The Trauma Triad of Death: Hypothermia, Acidosis, and Coagulopathy:

Retrospective analysis of the effects of hypocalcemia in severely injured trauma patients

BACKGROUND

It has been suggested that the Lethal Triad be modified to include hypocalcemia, coined as the Lethal Diamond. Hypocalcemia in trauma has been attributed to multiple mechanisms, but new evidence suggests that traumatic injury may result in the development of hypoCa independent of blood transfusion. We hypothesize that hypocalcemia is associated with increased blood product requirements and mortality.

METHODS

A retrospective study of 1,981 severely injured adult trauma patients from 2016 to 2019. Ionized calcium (iCa) levels were obtained on arrival and subjects were categorized by a threshold iCa level of 1.00 mmol/L and compared. Univariable and multivariable logistic regression analysis was performed.

RESULTS

The hypocalcemia (iCa <1.00 mmol/L) group had increased rate of overall (p = 0.001), 4-hr (p = 0.007), and 24-hr (p = 0.003) mortality. There was no difference in prehospital transfusion volume between groups (p = 0.25). Hypocalcemia was associated with increased blood product requirements at 4 h (p <0.001), 24 h (p <0.001), and overall hospital length of stay (p <0.001). Logistic regression analysis showed increased odds of 4-hour mortality (OR 0.077 [95 % CI 0.011, 0.523], p = 0.009) and 24-hour mortality (OR 0.121 [95 % CI 0.019, 0.758], p = 0.024) for every mmol/L increase in iCa.

CONCLUSIONS

This study shows the association of hypoCa and traumatic injury. Severe hypoCa was associated with increased odds of early and overall mortality and increased blood product requirements. These results support the need for future prospective trials assessing the role of hypocalcemia in trauma.

Massive transfusion in trauma

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of currently recommended treatment approaches for traumatic hemorrhage shock, with a special focus on massive transfusion.

RECENT FINDINGS

Severe trauma patients require massive transfusion, but consensual international definitions for traumatic hemorrhage shock and massive transfusion are missing. Current literature defines a massive transfusion as transfusion of a minimum of 3-4 packed red blood cells within 1 h. Using standard laboratory and/or viscoelastic tests, earliest diagnosis and treatment should focus on trauma-induced coagulopathy and substitution of substantiated deficiencies.

SUMMARY

To initiate therapy immediately massive transfusion protocols are helpful focusing on early hemorrhage control using hemostatic dressing and tourniquets, correction of metabolic derangements to decrease coagulopathy and substitution according to viscoelastic assays and blood gases analysis with tranexamic acid, fibrinogen concentrate, red blood cells, plasma and platelets are recommended. Alternatively, the use of whole blood is possible. If needed, further support using prothrombin complex, factor XIII or desmopressin is suggested.

Impact of physician-staffed ground emergency medical services-administered pre-hospital trauma care on in-hospital survival outcomes in Japan

PURPOSE

In Japan, the vehicle used in pre-hospital trauma care systems with physician-staffed ground emergency medical services (GEMS) is referred to as a "doctor car". Doctor cars are highly mobile physician-staffed GEMS that can provide complex pre-hospital trauma management using various treatment strategies. The number of doctor car operations for patients with severe trauma has increased. Considering facility factors, the association between doctor cars and patient outcomes remains unclear. Therefore, this study aimed to examine the relationship between doctor cars for patients with severe trauma and survival outcomes in Japan.

METHODS

A nationwide retrospective cohort study was conducted to compare the impact of the doctor car group with the non-physician-staffed GEMS group on in-hospital survival in adult patients with severe trauma. The data were analyzed using multivariable logistic regression models with generalized estimating equations.

RESULTS

This study included 372,365 patients registered in the Japan Trauma Data Bank between April 2009 and March 2019. Of the 49,144 eligible patients, 2361 and 46,783 were classified into the doctor car and non-physician staffed GEMS groups, respectively. The adjusted odds ratio (OR) for survival was significantly higher in the doctor car group than in the non-physician staffed GEMS group (adjusted OR = 1.228 [95% confidence interval 1.065-1.415]).

CONCLUSION

Using nationwide data, this novel study suggests that doctor cars improve the in-hospital survival rate of patients with severe trauma in Japan. Therefore, doctor cars could be an option for trauma strategies.

Accidental Hypothermia in the Largest Emergency Hospital in North-Eastern Romania

INTRODUCTION

Accidental hypothermia (AH) presents a significant mortality risk, even in individuals with good health. Early recognition of the parameters associated with negative prognosis could save more lives.

METHODS

This was a pilot, retrospective observational study, conducted in the largest Emergency Hospital in North Eastern Romania, which included all patients with AH (defined as body temperature below 35°C), hospitalized and treated in our hospital between 2019 and 2022.

RESULTS

A total of 104 patients with AH were included in our study, 90 of whom had data collected and statistically analyzed. The clinical, biological, and therapeutic parameters associated with negative outcomes were represented by a reduced GCS score (p=0.024), diminished systolic and diastolic blood pressure (p=0.007 respectively, 0.013), decreased bicarbonate (p=0.043) and hemoglobin levels (p=0.002), the presence of coagulation disorders (p=0.007), as well as the need for administration of inotropic or vasopressor medications (p=0.04).

CONCLUSION

In this pilot, retrospective, observational study, the negative outcomes observed in patients with AH hospitalized in the largest Emergency Hospital in North-Eastern Romania were associated with several clinical, biochemical, and therapeutic factors, which are easy to identify in clinical practice. Recognizing the significance of these associated factors empowers healthcare practitioners to intervene at an early stage to save more lives.

Emergent Management of Severe Hypothermia, Acidemia, and Coagulopathy in Operative Penetrating Ballistic Cranial Trauma

Hypothermia in a trauma patient has been associated with increased morbidity and mortality and is more frequently seen in those sustaining traumatic brain injuries (TBIs). Acidosis is an important consequence of hypothermia that leads to derangements across the spectrum of the coagulation cascade. Here, we present a case of a 31-year-old male presented after suffering a right parietal penetrating ballistic injury with an associated subdural hematoma and 7 mm midline shift requiring decompressive craniectomy and external ventricular drain (EVD) placement in the setting of severe hypothermia (28°C) and acidosis (pH 7.12). With aggressive rewarming intraoperatively, the use of full-body forced-air warming, warmed IV fluids, and increasing the ambient room temperature, the patient's acidosis and hypothermia improved to pH 7.20 and 34°C. Despite these aggressive attempts to rewarm the patient, he developed coagulopathy in the setting of concurrent hypothermia and acidosis. This case highlights the importance of prompt reversal of hypothermia due to its potentially fatal effects, particularly in the setting of severe TBIs. We discuss the critical aspects of surgical management of the injury and anesthetic management of hypothermia, acidosis, and coagulopathy perioperatively.

Using infrared cameras in drones to detect bleeding events

BACKGROUND

Hemorrhage is one of the main causes of death in trauma. Critical bleeding in patients needs to be detected as soon as possible to save the patient. Drones are gaining increasing importance in emergency services and can support rescue forces in accident scenarios such as a mass casualty incident.

METHODS

In this study, a simulated pelvic hemorrhage was detected using a drone from 7 m above the ground over a time span of 30 s.

