS-induced TNF-α release capacity of circulating leukocytes ex vivo was strongly declined both at the end of resuscitation (HSR) and 24 h later (HSR24) (1012 ± 259, 313 ± 154, 177 ± 63 ng TNF/mL, respectively). The LBC in WB was similar between CON and HSR and only moderately enhanced in HSR24 (57 ± 6, 56 ± 6, 71 ± 5 %, respectively).

CONCLUSION

Our data suggest that the overall inflammatory response capacity is decreased immediately after HSR, persisting up to 24 h, and is independent of LBC.

Vasopressin analog terlipressin attenuates kidney injury in hemorrhagic shock

Background

In hemorrhagic shock (HS), volume replacement with crystalloid solution can restore the hemodynamic status and decrease mortality. However, it can also lead to tissue edema and pulmonary congestion, as well as increasing vascular permeability. Here, we analyzed the effects that resuscitation with lactated Ringer's solution (LRS) or administration of the vasopressin analog terlipressin has on renal function in a porcine model of HS.

Methods

Using pressure-controlled bleeding, we induced pigs to HS, maintaining mean arterial pressure (MAP) at 40 mm Hg for 30 min. Animals were divided into 4 groups: sham (anesthesia only); shock-only (HS induction); shock+LRS (HS induction and subsequent resuscitation with LRS at 3 times the volume of blood removed); and shock+Terli (HS induction and subsequent bolus administration of 2 mg of terlipressin). Parameters were evaluated at baseline, then at 30, 60, and 120 min after treatment (T30, T60, and T120, respectively). Animals were euthanized at T60 or T120.

Results

Both treatments restored MAP to baseline values. At T30 and T60, creatinine clearance was highest in shock+LRS pigs, whereas it was highest in shock+Terli pigs at T120. Both treatments initially induced hyponatremia, although urinary excretion of all ions was higher in shock+LRS pigs at T30. Both treatments restored Na-K-2Cl cotransporter expression, whereas only terlipressin restored aquaporin 2 expression. Both treatments also prevented HS-induced acute tubular necrosis. Expression of the vasopressin receptors V1a and V2 was highest in shock-only pigs. At T120, V1a expression was lowest in shock+LRS pigs.

Discussion

Terlipressin might be useful for preventing HS-induced acute kidney injury.

Hypertonic Saline Primes Activation of the p53-p21 Signaling Axis in Human Small Airway Epithelial Cells That Prevents Inflammation Induced by Pro-inflammatory Cytokines

Uncontrolled inflammatory responses underlie the etiology of acute lung injury and acute distress respiratory syndrome, the most common late complications in trauma, the leading cause of death under the age of 59. Treatment with HTS decreases lung injury in clinical trials, rat models of trauma and hemorrhagic shock and inflammation in lung cell lines, although the mechanisms underlying these responses are still incompletely understood. Transcriptomics (RNaseq), proteomics, and U-¹³C-glucose tracing metabolomics experiments were performed to investigate the mechanisms of cellular responses to HTS treatment in primary small airway epithelial cells in the presence or absence of inflammatory injury mediated by a cocktail of cytokines (10 ng/mL of IFNγ, IL-1β, and TNFα). Modestly hyperosmolar HTS has an anti-inflammatory effect, triggers the p53-p21 signaling axis, and deregulates mitochondrial metabolism while inducing minimal apoptosis in response to a second hit by cytokines. Decreased transcription of pro-inflammatory cytokines suggested a role for the tumor suppressor protein p53 in mediating the beneficial effects of the HTS treatment. The anti-inflammatory mechanisms induced by HTS involves p53 gene regulation, promotes cell cycle arrest, and prevents ROS formation and mitochondria depolarization. Pharmaceutical targeting of the p53-p21 axis may mimic or reinforce the beneficial effects mediated by HTS when sustained hypertonicity cannot be maintained.

Comparison of Melatonin, Hypertonic Saline, and Hydroxyethyl Starch for Resuscitation of Secondary Intra-Abdominal Hypertension in an Animal Model

A variety of agents may have a beneficial effect in reducing injury-induced intestinal edema of fluid, but studies confirming the efficacy and mechanisms of these agents in secondary intra-abdominal hypertension (IAH) are lacking. This study was to compare the effectiveness of melatonin, 7.5% hypertonic saline (HS), and hydroxyethyl starch 130/0.4 (HES) on the resuscitation of secondary IAH in a rat model. Female SD rats were divided into: sham group, shock group, lactated Ringer solution (LR) group, melatonin group, HS group, and HES group. Except for the sham group, all rats underwent a combination of inducing portal hypertension, hemorrhaging to a MAP of 40 mmHg for 2 hr, and using an abdominal restraint device. The collected blood was reinfused and the rats were treated with LR (30ml/h), melatonin (50 mg/kg) + LR, HS (6 ml/kg) + LR, and HES (30 ml/kg) + LR, respectively. The shock group received no fluids. LR was continuously infused for 6hr. The intestinal permeability, immunofluorescence of tight junction proteins, transmission electron microscopy, level of inflammatory mediators (TNF-a, IL-1β, IL-6) and of biochemical markers of oxidative stress (malondialdehyde, myeloperoxidase activity, and glutathione peroxidase) were assessed. Expressions of the protein kinase B (Akt) and of tight junction proteins were detected by Western blot. Compared with LR, HS, and HES, melatonin was associated with less inflammatory and oxidative injury, less intestinal permeability and injury, and lower incidence of secondary IAH in this model. The salutary effect of melatonin in this model was associated with the upregulation of intestinal Akt phosphorylation.

