Hypertonic resuscitation after severe injury: is it of benefit?

Traumatic brain injury from a peripheral axis perspective: Uncovering the roles of liver and adipose tissue in temperature regulation

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Most current treatments for TBI and other neurological disorders focus on the brain, often overlooking the significant contributions of peripheral organs to disease progression. Emerging evidence suggests that organs such as the liver and adipose tissue play crucial roles in TBI pathogenesis. The liver synthesizes lipids and proteins vital for brain function, while adipose tissue provides hormones and metabolites that influence brain activity. New research indicates that the liver and adipose tissue work in concert with the hypothalamus to regulate essential processes, such as body temperature, which become disrupted in TBI. Additionally, the brain-peripheral axis-a complex network of visceral nerve pathways, hormones, and metabolites-plays a bidirectional role in regulating brain plasticity and function. Understanding how TBI leads to dysregulation of the liver, adipose tissue, and other organs could unlock new therapeutic opportunities for treating TBI and related neurological disorders. The intricate autonomic network involving hypothalamic and enteric neurons, along with visceral nerve pathways and hormones, presents both pathological targets and therapeutic potential. We examine scientific evidence suggesting that correcting disturbances in systemic physiology could enhance the brain's capacity for healing. However, the interdependence of this autonomic network implies that treating dysfunction in one area may affect others. Therefore, we also explore the mechanisms by which diet and exercise can comprehensively impact the brain-peripheral axis, supporting the healing process. CHEMICAL COMPOUNDS: D-Fructose (PubChem CID 2723872); docosahexaenoic acid (PubChem CID 45934466); eicosapentaenoic acid (PubChem 5282847).

Should Hypertonic Saline Be Considered for the Treatment of Intracranial Hypertension? A Review of Current Evidence and Clinical Practices

Intracranial hypertension (IH) is a critical neurological emergency that requires prompt intervention because failure to treat it properly can lead to severe outcomes, including secondary brain injury. Traditionally, mannitol (MNT) has been the cornerstone of hyperosmolar therapy. However, the use of hypertonic saline (HTS) has become increasingly important because of its unique advantages. Both HTS and MNT effectively reduce intracranial pressure by creating an osmotic gradient that draws fluid from brain tissue. However, unlike MNT, HTS does not induce diuresis or significantly lower blood pressure, making it more favorable for maintaining cerebral perfusion. Additionally, HTS does not cause rebound edema and carries a lower risk of renal injury than MNT. However, it is important to note that the use of HTS comes with potential risks, such as hypernatremia, hyperchloremia, and fluid overload. Due to its unique properties, HTS is a crucial agent in the management of IH, and understanding its appropriate use is essential to optimize patient outcomes.

Assessment of hemostasis in dogs with gastric-dilation-volvulus, during resuscitation with hydroxyethyl starch (130/0.4) or hypertonic saline (7.5%)

OBJECTIVE

To compare the impact of an IV bolus of hydroxyethyl starch 130/0.4 (HES) or hypertonic saline 7.5% (HS) on hemostasis in dogs resuscitated for gastric-dilation-volvulus (GDV).

DESIGN

Open-label, parallel-group randomized clinical trial.

ANIMALS

Twenty-three client-owned dogs.

INTERVENTIONS

Dogs affected by GDV and shock were randomly assigned to receive HES at 10 mL/kg or HS at 4 mL/kg every 15 minutes. Blood samples were collected for blood gas analysis, PCV, total plasma protein, albumin, standard coagulation profile, and thromboelastometry (ROTEM) at baseline (T0) and at the end of bolus (T1). To assess the differences between the 2 groups at T1, Student's t-test or Wilcoxon rank-sum test was used. To evaluate the differences between T0 and T1, ANOVA for paired data or Wilcoxon matched-pairs signed-ranks test was used. P < 0.05 was considered significant.

MEASUREMENT AND MAIN RESULTS

Hemostasis was evaluated by means of prothrombin time, activated partial thromboplastin time, fibrinogen, and ROTEM. The study included 13 dogs in the HES group and 10 dogs in the HS group. Differences were found between groups at T1: increase in clotting time (P = 0.018) and decrease in fibrinogen level (P = 0.021) in the HS-treated group. Between T0 and T1, there were differences for the HES group: increase in clot formation time (P = 0.046), decrease in maximum clot firmness (P = 0.002) in ex-TEM profile, and decrease in maximum clot firmness (P = 0.0117) in fib-TEM profile. Between T0 and T1, the following differences were noted for the HS group: increase in clotting time (P = 0.048) and clot formation time (P = 0.0019), decrease in maximum clot firmness (P = 0.031) and α angle (P = 0.036) in ex-TEM profile, decrease in α angle (P = 0.036) in in-TEM profile, and decrease in maximum clot firmness (P = 0.017) in fib-TEM profile.

