Injury-associated hypothermia: an analysis of the 2004 National Trauma Data Bank

Trauma Compendium: Management of the Entrapped Patient - a position statement and resource document of NAEMSP

Entrapped patients may be simply entombed or experiencing crush injury or entanglement. Patients with trauma who are entrapped are at higher risk of significant injury than patients not entrapped. Limited access and prolonged scene times further complicate patient management. Although patient entrapment is a significant focus of specialty teams, such as urban search & rescue (US&R) teams that operate as local, regional, and/or national resources in response to complex scenes and disaster scenarios, entrapment is a regular occurrence in routine EMS response. Therefore, all EMS clinicians must have the training and skills to manage entrapped patients and to support medically-directed rescue throughout the extrication process.NAEMSP recommends:EMS clinicians must perform a timely and thorough primary and secondary assessment and reassessments in parallel with dynamic extrication planning; the environment may require adaption of standard assessment techniques and devices.EMS clinicians should establish early, clear, and ongoing communications with rescue personnel to ensure a coordinated patient-centered medically directed approach to extrication. Communication with the patient should be frequent, clear, and reassuring.EMS clinicians should immediately take measures to effectively prevent and manage hypothermia.EMS clinicians should recognize airway management in the entrapped patient is always challenging. When required, advanced airway placement should be performed by the most experienced operator with proficiency in multiple modalities and alternative techniques in limited access situations.In entrapped patients who are experiencing or are at risk for crush syndrome, EMS clinicians should initiate large-volume (i.e., 1-1.5 liters/hour for adults and 20 milliliters/kilogram/hour for pediatric patients for the initial 3-4 hours) fluid resuscitation with crystalloid, preferably normal saline, as early as possible and prior to extrication.In entrapped patients who are experiencing or are at risk for crush syndrome, EMS clinicians should administer medications to mitigate risks of hyperkalemia, infection, and renal failure, early and prior to extrication.Tourniquet application should be considered in the setting of the crushed extremity as a potential adjunct to medical optimization before extrication of some patients.Patients with prolonged entrapment with the potential for severe injuries require complex resuscitation and may benefit from EMS physician management on scene. EMS systems should consider an early EMS physician response to entrapped patients.

Seasonal Association With Hypothermia in Combat Trauma

INTRODUCTION

Hypothermia increases mortality in trauma populations and frequently occurs in military casualties due to the nature of combat environments. The association between hypothermia and the time of year when injured remains unclear. We sought to determine the association between seasonal changes in temperature and hypothermia among combat casualties.

MATERIALS AND METHODS

This observational study was a secondary analysis of a previously described Department of Defense Trauma Registry dataset which included U.S. military and Coalition casualties who received prehospital care from January 2007 to March 2020 in Afghanistan and Iraq. We tested for associations between hypothermia (<36.2°C) and seasonal ambient temperatures by constructing multivariable logistic regression models. Summer was defined as June through August and winter as December through February. We assumed that the combat operations occurred in the area near the point of first contact with the deployed military treatment facilities. This study was determined to be exempt from Institutional Review Board oversight.

RESULTS

There were 5,821 that met inclusion for this study. Within the multivariable logistic regression model, we adjusted for injury severity score, mechanism of injury, and imputed transport time, finding that combat casualties were 2.28 (odds ratio, 95% confidence interval 1.93-2.69) times more likely to develop hypothermia in the winter versus summer. When using temperature as a continuous outcome, casualties had a lower emergency department temperature during the winter (parameter estimate -0.133°C, P < 0.001) after adjusting for confounders. In casualties experiencing hypothermia, mortality was higher (4% versus 1%, P < 0.001), and composite median injury severity score values were higher (10 versus 5, P < 0.001). Among hypothermic casualties, serious injuries were significantly more common (all P < 0.001) to the head (15% versus 7%), thorax (15% versus 7%), abdomen (9% versus 6%), extremities (35% versus 22%), and skin (4% versus 2%).

CONCLUSIONS

We found a seasonal variation in the occurrence of hypothermia in a large cohort of trauma casualties. Despite adjustment for multiple known confounders, our findings substantiate probable ambient temperature variations to trauma-induced hypothermia. Furthermore, our findings, when taken in the context of other studies on the efficacy of current hypothermia prevention and treatment strategies, support the need for better methods to mitigate hypothermia in future cold-weather operations.