Protective effects of polyethylene oxide on the vascular and organ function of rats with severe hemorrhagic shock

This study examined the effects of polyethylene oxide (PEO) on the survival rate, hemodynamics, blood gas indexes, lactic acid levels, microcirculation, and inflammatory cytokine levels in rats subjected to severe hemorrhagic shock. The shocked rats were resuscitated with either Ringer's lactate solution or 20 ppm of PEO in Ringer's lactate solution for 1 h. It was found that infusion of PEO effectively improved the survival, metabolic acidosis, oxygen delivery, hyperlactacidemia, tissue perfusion, and inflammatory responses of rats subjected to hemorrhagic shock. In addition, we found, for the first time, that PEO showed protective effects on hepatic and renal injury, as evidenced by the significant decreases in the elevated levels of alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, and creatinine caused by shock induction after infusion of PEO (p < 0.05, 60 min post-resuscitation by comparison with pre-resuscitation). All of these findings indicate that PEO exhibits strong therapeutic effects under conditions of severe hemorrhagic shock,which also provides theoretical and experimental bases for the clinical use of PEO.

Fed state prior to hemorrhagic shock and polytrauma in a porcine model results in altered liver transcriptomic response

Hemorrhagic shock is a leading cause of trauma-related mortality in both civilian and military settings. Resuscitation often results in reperfusion injury and survivors are susceptible to developing multiple organ failure (MOF). The impact of fed state on the overall response to shock and resuscitation has been explored in some murine models but few clinically relevant large animal models. We have previously used metabolomics to establish that the fed state results in a different metabolic response in the porcine liver following hemorrhagic shock and resuscitation. In this study, we used our clinically relevant model of hemorrhagic shock and polytrauma and the Illumina HiSeq platform to determine if the liver transcriptomic response is also altered with respect to fed state. Functional analysis of the response to shock and resuscitation confirmed several typical responses including carbohydrate metabolism, cytokine inflammation, decreased cholesterol synthesis, and apoptosis. Our findings also suggest that the fasting state, relative to a carbohydrate prefed state, displays decreased carbohydrate metabolism, increased cytoskeleton reorganization and decreased inflammation in response to hemorrhagic shock and reperfusion. Evidence suggests that this is a consequence of a shrunken, catabolic state of the liver cells which provides an anti-inflammatory condition that partially mitigates hepatocellar damage.

Prehospital hypertonic saline resuscitation attenuates the activation and promotes apoptosis of neutrophils in patients with severe traumatic brain injury

BACKGROUND

Activation of polymorphonuclear neutrophils (PMNs) is thought to contribute to traumatic brain injury (TBI). Since hypertonic fluids can inhibit PMN activation, we studied whether hypertonic fluid resuscitation can reduce excessive PMN activation in TBI patients.

METHODS

Trauma patients with severe TBI were resuscitated with 250 mL of either 7.5% hypertonic saline (HS; n = 22), HS + 6% dextran-70 (HSD; n = 22), or 0.9% normal saline (NS; n = 39), and blood samples were collected on hospital admission and 12 and 24 h after resuscitation. Polymorphonuclear neutrophil activation (CD11b, CD62L, CD64) and degranulation (CD63, CD66b, CD35) markers and oxidative-burst activity, as well as spontaneous PMN apoptosis were measured by flow cytometry.

RESULTS

Relative to healthy controls, TBI patients showed increased PMN activation and decreased apoptosis of PMNs. In the HS group, but not in the HSD group, markers of PMN adhesion (CD11b, CD64) and degranulation (CD35, CD66b) were significantly lower than those in the NS group. These effects were particularly pronounced 12 h after resuscitation. Treatment with HS and HSD inhibited PMN oxidative burst responses compared with NS-treated patients. Hypertonic saline alone partially restored delayed PMN apoptosis. Despite these differences, the groups did not differ in clinical outcome parameters such as mortality and Extended Glasgow Outcome Scale.

CONCLUSIONS

This study demonstrates that prehospital resuscitation with HS can partially restore normal PMN activity and the apoptotic behavior of PMNs, whereas resuscitation with HSD was largely ineffective. Although the results are intriguing, additional research will be required to translate these effects of HS into treatment strategies that improve clinical outcome in TBI patients.

Diaphragmatic function is preserved during severe hemorrhagic shock in the rat

BACKGROUND

Acute diaphragmatic dysfunction has been reported in septic and cardiogenic shock, but few data are available concerning the effect of hemorrhagic shock on diaphragmatic function. The authors examined the impact of a hemorrhagic shock on the diaphragm.

METHODS

Four parallel groups of adult rats were submitted to hemorrhagic shock induced by controlled exsanguination targeting a mean arterial blood pressure of 30 mmHg for 1 h, followed by a 1-h fluid resuscitation with either saline or shed blood targeting a mean arterial blood pressure of 80 mmHg. Diaphragm and soleus strip contractility was measured in vitro. Blood flow in the muscle microcirculation was measured in vivo using a Laser Doppler technique. Muscle proinflammatory cytokine concentrations were also measured.

RESULTS

Hemorrhagic shock was characterized by a decrease in mean arterial blood pressure to 34 ± 5 mmHg (-77 ± 4%; P< 0.05) and high plasma lactate levels (7.6 ± 0.9 mM; P < 0.05). Although tetanic tension of the diaphragm was not altered, hemorrhagic shock induced dramatic impairment of tetanic tension of the soleus (-40 ± 19%; P < 0.01), whereas proinflammatory cytokine levels were low and not different between the two muscles. Resuscitation with either blood or saline did not further modify either diaphragm or soleus performance and proinflammatory cytokine levels. The shock-induced decrease in blood flow was much more pronounced in the soleus than in the diaphragm (-75 ± 13% vs. -17 ± 10%; P = 0.02), and a significant interaction was observed between shock and muscle (P < 0.001).

CONCLUSION

Diaphragm performance is preserved during hemorrhagic shock, whereas soleus performance is impaired, with no further impact of either blood or saline fluid resuscitation.

Effect of Hypotensive Resuscitation with a Novel Combination of Fluids in a Rabbit Model of Uncontrolled Hemorrhagic Shock

Objective

The aim of this study was to compare the effects of hypotensive and normotensive resuscitation with a novel combination of fluids via lactate Ringer’s solution (LRS), 6% hydroxyethyl starch 130/0.4 solution (HES), and 7.5% hypertonic saline solution (HSS) at early stage of uncontrolled hemorrhagic shock (UHS) before hemostasis.