RESULTS

The results allow a good detection of the pelvic hemorrhage. Nevertheless, the simulated blood cools down quickly. After 30 s, there was no significant temperature difference compared to the rest of the body. At this point, further assessment is only possible via the RGB image.

CONCLUSION

The findings suggest that bleeding from an open and continuously bleeding wound would most likely be detectable using the drone's thermal imaging camera, even over a longer period of time.

[Treatment of pancreatic injuries after blunt abdominal trauma]

Pancreatic injuries resulting from blunt abdominal trauma are uncommon but carry a high risk of morbidity and mortality for patients. Prompt diagnosis and management are critical to optimize patient outcomes. This review article provides an overview of the different types of pancreatic injuries and the various management strategies available, based on the severity of the injury. In unstable patients with a positive focused assessment with sonography for trauma (FAST), immediate trauma laparotomy is required. Stable patients should be assessed with contrast-enhanced computed tomography (CT) imaging. Low-grade injuries can be managed with irrigation and drainage. In cases of left-sided ductal injury below the level of the portal vein, left-sided pancreatic resection is often necessary. Higher grade injuries to the pancreatic head need to be evaluated in the context of other accompanying injuries, where damage control may be required. Pancreaticoduodenectomy is a rare intervention and is usually only required in the later course in these cases.

From Death Triad to Death Tetrad-The Addition of a Hypotension Component to the Death Triad Improves Mortality Risk Stratification in Trauma Patients: A Retrospective Cohort Study

The death triad, including coagulopathy, hypothermia, and acidosis, is shown to be a strong predictor of mortality in trauma patients. We aimed to investigate whether the inclusion of hypotension, defined as systolic blood pressure (SBP) < 60 mmHg, as a fourth factor in the death triad would comprise a death tetrad to help stratify mortality risk in trauma patients. A total of 3361 adult trauma patients between 1 January 2009 and 31 December 2019 were allocated into groups to investigate whether hypotension matters in determining the mortality outcome of trauma patients who possess 1−3 death triad components compared to those without any component. Hypotension was added to the death tetrad, and the adjusted mortality outcome was compared among groups with 0−4 death tetrad components. Herein, we showed that SBP < 60 mmHg could be used to identify patients at risk of mortality among patients with one or two death triad components. Patients with one, two, and three death tetrad components had respective adjusted mortality rates of 3.69-, 10.10-, and 40.18-fold, determined by sex, age, and comorbidities. The mortality rate of trauma patients with all the four death tetrad components was 100%. The study suggested that hypotension, defined as an SBP < 60 mmHg, may act as a proper death tetrad component to stratify the mortality risk of trauma patients.

Accidental Hypothermia in a Swiss Alpine Trauma Centre-Not an Alpine Problem

BACKGROUND

Research in accidental hypothermia focuses on trauma patients, patients exposed to cold environments or patients after drowning but rarely on hypothermia in combination with intoxications or on medical or neurological issues. The aim of this retrospective single-centre cohort study was to define the aetiologies, severity and relative incidences of accidental hypothermia, methods of measuring temperature and in-hospital mortality.

METHODS

The study included patients ≥18 years with a documented body temperature ≤35 °C who were admitted to the emergency department (ED) of the University Hospital in Bern between 2000 and 2019.

RESULTS

439 cases were included, corresponding to 0.32 per 1000 ED visits. Median age was 55 years (IQR 39-70). A total of 167 patients (38.0%) were female. Furthermore, 63.3% of the patients suffered from mild, 24.8% from moderate and 11.9% from severe hypothermia. Exposure as a single cause for accidental hypothermia accounted for 12 cases. The majority were combinations of hypothermia with trauma (32.6%), medical conditions (34.2%), neurological conditions (5.2%), intoxications (20.3%) or drowning (12.0%). Overall mortality was 22.3% and depended on the underlying causes, severity of hypothermia, age and sex.

Effect of Hypothermia Therapy on Children with Traumatic Brain Injury: A Meta-Analysis of Randomized Controlled Trials

Hypothermia therapy is a promising therapeutic strategy for traumatic brain injury (TBI); however, some trials have shown that hypothermia therapy has a negative effect on patients with TBI. The treatment of hypothermia in children with TBI remains controversial. We conducted a search of six online databases to validate the literature on comparing hypothermia with normal therapy for children with TBI. Eight randomized controlled trials (514 patients) were included. The meta-analysis indicated that hypothermia therapy may increase the Glasgow Outcome Scale (GOS) scores. However, in terms of improving the rate of complications, intracranial pressure (ICP), mortality, cerebral perfusion pressure (CPP), and length of stay both in hospital as well as pediatric ICU, the difference was not statistically significant. Hypothermia therapy may have clinical advantages in improving the GOS scores in children with TBI compared with normothermic therapy, but hypothermia therapy may have no benefit in improving the incidence of complications, ICP, mortality, CPP, and length of stay both in pediatric ICU as well as hospital. The decision to implement hypothermia therapy for children with TBI depends on the advantages and disadvantages from many aspects and these must be considered comprehensively.

Viscoelastic Monitoring in Liver Transplantation

Cirrhosis and liver transplantation (LT) surgery are associated with substantial alterations to the patient's coagulation status. Accurate monitoring of these changes during LT can help manage bleeding proactively and potentially reduce transfusion requirements. Unlike conventional coagulation tests (CCTs), viscoelastic monitoring (VEM) can provide an accurate, real-time, point-of-care assessment of coagulation status during LT and hence has become an invaluable tool for anesthetists and intensive care physicians. However, it remains an enigmatic subject for transplantation surgeons who are more conversant with CCTs. This review discusses the principles of VEM, provides a primer to understanding and interpreting its output, and explains how it can be used to make real-world clinical decisions during LT.

Advancing in the understanding of coagulopathy during hemorrhagic shock: From the triad to the deadly pentad

The deadly triad concept represented a dogma in the definition of poor outcomes and death associated with major bleeding in trauma. This model of end-stage disease was then rapidly transferred to other major bleeding scenarios. However, and notwithstanding the fact that it represented a severe scenario, the original triad fails to establish a sequence, which would be relevant when defining the objectives during the initial treatment of severe bleeding.  It has been recently suggested that hypoxia and hyperglycemia should be included as isolated, determining factors in this model. Likewise, the model admits only one scenario where all the conditions shall co-exist, knowing that each one of them contributes with a different risk burden. Based on a structured review, we submit a pentad model that includes a natural pattern of events occurring with hypoxemia as the main trigger for the development of hypocalcemia, hyperglycemia, acidosis and hypothermia, as hallmarks of multiple system impairment. This severity model of major bleeding ends with coagulopathy as a result of the failure to resolve the rest of the previous components.

Assessing Factor V Antigen and Degradation Products in Burn and Trauma Patients

INTRODUCTION

Proposed mechanisms of acute traumatic coagulopathy (ATC) include decreased clotting potential due to factor consumption and proteolytic inactivation of factor V (FV) and activated factor V (FVa) by activated protein C (aPC). The role of FV/FVa depletion or inactivation in burn-induced coagulopathy is not well characterized. This study evaluates FV dynamics following burn and nonburn trauma.