CONCLUSION

In dogs affected by GDV, HES or HS infusion caused a similar tendency toward hypocoagulability, with few differences between the 2 groups.

Immunomodulatory Effect of Hypertonic Saline Solution in Traumatic Brain-Injured Patients and Intracranial Hypertension

Traumatic brain injury (TBI) is often associated with an increase in the intracranial pressure (ICP). This increase in ICP can cross the physiological range and lead to a reduction in cerebral perfusion pressure (CPP) and the resultant cerebral blood flow (CBF). It is this reduction in the CBF that leads to the secondary damage to the neural parenchyma along with the physical axonal and neuronal damage caused by the mass effect. In certain cases, a surgical intervention may be required to either remove the mass lesion (hematoma of contusion evacuation) or provide more space to the insulted brain to expand (decompressive craniectomy). Whether or not a surgical intervention is performed, all these patients require some form of pharmaceutical antiedema agents to bring down the raised ICP. These agents have been broadly classified as colloids (e.g., mannitol, glycerol, urea) and crystalloids (e.g., hypertonic saline), and have been used since decades. Even though mannitol has been the workhorse for ICP reduction owing to its unique properties, crystalloids have been found to be the preferred agents, especially when long-term use is warranted. The safest and most widely used agent is hypertonic saline in various concentrations. Whatever be the concentration, hypertonic saline has created special interest among physicians owing to its additional property of immunomodulation and neuroprotection. In this review, we summarize and understand the various mechanism by which hypertonic saline exerts its immunomodulatory effects that helps in neuroprotection after TBI.

Lung Protective Effects of Low-Volume Resuscitation and Pharmacologic Treatment of Swine Subjected to Polytrauma and Hemorrhagic Shock

Hemorrhage is a common cause of death in the battlefield. Valproic acid (VPA) has been associated with improved outcomes in multiple models of trauma, when combined with isotonic fluid resuscitation. However, isotonic fluid administered in this setting is logistically impractical and may be associated with complications. In this study, we sought to evaluate the feasibility and immunologic impact of combining VPA treatment with low-volume hypertonic saline (HTS). In vivo: female Yorkshire swine were subjected to hemorrhage (40% total blood volume) and polytrauma (rib fracture and delayed liver injury). Animals were kept in shock for 30 minutes and resuscitated with (1) normal saline (NS, 3× hemorrhaged volume), (2) HTS (7.5% saline, 4 mL/kg), or (3) HTS + VPA (4 mg/kg; 150 mg/kg; n = 3/cohort). After 18 hours of observation, animals were euthanized and the lungs evaluated for acute injury and expression of myeloperoxidase (MPO) and caveolin-1 (Cav-1). In vitro: human umbilical vein endothelial cells (HUVECs) were exposed to anoxic conditions (5% CO₂, 95% N₂) for 16 hours in (1) normosmotic, (2) hyperosmotic (400 mOsm), or (3) hyperosmotic + VPA (4 mM) media. Immunohistochemistry and Western blots were performed to determine Cav-1 expression. Lungs from VPA-treated animals demonstrated decreased acute injury, MPO expression, and endothelial expression of Cav-1 when compared to lungs from animals resuscitated with NS or HTS alone. Similarly, HUVECs cultured in hyperosmotic media containing VPA demonstrated decreased expression of Cav-1. This study demonstrates that combined treatment with VPA and HTS is a viable strategy in hemorrhagic shock and polytrauma. Attenuation of lung injury following VPA treatment may be related to modulation of the inflammatory response.