Methods

New Zealand white rabbits (n = 32) underwent UHS by transecting the splenic parenchyma, followed by blood withdrawal via the femoral artery to target mean arterial pressure (MAP) of 40–45 mmHg. Animals were distributed randomly into 4 groups (n = 8): in group Sham, sham operation was performed; in group HS, UHS was untreated; in group HS-HR, UHS was treated by hypotensive resuscitation with HSS and LRS+HES (ratio of 2∶1) to MAP of 50–55 mmHg; in group HS-NR, UHS was treated by normotensive resuscitation with HSS and LRS+HES (ratio of 2∶1) to MAP of 75–80 mmHg. Outcomes of hemodynamics, inflammatory and oxidative response, and other metabolic variables were measured and the histopathological studies of heart, lung and kidney were performed at the end of resusucitation.

Results

Hypotensive resuscitation with the novel combination of fluids for UHS rabbits decreased blood loss, maintained better stabilization of hemodynamics, and resulted in relatively higher hematocrit and platelet count, superior outcomes of blood gas, and lower plasma lactate concentration. Besides, hypotensive resuscitation attenuated the inflammatory and oxidative response significantly in UHS rabbits.

Conclusion

Hypotensive resuscitation with the novel combination of fluids via HSS and LRS+HES (ratio of 2∶1) has an effective treatment at early stage of UHS before hemostasis.

Effects of volume and composition of the resuscitative fluids in the treatment of hemorrhagic shock

Objectives:

To evaluate the effectiveness of normal saline, hypertonic saline, and Ringer's lactate solution followed by blood infusion in ameliorating the physiological, biochemical, and organ functions following hemorrhagic shock (HS) in rats.

Materials and Methods:

Anesthetized, male Sprague-Dawley rats underwent computer-controlled HS, and were randomly divided into five groups consisting of (1) sham, (2) HS without resuscitation, (3) resuscitation with normal saline, (4) resuscitation with hypertonic saline, and (5) resuscitation with Ringer's lactate solution. All resuscitated animals were infused with subsequent infusion of shed blood. Animals were continuously monitored for physiological, hemodynamic, biochemical parameters, and organ dysfunctions.

Results:

Non-resuscitated animals were unable to survive due to hypotension, poor oxygen metabolism, and lactic acidosis. Although these HS related parameters were corrected by all the fluids used in this study, additional blood infusion was more effective than fluid resuscitation alone. Also, hypertonic saline was more effective than Ringer's lactate solution, and normal saline was the least effective in preserving the liver and kidney functions and muscle damage.

Conclusions:

All crystalloid fluids were significantly more effective in reversing the HS outcome when used with blood infusion, but hypertonic salinewith blood was more effective in preventing the organ damage than Lactated Ringers solutions or normal saline in the treatment of HS.

The effectiveness of hypertonic saline and pentoxifylline (HTS-PTX) resuscitation in haemorrhagic shock and sepsis tissue injury: comparison with LR, HES, and LR-PTX treatments

PURPOSE

To compare lung and liver injury and laboratory results in haemorrhagic shock and sepsis models treated with combinations of lactated Ringer's solution (LR), 7.5% hypertonic saline (HTS), hydroxyethyl starch (HES), and pentoxifylline (PTX).

METHODS

Male Sprague-Dawley rats (200-290 g) were assigned randomly to one of four treatment groups (n=16 per group): (1) LR; (2) HES; (3) LR-PTX; and (4) HTS-PTX. Each group was subdivided into (1) haemorrhagic shock (n=8) and (2) sepsis (n=8) model groups. A venous catheter was used to inject resuscitation fluids, and an arterial catheter was used to withdraw blood and monitor mean arterial pressure (MAP). Lung and liver histology, bronchoalveolar lavage (BAL) fluid, and cytokine levels were evaluated.

RESULTS

The mean lung injury score was 1.7. At 24h after treatment, the total leucocyte count in the BAL fluid was significantly (p<0.05) higher with LR treatment (10 × 10(6) ± 0.8) than with other treatments in the sepsis model groups (HES, 6 × 10(6) ± 1.2; LR-PTX, 5 × 10(6) ± 1.5; HTS-PTX, 5 × 10(6) ± 0.6). The higher total leucocyte count after LR treatment was attributable to a greater increase in the number of neutrophils (17 ± 1.5%) compared with increases after the other treatments (HES, 6 ± 0.8%; LR-PTX, 10 ± 1.3%; HTS-PTX, 5 ± 0.4%). In the sepsis model groups, the total hepatic injury score was also significantly (p<0.05) higher with LR treatment (9.9 ± 0.5) than with the other treatments (HES, 6.7 ± 0.8; LR-PTX, 5.6 ± 0.7; HTS-PTX, 3.1 ± 0.9). This also occurred in the shock model (LR, 10.6 ± 2.1; HES, 5.8 ± 0.9; LR-PTX, 7.3 ± 0.9; HTS-PTX, 3.5 ± 0.9). As compared with LR treatment, HTS-PTX resuscitation resulted in a 49% decrease in TNF-α, 29% decrease in IL-1β, and 58% decrease in IL-6 in the shock model at 24h (p<0.05), and the respective decreases were 45, 24, and 35% in the sepsis model (p<0.05).

CONCLUSION

HTS-PTX was superior to HES, LR-PTX, and LR for treating shock and sepsis, and LR-PTX and HES gave better results than LR therapy alone.

Alteration of complement hemolytic activity in different trauma and sepsis models

Complement activation is involved in various diseases in which innate immunity plays a crucial role. However, its pathophysiological relevance is not clearly understood. Experimental models have been widely used to characterize the role of complement activation under different pathological conditions, such as hypoxemia, ischemia and reperfusion, tissue damage, and polymicrobial invasion. Screening of the complement status and function is, however, strongly dependent on the laboratory-specific techniques being used to sample and measure complement, making it difficult to compare the results found in different laboratories. Therefore, we evaluated complement function by measuring complement hemolytic activity (CH50) in various animal models of isolated ischemia reperfusion (I/R: kidney, liver, gut), hemorrhagic traumatic shock (HTS), endotoxic shock (LPS), and sepsis (CLP). Complement activation was less pronounced in isolated models of ischemia and reperfusion, whereas a strong complement response was observed early after HTS, CLP, and LPS. In summary, CH50 is a well-established, quick, and cost-effective screening method of complement function. However, because we obtained different results in clinically relevant animal models, further differentiation using specific complement factor analysis is necessary.