METHODS

Burn and trauma patients were prospectively enrolled. Western blotting was performed on admission plasma to quantitate levels of FV antigen and to assess for aPC or other proteolytically derived FV/FVa degradation products. Statistical analysis was performed with Spearman's, Chi-square, Mann-Whitney U test, and logistic regression.

RESULTS

Burn (n = 60) and trauma (n = 136) cohorts showed similar degrees of FV consumption with median FV levels of 76% versus 73% (P = 0.65) of normal, respectively. Percent total body surface area (TBSA) was not correlated with FV, nor were significant differences in median FV levels observed between low and high TBSA groups. The injury severity score (ISS) in trauma patients was inversely correlated with FV (ρ = -0.26; P = 0.01) and ISS ≥ 25 was associated with a lower FV antigen level (64% versus. 93%; P = 0.009). The proportion of samples showing proteolysis-derived FV was greater in trauma than burn patients (42% versus. 16%; P = 0.0006).

CONCLUSIONS

Increasing traumatic injury severity is associated with decreased FV antigen levels, and a greater proportion of trauma patient samples exhibit proteolytically degraded FV fragments. These associations are not present in burns, suggesting that mechanisms underlying FV depletion in burn and nonburn trauma are not identical.

Recent advances in materials for hemostatic management

Traumatic hemorrhage can be a fatal event, particularly when large quantities of blood are lost in a short period of time. Therefore, hemostasis has become a crucial part of emergency treatment. For small wounds, hemostasis can be achieved intrinsically depending on the body's own blood coagulation mechanism; however, for large-area wounds, particularly battlefield and complex wounds, materials delivering rapid and effective hemostasis are required. In parallel with the constant progress in science, technology, and society, advances in hemostatic materials have also undergone various iterations by integrating new ideas with old concepts. There are various natural and synthetic hemostatic materials, including hemostatic powders, adhesives, hydrogels, and tourniquets, for the treatment of severe external trauma. This review covers the differences among the currently available hemostatic materials and comprehensively describes the hemostatic effects of different materials based on the underlying mechanisms. Finally, solutions for current issues related to trauma bleeding are discussed, and the prospects of hemostatic materials are proposed.

Status quo of the use of DCS concepts and outcome with focus on blunt abdominal trauma : A registry-based analysis from the TraumaRegister DGU®

INTRODUCTION

Damage control surgery (DCS) is a standardized treatment concept in severe abdominal injury. Despite its evident advantages, DCS bears the risk of substantial morbidity and mortality, due to open abdomen therapy (OAT). Thus, identifying the suitable patients for that approach is of utmost importance. Furthermore, little is known about the use of DCS and the related outcome, especially in blunt abdominal trauma.

METHODS

Patients recorded in the TraumaRegister DGU® from 2008 to 2017, and with an Injury Severity Score (ISS) ≥ 9 and an abdominal injury with an Abbreviated Injury Scale (AIS) score ≥ 3 were included in that registry-based analysis. Patients with DCS and temporary abdominal closure (TAC) were compared with patients who were treated with a laparotomy and primary closure (non-DCS) and those who did receive non-operative management (NOM). Following descriptive analysis, a matched-pairs study was conducted to evaluate differences and outcomes between DCS and non-DCS group. Matching criteria were age, abdominal trauma severity, and hemodynamical instability at the scene.

RESULTS

The injury mechanism was predominantly blunt (87.1%). Of the 8226 patients included, 2351 received NOM, 5011 underwent laparotomy and primary abdominal closure (non-DCS), and 864 were managed with DCS. Thus, 785 patient pairs were analysed. The rate of hepatic injuries AIS > 3 differed between the groups (DCS 50.3% vs. non-DCS 18.1%). DCS patients had a higher ISS (p = 0.023), required more significant volumes of fluids, more catecholamines, and transfusions (p < 0.001). More DCS patients were in shock at the accident scene (p = 0.022). DCS patients had a higher number of severe hepatic (AIS score ≥ 3) and gastrointestinal injuries and more vascular injuries. Most severe abdominal injuries in non-DCS patients were splenic injuries (AIS, 4 and 5) (52.1% versus 37.9%, p = 0.004).

CONCLUSION

DCS is a strategy used in unstable trauma patients, severe hepatic, gastrointestinal, multiple abdominal injuries, and mass transfusions. The expected survival rates were achieved in such extreme trauma situations.

Acid-Sensing Ion Channels: Expression and Function in Resident and Infiltrating Immune Cells in the Central Nervous System

Peripheral and central immune cells are critical for fighting disease, but they can also play a pivotal role in the onset and/or progression of a variety of neurological conditions that affect the central nervous system (CNS). Tissue acidosis is often present in CNS pathologies such as multiple sclerosis, epileptic seizures, and depression, and local pH is also reduced during periods of ischemia following stroke, traumatic brain injury, and spinal cord injury. These pathological increases in extracellular acidity can activate a class of proton-gated channels known as acid-sensing ion channels (ASICs). ASICs have been primarily studied due to their ubiquitous expression throughout the nervous system, but it is less well recognized that they are also found in various types of immune cells. In this review, we explore what is currently known about the expression of ASICs in both peripheral and CNS-resident immune cells, and how channel activation during pathological tissue acidosis may lead to altered immune cell function that in turn modulates inflammatory pathology in the CNS. We identify gaps in the literature where ASICs and immune cell function has not been characterized, such as neurotrauma. Knowledge of the contribution of ASICs to immune cell function in neuropathology will be critical for determining whether the therapeutic benefits of ASIC inhibition might be due in part to an effect on immune cells.

Hypothermic Cardiac Arrest - Retrospective cohort study from the International Hypothermia Registry

AIM

The International Hypothermia Registry (IHR) was created to increase knowledge of accidental hypothermia, particularly to develop evidence-based guidelines and find reliable outcome predictors. The present study compares hypothermic patients with and without cardiac arrest included in the IHR.

METHODS

Demographic, pre-hospital and in-hospital data, method of rewarming and outcome data were collected anonymously in the IHR between 2010 and 2020.

RESULTS

Two hundred and one non-consecutive cases were included. The major causeof hypothermia was mountain accidents, predominantly in young men. Hypothermic Cardiac Arrest (HCA) occurred in 73 of 201 patients. Core temperature was significantly lower in the patients in cardiac arrest (25.0 vs. 30.0 °C, p < 0.001). One hundred and fifteen patients were rewarmed externally (93% with ROSC), 53 by extra-corporeal life support (ECLS) (40% with ROSC) and 21 with invasive internal techniques (71% with ROSC). The overall survival rate was 95% for patients with preserved circulation and 36% for those in cardiac arrest. Witnessed cardiac arrest and ROSC before rewarming were positive outcome predictors, asphyxia, coagulopathy, high potassium and lactate negative outcome predictors.

CONCLUSIONS

This first analysis of 201 IHR patients with moderate to severe accidental hypothermia shows an excellent 95% survival rate for patients with preserved circulation and 36% for HCA patients. Witnessed cardiac arrest, restoration of spontaneous circulation, low potassium and lactate and absence of asphyxia were positive survival predictors despite hypothermia in young, healthy adults after mountaineering accidents. However, accidental hypothermia is a heterogenous entity that should be considered in both treatment strategies and prognostication.