Investigating the Safety and Efficacy of Therapeutic Hypothermia in Pediatric Severe Traumatic Brain Injury: A Systematic Review and Meta-Analysis

BACKGROUND

Prior guidelines recommended maintaining normothermia following traumatic brain injury (TBI), but recent studies suggest therapeutic hypothermia as a viable option in pediatric cases. However, some others demonstrated a higher mortality rate. Hence, the impact of hypothermia on neurological symptoms and overall survival remains contentious.

METHODS

We conducted a systematic review and meta-analysis to evaluate the effects of hypothermia on neurological outcomes in pediatric TBI patients. The PubMed/Medline, Scopus, and Web of Science databases were searched until 1 January 2024 and data were analyzed using appropriate statistical methods.

RESULTS

A total of eight studies, comprising nine reports, were included in this analysis. Our meta-analysis did not reveal significant differences in mortality (RR = 1.58; 95% CI = 0.89-2.82, p = 0.055), infection (RR = 0.95: 95% CI = 0.79-1.1, p = 0.6), arrhythmia (RR = 2.85: 95% CI = 0.88-9.2, p = 0.08), hypotension (RR = 1.54: 95% CI = 0.91-2.6, p = 0.10), intracranial pressure (SMD = 5.07: 95% CI = -4.6-14.8, p = 0.30), hospital length of stay (SMD = 0.10; 95% CI = -0.13-0.3, p = 0.39), pediatric intensive care unit length of stay (SMD = 0.04; 95% CI = -0.19-0.28, p = 0.71), hemorrhage (RR = 0.86; 95% CI = 0.34-2.13, p = 0.75), cerebral perfusion pressure (SMD = 0.158: 95% CI = 0.11-0.13, p = 0.172), prothrombin time (SMD = 0.425; 95% CI = -0.037-0.886, p = 0.07), and partial thromboplastin time (SMD = 0.386; 95% CI = -0.074-0.847, p = 0.10) between the hypothermic and non-hypothermic groups. However, the heart rate was significantly lower in the hypothermic group (-1.523 SMD = -1.523: 95% CI = -1.81--1.22 p < 0.001).

CONCLUSIONS

Our findings challenge the effectiveness of therapeutic hypothermia in pediatric TBI cases. Despite expectations, it did not significantly improve key clinical outcomes. This prompts a critical re-evaluation of hypothermia's role as a standard intervention in pediatric TBI treatment.

Core temperature following pre-hospital induction of anaesthesia in trauma patients

INTRODUCTION

Hypothermia is a well-recognised finding in trauma patients, which can occur even in warmer climates. It is an independent predictor of increased morbidity and mortality. It is associated with pre-hospital intubation, although the reasons for this are likely to be multifactorial. Core temperature drop after induction of anaesthesia is a well-known phenomenon in the context of elective surgery, and the mechanisms of this are well established.

METHODS

We conducted a prospective observational study to examine the behaviour of core temperature in patients undergoing pre-hospital anaesthesia for traumatic injuries.

RESULTS

Between 2017 and 2021 data were collected on 48 patients. The data from 40 of these were included in the final analysis.

DISCUSSION

Our data do not show a decrease in the core temperatures of patients who receive pre-hospital anaesthesia, unlike patients who are anaesthetised without pre-warming, in operating theatres. The lack of a change could relate to patient, anaesthetic or environmental factors.

Changes in temperature in preheated crystalloids at ambient temperatures relevant to a prehospital setting: an experimental simulation study with the application of prehospital treatment of trauma patients suffering from accidental hypothermia

BACKGROUND

Accidental hypothermia is common in all trauma patients and contributes to the lethal diamond, increasing both morbidity and mortality. In hypotensive shock, fluid resuscitation is recommended using fluids with a temperature of 37-42°, as fluid temperature can decrease the patient's body temperature. In Sweden, virtually all prehospital services use preheated fluids. The aim of the present study was to investigate how the temperature of preheated infusion fluids is affected by the ambient temperatures and flow rates relevant for prehospital emergency care.