Transient increase of free iron in rat livers following hemorrhagic-traumatic shock and reperfusion is independent of heme oxygenase 1 upregulation

Hemorrhagic-traumatic shock (HTS) followed by reperfusion induces heme oxygenase (HO) 1. Free iron (Fe2+) may cause oxidative stress, if not adequately sequestered. We aimed to characterize HO-1-mediated effects on Fe2+ levels in liver and transferrin-bound iron (TFBI) in plasma following HTS, including laparotomy, bleeding, and inadequate and adequate reperfusion. Anesthetized rats showed upregulated HO-1 mRNA at 40 min after HTS, which was followed by increased HO activity at 3 h after shock. Fe2+ levels were transiently increased at 40 min after shock, a time point when HO activity was not affected yet. Levels of plasma TFBI were higher in HTS animals, showing the highest levels at 40 min after shock, and decreased thereafter. In addition, we modulated HO activity 6 h before HTS by administering an inhibitor (zinc-protoporphyrin IX) or an activator (hemin) of HO. At 18 h after HTS in all shock groups, HO activity was increased, the highest being in the hemin-pretreated group. The zinc-protoporphyrin IX-treated HTS animals showed increased HO-1 mRNA and Fe2+ levels in the liver compared with the untreated HTS animals. Transferrin-bound iron levels were affected by pharmacological modulation before shock. All animals undergoing HTS displayed increased TFBI levels after reperfusion; however, in animals pretreated with hemin, TFBI levels increased less. Our data indicate that increase in Fe2+ levels in liver and plasma early after HTS is not mediated by HO-1 upregulation, but possibly reflects an increased mobilization from internal iron stores or increased cell damage. Thus, upregulation of HO activity by hemin does not increase Fe2+ levels following HTS and reperfusion.

Influence of preoperative 7.5% hypertonic saline on neutrophil activation after reamed intramedullary nailing of femur shaft fractures: a prospective randomized pilot study

OBJECTIVES

Femoral reaming and intramedullary nailing (IMN) primes polymorphonuclear leukocytes (PMNL) and thereby increases the posttraumatic systemic inflammatory response. Resuscitation with hypertonic saline (HTS) attenuates PMNL activation after trauma-hemorrhage. We hypothesized that preoperative administration of 7.5% HTS attenuates PMNL priming after IMN of unilateral femur shaft fractures compared with 0.9% normal saline.

DESIGN

Prospective, randomized, double-blind study.

SETTING

Level I trauma center.

PATIENTS

Twenty patients between 18 and 80 years of age with an Injury Severity Score less than 25 and a unilateral femur shaft fracture amenable to IMN fixation within 24 hours after injury.

INTERVENTION

Patients were allocated to equally sized HTS or normal saline treatment groups (n = 10) before surgery. Solutions were administered in a blinded bag as a single bolus of 4 mL/kg body weight immediately before surgery. Whole blood samples were collected directly before saline application (t0) and at 6, 12, and 24 hours after surgery.

MAIN OUTCOME MEASUREMENTS

PMNL surface expression of CD11b and CD62L, as determined by flow cytometry analysis.

RESULTS

Demographic characteristics of both treatment groups were comparable. Baseline expression of CD11b and CD62L cell markers was in a similar range in the two cohorts. The expression levels of CD11b were comparable between the two groups throughout the observation time, whereas CD62L levels were significantly higher in the HTS group at 6 and 24 hours after surgery.

CONCLUSION AND SIGNIFICANCE

Preoperative infusion of HTS appears to exert an anti-inflammatory effect by attenuating the extent of postoperative PMNL activation after reamed IMN for femoral shaft fractures.

Damage control resuscitation decreases systemic inflammation after hemorrhage

BACKGROUND

Severe hemorrhagic shock and resuscitation initiates a dysfunctional systemic inflammatory response leading to end-organ injury. Clinical evidence supports the transfusion of high ratios of plasma and packed red blood cells (pRBCs) in the treatment of hemorrhagic shock. The effects of resuscitation with different ratios of fresh blood products on inflammation and organ injury have not yet been characterized.

MATERIALS AND METHODS

Mice underwent femoral artery cannulation and pressure-controlled hemorrhage for 60 min, then resuscitation with fresh plasma and pRBCs collected from donor mice. Plasma alone, pRBCs alone, and ratios of 2:1, 1:1, and 1:2 plasma:pRBCs were used for resuscitation strategies. Mice were sacrificed to determine biochemical and hematologic parameters, serum cytokine concentrations, tissue myeloperoxidase levels, and vascular permeability.

RESULTS

Compared with other resuscitation strategies, mice resuscitated with pRBCs alone exhibited increased hemoglobin levels, while other hematologic and biochemical parameters were not significantly different among groups. Compared with 1:1, mice resuscitated with varying ratios of plasma:pRBCs exhibited increased cytokine concentrations of KC, MIP-1α, and MIP-2, and increased intestinal and lung myeloperoxidase levels. Mice resuscitated with 1:1 had decreased vascular permeability in the intestine and lung as compared with other groups.

CONCLUSIONS

Resuscitation with a 1:1 ratio of fresh plasma:pRBCs results in decreased systemic inflammation and attenuated organ injury. These findings support the potential advantage of transfusing blood products in physiologic ratios to improve the treatment of severe hemorrhagic shock.