Hypothermia in Trauma

Hypothermia in trauma patients is a common condition. It is aggravated by traumatic hemorrhage, which leads to hypovolemic shock. This hypovolemic shock results in a lethal triad of hypothermia, coagulopathy, and acidosis, leading to ongoing bleeding. Additionally, hypothermia in trauma patients can deepen through environmental exposure on the scene or during transport and medical procedures such as infusions and airway management. This vicious circle has a detrimental effect on the outcome of major trauma patients. This narrative review describes the main factors to consider in the co-existing condition of trauma and hypothermia from a prehospital and emergency medical perspective. Early prehospital recognition and staging of hypothermia are crucial to triage to proper care to improve survival. Treatment of hypothermia should start in an early stage, especially the prevention of further cooling in the prehospital setting and during the primary assessment. On the one hand, active rewarming is the treatment of choice of hypothermia-induced coagulation disorder in trauma patients; on the other hand, accidental or clinically induced hypothermia might improve outcomes by protecting against the effects of hypoperfusion and hypoxic injury in selected cases such as patients suffering from traumatic brain injury (TBI) or traumatic cardiac arrest.

The AdHOC (age, head injury, oxygenation, circulation) score: a simple assessment tool for early assessment of severely injured patients with major fractures

Purpose

We sought to develop a simple, effective and accurate assessment tool using well-known prognostic parameters to predict mortality and morbidity in severely injured patients with major fractures at the stage of the trauma bay.

Methods

European Data from the TraumaRegister DGU^® were queried for patients aged 16 or older and with an ISS of 9 and higher with major fractures. The development (2012–2015) and validation (2016) groups were separated. The four prognostic aspects Age, Head injury, Oxygenation and Circulation along with parameters were identified as having a relevant impact on the outcome of severely injured patients with major fractures. The performance of the score was analyzed with the area under the receiver operating characteristics curve and compared to other trauma scores.

Results

An increasing AdHOC (Age, Head injury, Oxygenation, Circulation) score value in the 17,827 included patients correlated with increasing mortality (0 points = 0.3%, 1 point = 5.3%, 2 points = 15.6%, 3 points = 42.5% and 4 points = 62.6%). With an AUROC of 0.858 for the development (n = 14,047) and 0.877 for the validation (n = 3780) group dataset, the score is superior in performance compared to the Injury Severity Score (0.806/0.815).

Conclusion

The AdHOC score appears to be easy and accessible in every emergency room without the requirement of special diagnostic tools or knowledge of the exact injury pattern and can be useful for the planning of further surgical treatment.

Acidosis predicts mortality independently from hyperlactatemia in patients with sepsis

RATIONALE AND OBJECTIVES

Acidosis and hyperlactatemia predict outcome in critically ill patients. We assessed BE and pH for risk prediction capabilities in a sub-group of septic patients in the MIMIC-III database.

METHODS

Associations with mortality were assessed by logistic regression analysis in 5586 septic patients. Baseline parameters, lactate concentrations, pH, and BE were analyzed at baseline and after 6 hours.

MEASUREMENTS AND MAIN RESULTS

We combined acidosis (defined as either BE ≤-6 and/or pH ≤7.3) and hyperlactatemia and split the cohort into three subgroups: low-risk (no acidosis and lactate <2.3 mmol/L; n = 2294), medium-risk (either acidosis or lactate >2.3 mmol/L; n = 2125) and high-risk (both acidosis and lactate >2.3 mmol/L; n = 1167). Mortality was 14%, 20% and 38% (p<0.001) in low-risk, medium-risk and high-risk patients, respectively. The predictiveness of this model (AUC 0.63 95%CI 0.61-0.65) was higher compared to acidosis (AUC 0.59 95%CI 0.57-0.61; p<0.001) and lactate >2.3 mmol/L (AUC 0.60 95%CI 0.58-0.62; p<0.001) alone. Hyperlactatemia alone was only moderately predictive for acidosis (AUC 0.60 95%CI 0.59-0.62).

CONCLUSIONS

Acidosis and hyperlactatemia can occur independently to a certain degree. Combining acidosis and hyperlactatemia in a model yielded higher predictiveness for ICU-mortality. Septic patients with acidosis should be treated even more aggressively in the future.

End-tidal carbon dioxide underestimates plasma carbon dioxide during emergent trauma laparotomy leading to hypoventilation and misguided resuscitation: A Western Trauma Association Multicenter Study

BACKGROUND

End-tidal carbon dioxide (ETCO2) is routinely used during elective surgery to monitor ventilation. The role of ETCO2 monitoring in emergent trauma operations is poorly understood. We hypothesized that ETCO2 values underestimate plasma carbon dioxide (pCO2) values during resuscitation for hemorrhagic shock.

METHODS

Multicenter trial was performed analyzing the correlation between ETCO2 and pCO2 levels.

RESULTS

Two hundred fifty-six patients resulted in 587 matched pairs of ETCO2 and pCO2. Correlation between these two values was very poor with an R of 0.04. 40.2% of patients presented to the operating room acidotic and hypercarbic with a pH less than 7.30 and a pCO2 greater than 45 mm Hg. Correlation was worse in patients that were either acidotic or hypercarbic. Forty-five percent of patients have a difference greater than 10 mm Hg between ETCO2 and pCO2. A pH less than 7.30 was predictive of an ETCO2 to pCO2 difference greater than 10 mm Hg. A difference greater than 10 mm Hg was predictive of mortality independent of confounders.

CONCLUSION

Nearly one half (45%) of patients were found to have an ETCO2 level greater than 10 mm Hg discordant from their PCO2 level. Reliance on the discordant values may have contributed to the 40% of patients in the operating room that were both acidotic and hypercarbic. Early blood gas analysis is warranted, and a lower early goal of ETCO2 should be considered.

LEVEL OF EVIDENCE

Therapeutic, level IV.

Effect of hypothermia on haemostasis and bleeding risk: a narrative review

It must be remembered that clinically important haemostasis occurs in vivo and not in a tube, and that variables such as the number of bleeding events and bleeding volume are more robust measures of bleeding risk than the results of analyses.

In this narrative review, we highlight trauma, surgery, and mild induced hypothermia as three clinically important situations in which the effects of hypothermia on haemostasis are important. In observational studies of trauma, hypothermia (body temperature <35°C) has demonstrated an association with mortality and morbidity, perhaps owing to its effect on haemostatic functions. Randomised trials have shown that hypothermia causes increased bleeding during surgery. Although causality between hypothermia and bleeding risk has not been well established, there is a clear association between hypothermia and negative outcomes in connection with trauma, surgery, and accidental hypothermia; thus, it is crucial to rewarm patients in these clinical situations without delay. Mild induced hypothermia to ≥33°C for 24 hours does not seem to be associated with either decreased total haemostasis or increased bleeding risk.

The US military experience with THAM

BACKGROUND

Acidosis, a part of the lethal trauma triad, occurs frequently after major combat trauma. Tris-hydroxymethyl aminomethane (THAM) has been used to effectively treat acidosis in injured casualties. No research has been conducted assessing the safety of THAM in the military combat setting. We sought to describe the US military experience with THAM administration to battlefield injury subjects.

