Hypothermia in bleeding trauma: a friend or a foe?

Induced Moderate Hypothermia in Aortic Rupture With Retroperitoneal Bleeding: A Randomized Porcine Study

OBJECTIVE

Induced hypothermia improves outcome in aortic arch surgery, neonatal neurointensive care, and transplant surgery for example. In contrast, spontaneous hypothermia has been associated with worse outcomes in patients suffering from hemorrhagic shock, mostly explained by its adverse effects on the coagulation system. We investigated if induced hypothermia would impair short-term survival in experimental aortic rupture with retroperitoneal bleeding.

METHODS

Anesthetized pigs were randomized into 2 groups: hypothermia by peritoneal lavage of ice-cold Ringer's acetate and external cooling (n = 10) and normothermia (n = 10). Aortic rupture with retroperitoneal bleeding was induced by endovascular means creating a 6 mm hole in the retroperitoneal portion of abdominal aorta. Survival (primary outcome), hemodynamics, and arterial blood gases including lactate were collected and analyzed up to 180 min after aortic rupture.

RESULTS

The body temperature (mean ± standard deviation) in the hypothermic group was 31.5 ± 1.0 °C and 38.7 ± 0.4 °C in the normothermic group at the time for aortic rupture. Survival up to 180 min after the retroperitoneal bleeding was significantly higher in the hypothermic compared with the normothermic group (P = 0.023).

CONCLUSIONS

Induced hypothermia did not impair survival in this experimental retroperitoneal aortic bleeding model in anesthetized pigs. This finding may indicate a minor role for the coagulation system in this type of bleeding.

Cold temperature induces a TRPM8-independent calcium release from the endoplasmic reticulum in human platelets

The detection of temperature by the human sensory system is life-preserving and highly evolutionarily conserved. Platelets are sensitive to temperature changes and are activated by a decrease in temperature, akin to sensory neurons. However, the molecular mechanism of this temperature-sensing ability is unknown. Yet, platelet activation by temperature could contribute to numerous clinical sequelae, most importantly to reduced quality of ex vivo-stored platelets for transfusion. In this multidisciplinary study, we present evidence for the expression of the temperature-sensitive ion channel transient receptor potential cation channel subfamily member 8 (TRPM8) in human platelets and precursor cells. We found the TRPM8 mRNA and protein in MEG-01 cells and platelets. Inhibition of TRPM8 prevented temperature-induced platelet activation and shape change. However, chemical agonists of TRPM8 did not seem to have an acute effect on platelets. When exposing platelets to below-normal body temperature, we detected a cytosolic calcium increase which was independent of TRPM8 but was completely dependent on the calcium release from the endoplasmic reticulum. Because of the high interindividual variability of TRPM8 expression, a population-based approach should be the focus of future studies. Our study suggests that the cold response of platelets is complex and TRPM8 appears to play a role in early temperature-induced activation of platelets, while other mechanisms likely contribute to later stages of temperature-mediated platelet response.

INTRACOLON COOLING INCREASES SURVIVAL RATE IN THE RAT MODEL OF LETHAL HEMORRHAGE

ABSTRACT

Background: The objective of this study was to investigate whether transrectal intracolon (TRIC) cooling can prolong the survival duration in a rat hemorrhagic shock (HS) model. Methods: A lethal HS was induced by bleeding 47% of the total blood volume. A TRIC device was placed into the colon to maintain the intracolon temperature either at 37°C (TRIC37) or at 10°C (TRIC10) post-HS. In the surface cooling (SC) rats, the body temperatures were maintained at the same level as the esophageal temperature of the TRIC10 rats. A separated group of TRIC10 rats were resuscitated (Res) at 90 min post-HS. A total of six groups were as follows: (i) Sham TRIC37 (n = 5), (ii) Sham TRIC10 (n = 5), (iii) HS TRIC37 (n = 5), (iv) HS TRIC10 (n = 6), (v) HS SC (n = 6), and (vi) HS TRIC10 + Res (n = 6). Results: An average post-HS survival time was 18.4 ± 9.4 min in HS TRIC37 and 82 ± 27.82 min in the HS SC group. In striking contrast, the HS TRIC10 group exhibited an average survival time of 150.2 ± 66.43 min. The post-HS blood potassium level rose significantly in the HS TRIC37 and HS SC, whereas it remained unchanged in the TRIC10 groups. Post-HS intestinal damage occurred in HS TRIC37 and HS SC groups but virtually absent in HS TRIC10 groups. After resuscitation at 90 min post-HS, all HS TRIC10 rats were fully recovered from the lethal HS. Conclusions: TRIC10 reversed the high blood potassium level, prevented the intestinal damage, and prolonged the survival duration by sixfold relative to normothermia and by twofold compared with SC post-HS. All TRIC10 rats were successfully resuscitated at 90 min post-HS.

The efficacy of temperature intervention combined with tranexamic acid in reducing blood loss and accelerating recovery during spinal fusion

OBJECTIVE

This study aimed to evaluate the effect of temperature intervention combined with tranexamic acid (TXA) on perioperative blood loss during spinal fusion and accelerated rehabilitation.

METHOD

Between August 2014 and July 2019, 310 lumbar fusion at our hospital were randomly divided into 4 groups as follows. Group A (placebo): no TXA and no temperature intervention. Group B: TXA (15 mg/kg) before skin incision. Group C: TXA (15 mg/kg) before skin incision and temperature intervention. Group D: temperature intervention without TXA. The primary outcomes were intraoperative blood loss, postoperative blood loss, total blood loss, and core temperature at different stages. We also recorded the hemoglobin level, blood transfusion rate, prothrombin time on postoperative day 1 (POD1), length of hospital stay, and the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE).

RESULTS

The 4 groups showed statistically significant differences in intraoperative blood loss, postoperative blood loss, total blood loss, core temperature after anesthesia, average temperature during the operation, hemoglobin on POD1, and length of stay (P < .05). In contrast, prothrombin time on POD1 and the incidence of DVT or PE did not differ between the groups (P > .05). Comparing the transfusion rate in Group C (6/77, 7.79%) and Group A (17/78, 21.79%), the difference was statistically significant.

CONCLUSION

Temperature intervention combined with TXA can significantly reduce blood loss and the transfusion rate of spinal fusion in the perioperative period, reduce the length of stay and accelerate rehabilitation after surgery without increasing the incidence of DVT or PE.

Prevalence of Postoperative Hypothermia in the Post-anesthesia Care Unit

Background

Unwanted postoperative hypothermia is an unpleasant event that can cause various complications.

Objectives

As this serious complication and its provoking causes have not been investigated sufficiently, this study was designed and conducted to determine the prevalence of hypothermia and its associated factors in the post-anesthesia care unit after elective surgery.