Resuscitative effect of hyperoxia fluid on high-altitude hemorrhagic shock in rats and antishock mechanisms

Pathophysiological characteristics of hemorrhagic shock at high altitude are different from that at plain which involve severe injury, high mortality, difficult treatment and compromised liquid tolerance. High-altitude pulmonary/cerebral edema and multiple-organ dysfunction render the conventional treatment ineffective. Herein, we evaluated the resuscitation effects of hyperoxia solution on high-altitude hemorrhagic shock in rats. For this purpose, a rat model of high-altitude (3,658 m) hemorrhagic shock was established on the plateau and hyperoxia solution (4 ml/kg) was infused through external jugular vein for resuscitation at 60 min post-hemorrhage. Blood pressure, blood gas, left and right ventricular pressure, lung and brain water content, survival time, survival rate at 2 h, levels of inflammatory cytokines and free oxygen radicals in blood and tissue were determined. After resuscitation with hyperoxia solution, blood pressure, arterial oxygen partial pressure, left and right ventricular systolic pressure, ±dp/dt max, survival time and rate were significantly increased. Lung and brain water content were unchanged, malondialdehyde activity in lung, brain and plasma and levels of TNF-α, IL-1, IL-6, and endothelin were significantly decreased. Besides, CGRP was elevated with reduced injury and improved lung and kidney functions. Concludingly, resuscitation with hyperoxia solution is feasible and more effective than other classical liquids, making it the first choice of treatment for high-altitude hemorrhagic shock.

Small volume 7.5% NaCl with 6% Dextran-70 or 6% and 10% hetastarch are associated with arrhythmias and death after 60 minutes of severe hemorrhagic shock in the rat in vivo

BACKGROUND

Hypertonic saline solutions in combination with colloids may have some applications in critically ill patients. Our aim was to examine the effects of small volumes (0.7-1 mL/kg intravenous) of 7.5% NaCl with different colloids on cardiac stability, hemodynamics, and mortality after severe hemorrhagic shock.

METHODS

Male fed Sprague-Dawley rats (300-450 g, n = 48) were anesthetized and randomly assigned to one of six groups: (1) untreated (bleed only), (2) 7.5% NaCl, (3) 7.5% NaCl/6% dextran-70, (4) 7.5% NaCl/6% hetastarch (HES), (5) 6% HES alone, and (6) 7.5% NaCl/10% HES. Hemorrhagic shock was induced by phlebotomy until the mean arterial pressure (MAP) was 35 mm Hg to 40 mm Hg and continued for 20 minutes until ∼40% blood loss. Animals were left in shock for 60 minutes at 34°C. 0.3 mL (<4% of shed blood) was injected as a 10 seconds bolus into the femoral vein. Lead II electrocardiogram, blood pressures, MAP, and heart rate were monitored.

RESULTS

Untreated rats were highly arrhythmogenic with 38% mortality. 7.5% NaCl increased MAP from 39 mm Hg to 44 mm Hg with no severe arrhythmias or mortality. Dextran-70 increased MAP from 38 mm Hg to 49 mm Hg, transiently increased QRS amplitude (1.5 times) and was arrhythmogenic affecting 50% of animals with no deaths. Addition of 6% HES to hypertonic saline resulted in aberrant arrhythmias and 38% mortality. Six percent HES alone was proarrhythmic and led to 38% mortality. 7.5% NaCl with 10% HES resulted in 100% mortality (p < 0.05) from arrhythmias within 5 minutes of resuscitation.

CONCLUSIONS

Small volumes of 7.5% NaCl led to fewer arrhythmias and a 2.6 times survival benefit over untreated rats, and a partial resuscitation of MAP into the "permissive range." Dextran-70 or HES in 7.5% NaCl were proarrhythmic and HES led to increased mortality (p < 0.05). Because optimal heart function is critical for successful resuscitation, care should be exercised when using dextran-70 or 6 and 10% HES in small volume hypertonic saline solutions for early hypotensive resuscitation.

Effect of protein C gene mutation on coagulation and inflammation in hemorrhagic shock

INTRODUCTION

Trauma patients are at high risk of complications and death from coagulopathy and inflammatory organ failure. Recent evidence implicates protein C (PC) as a key mediator of this process. We hypothesized that a mutation in the PC gene would ameliorate the inflammatory and coagulopathic response to hemorrhagic shock (HS) and resuscitation.

METHODS

FHH wild type and PC mutant rats underwent controlled hemorrhage for 120 min with 70% of blood volume removed. Rats were resuscitated with Ringers lactate (2x shed blood volume) and shed blood. Animals were sacrificed 4 h post-HS. Controls were untreated naïve rats.

RESULTS

AST and NFkB lung protein levels were elevated similarly in both WT and mutants compared with naïve rats. Plasma fibrinogen levels decreased significantly with progression of HS compared with baseline (BL) levels and returned towards normal 4 h after resuscitation. PC activity was similar in both groups at BL (0.5 ± 0.08 versus 0.6 ± 0.14; P = 0.14) and decreased from BL by 53% ± 24% in WT (P =0.08), by 67% ± 11% in mutants (P = 0.03) at sacrifice, and was not different between groups (P = 0.29).

CONCLUSIONS

Our model of HS and resuscitation produced a hypocoaguable, hyperinflammatory state with increased levels of NFkB and decreased levels of fibrinogen and PC levels. The mutated PC did not appear to alter these responses in our model of HS and resuscitation.

Blast injury research models

Blast injuries are an increasing problem in both military and civilian practice. Primary blast injury to the lungs (blast lung) is found in a clinically significant proportion of casualties from explosions even in an open environment, and in a high proportion of severely injured casualties following explosions in confined spaces. Blast casualties also commonly suffer secondary and tertiary blast injuries resulting in significant blood loss. The presence of hypoxaemia owing to blast lung complicates the process of fluid resuscitation. Consequently, prolonged hypotensive resuscitation was found to be incompatible with survival after combined blast lung and haemorrhage. This article describes studies addressing new forward resuscitation strategies involving a hybrid blood pressure profile (initially hypotensive followed later by normotensive resuscitation) and the use of supplemental oxygen to increase survival and reduce physiological deterioration during prolonged resuscitation. Surprisingly, hypertonic saline dextran was found to be inferior to normal saline after combined blast injury and haemorrhage. New strategies have therefore been developed to address the needs of blast-injured casualties and are likely to be particularly useful under circumstances of enforced delayed evacuation to surgical care.

Use of hypertonic saline injection in trauma

PURPOSE

The use of hypertonic saline injection in trauma patients is discussed.