METHODS

We conducted a retrospective descriptive cohort study reviewing the trauma data from the Department of Defense Trauma Registry. US military personnel with an injury severity score greater than 15, between September 2001 and December 2014, were analyzed. Our primary outcome was the 30-day all-cause mortality among cohort treated with THAM versus those who were not. Differences between the cohort were examined using a student t-test (continuous variables), Wilcoxon Rank Sum test (ordinal variables), and chi-squared test (nominal variables).

RESULTS

4558 subjects met the inclusion criteria. 69 received THAM and 4489 did not. Casualties receiving THAM had higher mean ISS scores (33 vs. 27, p < 0.001), and required significantly higher amounts of packed red blood cells (RBCs, 37 vs. 10, p < 0.001). THAM cohort had longer ventilator and intensive care unit (ICU) days with an overall lower survival to hospital discharge. On univariable analysis, THAM was associated with lower odds of survival (OR 0.18, 95% CI 0.11-0.31) but on multivariable analysis, when controlling for confounders, THAM use was not associated with a worse odds of survival (OR 0.83, 95% CI 0.21-3.24).

CONCLUSIONS

Within our combat trauma population, we were unable to detect worse 30 day mortality associated with THAM administration. Prospective investigations are needed to validate its use in critically injured combat casualties.

Assessment of the Initial Risk Factors for Mortality among Patients with Severe Trauma on Admission to the Emergency Department

Background

For decades, trauma has been recognized globally as a major cause of death. Reducing the mortality of patients with trauma is an extremely pressing issue, particularly for those with severe trauma. An early and accurate assessment of the risk of mortality among patients with severe trauma is important for improving patient outcomes.

Methods

We performed a retrospective medical record review of 582 patients with severe trauma admitted to the emergency department between July 2011 and June 2016. We analyzed the associations of in-hospital mortality with the baseline characteristics and initial biochemical markers of patients with severe trauma on admission.

Results

The overall in-hospital mortality rate was 14.9%. Multivariate logistic regression analysis showed that the patient’s Rapid Emergency Medicine Score (REMS; odds ratio [OR], 1.186; 95% confidence interval [CI], 1.018–1.383; p=0.029), Emergency Trauma Score (EMTRAS; OR, 2.168; 95% CI, 1.570–2.994; p<0.001), serum lactate levels (SLL; OR, 1.298; 95% CI, 1.118–1.507; p<0.001), and Injury Severity Score (ISS; OR, 1.038; 95% CI, 1.010–1.130; p=0.021) were significantly associated with in-hospital mortality.

Conclusion

The REMS, EMTRAS, and SLL can easily and rapidly be used as alternatives to the injury severity score to predict in-hospital mortality for patients who present to the emergency department with severe trauma.

Incidence and strategies for preventing sustained hypothermia of crash victims during prolonged vehicle extrication

BACKGROUND

Vehicle extrication of crash victims is a highly-demanding challenge, due to the frequently life-threatening injuries of entrapped occupants. In this phase, crash victims are often exposed to the outdoor-temperature, with the risk of sustained hypothermia. Hypothermia can significantly raise the morbidity and mortality rates of crash victims. Therefore, we have correlated the incidence of severe car accidents with entrapped patients, the outdoor conditions, and expenditure of time for extrication. Furthermore, different warming strategies have been evaluated regarding their integrability within the rescue procedure.

METHODS

To estimate the incidence of severe car accidents with entrapped patients, we performed retrospective data mining for the cold season of a three-year period in a rural district in Germany. We evaluated the integrability of a chemical heated blanket, its combined application with a forced-air warmer, or with an infrared radiator for patient warming. Therefore, we analysed the time tracking of extrication reference points during extrication exercises undertaken by the rescue services, simulating a severe vehicle accident and evaluated questionnaires administered to rescue personnel and subjects. Furthermore, we monitored subjects' physiologic parameters to estimate the warming effect.

RESULTS

Incidence analysis resulted in extrication times of up to 80 min, representing two severely-entrapped patients per month in the cold seasons, corresponding to about four entrapments per 100.000 inhabitants every year. Of the different warming strategies analysed, the chemical blanket and the combination infrared radiator/chemical blanket were favoured regarding the items 'operator convenience', 'weight/size/handling', 'stability in positioning', 'time needed for installation', 'manpower requirement', 'hindrance during extrication operation', 'versality during extrication process', and 'robustness' by the rescue personnel; the forced-air warmer and the infrared radiator were preferred with regard to 'warming effect', the forced-air warmer and the chemical blanket was advantageous with regard to 'physical protection'.

CONCLUSIONS

Vehicle extrication procedures are time consuming, a relevant finding that provides a rationale for discussing and optimising the rescue procedure to prevent sustained hypothermia. We determined that combined application of an infrared radiator and a chemical blanket is advantageous in terms of integration into the rescue process. However, a more detailed investigation, focussing on warming efficacy, must be performed.

The evolution and impact of the "damage control orthopedics" paradigm in combat surgery: a review

The idea of damage control (DC) is grounded on a sequential therapeutic strategy that supports physiological restoration over anatomic repair in critically injured patients. This concept is firstly described as damage control surgery (DCS) for war-wounded patients with abdominal exsanguinating trauma. The goal was to avoid prolonged operative times and prevent the outset of the lethal cycle of hypothermia, acidosis and coagulopathy. Damage control orthopedics (DCO) is also based on this concept and it is applied in the treatment of some polytrauma patients with pelvic and long bones fractures as to avoid the "second hit" of a lengthy definitive operation and eliminate initial morbidity and mortality. It is in favor of primary fracture stabilization utilizing provisional external fixation. When the patient is in stable condition, conversion to definitive open reduction and intramedullary nailing can be done. This stepwise approach should be considered as a part of the resuscitation process, and it follows the saying "do no further harm".

Effect of Hypothermia in the Emergency Department on the Outcome of Trauma Patients: A Cross-Sectional Analysis

This study aimed to assess whether hypothermia is an independent predictor of mortality in trauma patients in the condition of defining hypothermia as body temperatures of <36 °C. Data of all hospitalized adult trauma patients recorded in the Trauma Registry System at a level I trauma center between 1 January 2009 and 12 December 2015 were retrospectively reviewed. A multivariate logistic regression analysis was performed in order to identify factors related to mortality. In addition, hypothermia and normothermia were defined as temperatures <36 °C and from 36 °C to 38 °C, respectively. Propensity score-matched study groups of hypothermia and normothermia patients in a 1:1 ratio were grouped for mortality assessment after adjusting for potential confounders such as age, sex, preexisting comorbidities, and injury severity score (ISS). Of 23,705 enrolled patients, a total of 401 hypothermic patients and 13,368 normothermic patients were included in this study. Only 3.0% of patients had hypothermia upon arrival at the emergency department (ED). Compared to normothermic patients, hypothermic patients had a significantly higher rate of abbreviated injury scale (AIS) scores of ≥3 in the head/neck, thorax, and abdomen and higher ISS. The mortality rate in hypothermic patients was significantly higher than that in normothermic patients (13.5% vs. 2.3%, odds ratio (OR): 6.6, 95% confidence interval (CI): 4.86–9.01, p < 0.001). Of the 399 well-balanced propensity score-matched pairs, there was no significant difference in mortality (13.0% vs. 9.3%, OR: 1.5, 95% CI: 0.94–2.29, p = 0.115). However, multivariate logistic regression analysis revealed that patients with low body temperature were significantly associated with the mortality outcome. This study revealed that low body temperature is associated with the mortality outcome in the multivariate logistic regression analysis but not in the propensity score matching (PSM) model that compared patients with hypothermia defined as body temperatures of <36 °C to those who had normothermia. These contradicting observations indicated the limitation of the traditional definition of body temperature for the diagnosis of hypothermia. Prospective randomized control trials are needed to determine the relationship between hypothermia following trauma and the clinical outcome.