Methods

Four hundred patients undergoing elective surgeries were enrolled in the present cross-sectional research after termination of surgery and at the time of arrival at the post-anesthesia care unit of Poursina Public University Hospital. The tympanic membrane temperature was measured and recorded at the time of arrival at the post-anesthesia care unit and every 30 minutes after arrival. The required data were collected in a researcher-made checklist and analyzed after entering the SPSS software version 25.

Results

Considering the 5% error, it can be said that the prevalence of hypothermia in patients undergoing elective surgery ranges from 20 to 28% at the time of arrival at the post-anesthesia care unit and 18.5 to 26% 30 minutes after arrival.

Conclusions

More than a quarter of patients experienced hypothermia following elective surgery. Therefore, appropriate treatment and control measures are necessary to manage this complication, particularly in patients with predisposing risk factors and comorbidities.

Cold temperature induces a TRPM8-independent calcium release from the endoplasmic reticulum in human platelets

Platelets are sensitive to temperature changes and akin to sensory neurons, are activated by a decrease in temperature. However, the molecular mechanism of this temperature-sensing ability is unknown. Yet, platelet activation by temperature could contribute to numerous clinical sequelae, most importantly to reduced quality of ex vivo-stored platelets for transfusion. In this interdisciplinary study, we present evidence for the expression of the temperature-sensitive ion channel transient receptor potential cation channel subfamily member 8 (TRPM8) in human platelets and precursor cells. We found the TRPM8 mRNA and protein in MEG-01 cells and platelets. Inhibition of TRPM8 prevented temperature-induced platelet activation and shape change. However, chemical agonists of TRPM8 did not seem to have an acute effect on platelets. When exposing platelets to below-normal body temperature, we detected a cytosolic calcium increase which was independent of TRPM8 but was completely dependent on the calcium release from the endoplasmic reticulum. Because of the high interindividual variability of TRPM8 expression, a population-based approach should be the focus of future studies. Our study suggests that the cold response of platelets is complex and TRPM8 appears to play a role in early temperature-induced activation of platelets, while other mechanisms likely contribute to later stages of temperature-mediated platelet response.

Platelet Hemostasis Reactions at Different Temperatures Correlate with Intracellular Calcium Concentration

Hypo- and hyperthermia affect both primary and secondary hemostasis; however, there are controversial data concerning platelet activation and the underlying mechanisms under hypo- and hyperthermia. The discrepancies in the data could be partly explained by different approaches to hemostatic reactions analysis. We applied a new LaSca-TMF laser particle analyzer for a simultaneous fluorescence and laser scattering analysis of platelet responses at different temperatures. Human platelets were activated by ADP in a wide range of temperatures, and platelet transformations (e.g., a shape change reaction, aggregation and clot formation) and the intracellular calcium concentration ([Ca²⁺]_i) were analyzed by LaSca-TMF and confocal microscopy. The platelet shape change reaction gradually increased with a rising temperature. The platelet aggregation strongly decreased at low ADP concentrations with the augmentation of the temperature and was independent of the temperature at high ADP concentrations. In contrast, the clotting time decreased with a temperature increase. Similar to the aggregation response, a rise in [Ca²⁺]_i triggered by low ADP concentrations was higher under hypothermic conditions and the differences were independent of the temperature at high ADP concentrations. We showed that the key reactions of cellular hemostasis are differentially regulated by temperature and demonstrated for the first time that an accelerated aggregation under hypothermic conditions directly correlated with an increased level in [Ca²⁺]_i in platelets.

Directly Cooling Gut Prevents Mortality in the Rat Model of Reboa Management of Lethal Hemorrhage

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a lifesaving technique for the management of lethal torso hemorrhage. Its benefit, however, must be weighed against the lethal distal organ ischemia-reperfusion injury (IRI). This study uses a novel direct gut cooling technique to manage the distal organ IRI.

METHODS

A rat lethal hemorrhage model was established by bleeding of 50% of the estimated total blood volume via inferior vena cava. A novel TransRectal Intra-Colon (TRIC) temperature management device was positioned in the descending colon either to maintain intra-colon temperature at 37°C or 12°C. The upper body temperature was maintained at as close to 37°C as possible in both groups. A 2F Fogarty balloon catheter was inserted via the femoral artery into the descending thoracic aorta for the implementation of REBOA. After REBOA, the balloon was deflated, and the shed blood was returned. The temperature managements were continued for additional 180 to 270 min during the post-REBOA period.

RESULTS

All rats subjected to REBOA management of lethal hemorrhage at 37°C had severe histopathological gut and abdominal organ IRI, severe functional deficits, and died within 24 h with 100% mortality. By contrast, directly cooling the colon to 10°C to 12°C with the novel TRIC device abolished mortality, and dramatically improved ABG parameters, prevented the abdominal organ injury, and reduced the functional deficits during the 7-day post-REBOA period.

CONCLUSIONS

Direct trans-rectal colon cooling during REBOA management of lethal hemorrhage offers extraordinary functional improvement and amazing tissue protection, and abolishes mortality.

Transrectal intracolon cooling prevents paraplegia and mortality in a rat model of aortic occlusion-induced spinal cord ischemia

OBJECTIVE

Spinal cord ischemia-reperfusion injury (SC-IRI) occurs in many medical conditions such as aneurysm surgical repair but no treatment of SC-IRI is available in clinical practice. The objective of the present study was to develop a novel medical device for the treatment of SC-IRI.

METHODS

A rat model of SC-IRI was used. A novel transrectal intracolon (TRIC) temperature management device was developed to maintain an intracolon wall temperature at either 37°C (TRIC37°C) or 12°C (TRIC12°C). The upper body temperature was maintained as close as possible to 37°C in both groups. A 2F Fogarty balloon catheter was inserted via the left common carotid artery to block the distal aortic blood flow to the spinal cord. The proximal blood pressure was controlled by the withdrawal and infusion of blood via the jugular vein catheter, such that the distal tail artery blood pressure was maintained at ∼10 mmHg for 13 and 20 minutes, respectively. Next, the balloon was deflated, and TRIC temperature management was continued for an additional 30 minutes to maintain the colon wall temperature at either 37°C or 12°C during the reperfusion period.

RESULTS

All the rats subjected to 13 minutes of spinal cord ischemia in the TRIC37°C group had developed paraplegia during the postischemic phase. In striking contrast, TRIC at 12°C completely prevented the paraplegia, dramatically improved the arterial blood gas parameters, and avoided the histopathologic injuries to the spinal cord in rats subjected to 13 minutes of spinal cord ischemia. Furthermore, TRIC12°C allowed for the extension of the ischemia duration from 13 minutes to 20 minutes, with significantly reduced functional deficits.

CONCLUSIONS

Directly cooling the intestine focally with the TRIC device offered an exceptional survival rate and functional improvement after aortic occlusion-induced spinal cord ischemia.

Prevention of hypothermia in trauma victims - the HYPOTRAUM 2 study

INTRODUCTION

Hypothermia is common in trauma patients. It contributes to increasing mortality rate. Hypothermia is multifactorial, favoured by exposure to cold, severity of the patient's state and interventions such as infusion of fluids at room temperature.