SUMMARY

Patients with hemorrhage, burns, and traumatic brain injury (TBI) may develop hypovolemic shock and require resuscitation. Compared with conventional isotonic crystalloids, hypertonic saline has several advantages, including hemodynamic, immune-modulating, and antiinflammatory effects, for use in trauma patients for resuscitation. In addition, hypertonic saline is also used in patients with TBI to reduce intracranial pressure (ICP). Overall, studies have not shown a difference in mortality or other clinically important outcomes with the use of hypertonic saline for resuscitation in trauma patients; however, most of these studies were not adequately powered to show significant differences. A recent Cochrane review concluded that there is no evidence that hypertonic crystalloids are better than isotonic or near-isotonic crystalloids for fluid resuscitation in trauma patients. Two recent trials that were adequately powered to investigate a mortality endpoint were halted for futility. A few small randomized controlled studies found that hypertonic saline was more effective than mannitol as a hyperosmolar agent for ICP reduction. Recent guidelines from the American Burn Association have suggested that hypertonic saline may be used for burn shock resuscitation by experienced providers with close monitoring to avoid excessive hypernatremia. One of the main concerns with the use of hypertonic saline is its potential to cause central pontine myelinolysis due to a rapid increase in serum sodium levels.

CONCLUSION

There is no evidence that hypertonic saline provides any additional benefit over isotonic crystalloid solutions for trauma resuscitation. Hypertonic saline may be more effective than mannitol at reducing ICP in patients with TBI.

Rons formation under restrictive reperfusion does not affect organ dysfunction early after hemorrhage and trauma

Reactive oxygen species have been implicated in the pathophysiology of early reperfusion. We aimed to determine 1) reactive oxygen and nitrogen species (RONS) formation in organs of rats and 2) its pathophysiological relevance during a phase of restrictive reperfusion after hemorrhagic/traumatic shock (HTS). Fifty-seven male Sprague-Dawley rats were subjected to a clinically relevant HTS model, featuring laparotomy, bleeding, and a phase of restrictive reperfusion. The RONS scavenger 1-hydroxy-3-carboxy-2,2,5,5-tetramethyl-pyrrolidine hydrochloride (continuous i.v. infusion) and electron paramagnetic resonance spectroscopy were applied for RONS (primarily superoxide and peroxynitrite) detection. Compared with sham-operated animals, the organ-specific distribution of RONS changed during restrictive reperfusion after HTS. Reactive oxygen and nitrogen species formation increased during restrictive reperfusion in red blood cells and ileum only but decreased in the kidney and remained unchanged in other organs. Hemorrhagic traumatic shock followed by restrictive reperfusion resulted in metabolic acidosis, dysfunction of liver and kidney, and increased oxidative burst capacity in circulating cells. Plasma RONS correlated with shock severity and organ dysfunction. However, RONS scavenging neither affected organ dysfunction nor oxidative burst capacity nor myeloperoxidase activity in lung when compared with the shock controls. In summary, a phase of restrictive reperfusion does not increase RONS formation in most organs except in intestine and red blood cells. Moreover, scavenging of RONS does not affect the early organ dysfunction manifested at the end of a phase of restrictive reperfusion.

Effects of fluid resuscitation with hypertonic saline dextrane or Ringer's acetate after nonhemorrhagic shock caused by pulmonary contusion

BACKGROUND

Injured lungs are sensitive to fluid resuscitation after trauma. Such treatment can increase lung water content and lead to desaturation. Hypertonic saline with dextran (HSD) has hyperosmotic properties that promote plasma volume expansion, thus potentially reducing these side effects. The aim of this study was to (1) evaluate whether fluid treatment counteracts hypotension and improves survival after nonhemorrhagic shock caused by lung contusion and (2) analyze whether resuscitation with HSD is more efficient than treatment with Ringer's acetate (RA) in terms of blood oxygenation, the amount of lung water, circulatory effects, and inflammatory response.

METHODS

Twenty-nine pigs, all wearing body armor, were shot with a 7.62-mm assault rifle to produce a standardized pulmonary contusion. These animals were allocated into three groups: HSD, RA, and an untreated shot control group. Exposed animals were compared with animals not treated with fluid and shot with blank ammunition. For 2 hours after the shot, the inflammatory response and physiologic parameters were monitored.

RESULTS

The impact induced pulmonary contusion, desaturation, hypotension, increased heart rate, and led to an inflammatory response. No change in blood pressure was observed after fluid treatment. HSD treatment resulted in significantly less lung water (p < 0.05) and tended to give better Pao2 (p = 0.09) than RA treatment. Tumor necrosis factor-α release and heart rate were significantly lower in animals given fluids.

CONCLUSION

Fluid treatment does not affect blood pressure or mortality in this model of nonhemorrhagic shock caused by lung contusion. However, our data indicate that HSD, when compared with RA, has advantages for the injured lung.

Advances in resuscitation strategies

Shock, regardless of etiology is characterized by decreased delivery of oxygen and nutrients to the tissues and our interventions are directed towards reversing the cellular ischemia and preventing its consequences. The treatment strategies that are most effective in achieving this goal obviously depend upon the different types of shock (hemorrhagic, septic, neurogenic and cardiogenic). This brief review focuses on the two leading etiologies of shock in the surgical patients: bleeding and sepsis, and addresses a number of new developments that have profoundly altered the treatment paradigms. The emphasis here is on new research that has dramatically altered our treatment strategies rather than the basic pathophysiology of shock.