Prehospital Blood Transfusions in Pediatric Patients by a Helicopter Emergency Medical Service

OBJECTIVE

In the prehospital setting, the Nijmegen and Rotterdam helicopter emergency medical services administer packed red blood cells to critically ill or injured pediatric patients. Blood is given on scene or during transport and is derived from nearby hospitals. We summarize our experience with prehospital blood use in pediatric patients.

METHODS

The databases from both the Nijmegen and Rotterdam helicopter emergency medical services were reviewed for all pediatric (< 18 years) patients who received packed red blood cells on scene or during transport to the hospital.

RESULTS

Between 2007 and 2015, 10 pediatric patients out of approximately 2,400 pediatric patients received blood in the prehospital setting. The median Injury Severity Score was 41. Seven hospitals delivered blood in the prehospital setting at the scene. All patients were in hypovolemic shock. Two patients died. Two patients were believed to be unexpected survivors; 1 was predicted by the Trauma and Injury Severity Score, and a second unexpected survivor was a neonate who was in hypovolemic shock and cardiopulmonary arrest.

CONCLUSION

The incidence of prehospital use of blood in injured or critically ill children is low. This intervention presented a potential to limit acid-base disturbance, low hemoglobin levels, and coagulopathy in this group. We believe this cohort also contains 2 unexpected survivors.

When do trauma patients lose temperature? - a prospective observational study

BACKGROUND

The prevalence of hypothermia in trauma patients is high and rapid recognition is important to prevent further heat loss. Hypothermia is associated with poor patient outcomes and is an independent predictor of increased mortality. The aim of this study was to analyze the changes in core body temperature of trauma patients during different treatment phases in the pre-hospital and early in-hospital settings.

METHODS

A prospective observational cohort study in severely injured patients. Continuous core temperature monitoring using an epitympanic sensor in the auditory canal was initiated at the scene of injury and continued for 3 h. The degree of patient insulation was photo-documented throughout, and graded on a binary scale. The outcome variable was temperature change in each treatment phase.

RESULTS

Twenty-two patients were included with a median injury severity score (ISS) of 21 (IQR 14-29). Most patients (N = 16, 73%) were already hypothermic (< 36°C) on scene at their first measurement. Twenty patients (91%) became colder at the scene of injury; on average, the decline was -1.7°C/h. Full clothing reduced this value to -1.1°C/h. Temperature remained essentially stable during ambulance and emergency department phases.

CONCLUSION

Trauma patients are at risk for hypothermia already at the scene of injury. Lay persons and professionals should focus on early prevention of heat loss. An active, individually tailored approach to counter hypothermia in trauma should begin immediately at the scene of injury and continue during transportation to hospital. Active rewarming during evacuation should be considered.

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.

Civilian and military doctors’ knowledge of tranexamic acid (TXA) use in major trauma: a comparison study

Introduction

Tranexamic acid (TXA) administration within the recommended time of 3 hours has been demonstrated to improve outcomes following trauma. The aim of this study was to identify potential knowledge gaps in the administration of TXA in order to target further educational training in those doctors responsible for the management of acute trauma.

Methods

104 military and 852 civilian doctors were invited to complete a four-item web-based questionnaire pertaining to the indications, dose, side effects and evidence base for TXA administration in trauma. Doctors of all grades and surgical specialties including emergency trainees and anaesthetics were surveyed.

Results

65 military and 460 civilian doctors responded with a response rate of 62% and 54%, respectively. Responses were required for every question to allow progression and submission. 93% of military doctors knew the initial dose of TXA compared with 34% of civilian doctors. The Clinical randomisation of an Antifibrinolytic in Significant Haemorrhage (CRASH) 2 trial was known to 91% of military doctors compared with 24% of civilian doctors. The optimal time for delivery of TXA in under 3 hours was correctly identified by 91% of military doctors compared with 10% by civilian doctors.

Discussion

Military doctors are more familiar with TXA and its side effect profile. Given the potential impact of TXA on patient outcome and the findings of this study, further education of all doctors is recommended including dose, timing and potential side effects.

Returning from the acidotic abyss: Mortality in trauma patients with a pH < 7.0

INTRODUCTION

We hypothesized that a pH of <7.0 on presentation would correlate with almost universal mortality in trauma patients.

METHODS

A retrospective cohort study was performed on a Level I trauma center registry from 2013 to 2014. Hospital mortality was the primary outcome, which was compared by pH cohort (<7.0 or ≥7.0) using standard univariate statistics and multivariate logistic regression.

RESULTS

There were 593 patients included in the analysis: 66 in <7.0, 527 in ≥7.0. Mortality was 3× higher in the <7.0 pH cohort (62.1 vs. 20.3%; p < 0.0001), however there was no threshold for a pH below which there was 100% mortality. After controlling for these confounding variables, initial pH was found to be an independent predictor of inpatient mortality: pH < 7.0 (OR 6.33, 3.29-12.19; p < 0.0001).

CONCLUSION

This data indicates that while patients with severe acidosis are at increased risk for mortality, a pH < 7.0 is still recoverable in select cases.

Biochemical Markers as Predictors of In-Hospital Mortality in Patients with Severe Trauma: A Retrospective Cohort Study

Background

Initial evaluation of injury severity in trauma patients is an important and challenging task. We aimed to assess whether easily measurable biochemical parameters (hemoglobin, pH, and prothrombin time/international normalized ratio [PT/INR]) can predict in-hospital mortality in patients with severe trauma.

Methods

This retrospective study involved review of the medical records of 315 patients with severe trauma and an injury severity score >15 who were managed at Gyeongsang National University Hospital between January 2005 and December 2015. We extracted the following data: in-hospital mortality, injury severity score, and initial hemoglobin level, pH, and PT/INR. The predictive values of these variables were compared using receiver operation characteristic curves.

Results

Of the 315 patients, 72 (22.9%) died. The in-hospital mortality rates of patients with hemoglobin levels <8.4 g/dl and ≥8.4 g/dl were 49.8% and 9.9%, respectively (P < 0.001). At a cutoff hemoglobin level of 8.4 g/dl, the sensitivity and specificity values for mortality were 81.9% and 86.4%, respectively. At a pH cutoff of 7.25, the sensitivity and specificity values for mortality were 66.7% and 77.8%, respectively; 66.7% of patients with a pH <7.25 died versus 22.2% with a pH ≥7.25 (P < 0.001). The in-hospital mortality rates for patients with PT/INR values ≥1.4 and <1.4 were 37.5% and 16%, respectively (P < 0.001; sensitivity, 37.5%; specificity, 84%).