METHODS

In this experimental simulation study, temperature changes in crystalloids preheated to 39 °C were evaluated. The fluid temperature changes were measured both in the infusion bag and at the patient end of the infusion system. Measurements were conducted in conditions relevant to prehospital emergency care, with ambient temperatures varying between - 4 and 28 °C and flow rates of 1000 ml/h and 6000 ml/h, through an uninsulated infusion set at a length of 175 cm.

RESULTS

The flow rate and ambient temperature affected the temperature in the infusion fluid both in the infusion bag and at the patient end of the system. A lower ambient temperature and lower flow rate were both associated with a greater temperature loss in the infusion fluid.

CONCLUSION

This study shows that both a high infusion rate and a high ambient temperature are needed if an infusion fluid preheated to 39 °C is to remain above 37 °C when it reaches the patient using a 175-cm-long uninsulated infusion set. It is apparent that the lower the ambient temperature, the higher the flow rate needs to be to limit temperature loss of the fluid.

Impact of accidental hypothermia in trauma patients: A retrospective cohort study

BACKGROUND

Trauma patients with hypothermia have substantial increases in mortality and morbidity. In severely injured patients, hypothermia is common with a rate up to 50% in various geographic areas. This study aims to elucidate the incidence, predictors, and impact of hypothermia on outcomes in severely injured patients.

METHODS

This was a retrospective cohort study which included trauma patients with an Injury Severity Score (ISS) ≥ 16 admitted to a level 1 trauma center in the Netherlands between January 1, 2015 and December 31, 2021. Primary outcome was incidence of hypothermia on arrival at the emergency department. Factors associated with hypothermia were identified. Secondary outcomes were transfusion requirement, mortality, and intensive care unit (ICU) admission. Logistic regression analysis was used to identify associations.

RESULTS

A total of 2032 severely injured patients were included of which 257 (12.6%) were hypothermic on hospital arrival. Predictors for hypothermia on hospital arrival included higher ISS, prehospital intubation, cervical spine immobilization, winter months, systolic blood pressure (SBP) < 90 mmHg and Glasgow Coma Scale (GCS) ≤ 8. Hypothermia was independently associated with transfusion requirement (OR, 2.68; 95% CI, 1.94 - 3.73; p < 0.001), mortality (OR, 2.12; 95% CI, 1.40 - 3.19; p < 0.001) and more often ICU admission (OR, 1.81; 95% CI, 1.10 - 2.97, p = 0.019).

CONCLUSIONS

In this study, hypothermia was present in 12.6% of severely injured patients. Hypothermia was associated with increased transfusion requirement, mortality, and ICU admission. Identified predictors for hypothermia included the severity of injury, intubation, and immobilization, as well as winter season, SBP < 90 mmHg, and GCS ≤ 8.

Development and validation of a nomogram for predicting in-hospital mortality in patients with nonhip femoral fractures

BACKGROUND

The incidence of nonhip femoral fractures is gradually increasing, but few studies have explored the risk factors for in-hospital death in patients with nonhip femoral fractures in the ICU or developed mortality prediction models. Therefore, we chose to study this specific patient group, hoping to help clinicians improve the prognosis of patients.

METHODS

This is a retrospective study based on the data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Least absolute shrinkage and selection operator (LASSO) regression was used to screen risk factors. The receiver operating characteristic (ROC) curve was drawn, and the areas under the curve (AUC), net reclassification index (NRI) and integrated discrimination improvement (IDI) were calculated to evaluate the discrimination of the model. The consistency between the actual probability and the predicted probability was assessed by the calibration curve and Hosmer-Lemeshow goodness of fit test (HL test). Decision curve analysis (DCA) was performed, and the nomogram was compared with the scoring system commonly used in clinical practice to evaluate the clinical net benefit.

RESULTS

The LASSO regression analysis showed that heart rate, temperature, red blood cell distribution width, blood urea nitrogen, Glasgow Coma Scale (GCS), Simplified Acute Physiology Score II (SAPSII), Charlson comorbidity index and cerebrovascular disease were independent risk factors for in-hospital death in patients with nonhip femoral fractures. The AUC, IDI and NRI of our model in the training set and validation set were better than those of the GCS and SAPSII scoring systems. The calibration curve and HL test results showed that our model prediction results were in good agreement with the actual results (P = 0.833 for the HL test of the training set and P = 0.767 for the HL test of the validation set). DCA showed that our model had a better clinical net benefit than the GCS and SAPSII scoring systems.