Reperfusion does not induce oxidative stress but sustained endoplasmic reticulum stress in livers of rats subjected to traumatic-hemorrhagic shock

Oxidative stress is believed to accompany reperfusion and to mediate dysfunction of the liver after traumatic-hemorrhagic shock (THS). Recently, endoplasmic reticulum (ER) stress has been suggested as an additional factor. This study investigated whether reperfusion after THS leads to increased oxidative and/or ER stress in the liver. In a rat model, including laparotomy, bleeding until decompensation, followed by inadequate or adequate reperfusion phase, three time points were investigated: 40 min, 3 h, and 18 h after shock. The reactive oxygen and nitrogen species and its scavenging capacity (superoxide dismutase 2), the nitrotyrosine formation in proteins, and the lipid peroxidation together with the status of endogenous antioxidants (alpha-tocopherylquinone-alpha-tocopherol ratio) were investigated as markers for oxidative or nitrosylative stress. Mitochondrial function and cytochrome P450 isoform 1A1 activity were analyzed as representatives for hepatocyte function. Activation of the inositol-requiring enzyme 1/X-box binding protein pathway and up-regulation of the 78-kDa glucose-regulated protein were recorded as ER stress markers. Plasma levels of alanine aminotransferase and Bax/Bcl-XL messenger RNA (mRNA) ratio were used as indicators for hepatocyte damage and apoptosis induction. Oxidative or nitrosylative stress markers or representatives of hepatocyte function were unchanged during and short after reperfusion (40 min, 3 h after shock). In contrast, ER stress markers were elevated and paralleled those of hepatocyte damage. Incidence for sustained ER stress and subsequent apoptosis induction were found at 18 h after shock. Thus, THS or reperfusion induces early and persistent ER stress of the liver, independent of oxidative or nitrosylative stress. Although ER stress was not associated with depressed hepatocyte function, it may act as an early trigger of protracted cell death, thereby contributing to delayed organ failure after THS.

Resuscitation with fresh whole blood ameliorates the inflammatory response after hemorrhagic shock

BACKGROUND

Hemorrhagic shock is the leading cause of potentially preventable death after traumatic injury. Hemorrhage and subsequent resuscitation may result in a dysfunctional systemic inflammatory response and multisystem organ failure, leading to delayed mortality. Clinical evidence supports improved survival and reduced morbidity when fresh blood products are used as resuscitation strategies. We hypothesized that the transfusion of fresh whole blood (FWB) attenuates systemic inflammation and reduces organ injury when compared with conventional crystalloid resuscitation after hemorrhagic shock.

METHODS

Male mice underwent femoral artery cannulation and hemorrhage to a systolic blood pressure of 25 mm Hg +/- 5 mm Hg. After 60 minutes, the mice were resuscitated with either FWB or lactated Ringer's solution (LR). Mice were decannulated and killed at intervals for tissue histology, serum cytokine analysis, and vascular permeability studies. Separate groups of mice were followed for survival studies.

RESULTS

When compared with FWB, mice resuscitated with LR required increased resuscitation fluid volume to reach goal systolic blood pressure. When compared with sham or FWB-resuscitated mice, LR resuscitation resulted in increased serum cytokine levels of macrophage inflammatory protein-1alpha, interleukin-6, interleukin-10, macrophage-derived chemokine, KC, and granulocyte macrophage colony stimulating factor as well as increased lung injury and pulmonary capillary permeability. No survival differences were seen between animals resuscitated with LR or FWB.

CONCLUSIONS

Resuscitation with LR results in increased systemic inflammation, vascular permeability, and lung injury after hemorrhagic shock. Resuscitation with FWB attenuates the inflammation and lung injury seen with crystalloid resuscitation. These findings suggest that resuscitation strategies using fresh blood products potentially reduce systemic inflammation and organ injury after hemorrhagic shock.

Effect of estrogen on mitochondrial function and intracellular stress markers in rat liver and kidney following trauma-hemorrhagic shock and prolonged hypotension

Trauma-hemorrhage (T-H) is known to impair tissue perfusion, leading to tissue hypoxia, and thus affecting mitochondria, the organelles with the highest oxygen demand. In a model of T-H and prolonged hypotension without fluid resuscitation, administration of a small volume of 17beta-estradiol (E2), but not vehicle, prolonged the survival of rats for 3 h, even in the absence of fluid resuscitation. The main finding of this study is that T-H followed by prolonged hypotension significantly affects mitochondrial function, endoplasmic reticulum (ER) stress markers and free iron levels, and that E2 ameliorated all these changes. All of these changes were observed in the liver but not in the kidney. The sensitivity of mitochondrial respiration to exogenous cytochrome c can reflect increased permeability of the outer mitochondrial membrane for cytochrome c. Increased levels of free iron are indicative of oxidative stress, but neither oxidative nor nitrosylative stress markers changed. The spliced isoform of XBP1 mRNA (an early marker of ER stress) and the expression of C/EBP homologous protein (CHOP) (a protein regulating ER stress-induced apoptosis) were elevated in T-H animals but remained unchanged if T-H rats received E2. Both the prevention of elevated sensitivity of mitochondrial respiration to cytochrome c and a decrease in ER stress by E2 maintain functional integrity of the liver and may help the organ during prolonged hypotension and following resuscitation. A decrease in free iron levels by E2 is more relevant for resuscitation, often accompanied by oxidative stress reaction. Thus, E2 appears to be a novel hormonal adjunct that prolongs permissive hypotension during lengthy transportation of the injured patient between the injury site and the hospital in both civilian and military injuries.

Fluid resuscitation: past, present, and the future

Hemorrhage remains a major cause of preventable death following both civilian and military trauma. The goals of resuscitation in the face of hemorrhagic shock are restoring end-organ perfusion and maintaining tissue oxygenation while attempting definitive control of bleeding. However, if not performed properly, resuscitation can actually exacerbate cellular injury caused by hemorrhagic shock, and the type of fluid used for resuscitation plays an important role in this injury pattern. This article reviews the historical development and scientific underpinnings of modern resuscitation techniques. We summarized data from a number of studies to illustrate the differential effects of commonly used resuscitation fluids, including isotonic crystalloids, natural and artificial colloids, hypertonic and hyperoncotic solutions, and artificial oxygen carriers, on cellular injury and how these relate to clinical practice. The data reveal that a uniformly safe, effective, and practical resuscitation fluid when blood products are unavailable and direct hemorrhage control is delayed has been elusive. Yet, it is logical to prevent this cellular injury through wiser resuscitation strategies than attempting immunomodulation after the damage has already occurred. Thus, we describe how some novel resuscitation strategies aimed at preventing or ameliorating cellular injury may become clinically available in the future.