Conclusions

Using the suggested cutoff values, hemoglobin level, pH, and PT/INR can simply and easily be used to predict in-hospital mortality in patients with severe trauma.

Whole blood transfusion closest to the point-of-injury during French remote military operations

To improve the survival of combat casualties, interest in the earliest resort to whole blood (WB) transfusion on the battlefield has been emphasized. Providing volume, coagulation factors, plasma, and oxygenation capacity, WB appears actually as an ideal product severe trauma management. Whole blood can be collected in advance and stored for subsequent use, or can be drawn directly on the battlefield, once a soldier is wounded, from an uninjured companion and immediately transfused.Such concepts require a great control of risks at each step, especially regarding ABO mismatches, and transfusion-transmitted diseases. We present here the "warm and fresh" WB field transfusion program implemented among the French armed forces. We focus on the followed strategies to make it applicable on the battlefield, even during special operations and remote settings, and safe for recipients as well as for donors.

An Analysis of the Temperature Change in Warmed Intravenous Fluids During Administration in Cold Environments

This nonhuman simulation study was conducted to determine the decrease in temperature that occurred to 1-L bags of normal saline in a cold environment. The bags were warmed to 39°C and administered through intravenous (IV) tubing at a set flow rate while in a cold environment. The goal was to determine if there was a significant decrease in fluid temperature from the bag to the catheter site. Three trials were completed at temperatures of 0°C, -7°C, -12°C, and 22°C (control). Each bag of normal saline was warmed to 39°C using the SoftSack IV Fluid Warmer (Smithworks Med Inc, Lindale, TX). Fluid was collected and temperatures recorded at 5-minute intervals. The results showed a statistically significant (P = .003) change in temperature between the IV bag and the administration site. The most rapid change occurred within the first 5 minutes. The temperature change was more significant with colder ambient temperatures, with an average of a 28.7°C difference at -7°C and -12°C after 30 minutes. It appears that the most significant heat loss occurs through the IV tubing itself. Therefore, it may be beneficial to insulate the tubing on a trauma patient receiving warmed IV fluids in a cold environment to help prevent hypothermia.

Extracorporeal Life Support for Refractory Cardiac Arrest from Accidental Hypothermia: A 10-Year Experience in Edinburgh

BACKGROUND

Cardiac arrest caused by accidental hypothermia is a rare phenomenon with a significant mortality rate if untreated. The consensus is that these patients should be rewarmed with extracorporeal life support (ECLS) with the potential for excellent survival and neurologic outcomes. However, given the lack of robust data and clinical trials, the optimal management of such patients remains elusive.

OBJECTIVE

In this single-center study, we looked at the outcomes of all adult patients undergoing salvage ECLS for cardiac arrest caused by accidental hypothermia over a 10-year period from June 2006 to June 2016.

METHODS

These data were obtained from the Royal Infirmary of Edinburgh cardiothoracic surgery database. The patients' hard copy case notes, TrakCare (InterSystems Corp, Cambridge, MA), picture archiving and communications system (PACS), and WardWatcher databases were used to cross-check the accuracy of the acquired data.

RESULTS

Eleven patients met the inclusion criteria. The etiology of hypothermia was exposure to cold air (64%) and cold water immersion (36%). Two (18%) were treated with extracorporeal membrane oxygenation and the rest with cardiopulmonary bypass. The mean age was 51 years (range 32-73), and the mean core body temperature on admission was 20.6°C (range <18-24°C). The overall survival rate to hospital discharge was 72%, with 75% of survivors having no chronic neurologic impairment.

CONCLUSION

Our case series shows the remarkable salvageability of patients suffering prolonged cardiac arrest caused by accidental hypothermia, particularly in the absence of asphyxia, trauma, or severe hyperkalemia. ECLS is a safe and effective rewarming treatment and should be used to aggressively manage this patient group.

The impact of mild induced hypothermia on the rate of transfusion and the mortality in severely injured patients: a retrospective multi-centre study

BACKGROUND

Although under discussion, induced hypothermia (IH) is an established therapy for patients with cardiac arrest or traumatic brain injuries. The influences on coagulopathy and bleeding tendency in severely injured patients (SIP) with concomitant traumatic brain injury are most widely unclear. Therefore, the aim of this study was to quantify the effect of mild IH in SIP with concomitant severe traumatic brain injuries on transfusion rate and mortality.

METHODS

In this retrospective multi-centre study, SIP from three European level-1 trauma centres with an ISS ≥16 between 2009 and 2011 were included. At hospital A, patients qualified for IH with age ≤70 years and a severe head injury with an abbreviated injury scale (AIS_Head) of ≥3. IH was defined as target core body temperature of 35 °C. Hypothermic patients were matched with two patients, one from hospital B and one from hospital C using age and AIS_Head. The effect of IH on the transfusion rate, complications and mortality was quantified with 95 % confidence intervals (CI). Patients not treated with IH in hospital A and those from hospital B and C, who were not matched, were used to adjust the CI for the effect of inter-hospital therapy protocol differences.

RESULTS

Mean age of patients in the IH-group (n = 43) was 35.7 years, mean ISS 30 points and sex distribution showed 83.7 % male. Mean age of matched patients in the normotherm-group (n = 86) was 36.7 years, mean ISS 33 points and there were 75.6 % males. For the hypothermic patients, we pointed out an estimate of mean difference for the number of transfused units of packed red blood cells as well as for mortality which does not indicate a decrease in the benefit gained by hypothermia. It is suggested that hypothermic patients tend to a higher rate of lung failure and thromboembolisms.

CONCLUSION

Though tending to an increased rate of complications, there is no evidence for a difference in both; rate of transfusion and mortality in SIP. Mild IH as an option for severe head injuries seems as well-being practicable in the presence of multiple severe injuries. Further, clinical studies regarding the side effects are necessary.

Effects of an acidic environment on coagulation dynamics

Essentials Acidosis, an outcome of traumatic injury, has been linked to impaired procoagulant efficiency. In vitro model systems were used to assess coagulation dynamics at pH 7.4 and 7.0. Clot formation dynamics are slightly enhanced at pH 7.0 in blood ex vivo. Acidosis induced decreases in antithrombin efficacy offset impairments in procoagulant activity.