CONCLUSION

In this study, the independent risk factors for in-hospital death in patients with nonhip femoral fractures were determined, and a prediction model was constructed. The results of this study may help to improve the clinical prognosis of patients with nonhip femoral fractures.

What is the best way to keep the patient warm during technical rescue? Results from two prospective randomised controlled studies with healthy volunteers

BACKGROUND

Accidental hypothermia is a manifest problem during the rescue of entrapped victims and results in different subsequent problems as coagulopathy and wound infection. Different warming methods are available for the preclinicial use. However, their effectiveness has hardly been evaluated.

METHODS

In a first step a survey among German fire brigades was performed with questions about the most used warming methods. In a second step two crossover studies were conducted. In each study two different warming method were compared with forced air warming - which is the most frequently used and highly effective warming method in operation rooms (Study A: halogen floodlight vs. forced air warming; Study B: forced air warming vs. fleece blanket). In both studies healthy volunteers (Study A: 30 volunteers, Study B: 32 volunteers) were sitting 60 min in a cold store. In the first 21 min there was no subject warming. Afterwards the different warming methods were initiated. Every 3 min parameters like skin temperature, core body temperature and cold perception on a 10-point numeric rating scale were recorded. Linear mixed models were fitted for each parameter to check for differences in temperature trajectories and cold perception with regard to the different warming methods.

RESULTS

One hundred fifty-one German fire brigades responded to the survey. The most frequently used warming methods were different rescue blankets (gold/silver, wool) and work light (halogen floodlights). Both studies (A and B) showed significantly (p < 0.05) higher values in mean skin temperature, mean body temperature and total body heat for the forced air warming methods compared to halogen floodlight respectively fleece blanket shortly after warming initiation. In contrast, values for the cold perception were significantly lower (less unpleasant cold perception) during the phase the forced air warming methods were used, compared to the fleece blanket or the halogen floodlight was used.

CONCLUSION

Forced air warming methods used under the standardised experimental setting are an effective method to keep patients warm during technical rescue. Halogen floodlight has an insufficient effect on the patient's heat preservation. In healthy subjects, fleece blankets will stop heat loss but will not correct heat that has already been lost.

TRIAL REGISTRATION

The studies were registered retrospectively on 14/02/2022 on the German Clinical Trials registry (DRKS) with the number DRKS00028079.

Comprehensive Management of the Patient With Traumatic Cardiac Injury

Cardiac injuries are rare but potentially life-threatening, with a significant proportion of victims dying before arrival at the hospital. The in-hospital mortality among patients who arrive in-hospital alive also remains significantly high, despite major advancements in trauma care including the continuous updating of the Advanced Trauma Life Support (ATLS) program. Stab and gunshot wounds due to assault or self-inflicted injuries are the common causes of penetrating cardiac injuries, while motor vehicular accidents and fall from height are attributable causes of blunt cardiac injury. Rapid transport of victim to trauma care facility, prompt recognition of cardiac trauma by clinical evaluation and focused assessment with sonography for trauma (FAST) examination, quick decision-making to perform emergency department thoracotomy, and/or shifting the patient expeditiously to the operating room for operative intervention with ongoing resuscitation are the key components for a successful outcome in cardiac injury victims with cardiac tamponade or exsanguinating hemorrhage. Blunt cardiac injury with arrhythmias, myocardial dysfunction, or cardiac failure may need continuous cardiac monitoring or anesthetic care for operative procedure of other associated injuries. This mandates a multidisciplinary approach working in concert with agreed local protocols and shared goals. An anesthesiologist has a pivotal role to play as a team leader or member in the trauma pathway of severely injured patients. They are not only involved in in-hospital care as a perioperative physician but also participate in the organizational aspects of prehospital trauma systems and training of prehospital care providers/paramedics. There is sparse literature available on the anesthetic management of cardiac injury (penetrating as well as blunt) patients. This narrative review discusses the comprehensive management of cardiac injury patients, focusing on the anesthetic concerns and is guided by our experience in managing cardiac injury cases at Jai Prakash Narayan Apex Trauma Center (JPNATC), All India Institute of Medical Sciences, New Delhi. JPNATC is the only level 1 trauma center in north India, providing services to a population of approximately 30 million with around 9000 operations being performed annually.