Fluid resuscitation in the trauma patient

Trauma is responsible for 25% of all emergency department visits causing a healthcare burden of more than $400 billion a year. Timely and appropriate fluid resuscitation may mean the difference between survival and death. Controversy surrounds the best method of fluid resuscitation for optimum recovery. This article will evaluate current research regarding the various types of fluid resuscitation in the trauma population. Colloid and crystalloid fluid will be compared describing the risks and benefits of each.

The role of erythropoietin in hemorrhagic shock-induced liver and renal injury in rats

INTRODUCTION

The aim of the present study was to evaluate the role of erythropoietin (EPO) in liver and renal injury following hemorrhagic shock (HS) after inhibition of tyrosine kinase activity in rats..

METHODS

Forty-eight Sprague-Dawley rats were assigned to six groups: (I) HS alone; (II) HS followed by retransfusion; (III) EPO and genistein followed by HS; (IV) EPO and genistein followed by HS, followed by retransfusion; (V) HS followed by EPO and genistein; and (VI) HS followed by EPO and genistein, followed by retransfusion. HS was induced for 60 minutes after withdrawal of 30% of the calculated total blood volume of each rat from the left femoral artery. Blood and tissue samples (from the kidney and liver) were obtained 60 minutes after HS in Group I, III, and V; blood and tissue samples were obtained 60 minutes after retransfusion in Group II, IV, and VI. In Group III and IV, EPO was given 60 minutes before HS, and genistein 30 minutes before HS. In Group V and VI, EPO and genistein were given 30 minutes after HS.

RESULTS

Liver and renal injury were significantly attenuated with EPO and genistein administration.

CONCLUSION

These results suggest that EPO is effective in attenuating liver and renal injury in HS, even with inhibition of tyrosine kinase activity with genistein.

The influence of volume management on outcome

PURPOSE OF REVIEW

Fluid (volume) therapy is an integral component in the management of critically ill patients and fluid management may influence outcome. There is much controversy, however, about the type, timing and amount of fluid therapy. Here, we discuss the evidence available to guide such choices.

RECENT FINDINGS

Fluid therapy is widely endorsed for resuscitation of critically ill patients across a range of conditions. Yet, the approach to fluid therapy is subject to substantial variation in clinical practice. Emerging data show that the choice, timing and amount of fluid therapy may affect clinical outcomes. Synthetic colloids may increase the risk of acute kidney injury. Albumin may benefit hypoalbuminemic patients with sepsis and acute lung injury but may worsen outcome in traumatic brain injury. Early administration of fluid therapy in sepsis may improve survival but may be unnecessary in patients with penetrating trauma. Later fluid therapy in acute lung injury patients will increase the duration of ventilator dependence without achieving better survival. A positive cumulative balance likely contributes to increased morbidity and mortality after major surgery.

SUMMARY

Emerging evidence shows that choice, timing and amount of fluid therapy affect outcome. Future studies need to focus on these aspects of fluid therapy by means of larger, more rigorous and blinded controlled trials.

Effect of hypertonic saline concentration on cerebral and visceral organ water in an uninjured rodent model

OBJECTIVE

Hypertonic saline has been shown to be an effective osmotic agent to reduce brain water and hence brain volume and intracranial pressure. A direct correlation between dose and effect has been demonstrated, but no studies have compared the effects of different concentrations of the same osmotic load of hypertonic saline over time. We compared the effects of different tonicity of infused hypertonic saline on cerebral, lung, and small bowel water extraction over time under controlled conditions.

DESIGN

Laboratory study.

SETTING

Medical school.

SUBJECTS

Male Wistar rats (280-450 g).

INTERVENTIONS

Anesthetized rats were randomized to a 15-min intravenous bolus infusion of 0.9% NaCl or five equisodium but different concentrations of hypertonic saline: 4.2%, 7.5%, 10%, 23.4%, and 30%. Following infusion, animals remained anesthetized for 60, 180, or 300 mins without additional fluids given (n > or = 6 per group). Blood was sampled, total urine output was measured, and the animal was then killed under deep anesthesia. Cerebral, lung, and small bowel water contents were derived by wet/dry weight measures.

MEASUREMENTS AND MAIN RESULTS

After 60 mins, hypertonic saline administered at 50 mosm/kg resulted in an increase in serum osmolarity in all hypertonic saline groups (p < .05 vs. normal saline), with a significantly greater increase measured using 23.4% or 30% hypertonic saline (23.4%, 365.0 +/- 8.8 mosm/L, p < .05 vs. other lesser hypertonic saline doses). The durable effect was present throughout the 300-min period by all but the lowest hypertonic saline (4.2% NaCl). Lung but not small bowel organ water was diminished by hypertonic saline. Brain water content (79.1 +/- 0.2% in normal saline controls) was, however, significantly reduced.

CONCLUSIONS

Hypertonic saline is effective in reducing organ water content in a setting of preserved blood-brain barrier but is not as effective in visceral organs. At equiosmotic doses of hypertonic saline, concentration plays no substantial role in altering serum osmolarity but appears to benefit duration of action. At very high concentrations, such as 23.4% NaCl, additional water extraction is also manifested. At such high concentration of NaCl, tonicity, indeed, matters, especially in water shifts across the blood-brain barrier.

Relevance of granulocyte apoptosis to resolution of inflammation at the respiratory mucosa

The respiratory mucosa is responsible for gas exchange and is therefore, of necessity, exposed to airborne pathogens, allergens, and foreign particles. It has evolved a multi-faceted, physical and immune defense system to ensure that in the majority of instances, potentially injurious invaders are repelled. Inflammation, predominantly mediated by effector cells of the granulocyte lineage including neutrophils and eosinophils, is a form of immune defense. Where inflammation proves unable to remove an inciting stimulus, chronic inflammatory disease may supervene because of the potential for tissue damage conferred by the presence of large numbers of frustrated, activated granulocytes. Successful recovery from inflammatory disease and resolution of inflammation rely on the clearance of these cells. Ideally, they should undergo apoptosis prior to phagocytosis by macrophage, dendritic, or epithelial cells. The outcome of inflammation can have serious sequelae for the integrity of the respiratory mucosa leading to disease. Therapeutic strategies to drive resolution of inflammation may be directed at the induction of granulocyte apoptosis and the enhancement of granulocyte clearance.