A Systematic Review of Neuroprotective Strategies during Hypovolemia and Hemorrhagic Shock

Severe trauma constitutes a major cause of death and disability, especially in younger patients. The cerebral autoregulatory capacity only protects the brain to a certain extent in states of hypovolemia; thereafter, neurological deficits and apoptosis occurs. We therefore set out to investigate neuroprotective strategies during haemorrhagic shock. This review was performed in accordance to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Before the start of the search, a review protocol was entered into the PROSPERO database. A systematic literature search of Pubmed, Web of Science and CENTRAL was performed in August 2017. Results were screened and evaluated by two researchers based on a previously prepared inclusion protocol. Risk of bias was determined by use of SYRCLE's risk of bias tool. The retrieved results were qualitatively analysed. Of 9093 results, 119 were assessed in full-text form, 16 of them ultimately adhered to the inclusion criteria and were qualitatively analyzed. We identified three subsets of results: (1) hypothermia; (2) fluid therapy and/or vasopressors; and (3) other neuroprotective strategies (piracetam, NHE1-inhibition, aprotinin, human mesenchymal stem cells, remote ischemic preconditioning and sevoflurane). Overall, risk of bias according to SYRCLE's tool was medium; generally, animal experimental models require more rigorous adherence to the reporting of bias-free study design (randomization, etc.). While the individual study results are promising, the retrieved neuroprotective strategies have to be evaluated within the current scientific context-by doing so, it becomes clear that specific promising neuroprotective strategies during states of haemorrhagic shock remain sparse. This important topic therefore requires more in-depth research.

Purinergic Signaling and the Immune Response in Sepsis: A Review

PURPOSE

Sepsis remains an unresolved clinical problem with high in-hospital mortality. Despite intensive research over decades, no treatments for sepsis have become available. Here we explore the role of ATP in the pathophysiology of sepsis. ATP is not only a universal energy carrier but it also acts as an extracellular signaling molecule that regulates immune function. ATP stimulates a large family of purinergic receptors found on the cell surface of virtually all mammalian cells. In severe sepsis and septic shock, ATP is released in large amounts into the extracellular space where it acts as a "danger" signal. In this review, we focus on the roles of ATP as a key regulator of immune cell function and as a disruptive signal that contributes to immune dysfunction in sepsis.

METHODS

We summarized the current understanding of the pathophysiology of sepsis, with special emphasis on the emerging role of systemic ATP as a disruptive force that promotes morbidity and mortality in sepsis.

FINDINGS

Over the past two decades, the discovery that regulated ATP release and purinergic signaling represent a novel regulatory mechanism in immune cell physiology has opened up new possibilities in the treatment of sepsis. Immune cells respond to stimulation with the release of cellular ATP, which regulates cell functions in autocrine and paracrine fashions. In sepsis, large amounts of systemic ATP produced by tissue damage and inflammation disrupt these regulatory purinergic signaling mechanisms, leading to immune dysfunction that promotes the pathophysiologic processes involved in sepsis.

IMPLICATIONS

The knowledge of these ATP-dependent signaling processes is likely to reveal exciting new avenues in the treatment of the unresolved clinical problem of sepsis.

Inhibition of Neutrophils by Hypertonic Saline Involves Pannexin-1, CD39, CD73, and Other Ectonucleotidases

Hypertonic saline (HS) resuscitation has been studied as a possible strategy to reduce polymorphonuclear neutrophil (PMN) activation and tissue damage in trauma patients. Hypertonic saline blocks PMNs by adenosine triphosphate (ATP) release and stimulation of A2a adenosine receptors. Here, we studied the underlying mechanisms in search of possible reasons for the inconsistent results of recent clinical trials with HS resuscitation. Purified human PMNs or PMNs in whole blood were treated with HS to simulate hypertonicity levels found after HS resuscitation (40 mmol/L beyond isotonic levels). Adenosine triphosphate release was measured with a luciferase assay. Polymorphonuclear neutrophil activation was assessed by measuring oxidative burst. The pannexin-1 (panx1) inhibitor panx1 and the gap junction inhibitor carbenoxolone (CBX) blocked ATP release from PMNs in purified and whole blood preparations, indicating that HS releases ATP via panx1 and gap junction channels. Hypertonic saline blocked N-formyl-Met-Leu-Phe-induced PMN activation by 40% in purified PMN preparations and by 60% in whole blood. These inhibitory effects were abolished by panx1 but only partially reduced by CBX, which indicates that panx1 has a central role in the immunomodulatory effects of HS. Inhibition of the ectonucleotidases CD39 and CD73 abolished the suppressive effect of HS on purified PMN cultures but only partially reduced the effect of HS in whole blood. These findings suggest redundant mechanisms in whole blood that may strengthen the immunomodulatory effect of HS in vivo. We conclude that HS resuscitation exerts anti-inflammatory effects that involve panx1, CD39, CD73, and other ectonucleotidases, which produce the adenosine that blocks PMNs by stimulating their A2a receptors. Our findings shed new light on the immunomodulatory mechanisms of HS and suggest possible new strategies to improve the clinical efficacy of hypertonic resuscitation.