How to Clear Polytrauma Patients for Fracture Fixation: Results of a systematic review of the literature

INTRODUCTION

Early patient assessment is relevant for surgical decision making in severely injured patients and early definitive surgery is known to be beneficial in stable patients. The aim of this systematic review is to extract parameters indicative of risk factors for adverse outcome. Moreover, we aim to improve decision making and separate patients who would benefit from early versus staged definitive surgical fixation.

METHODS

Following the PRISMA guidelines, a systematic review of peer-reviewed articles in English or German language published between (2000 and 2022) was performed. The primary outcome was the pathophysiological response to polytrauma including coagulopathy, shock/haemorrhage, hypothermia and soft tissue injury (trauma, brain injury, thoracic and abdominal trauma, and musculoskeletal injury) to determine the treatment strategy associated with the least amount of complications. Articles that had used quantitative parameters to distinguish between stable and unstable patients were summarized. Two authors screened articles and discrepancies were resolved by consensus. Quantitative values for relevant parameters indicative of an unstable polytrauma patient were obtained.

RESULTS

The initial systematic search using MeSH criteria yielded 1550 publications deemed relevant to the following topics (coagulopathy (n = 37), haemorrhage/shock (n = 7), hypothermia (n = 11), soft tissue injury (n = 24)). Thresholds for stable, borderline, unstable and in extremis conditions were defined according to the existing literature as follows: Coagulopathy; International Normalized Ratio (INR) and viscoelastic methods (VEM)/Blood/shock; lactate, systolic blood pressure and haemoglobin, hypothermia; thresholds in degrees Celsius/Soft tissue trauma: traumatic brain injury, thoracic and abdominal trauma and musculoskeletal trauma.

CONCLUSION

In this systematic literature review, we summarize publications by focusing on different pathways that stimulate pathophysiological cascades and remote organ damage. We propose that these parameters can be used for clinical decision making within the concept of safe definitive surgery (SDS) in the treatment of severely injured 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.

Barriers to body temperature monitoring among prehospital personnel: a qualitative study using the modified nominal group technique

OBJECTIVES

To identify and explore barriers that healthcare professionals working as prehospital care (PHC) providers at the University Hospital of North Norway experience with temperature monitoring and discover solutions to these problems.

STUDY DESIGN

Qualitative study using the modified nominal group technique.

MATERIALS AND METHODS

14 experienced healthcare professionals working in air and ground emergency medical services were invited to the study. Initially, each participant was asked to suggest through email topics of importance regarding barriers to prehospital thermometry. Afterwards, they received a list of all disparate topics and were asked to individually rank them by importance. The top-ranked topics were discussed in a consensus meeting. The meeting was audio-recorded and a transcript was written and then analysed through an inductive thematic analysis.

RESULTS

13 participants accepted the invitation. 63 suggestions were reduced to 24 disparate topics after removal of duplicates. Twelve highly ranked topics were discussed during the consensus meeting. Thematic analysis revealed 47 codes that were grouped together into six overarching themes, of which four described challenges to monitoring and two described potential solutions: equipment dissatisfaction, little focus on patient temperature, fear of iatrogenic complications, thermometry subordinated, more focus on temperature and simplification of thermometry.

CONCLUSION

To increase the frequency of temperature measurement on correct indication, we suggest introducing PHC protocols that specify patients and conditions where an accurate temperature measurement should have high priority. Furthermore, there is a profound need for more suitable techniques for temperature monitoring in the prehospital setting.

Hypothermia Induced Impairment of Platelets: Assessment With Multiplate vs. ROTEM—An In Vitro Study

Introduction: This experimental in vitro study aimed to identify and characterize hypothermia-associated coagulopathy and to compare changes in mild to severe hypothermia with the quantitative measurement of rotational thromboelastometry (ROTEM) and multiple-electrode aggregometry (MULTIPLATE).