SUMMARY

Background Disruption of hydrogen ion homeostasis is a consequence of traumatic injury often associated with clinical coagulopathy. Mechanisms by which acidification of the blood leads to aberrant coagulation require further elucidation. Objective To examine the effects of acidified conditions on coagulation dynamics using in vitro models of increasing complexity. Methods Coagulation dynamics were assessed at pH 7.4 and 7.0 as follows: (i) tissue factor (TF)-initiated coagulation proteome mixtures (±factor [F]XI, ±fibrinogen/FXIII), with reaction progress monitored as thrombin generation or fibrin formation; (ii) enzyme/inhibitor reactions; and (iii) TF-dependent or independent clot dynamics in contact pathway-inhibited blood via viscoelastometry. Results Rate constants for antithrombin inhibition of FXa and thrombin were reduced by ~ 25-30% at pH 7.0. At pH 7.0 (+FXI), TF-initiated thrombin generation showed a 20% increase in maximum thrombin levels and diminished thrombin clearance rates. Viscoelastic analyses showed a 25% increase in clot time and a 25% reduction in maximum clot firmness (MCF). A similar MCF reduction was observed at pH 7.0 when fibrinogen/FXIII were reacted with thrombin. In contrast, in contact pathway-inhibited blood (n = 6) at pH 7.0, MCF values were elevated 6% (95% confidence interval [CI]: 1%-11%) in TF-initiated blood and 15% (95% CI: 1%- 29%) in the absence of TF. Clot times at pH 7.0 decreased 32% (95% CI: 15%-49%) in TF-initiated blood and 51% (95% CI: 35%-68%) in the absence of TF. Conclusions Despite reported decreased procoagulant catalysis at pH 7.0, clot formation dynamics are slightly enhanced in blood ex vivo and suppression of thrombin generation is not observed. A decrease in antithrombin reactivity is one potential mechanism contributing to these outcomes.

Tactical damage control resuscitation in austere military environments

BACKGROUND

Despite the early uses of tourniquets and haemostatic dressings, blood loss still accounts for the vast majority of preventable deaths on the battlefield. Over the last few years, progress has been made in the management of such injuries, especially with the use of damage control resuscitation concepts. The early application of these procedures, on the field, may constitute the best opportunity to improve survival from combat injury during remote operations.

DATA SOURCES

Currently available literature relating to trauma-induced coagulopathy treatment and far-forward transfusion was identified by searches of electronic databases. The level of evidence and methodology of the research were reviewed for each article. The appropriateness for field utilisation of each medication was then discussed to take into account the characteristics of remote military operations.

CONCLUSIONS

In tactical situations, in association with haemostatic procedures (tourniquet, suture, etc), tranexamic acid should be the first medication used according to the current guidelines. The use of fibrinogen concentrate should also be considered for patients in haemorrhagic shock, especially if point-of-care (POC) testing of haemostasis or shock severity is available. If POC evaluation is not available, it seems reasonable to still administer this treatment after clinical assessment, particularly if the evacuation is delayed. In this situation, lyophilised plasma may also be given as a resuscitation fluid while respecting permissive hypotension. Whole blood transfusion in the field deserves special attention. In addition to the aforementioned treatments, if the field care is prolonged, whole blood transfusion must be considered if it does not delay the evacuation.

Performance comparison of improvised prehospital blood warming techniques and a commercial blood warmer

INTRODUCTION

Prehospital transfusion of packed red blood cells (PRBC) may be life saving for hypovolaemic trauma patients. PRBCs should preferably be warmed prior to administration but practical prehospital devices have only recently become available. The effectiveness of purpose designed prehospital warmers compared with previously used improvised methods of warming has not previously been described.

MATERIALS AND METHODS

Expired units of PRBCs were randomly assigned to a warming method in a bench study. Warming methods were exposure to body heat of an investigator, leaving the blood in direct sunlight on a dark material, wrapping the giving set around gel heat pads or a commercial fluid warmer (Belmont Buddy Lite). Methods were compared with control units that were run through the fluid circuit with no active warming strategy.

RESULTS

The mean temperature was similar for all methods on removal from the fridge (4.5°C). The mean temperatures (degrees centigrade) for all methods were higher than the control group at the end of the circuit (all P≤0.001). For each method the mean (95% CI) temperature at the end of the circuit was; body heat 17.2 (16.4-18.0), exposure to sunlight 20.2 (19.4-21.0), gel heat pads 18.8 (18.0-19.6), Buddy Lite 35.2 (34.5-36.0) and control group 14.7 (13.9-15.5).

CONCLUSIONS

All of the warming methods significantly warmed the blood but only the Buddy Lite reliably warmed the blood to a near normal physiological level. Improvised warming methods therefore cannot be recommended.

A hybrid simulator model for the control of catastrophic external junctional haemorrhage in the military environment

Catastrophic haemorrhage from extremity injuries has for a long time been the single most common cause of preventable death in the military environment. The effective use of extremity tourniquets has increased the survival of combat casualties, and exsanguination from isolated limb injuries is no longer the most common cause of death. Today, the most common cause of potentially preventable death is haemorrhage from the junctional zones, i.e. the most proximal part of the extremities, not amenable to standard tourniquets.

Different training techniques to control catastrophic haemorrhage have been used by the Swedish Armed Forces in the pre-deployment training of physicians, nurses and medics for many years. The training techniques include different types of human patient simulators such as moulage patients and manikins. Preferred training conditions for the control of catastrophic haemorrhage include a high degree of realism, in combination with multiple training attempts.

This report presents a new hybrid training model for catastrophic external junctional haemorrhage control. It offers a readily reproducible, simple and inexpensive opportunity to train personnel to deal with life threatening catastrophic junctional haemorrhage. In particular, this model offers an opportunity for non-medical military personnel in Sweden to practice control of realistic catastrophic haemorrhage, with multiple training attempts.

PolySTAT-modified chitosan gauzes for improved hemostasis in external hemorrhage

Positively-charged chitosan gauzes stop bleeding from wounds by electrostatically interacting with negatively-charged cell membranes of erythrocytes to cause erythrocyte agglutination and by sealing wounds through tissue adhesion. In the following work, nonwoven chitosan gauze was impregnated with PolySTAT, a synthetic polymer that enhances coagulation by cross-linking fibrin, to generate PolySTAT/chitosan gauzes with improved hemostatic efficacy. When comparing nonwoven chitosan and PolySTAT/chitosan to a commercially-available chitosan-containing gauze (Celox® Rapid), no appreciable differences were observed in fiber size, morphology, and pore size. However, PolySTAT/chitosan demonstrated more rapid blood absorption compared to Celox® Rapid. In a rat model of femoral artery injury, PolySTAT/chitosan gauzes reduced blood loss and improved survival rate compared to non-hemostatic controls and Celox® Rapid. While Celox® Rapid had stronger adherence to tissues compared to PolySTAT/chitosan gauzes, blood loss was greater due to hematoma formation under the Celox® dressing. Animals treated with PolySTAT/chitosan gauzes required less saline infusion to restore and maintain blood pressure above the target blood pressure (60mmHg) while other treatment groups required more saline due to continued bleeding from the wound. These results suggest that PolySTAT/chitosan gauzes are able to improve blood clotting and withstand increasing arterial pressure with the addition of a fibrin cross-linking hemostatic mechanism.

STATEMENT OF SIGNIFICANCE

Blood loss remains one of the leading causes of death after traumatic injury in civilian populations and on the battlefield. Advanced biomaterials that interact with blood components and/or accelerate the clotting process to form a hemostatic plug are necessary to staunch bleeding after injury. Chitosan-based gauzes, which stop bleeding by causing red blood cell aggregation, are currently used on the battlefield and have shown variable performance under high pressure arterial blood flow in animal studies, suggesting that red blood cell aggregates require further mechanical stabilization for more reliable performance. In this work, we investigate the binding and cross-linking of fibrin, a major component in blood clots, on chitosan gauze fiber surfaces to structurally reinforce red blood cell aggregates.