Prehospital Resuscitation of Traumatic Hemorrhagic Shock with Hypertonic Solutions Worsens Hypocoagulation and Hyperfibrinolysis

Impaired hemostasis frequently occurs after traumatic shock and resuscitation. The prehospital fluid administered can exacerbate subsequent bleeding and coagulopathy. Hypertonic solutions are recommended as first-line treatment of traumatic shock; however, their effects on coagulation are unclear. This study explores the impact of resuscitation with various hypertonic solutions on early coagulopathy after trauma. We conducted a prospective observational subgroup analysis of large clinical trial on out-of-hospital single-bolus (250 mL) hypertonic fluid resuscitation of hemorrhagic shock trauma patients (systolic blood pressure, ≤70 mmHg). Patients received 7.5% NaCl (HS), 7.5% NaCl/6% Dextran 70 (HSD), or 0.9% NaCl (normal saline [NS]) in the prehospital setting. Thirty-four patients were included: 9 HS, 8 HSD, 17 NS. Treatment with HS/HSD led to higher admission systolic blood pressure, sodium, chloride, and osmolarity, whereas lactate, base deficit, fluid requirement, and hemoglobin levels were similar in all groups. The HSD-resuscitated patients had higher admission international normalized ratio values and more hypocoagulable patients, 62% (vs. 55% HS, 47% NS; P < 0.05). Prothrombotic tissue factor was elevated in shock treated with NS but depressed in both HS and HSD groups. Fibrinolytic tissue plasminogen activator and anti-fibrinolytic plasminogen activator inhibitor type 1 were increased by shock but not thrombin-activatable fibrinolysis inhibitor. The HSD patients had the worst imbalance between procoagulation/anticoagulation and profibrinolysis/antifibrinolysis, resulting in more hypocoagulability and hyperfibrinolysis. We concluded that resuscitation with hypertonic solutions, particularly HSD, worsens hypocoagulability and hyperfibrinolysis after hemorrhagic shock in trauma through imbalances in both procoagulants and anticoagulants and both profibrinolytic and antifibrinolytic activities.

Can empirical hypertonic saline or sodium bicarbonate treatment prevent the development of cardiotoxicity during serious amitriptyline poisoning? Experimental research

OBJECTIVE

The aim of this experimental study was to investigate whether hypertonic saline or sodium bicarbonate administration prevented the development of cardiotoxicity in rats that received toxic doses of amitriptyline.

METHOD

Thirty-six Sprague Dawley rats were used in the study. The animals were divided into six groups. Group 1 received toxic doses of i.p. amitriptyline. Groups 2 and 3 toxic doses of i.p. amitriptyline, plus i.v. sodium bicarbonate and i.v. hypertonic saline, respectively. Group 4 received only i.v. sodium bicarbonate, group 5 received only i.v. hypertonic saline, and group 6 was the control. Electrocardiography was recorded in all rats for a maximum of 60 minutes. Blood samples were obtained to measure the serum levels of sodium and ionised calcium.

RESULTS

The survival time was shorter in group 1. In this group, the animals' heart rates also decreased over time, and their QRS and QTc intervals were significantly prolonged. Groups 2 and 3 showed less severe changes in their ECGs and the rats survived for a longer period. The effects of sodium bicarbonate or hypertonic saline treatments on reducing the development of cardiotoxicity were similar. The serum sodium levels decreased in all the amitriptyline-applied groups. Reduction of serum sodium level was most pronounced in group 1.

CONCLUSION

Empirical treatment with sodium bicarbonate or hypertonic saline can reduce the development of cardiotoxicity during amitriptyline intoxication. As hypertonic saline has no adverse effects on drug elimination, it should be considered as an alternative to sodium bicarbonate therapy.

Collider bias in trauma comparative effectiveness research: the stratification blues for systematic reviews

BACKGROUND

Collider bias, or stratifying data by a covariate consequence rather than cause (confounder) of treatment and outcome, plagues randomised and observational trauma research. Of the seven trials of prehospital hypertonic saline in dextran (HSD) that have been evaluated in systematic reviews, none found an overall between-group difference in survival, but four reported significant subgroup effects. We hypothesised that an avoidable type of collider bias often introduced inadvertently into trauma comparative effectiveness research could explain the incongruous findings.