AIM

To demonstrate that specific management of hypothermia (or of the risk of hypothermia) increases the number of trauma patients arriving at the hospital with a temperature >35°C.

DESIGN

This is a prospective, multicentre, open-label, pragmatic, cluster randomized clinical trial of an expected 1,200 trauma patients included by 12 out-of-hospital mobile intensive care units (MICU). Trauma patients are included in a prehospital setting if they present at least one of the following criteria known to be associated with an increased incidence of hypothermia: ambient temperature <18°C, Glasgow coma scale <15, systolic arterial blood pressure <100 mm Hg or body temperature <35°C. Patients are randomized, by cluster, to receive a conventional management or 'interventional' nursing management associating: continuous epitympanic temperature monitoring, early installation in the heated ambulance (temperature target >30°C controlled by infrared thermometer), protection by a survival blanket, and use of heated solutes (temperature objective >35°C controlled by infrared thermometer). The primary end point is the prevalence of hypothermia on arrival at the hospital. The hypothesis tested is a reduction from 20% to 13% in the prevalence of hypothermia. Secondary end points are to evaluate the interaction between the effectiveness of the measures taken and: (1) the severity of the patients assessed by the Revised Trauma Score; (2) the meteorological conditions when they are managed; (3) the time of care; and (4) therapeutic interventions.

DISCUSSION

This trial will assess the effectiveness of an invasive, out-of-hospital, temperature management on the onset of hypothermia in moderate to severe trauma patients.

IMPACT

Specific management of hypothermia is expected to decrease hypothermia in trauma patients.

Effects of preoperative warming on the occurrence of surgical site infection: A systematic review and meta-analysis

OBJECTIVE

To determine whether preoperative warming can reduce the risk of surgical site infection (SSI) after surgery.

BACKGROUND

Intraoperative hypothermia is a risk factor for the occurrence of SSI in patients after surgery. However, the effectiveness of preoperative warming in reducing the incidence of the condition remains unclear.

MATERIALS AND METHODS

A systematic review was conducted using Medline, EMBASE, and the Cochrane Library to identify randomized controlled trials (RCTs) that evaluated the risk of SSI after surgery with and without the use of a preoperative warming protocol. The primary outcome measure was the diagnosis of SSI within 10-90 days of surgery. The pooled risk ratio was estimated with a fixed-effect meta-analysis. Sensitivity analyses were performed to examine the impact of the structural design of preoperative warming on the pooled risk of SSI.

RESULTS

Of the 249 studies identified, seven RCTs representing 1086 patients were included in the present meta-analysis. The use of preoperative warming was associated with a significant decrease in SSI (RR = 0.60, 95% CI 0.42-0.87, P = 0.072). Specifically, we defined patients who used forced-air warming (FAW) and integrated measures such as liquid heating and warming blankets as the MIX group and patients who used only FAW as the FAW group. Patients who used MIX methods (temperature set <43 °C and 30-min prewarming) before surgery benefited more from prewarming.

CONCLUSIONS

The results of this study suggest that preoperative warming can reduce rates of SSI after surgery. We, therefore, recommend the application of MIX warming methods before surgery.

Hibernation-Based Approaches in the Treatment of Hemorrhagic Shock

Hemorrhagic shock is the leading cause of preventable death after trauma. Hibernation-based treatment approaches have been of increasing interest for various biomedical applications. Owing to apparent similarities in tissue perfusion and metabolic activity between severe blood loss and the hibernating state, hibernation-based approaches have also emerged for the treatment of hemorrhagic shock. Research has shown that hibernators are protected from shock-induced injury and inflammation. Utilizing the adaptive mechanisms that prevent injury in these animals may help alleviate the detrimental effects of hemorrhagic shock in non-hibernating species. This review describes hibernation-based preclinical and clinical approaches for the treatment of severe blood loss. Treatments include the delta opioid receptor agonist D-Ala-Leu-enkephalin (DADLE), the gasotransmitter hydrogen sulfide, combinations of adenosine, lidocaine, and magnesium (ALM) or D-beta-hydroxybutyrate and melatonin (BHB/M), and therapeutic hypothermia. While we focus on hemorrhagic shock, many of the described treatments may be used in other situations of hypoxia or ischemia/reperfusion injury.

The prehospital management of hypothermia - An up-to-date overview

BACKGROUND

Accidental hypothermia concerns a body core temperature of less than 35°C without a primary defect in the thermoregulatory system. It is a serious threat to prehospital patients and especially injured patients, since it can induce a vicious cycle of the synergistic effects of hypothermia, acidosis and coagulopathy; referred to as the trauma triad of death. To prevent or manage deterioration of a cold patient, treatment of hypothermia should ideally begin prehospital. Little effort has been made to integrate existent literature about prehospital temperature management. The aim of this study is to provide an up-to-date systematic overview of the currently available treatment modalities and their effectiveness for prehospital hypothermia management.

DATA SOURCES

Databases PubMed, EMbase and MEDLINE were searched using the terms: "hypothermia", "accidental hypothermia", "Emergency Medical Services" and "prehospital". Articles with publications dates up to October 2017 were included and selected by the authors based on relevance.

RESULTS

The literature search produced 903 articles, out of which 51 focused on passive insulation and/or active heating. The most effective insulation systems combined insulation with a vapor barrier. Active external rewarming interventions include chemical, electrical and charcoal-burning heat packs; chemical or electrical heated blankets; and forced air warming. Mildly hypothermic patients, with significant endogenous heat production from shivering, will likely be able to rewarm themselves with only insulation and a vapor barrier, although active warming will still provide comfort and an energy-saving benefit. For colder, non-shivering patients, the addition of active warming is indicated as a non-shivering patient will not rewarm spontaneously. All intravenous fluids must be reliably warmed before infusion.

CONCLUSION

Although it is now accepted that prehospital warming is safe and advantageous, especially for a non-shivering hypothermic patient, this review reveals that no insulation/heating combinations stand significantly above all the others. However, modern designs of hypothermia wraps have shown promise and battery-powered inline fluid warmers are practical devices to warm intravenous fluids prior to infusion. Future research in this field is necessary to assess the effectiveness expressed in patient outcomes.

Multifunctional Shape-Memory Polymer Foams with Bio-inspired Antimicrobials

Despite a number of clinically available hemostats, uncontrolled bleeding is the primary cause of trauma-related death. Shape-memory polymer (SMP) foams have a number of desirable properties for use as hemostats, including shape recovery to enable delivery into bleed sites, biocompatibility, and rapid blood clotting. To expand upon this material system, the current work aims to incorporate phenolic acids, which are honey-based antimicrobial agents, into SMP foams. We showed that cinnamic acid (CA) can be utilized as a monomer in SMP synthesis to provide foams with comparable pore structure and retained cytocompatibility. The addition of CA enabled tuning of thermal and shape-memory properties within clinically relevant ranges. Furthermore, the modified foams demonstrated initial and sustained antimicrobial effects against gram-positive and gram-negative bacteria. These multifunctional scaffolds demonstrate potential for use as hemostats to improve upon current hemorrhage treatments and provide a new tool in tuning the biological and material properties of SMP foams.