Methods: Whole blood samples from 18 healthy volunteers were analyzed at the target temperatures of 37, 32, 24, 18, and 13.7°C with ROTEM (ExTEM, InTEM and FibTEM) and MULTIPLATE using the arachidonic acid 0.5 mM (ASPI), thrombin receptor-activating peptide-6 32 µM (TRAP) and adenosine diphosphate 6.4 µM (ADP) tests at the corresponding incubating temperatures for coagulation assessment.

Results: Compared to baseline (37°C) values ROTEM measurements of clotting time (CT) was prolonged by 98% (at 18°C), clot formation time (CFT) was prolonged by 205% and the alpha angle dropped to 76% at 13.7°C (p < 0.001). At 24.0°C CT was prolonged by 56% and CFT by 53%. Maximum clot firmness was only slightly reduced by ≤2% at 13.7°C. Platelet function measured by MULTIPLATE was reduced with decreasing temperature (p < 0.001): AUC at 13.7°C −96% (ADP), −92% (ASPI) and −91% (TRAP).

Conclusion: Hypothermia impairs coagulation by prolonging coagulation clotting time and by decreasing the velocity of clot formation in ROTEM measurements. MULTIPLATE testing confirms a linear decrease in platelet function with decreasing temperatures, but ROTEM fails to adequately detect hypothermia induced impairment of platelets.

Continued Relevance of Initial Temperature Measurement in Trauma Patients

OBJECTIVES

Hypothermia occurs in 30-50% of severely injured trauma patients and is associated with multiple metabolic derangements and worsened outcomes. However, hypothermia continues to be under-diagnosed which leads to inadequate triage and treatment in trauma patients. Our study set out to determine if hypothermia is an independent predictor of mortality in trauma patients.

METHODS

We retrospectively reviewed data of all trauma activation patients over a 5-year period. Data were collected on patient demographics, initial core temperature, Glasgow Coma Scale (GCS) on presentation, and injury severity score (ISS). Patients were then stratified into groups based on presenting temperature, ISS, and GCS. Outcomes compared were mortality, blood products received, and intensive care unit (ICU) length of stay. Correlations and logistic regression were used to test the hypotheses.

RESULTS

Survival and temperature data were reviewed on 15,567 patients. Initial temperature was not significantly associated with ICU length of stay or blood products transfused (P = .21 and P = .08, respectively). However, odds ratio of mortality in hypothermic patients (<35°C) compared to normothermic patients (35-39°C) was 3.95 (95% CI 2.90-5.41). When controlling for GCS and ISS, separately, temperature remained an independent predictor of mortality.

CONCLUSIONS

Hypothermia is an independent risk factor for mortality in trauma patients. It remains crucial to obtain accurate presenting temperatures in trauma patients in order to triage and treat hypothermia. Based on our data, obtaining core temperatures and rapidly treating hypothermia continues to be a vital part of the secondary survey of trauma patients.

Efficacy of an Infrared Radiator for Hypothermia Prevention in a Simulated Setup of Entrapped Vehicle Accident Victims

BACKGROUND

Prolonged extrication of entrapped patients after road traffic accidents increases the risk of sustained hypothermia. Accident-related hypothermia increases mortality in severely injured patients, and prehospital efforts to prevent hypothermia are essential. We evaluated various warming measures regarding their preclinical suitability and efficacy for patient warming, tested in realistically-simulated road traffic accident scenarios under cold ambient conditions in a climate chamber.

METHODS

The effects of a chemical warming blanket (CWB), forced-air warming (FAW) device, or infrared radiator (IRR) on the core body and skin surface temperature of a subject previously exposed to a cold environment (5°C for 12 minutes) was recorded via temperature sensors and thermographically, respectively. Physiological parameters such as oxygen saturation, blood pressure, and heart rate were also monitored.

RESULTS

Under cold environmental conditions, all devices were able to compensate or overcompensate the cooling of body parts directly exposed to the heating measure. In the body areas that were not directly warmed (back, lower extremities), only the CWB limited further cooling. FAW and IR irradiation rapidly and effectively warmed the heat-exposed areas (head and arms). However, both methods - but especially the IRR - led to a noticeably accelerated cooling in body parts not directly exposed to heat (back, legs).