METHODS

The two most recent HSD trials, a single-site pilot and a multi-site pivotal study, provided data for a secondary analysis to more closely examine the potential for collider bias. The two trials had followed the a priori statistical analysis plan to subgroup patients by a post-randomisation covariate and well-established surrogate for bleeding severity, massive transfusion (MT), ≥ 10 unit of red blood cells within 24h of admission. Despite favourable HSD effects in the MT subgroup, opposite effects in the non-transfused subgroup halted the pivotal trial early. In addition to analyzing the data from the two trials, we constructed causal diagrams and performed a meta-analysis of the results from all seven trials to assess the extent to which collider bias could explain null overall effects with subgroup heterogeneity.

RESULTS

As in previous trials, HSD induced significantly greater increases in systolic blood pressure (SBP) from prehospital to admission than control crystalloid (p=0.003). Proportionately more HSD than control decedents accrued in the non-transfused subgroup, but with paradoxically longer survival. Despite different study populations and a span of over 20 years across the seven trials, the reported mortality effects were consistently null, summary RR=0.99 (p=0.864, homogeneity p=0.709).

CONCLUSIONS

HSD delayed blood transfusion by modifying standard triggers like SBP with no detectable effect on survival. The reported heterogeneous HSD effects in subgroups can be explained by collider bias that trauma researchers can avoid by improved covariate selection and data capture strategies.

Effect of hypertonic saline on hypotension following induction of general anesthesia: A randomized controlled trial

Background:

The aim of this study was to examine the effects of preoperatively administered i.v. hypertonic saline on hypotension following induction of general anesthesia.

Materials and Methods:

Fifty-four patients who scheduled for elective surgery were randomly allocated to two groups of 27 patients who received hypertonic saline 5% (2.3 ml/kg) or received normal saline (13 ml/kg). Infusion of hypertonic saline was done half an hour before induction of anesthesia during 30 minutes. Anesthesia was conducted in a standard protocol for all patients. Age, sex, body mass index (BMI), systolic and diastolic blood pressure (SBP, DBP), heart rate (HR) and mean arterial pressure (MAP) were assessed in all patients.

Results:

The mean age of patients was 36.68 ± 10.8 years. Forty percent of patients were male. The mean SBP at min 2 and min 5, mean of DBP at min 2, 5, and 15, mean of HR at all time points and mean of MAP at min 2 and 15 between groups were no significantly different (P > 0.05), but mean of SBP at min 10 and 15, mean of DBP at min 10, and mean of MAP at min 5 and 10 in hypertonic saline group was significantly more than the normal group (P < 0.05). Trend of SBP, DBP, HR and MAP between groups were not significantly different (P > 0.05).

Conclusions:

Infusion of hypertonic saline 5% (2.3 mg/kg) before the general anesthesia led to a useful reduction in MAP and reduced heart rate, with no episodes of severe hypotension.

The ebb and flow of fluid (as in resuscitation)

Since the early 1960's "resuscitation" following major trauma involved use of replacement crystalloid fluid/estimated blood loss in volumes of 3/1, in the ambulance, emergency room, operating room and surgical intensive care unit. During the past 20 years, MAJOR paradigm shifts have occurred in this concept. As a result hypotensive resuscitation with a view towards restriction of crystalloid, and prevention of complications has occurred. Improved results in both civilian and military environments have been reported. As a result there is new focus on trauma surgical involvement in all aspects of trauma patient management, focus on early aggressive surgical approaches (which may or may not involve an operation), and movement from crystalloid to blood, plasma, and platelet replacement therapy.

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.

General intensive care for patients with traumatic brain injury: An update

Background:

Traumatic brain injury (TBI) is a growing epidemic throughout the world and may present as major global burden in 2020. Some intensive care units throughout the world still have no access to specialized monitoring methods, equipments and other technologies related to intensive care management of these patients; therefore, this review is meant for providing generalized supportive measurement to this subgroup of patients so that evidence based management could minimize or prevent the secondary brain injury.

Methods:

Therefore, we have included the PubMed search for the relevant clinical trials and reviews (from 1 January 2007 to 31 March 2013), which specifically discussed about the topic.

Results:

General supportive measures are equally important to prevent and minimize the effects of secondary brain injury and therefore, have a substantial impact on the outcome in patients with TBI. The important considerations for general supportive intensive care unit care remain the prompt reorganization and treatment of hypoxemia, hypotension and hypercarbia. Evidences are found to be either against or weak regarding the use of routine hyperventilation therapy, tight control blood sugar regime, use of colloids and late as well as parenteral nutrition therapy in patients with severe TBI.