Evaluation for effects of severe acidosis on hemostasis in trauma patients using thrombelastography analyzer

OBJECTIVE

To investigate effects of metabolic acidosis on hemostasis function in trauma patients using thromboelastography analyzer.

METHODS

65 critically injured patients and 19 healthy volunteers were enrolled in the study. Three samples of whole blood were collected from each patient or healthy volunteer. These three samples were acidified with 50mmol/l phosphate-buffered saline (PBS) (pH5.8) or a neutral buffer (50mmol/l phosphate, pH7.4) and acidified blood sample with target pH of 6.95, 7.15 or 7.35 was obtained respectively. These three samples with target pH value were added into thrombelastography analyzer (TEG® 5000 Thrombelastograph Hemostasis Analyzers; Haemoscope Corporation, Niles, Illinois, USA) respectively and variables of Clot time (r), Rate of clot formation (α Angle), Clot formation time (K), Coagulation Index (CI) and Maximum strength (MA) were monitored at 37°C. Besides, association between TEG® parameters and clinicopathological features was analyzed by the Pearson χ² test.

RESULTS

In trauma patients, all 5 thrombelastographic variables, Clot time (r), Clot formation time (K), Maximum Amplitude (MA), Rate of clot formation (α Angle) and Coagulation Index (CI), were significantly affected by blood acidification, F(1.321,83.213)=88.960, P<0.001, F(2,128)=112.738, P<0.001, F(1.199,76.748)=37.964, P<0.001, F(1.195,76.452)=16.789, P<0.001 and F(2,128)=178.674, P<0.001. Post hoc tests showed that moderate acidosis (pH7.15) significantly elongated K time (from 2.6 to 3.4min, P=0.0013) and increased α Angle (from 51.9°to 52.2°, P=0.0040). r, MA and CI were not markedly influenced under moderate acidification. Comparing to mild acidosis (pH7.15), severe acidosis (pH6.95) induced more serious impairment to hemostasis and all 5 variables was substantially affected, r (from 5.9 to 6.8min, P<0.001), K (from 3.4 to 3.9min, P<0.001), α Angle (from 52.2°to 50.8°, P=0.002), MA (from 52.9 to 51.6mm, P<0.001) and CI (from -2.3 to -4.2, P<0.001). Additionally, higher r elongation under severe acidosis was significantly associated with an increased mortality rate and transfusion requirement (P=0.019 and 0.031). In healthy volunteers, similar effects on hemostasis were detected. Inhibition ratios of thrombelastographic parameters were significantly higher in trauma patients than in healthy volunteers indicating severer impairment of metabolic acidosis to hemostasis in critically injured patients.

CONCLUSIONS

The degree of metabolic acidosis in trauma patients is positively correlated to the severity of hemostasis dysfunction. Additionally, acidosis induces more serious impairment to hemostasis in trauma patients than in healthy volunteers. Moreover, acidosis-induced r time elongation is positively related to a higher death rate and increased transfusion requirement and this indicates a predictive role of TEG® variables for prognosis of traumatized patients.

Hemorrhagic Shock and the Microvasculature

The microvasculature plays a central role in the pathophysiology of hemorrhagic shock and is also involved in arguably all therapeutic attempts to reverse or minimize the adverse consequences of shock. Microvascular studies specific to hemorrhagic shock were reviewed and broadly grouped depending on whether data were obtained on animal or human subjects. Dedicated sections were assigned to microcirculatory changes in specific organs, and major categories of pathophysiological alterations and mechanisms such as oxygen distribution, ischemia, inflammation, glycocalyx changes, vasomotion, endothelial dysfunction, and coagulopathy as well as biomarkers and some therapeutic strategies. Innovative experimental methods were also reviewed for quantitative microcirculatory assessment as it pertains to changes during hemorrhagic shock. The text and figures include representative quantitative microvascular data obtained in various organs and tissues such as skin, muscle, lung, liver, brain, heart, kidney, pancreas, intestines, and mesentery from various species including mice, rats, hamsters, sheep, swine, bats, and humans. Based on reviewed findings, a new integrative conceptual model is presented that includes about 100 systemic and local factors linked to microvessels in hemorrhagic shock. The combination of systemic measures with the understanding of these processes at the microvascular level is fundamental to further develop targeted and personalized interventions that will reduce tissue injury, organ dysfunction, and ultimately mortality due to hemorrhagic shock. Published 2018. Compr Physiol 8:61-101, 2018.

Adenosine, lidocaine and Mg2+ (ALM) fluid therapy attenuates systemic inflammation, platelet dysfunction and coagulopathy after non-compressible truncal hemorrhage

Background

Systemic inflammation and coagulopathy are major drivers of injury progression following hemorrhagic trauma. Our aim was to examine the effect of small-volume 3% NaCl adenosine, lidocaine and Mg²⁺ (ALM) bolus and 0.9% NaCl/ALM ‘drip’ on inflammation and coagulation in a rat model of hemorrhagic shock.

Methods

Sprague-Dawley rats (429±4 g) were randomly assigned to: 1) shams, 2) no-treatment, 3) saline-controls, 4) ALM-therapy, and 5) Hextend^®. Hemorrhage was induced in anesthetized-ventilated animals by liver resection (60% left lateral lobe and 50% medial lobe). After 15 min, a bolus of 3% NaCl ± ALM (0.7 ml/kg) was administered intravenously (Phase 1) followed 60 min later by 4 hour infusion of 0.9% NaCl ± ALM (0.5 ml/kg/hour) with 1-hour monitoring (Phase 2). Plasma cytokines were measured on Magpix^® and coagulation using Stago/Rotational Thromboelastometry.

Results

After Phase 1, saline-controls, no-treatment and Hextend^® groups showed significant falls in white and red cells, hemoglobin and hematocrit (up to 30%), whereas ALM animals had similar values to shams (9–15% losses). After Phase 2, these deficits in non-ALM groups were accompanied by profound systemic inflammation. In contrast, after Phase 1 ALM-treated animals had undetectable plasma levels of IL-1α and IL-1β, and IL-2, IL-6 and TNF-α were below baseline, and after Phase 2 they were less or similar to shams. Non-ALM groups (except shams) also lost their ability to aggregate platelets, had lower plasma fibrinogen levels, and were hypocoagulable. ALM-treated animals had 50-fold higher ADP-induced platelet aggregation, and 9.3-times higher collagen-induced aggregation compared to saline-controls, and had little or no coagulopathy with significantly higher fibrinogen shifting towards baseline. Hextend^® had poor outcomes.

Conclusions

Small-volume ALM bolus/drip mounted a frontline defense against non-compressible traumatic hemorrhage by defending immune cell numbers, suppressing systemic inflammation, improving platelet aggregation and correcting coagulopathy. Saline-controls were equivalent to no-treatment. Possible mechanisms of ALM's immune-bolstering effect are discussed.

Deep and profound hypothermia in haemorrhagic shock, friend or foe? A systematic review

INTRODUCTION

Survival in exsanguinating cardiac arrest patients is poor, as is neurological outcome in survivors. Hypothermia has traditionally been seen as harmful to trauma patients and associated with increased mortality; however, there has been speculation that cooling to very low temperatures (≤20°C) could be used to treat haemorrhagic trauma patients by the induction of a suspended animation period through extreme cooling, which improves survival and preserves neurological function. This has been termed emergency preservation and resuscitation (EPR).

METHODS

A systematic review of the literature was used to examine the evidence base behind the use of deep and profound hypothermia in haemorrhagic shock (HS). It included original research articles (human or animal) with cooling to ≤20°C after HS or an experimental model replicating it. Normovolaemic cardiac arrest, central nervous system injury and non-HS models were excluded.

RESULTS

Twenty articles using 456 animal subjects were included, in which 327 were cooled to ≤20°C. All studies describing good survival rates were possible using EPR and 19/20 demonstrated that EPR can preserve neurological function after prolonged periods of circulatory arrest or minimal circulatory flow. This additional period can be used for surgical intervention to arrest haemorrhage in HS that would otherwise be lethal.

CONCLUSIONS

The outcomes of this review have significant implications for application to human patients and the ongoing human clinical trial (EPR for Cardiac Arrest from Trauma). Current evidence suggests that hypothermia ≤20°C used in the form of EPR could be beneficial to the HS patient.

Hemodynamic Stability to Surface Warming and Cooling During Sustained and Continuous Simulated Hemorrhage in Humans

One in 10 deaths worldwide is caused by traumatic injury, and 30% to 40% of those trauma-related deaths are due to hemorrhage. Currently, warming a bleeding victim is the standard of care due to the adverse effects of combined hemorrhage and hypothermia on survival. We tested the hypothesis that heating is detrimental to the maintenance of arterial pressure and cerebral perfusion during hemorrhage, while cooling is beneficial to victims who are otherwise normothermic. Twenty-one men (31 ± 9 y) were examined under two separate protocols designed to produce central hypovolemia similar to hemorrhage. Following 15 min of supine rest, 10 min of 30 mm Hg of lower body negative pressure (LBNP) was applied. On separate randomized days, subjects were then exposed to skin surface cooling (COOL), warming (WARM), or remained thermoneutral (NEUT), while LBNP continued. Subjects remained in these thermal conditions for either 40 min of 30 mm Hg LBNP (N = 9), or underwent a continuous LBNP ramp until hemodynamic decompensation (N = 12). Arterial blood pressure during LBNP was dependent on the thermal perturbation as blood pressure was greater during COOL (P >0.001) relative to NEUT and WARM for both protocols. Middle cerebral artery blood velocity decreased (P <0.001) from baseline throughout sustained and continuous LBNP, but the magnitude of reduction did not differ between thermal conditions. Contrary to our hypothesis, WARM did not reduce cerebral blood velocity or LBNP tolerance relative to COOL and NEUT in normothermic individuals. While COOL increased blood pressure, cerebral perfusion and time to presyncope were not different relative to NEUT or WARM during sustained or continuous LBNP. Warming an otherwise normothermic hemorrhaging victim is not detrimental to hemodynamic stability, nor is this stability improved with cooling.

Advances in understanding role of enhanced recovery after surgery and damage control surgery in acute abdominal disease

Enhanced recovery after surgery and damage control surgery have been gradually applied to clinical surgery in recent years, aimed to reduce perioperative stress response in surgical patients. Research on the perioperative period of selective surgery proves that enhanced recovery after surgery and damage control surgery play an important role in reducing perioperative stress reaction, especially in patients with acute abdominal pain. This article briefly summarizes the recent progress in understanding the role of enhanced recovery after surgery and damage control surgery in acute abdominal disease.

Endovascular Cooling Method for Hypothermia in Injured Swine

We evaluated an endovascular cooling method to modulate core temperature in trauma swine models with and without fluid support. Anesthetized swine (N = 80) were uninjured (SHAM) or injured through a bone fracture plus soft tissue injury or an uncontrolled hemorrhage and then subdivided to target body temperatures of 38°C (normothermia) or 33°C (hypothermia) by using a Thermogard endovascular cooling device (Zoll Medical). Temperature regulation began simultaneously at onset of injury (T0). Body temperatures were recorded from a rectal probe (Rec Temp) and from a central pulmonary artery catheter (PA Temp). At T15, swine received 500 mL IV Hextend over 30 minutes or no treatment (NONE) with continued monitoring until 3 hours from injury. Hypothermia was attained in 105 ± 39 minutes, at a cooling rate of -0.061°C ± 0.007°C/min for NONE injury groups. Postinjury Hextend administration resulted in faster cooling (-0.080°C ± 0.006°C/min); target temperature was reached in 83 ± 11 minutes (p < 0.05). During active cooling, body temperature measured by the PA Temp was significantly cooler than the Rec Temp due to the probe's closer proximity to the blood-cooling catheter balloons (p < 0.05). This difference was smaller in SHAM and fluid-supported injury groups (1.1°C ± 0.4°C) versus injured NONE groups (2.1°C ± 0.3°C). Target temperatures were correctly maintained thereafter in all groups. In normothermia groups, there was a small initial transient overshoot to maintain 38°C. Despite the noticeable difference between PA Temp and Rec Temp until target temperature was attained, this endovascular method can safely induce moderate hypothermia in anesthetized swine. However, likely due to their compromised hemodynamic state, cooling in hypovolemic and/or injured patients will be different from those without injury or those that also received fluids.

Valproic acid protects against haemorrhagic shock-induced signalling changes via PPARγ activation in an in vitro model

BACKGROUND AND PURPOSE

Valproic acid (VPA), a widely used epilepsy and bipolar disorder treatment, provides acute protection against haemorrhagic shock-induced mortality in a range of in vivo models through an unknown mechanism. In the liver, this effect occurs with a concomitant protection against a decrease in GSK3β-Ser(9) phosphorylation. Here, we developed an in vitro model to investigate this protective effect of VPA and define a molecular mechanism.

EXPERIMENTAL APPROACH

The human hepatocarcinoma cell line (Huh7) was exposed to conditions occurring during haemorrhagic shock (hypoxia, hypercapnia and hypothermia) to investigate the changes in GSK3β-Ser(9) phosphorylation for a 4 h period following treatment with VPA, related congeners, PPAR agonists, antagonists and siRNA.