Conclusion:

There is also a need to develop some evidence based protocols for the health-care sectors, in which there is still lack of specific management related to monitoring methods, equipments and other technical resources. Optimization of physiological parameters, understanding of basic neurocritical care knowledge as well as incorporation of newer guidelines would certainly improve the outcome of the TBI patients.

Specific intensive care management of patients with traumatic brain injury: Present and future

Traumatic brain injury (TBI) is a major global problem and affects approximately 10 million peoples annually; therefore has a substantial impact on the health-care system throughout the world. In this article, we have summarized various aspects of specific intensive care management in patients with TBI including the emerging evidence mainly after the Brain Trauma Foundation (BTF) 2007 and also highlighted the scope of the future therapies. This review has involved the relevant clinical trials and reviews (from 1 January 2007 to 31 March 2013), which specifically discussed about the topic. Though, BTF guideline based management strategies could provide standardized protocols for the management of patients with TBI and have some promising effects on mortality and morbidity; there is still need of inclusion of many suggestions based on various published after 2007. The main focus of majority of these trials remained to prevent or to treat the secondary brain injury. The future therapy will be directed to treat injured neurons and may benefit the outcome. There is also urgent need to develop some good prognostic indicators as well.

Update on prehospital emergency care of severe trauma patients

The prognosis of severe trauma patients is determined by the ability of a healthcare system to provide high intensity therapeutic treatment on the field and to transport patients as quickly as possible to the structure best suited to their condition. Direct admission to a specialized center ("trauma center") reduces the mortality of the most severe trauma at 30 days and one year. Triage in a non-specialized hospital is a major risk of loss of chance and should be avoided whenever possible. Medical dispatching plays a major role in determining patient care. The establishment of a hospital care network is an important issue that is not formalized enough in France. The initial triage of severe trauma patients must be improved to avoid taking patients to hospitals that are not equipped to take care of them. For this purpose, the MGAP score can predict severity and help decide where to transport the patient. However, it does not help predict the need for urgent resuscitation procedures. Hemodynamic management is central to the care of hemorrhagic shock and severe head trauma. Transport helicopter with a physician on board has an important role to allow direct admission to a specialized center in geographical areas that are difficult to access.

Synergistic effects of hypertonic saline and valproic acid in a lethal rat two-hit model

BACKGROUND

Hemorrhagic shock (HS) followed by an infection ("second hit") can lead to severe systemic inflammatory response and multiple-organ failure. Studies have shown that resuscitation with hypertonic saline (HTS) can blunt the inflammatory response. We demonstrated that large doses of valproic acid (VPA, 300 mg/kg), a histone deacetylase inhibitor, improves survival in a rodent two-hit model (HS followed by cecal ligation and puncture [CLP]). In the present study, we examined whether combination of HTS with VPA would allow us to achieve survival advantage at a lower dose of VPA (200 mg/kg).

METHODS

Male Sprague-Dawley rats were subjected to HS (50% blood loss) and randomized into five groups (n = 7-8 per group) as follows: (1) isotonic sodium chloride solution (ISCS), (2) 7.5% saline, (3) VPA, (4) ISCS + VPA, and (5) HTS + VPA. After 24 hours, they underwent CLP, followed by the same doses of ISCS, HTS, and/or VPA and were monitored for 10 days. In a parallel experiment, blood, peritoneal irrigation fluid and lung homogenate were subjected to enzyme-linked immunosorbent assay 3 hours and 24 hours after CLP to measure myeloperoxidase activity and proinflammatory cytokines tumor necrosis factor α and interleukin 1β levels. Western blotting was performed to investigate the expression of pentraxin 3 protein in the lung homogenate at 24 hours after CLP. Hematoxylin and eosin staining of lungs at the 24 hours were performed to quantify the degree of acute lung injury.

RESULTS

HTS + VPA treatment significantly improved survival (87.5%), compared with the other groups (14.3%; p < 0.05), while attenuating peritoneal myeloperoxidase levels and proinflammatory cytokine tumor necrosis factor α and interleukin 1β levels in the serum, peritoneal cavity, and lung. The degree of acute lung injury and expression of pentraxin 3 in the lung were significantly reduced in the HTS + VPA group.

CONCLUSION

This is the first study to show that VPA and HTS can work synergistically to attenuate inflammation and improve survival in a lethal two-hit model.