KEY RESULTS

Huh7 cells undergoing combined hypoxia, hypercapnia, and hypothermia reproduced the reduced GSK3β-Ser(9) phosphorylation shown in vivo during haemorrhagic shock, and this change was blocked by VPA. The protective effect occurred through upstream PTEN and Akt signalling, and prevented downstream β-catenin degradation while increasing histone 2/3 acetylation. This effect was reproduced by several VPA-related compounds with known PPARγ agonist activity, independent of histone deacetylase (HDAC) inhibitory activity. Specific pharmacological inhibition (by T0070907) or knockdown of PPARγ blocked the protective effect of VPA against these signalling changes and apoptosis. In addition, specific activation of PPARγ using ciglitazone reproduced the changes induced by VPA in haemorrhagic shock-like conditions.

CONCLUSION AND IMPLICATIONS

Changes in GSK3β-Ser(9) phosphorylation in in vivo haemorrhagic shock models can be modelled in vitro, and this has identified a role for PPARγ activation in the protective role of VPA.

Hypothermia: effects on platelet function and hemostasis

Mild therapeutic hypothermia is considered standard care in the treatment of patients resuscitated from cardiac arrest. With increasingly more frequent concomitant use of platelet-inhibiting drugs, clinicians must be cognizant of the ramifications of hypothermia on platelet function as part of hemostasis. The effects of hypothermia on platelet function have been studied for more than 50 years, but the results are inconsistent and may be related to the circumstances during which hypothermia is achieved. This review summarizes current knowledge of platelet function during hypothermia and the impact on hemostasis.

[Influence of temperature on spatial fibrin clot formation process in thrombodynamics]

In this study we have investigated the process of spatial fibrin clot formation in non-steered platelet-free plasma at the temperatures from 20°C to 43°C using thrombodynamics - the novel in vitro hemostasis assay, which imitates the process of hemostatic clot growth in vivo. During data processing the following parameters were calculated: initial (V i ) and stationary (V st ) rates of clot growth which characterize initiation and propagation phases of clotting process, and clot size on the 30 th minute. The temperature dependence of extrinsic and intrinsic tenase activities, which determine values of the initial and stationary clot growth rates, respectively, have been also measured. It was established that the temperature lowering from 37°C to 24°C extends mainly on the initiation phase of clot growth, while the stationary rate of clot growth changes insignificantly. Meanwhile none of the thrombodynamics parameters shows the dramatic change of plasma coagulation system condition at the temperature of 24°C (acute hypothermia). Using the thrombodynamics assay an assumption, that the temperature lowering does not change the state of plasma hemostasis system significantly has been confirmed.

The evidence base for nursing care and monitoring of patients during therapeutic temperature management

Therapeutic temperature management (TTM) is fast becoming a primary management strategy for a variety of medical conditions treated in critical care settings throughout the world. Nurses who provide direct care and who are tasked with developing multidisciplinary protocols and pathways are struggling to collate evidence from which to support specific nursing interventions. The aim of this project was to create the first comprehensive set of evidence-based guidelines specific to nursing care of the patient for whom TTM is medically necessary. Evidence-based nursing practice summaries are provided for nine nursing content areas: interventions to manage temperature, monitoring temperature, neurologic, cardiac, pulmonary, skin care, gastrointestinal/endocrine, laboratory findings, and general considerations for nursing care.

Clinical and translational aspects of hypothermia in major trauma patients: from pathophysiology to prevention, prognosis and potential preservation

The human body strives at maintaining homeostasis within fairly tight regulated mechanisms that control vital regulators such as core body temperature, mechanisms of metabolism and endocrine function. While a wide range of medical conditions can influence thermoregulation the most common source of temperature loss in trauma patients includes: exposure (environmental, as well as cavitary), the administration of i.v. fluids, and anaesthesia/loss of shivering mechanisms, and blood loss per se. Loss of temperature can be classified either according to the aetiology (i.e. accidental/spontaneous versus trauma/haemorrhage-induced temperature loss), or according to an unintended, accidental induction in contrast to a medically intended therapeutic hypothermia. Hypothermia occurs infrequently (prevalence<10% of all injured), but more often (30-50%) in the severely injured. Hypothermia usually come together with and may aggravate acidosis and coagulopathy (the "lethal triad of trauma"), which again may be associated with a high mortality. However, recent studies disagree in the independent predictive role of hypothermia and mortality. Prevention of hypothermia is imperative through all phases of trauma care and must be an interest among all team members. Hypothermia in the trauma setting has attracted focus in the past from a pathophysiological, preventive and prognostic perspective; yet recent focus has shifted towards the potential for using hypothermia for pre-emptive and cellular protective purposes. This paper gives a brief update on some of the clinically relevant aspects of hypothermia in the injured patient.

Potential role of therapeutic hypothermia in the salvage of traumatic hemorrhagic shock

Although therapeutic hypothermia could serve as a potential therapeutic strategy for treatment of traumatic hemorrhagic shock, significant controversy exists regarding its safety and feasibility. The current resuscitation strategy in traumatic hemorrhagic shock may also require updating. In this article, we have carried out an extensive literature search in this field and propose an initial algorithm for use of therapeutic hypothermia in traumatic hemorrhagic shock. This work lays essential groundwork for future investigations in this field.

Topical menthol, ice, peripheral blood flow, and perceived discomfort

CONTEXT

Injury management commonly includes decreasing arterial blood flow to the affected site in an attempt to reduce microvascular blood flow and edema and limit the induction of inflammation. Applied separately, ice and menthol gel decrease arterial blood flow, but the combined effects of ice and menthol gel on arterial blood flow are unknown.

OBJECTIVES

To compare radial artery blood flow, arterial diameter, and perceived discomfort before and after the application of 1 of 4 treatment conditions.

DESIGN

Experimental crossover design.

SETTING

Clinical laboratory. PARTICIPANTS OR OTHER PARTICIPANTS: Ten healthy men, 9 healthy women (mean age = 25.68 years, mean height = 1.73 m, mean weight = 76.73 kg).

INTERVENTION(S)

Four treatment conditions were randomly applied for 20 minutes to the right forearm of participants on 4 different days separated by at least 24 hours: (1) 3.5 mL menthol gel, (2) 0.5 kg of crushed ice, (3) 3.5 mL of menthol gel and 0.5 kg of crushed ice, or (4) no treatment (control).

MAIN OUTCOME MEASURE(S)

Using high-resolution ultrasound, we measured right radial artery diameter (cm) and blood flow (mL/min) every 5 minutes for 20 minutes after the treatment was applied. Discomfort with the treatment was documented using a 1-to-10 intensity scale.

RESULTS

Radial artery blood flow decreased (P < .05) from baseline in the ice (-20% to -24%), menthol (-17% to -24%), and ice and menthol (-36% to -39%) treatments but not in the control (3% to 9%) at 5, 10, and 15 minutes. At 20 minutes after baseline, only the ice (-27%) and combined ice and menthol (-38%) treatments exhibited reductions in blood flow (P < .05). Discomfort was less with menthol than with the ice treatment at 5, 10, and 20 minutes after application (P < .05). Arterial diameter and heart rate did not change.

CONCLUSIONS

The application of 3.5 mL of menthol was similar to the application of 0.5 kg of crushed ice in reducing peripheral blood flood. Combining crushed ice with menthol appeared to have an additive effect on reducing blood flow.

Hypothermia in trauma

Hypovolaemic shock that results through traumatically inflicted haemorrhage can have disastrous consequences for the victim. Initially the body can compensate for lost circulating volume, but as haemorrhage continues compensatory mechanisms fail and the patient's condition worsens significantly. Hypovolaemia results in the lethal triad, a combination of hypothermia, acidosis and coagulopathy, three factors that are interlinked and serve to worsen each other. The lethal triad is a form of vicious cycle, which unless broken will result in death. This report will focus on the role of hypothermia (a third of the lethal triad) in trauma, examining literature to assess how prehospital temperature control can impact on the trauma patient. Spontaneous hypothermia following trauma has severely deleterious consequences for the trauma victim; however, both active warming of patients and clinically induced hypothermia can produce particularly positive results and improve patient outcome. Possible coagulopathic side effects of clinically induced hypothermia may be corrected with topical haemostatic agents, with the benefits of an extended golden hour given by clinically induced hypothermia far outweighing these risks. Active warming of patients, to prevent spontaneous trauma induced hypothermia, is currently the only viable method currently available to improve patient outcome. This method is easy to implement requiring simple protocols and contributes significantly to interrupting the lethal triad. However, the future of trauma care appears to lie with clinically induced therapeutic hypothermia. This new treatment provides optimism that in the future the number of deaths resulting from catastrophic haemorrhaging may be significantly lessened.

Therapeutic mild hypothermia improves early outcomes in rabbits subjected to traumatic uncontrolled hemorrhagic shock

BACKGROUND

Survival benefits of mild hypothermia in animals suffering from uncontrolled hemorrhagic shock (HS) may be influenced by trauma severity. We hypothesized that mild hypothermia would improve early outcomes based on our rabbit model of severe traumatic HS.

MATERIALS AND METHODS

Fifty male New Zealand rabbits weighing between 1.6 and 2.2 kg were randomized into one of the five groups: group 1 (sham), group 2 (37°C/80 mm Hg), group 3 (37°C/40 mm Hg), group 4 (34°C/80 mm Hg), and group 5 (34°C/40 mm Hg). Under urethane anesthesia, animals that suffered fractures and uncontrolled HS received prehospital fluid resuscitation (aggressive or limited) with temperature controlled at normothermia or mild hypothermia, hemostasis, and hospital resuscitation followed by observation.

RESULTS

Mild hypothermia significantly improved cardiac systolic function and decreased lung wet-to-dry weight ratios and total injury score compared with normothermia. Group 5 manifested the best results in lung injury. The decreased base excess and pH and increased lactate levels during HS and limited fluid resuscitation were not exacerbated by mild hypothermia. Electrolytes including potassium and calcium and blood glucose levels as well as coagulation were not significantly influenced after mild hypothermia treatment. Seven-hour survival in the hypothermic groups was higher than that in the normothermic groups, although there was no significant difference in survival between groups 5 and 3.

CONCLUSIONS

Therapeutic mild hypothermia improves early outcomes through improving lung and cardiac performance without causing evident homeostasis disturbances in the rabbit model of traumatic uncontrolled HS. Animals may benefit most under the combination treatment with mild hypothermia and limited fluid resuscitation.

Critical care considerations in the management of the trauma patient following initial resuscitation

Background

Care of the polytrauma patient does not end in the operating room or resuscitation bay. The patient presenting to the intensive care unit following initial resuscitation and damage control surgery may be far from stable with ongoing hemorrhage, resuscitation needs, and injuries still requiring definitive repair. The intensive care physician must understand the respiratory, cardiovascular, metabolic, and immunologic consequences of trauma resuscitation and massive transfusion in order to evaluate and adjust the ongoing resuscitative needs of the patient and address potential complications. In this review, we address ongoing resuscitation in the intensive care unit along with potential complications in the trauma patient after initial resuscitation. Complications such as abdominal compartment syndrome, transfusion related patterns of acute lung injury and metabolic consequences subsequent to post-trauma resuscitation are presented.

Methods

A non-systematic literature search was conducted using PubMed and the Cochrane Database of Systematic Reviews up to May 2012.

Results and conclusion

Polytrauma patients with severe shock from hemorrhage and massive tissue injury present major challenges for management and resuscitation in the intensive care setting. Many of the current recommendations for “damage control resuscitation” including the use of fixed ratios in the treatment of trauma induced coagulopathy remain controversial. A lack of large, randomized, controlled trials leaves most recommendations at the level of consensus, expert opinion. Ongoing trials and improvements in monitoring and resuscitation technologies will further influence how we manage these complex and challenging patients.

Translational barriers and opportunities for emergency preservation and resuscitation in severe injuries

BACKGROUND

Hypothermia is commonly used for organ and tissue preservation in multiple clinical settings, but its role in the management of injured patients remains controversial. There is no doubt that temperature modulation is a powerful tool, and hypothermia has been shown to protect cells during ischaemia and reperfusion, decrease organ damage and improve survival. Yet hypothermia is a double-edged sword: unless carefully managed, its induction can be associated with a number of complications.

METHODS

A literature review was performed to include important papers that address the impact of hypothermia on key biological processes, and explore the potential therapeutic role of hypothermia in trauma/haemorrhage models.

RESULTS

No clinical studies have been conducted to test the therapeutic benefits of hypothermia in injured patients. However, numerous well designed animal studies support this concept. Despite excellent preclinical data, there are several potential barriers to translating hypothermia into clinical practice.

CONCLUSION

Therapeutic hypothermia is a promising life-saving strategy. Appropriate patient selection requires a thorough understanding of how temperature modulation affects various biological mechanisms.

Year in review 2010: Critical Care--Cardiac arrest and cardiopulmonary resuscitation

This review will summarize some of the data published in 2010 and focus on papers published in Critical Care in regard to cardiac arrest and cardiopulmonary resuscitation. In particular, we discuss the latest research in therapeutic hypothermia after cardiac arrest, including methods of inducing hypothermia, potential protective mechanisms, spontaneous hypothermia versus therapeutic hypothermia, and several predictors of outcome. Furthermore, we will discuss the effects of bystander-initiated cardiopulmonary resuscitation (CPR) in patients with physician-assisted advanced cardiac life support, the role of hypercapnea in near-death experiences during cardiac arrest, markers of endothelial injury and endothelial repair after CPR, and the prognostic value of cell-free plasma DNA as a marker of poor outcome after cardiac arrest.

Clinical and cellular effects of hypothermia, acidosis and coagulopathy in major injury

BACKGROUND

Hypothermia, acidosis and coagulopathy have long been considered critical combinations after severe injury. The aim of this review was to give a clinical update on this triad in severely injured patients.

METHODS

A non-systematic literature search on hypothermia, acidosis and coagulopathy after major injury was undertaken, with a focus on clinical data from the past 5 years.

RESULTS

Hypothermia (less than 35 °C) is reported in 1·6-13·3 per cent of injured patients. The occurrence of acidosis is difficult to estimate, but usually follows other physiological disturbances. Trauma-induced coagulopathy (TIC) has both endogenous and exogenous components. Endogenous acute traumatic coagulopathy is associated with shock and hypoperfusion. Exogenous effects of dilution from fluid resuscitation and consumption through bleeding and loss of coagulation factors further add to TIC. TIC is present in 10-34 per cent of injured patients, depending on injury severity, acidosis, hypothermia and hypoperfusion. More expedient detection of coagulopathy is needed. Thromboelastography may be a useful point-of-care measurement. Management of TIC is controversial, with conflicting reports on blood component therapy in terms of both outcome and ratios of blood products to other fluids, particularly in the context of civilian trauma.

CONCLUSION

The triad of hypothermia, acidosis and coagulopathy after severe trauma appears to be fairly rare but does carry a poor prognosis. Future research should define modes of early detection and targeted therapy.

The incidence and significance of accidental hypothermia in major trauma--a prospective observational study

BACKGROUND

Serious sequelae have been associated with injured patients who are hypothermic (<35°C) including coagulopathy, acidosis, decreased myocardial contractility and risk of mortality.

AIM

Establish the incidence of accidental hypothermia in major trauma patients and identify causative factors.

METHOD

Prospective identification and subsequent review of 732 medical records of major trauma patients presenting to an Adult Major Trauma Centre was undertaken between January and December 2008. Multivariate analysis was performed using logistic regression. Significant and clinically relevant variables from univariate analysis were entered into multivariate models to evaluate determinants for hypothermia and for death. Goodness of fit was determined with the use of the Hosmer-Lemeshow statistic.

MAIN RESULTS

Overall mortality was 9.15%. The incidence of hypothermia was 13.25%. The mortality of patients with hypothermia was 29.9% with a threefold independent risk of death: OR (CI 95%) 3.44 (1.48-7.99), P = 0.04. Independent determinants for hypothermia were pre-hospital intubation: OR (CI 95%) 5.18 (2.77-9.71), P < 0.001, Injury Severity Score (ISS): 1.04 (1.01-1.06), P = 0.01, Arrival Systolic Blood Pressure (ASBP) < 100 mm Hg: 3.04 (1.24-7.44), P = 0.02, and winter time: 1.84 (1.06-3.21), P = 0.03. Of the 87 hypothermic patients who had repeat temperatures recorded in the Emergency Department, 77 (88.51%) patients had a temperature greater than the recorded arrival temperature. There was no change in recorded temperature for four (4.60%) patients, whereas six (6.90%) patients were colder at Emergency Department discharge.

CONCLUSION

Seriously injured patients with accidental hypothermia have a higher mortality independent of measured risk factors. For patients with multiple injuries a coordinated effort by paramedics, nurses and doctors is required to focus efforts toward early resolution of hypothermia aiming to achieve a temperature >35 °C.

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.

Spontaneous hypothermia on intensive care unit admission is a predictor of unfavorable neurological outcome in patients after resuscitation: an observational cohort study

Introduction

A large number of patients resuscitated for primary cardiac arrest arrive in the intensive care unit (ICU) with a body temperature < 35.0°C. The aim of this observational cohort study was to determine the association between ICU admission temperature and neurological outcome in this patient group.

Methods

Demographics and parameters influencing neurological outcome were retrieved from the charts of all patients resuscitated for primary cardiac arrest and treated with induced mild hypothermia in our ICU from January 2006 until January 2008. Patients were divided into two groups according to their body temperature on ICU admission: a hypothermia group (< 35.0°C) and a non-hypothermia group (≥35.0°C). Neurological outcome after six months was assessed by means of the Glasgow Outcome Score (GOS), with GOS 1 to 3 defined as unfavorable and GOS 4 to 5 as favorable. A logistic regression model was used to analyze the influence of the different parameters on neurological outcome.

Results

The data of 105 consecutive patients resuscitated for primary cardiac arrest and treated with induced mild hypothermia were analyzed. Median ICU admission temperature was 35.1°C (interquartile range (IQR) 34.3 to 35.7). After six months, 61% of the patients had an unfavorable outcome (59% died and 2% were severely disabled), whereas 39% had a favorable outcome (moderate disability or good recovery). Among patients with spontaneous hypothermia on ICU admission, the percentage with unfavorable outcome was higher (69% versus 50%, P = 0.05). Logistic regression showed that age, acute physiology and chronic health evaluation (APACHE) II and sequential organ failure assessment (SOFA) scores and spontaneous hypothermia on ICU admission all had an increased odds ratio (OR) for an unfavorable outcome after six months. Spontaneous hypothermia had the strongest association with unfavorable outcome (OR 2.6, 95% CI (confidence interval) 1.1 to 5.9), which became even stronger after adjustment for age, presenting heart rhythm, APACHE II and SOFA scores (OR 3.8, CI 1.3 to 11.0).

Conclusions

In this observational cohort study, spontaneous hypothermia on ICU admission was the strongest predictor of an unfavorable neurological outcome in patients resuscitated for primary cardiac arrest.

A review of metabolic staging in severely injured patients

An interpretation of the metabolic response to injury in patients with severe accidental or surgical trauma is made. In the last century, various authors attributed a meaning to the post-traumatic inflammatory response by using teleological arguments. Their interpretations of this response, not only facilitates integrating the knowledge, but also the flow from the bench to the bedside, which is the main objective of modern translational research. The goal of the current review is to correlate the metabolic changes with the three phenotypes -ischemia-reperfusion, leukocytic and angiogenic- that the patients express during the evolution of the systemic inflammatory response. The sequence in the expression of multiple metabolic systems that becomes progressively more elaborate and complex in severe injured patients urges for more detailed knowledge in order to establish the most adequate metabolic support according to the evolutive phase. Thus, clinicians must employ different treatment strategies based on the different metabolic phases when caring for this challenging patient population. Perhaps, the best therapeutic option would be to favor early hypometabolism during the ischemia-reperfusion phase, to boost the antienzymatic metabolism and to reduce hypermetabolism during the leukocytic phase through the early administration of enteral nutrition and the modulation of the acute phase response. Lastly, the early epithelial regeneration of the injured organs and tissues by means of an oxidative metabolism would reduce the fibrotic sequelae in these severely injured patients.