CONCLUSION

The increased mortality associated with hypothermia in severely injured crash victims during prolonged vehicle extrication has intensified efforts to prevent sustained hypothermia. The use of a CWB, FAW or IRR are in principle all suitable for reducing or compensating for heat loss. The ongoing cooling of those body parts not directly exposed to the heat source was interpreted as a steal phenomenon in regional blood flow. However, the practicality and effectiveness of these measures, combined with their logistical requirements, must be evaluated in real extrication scenarios.

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.

Hypothermia as an Outcome Predictor Tool in Pediatric Trauma: A Propensity-Matched Analysis

OBJECTIVE

Hypothermia is an independent risk factor for mortality in adult trauma patients. Two small studies have shown similar results in pediatric trauma patients. Temperature is not included in any pediatric trauma assessment scores. This study sought to compare mortality and various descriptive outcomes between pediatric hypothermic and normothermic trauma patients.

METHODS

Data were obtained from the National Trauma Database from 2009 to 2012. Patients meeting inclusion criteria were stratified by presence of isolated head injury, head injury with multiple trauma, and absence of head injury. These groups were then subdivided into hypothermic (temperature ≤36°C) and normothermic groups. We used propensity score matching to 1:1 match hypothermic and normothermic patients. Mortality, neurosurgical interventions, endotracheal intubation, blood transfusion, length of stay, laparotomy, thoracotomy, conversion of cardiac rhythm, and time receiving mechanical ventilation were evaluated.

RESULTS

Data from 3,011,482 patients were obtained. There were 414,562 patients who met the inclusion criteria. In all patients meeting inclusion criteria, hypothermia was a significant risk factor in all outcomes measured. Following stratification and 1:1 matching, in all groups, hypothermia was associated with increased mortality (P < 0.0001), increased rate of endotracheal intubation (P < 0.0002), increased need for blood transfusion (P < 0.0025), and conversion of cardiac rhythm (P < 0.0027).

CONCLUSION

Hypothermia has been shown to be a significant prognostic indicator in the pediatric trauma patient with further potential application. Future studies are indicated to evaluate the incorporation of hypothermia into the Pediatric Trauma Score not only to help predict injury severity and mortality but also to improve appropriate and expeditious patient transfer to pediatric trauma centers and potentially facilitate earlier intervention.

Prehospital Damage Control: The Management of Volume, Temperature… and Bleeding!

Damage control resuscitation should be initiated as soon as possible after a trauma event to avoid metabolic decompensation and high mortality rates. The aim of this article is to assess the position of the Trauma and Emergency Surgery Group (CTE) from Cali, Colombia regarding prehospital care, and to present our experience in the implementation of the “Stop the Bleed” initiative within Latin America. Prehospital care is phase 0 of damage control resuscitation. Prehospital damage control must follow the guidelines proposed by the “Stop the Bleed” initiative. We identified that prehospital personnel have a better perception of hemostatic techniques such as tourniquet use than the hospital providers. The use of tourniquets is recommended as a measure to control bleeding. Fluid management should be initiated using low volume crystalloids, ideally 250 cc boluses, maintaining the principle of permissive hypotension with a systolic blood pressure range between 80- and 90-mm Hg. Hypothermia must be management using warmed blankets or the administration of intravenous fluids warmed prior to infusion. However, these prehospital measures should not delay the transfer time of a patient from the scene to the hospital. To conclude, prehospital damage control measures are the first steps in the control of bleeding and the initiation of hemostatic resuscitation in the traumatically injured patient. Early interventions without increasing the transfer time to a hospital are the keys to increase survival rate of severe trauma patients.

Efficacy of warming systems in mountain rescue: an experimental manikin study

Mountain accident casualties are often exposed to cold and windy weather. This may induce post-traumatic hypothermia which increases mortality. The aim of this study was to assess the ability of warming systems to compensate for the victim's estimated heat loss in a simulated mountain rescue operation. We used thermal manikins and developed a thermodynamic model of a virtual patient. Manikins were placed on a mountain rescue stretcher and exposed to wind chill indices of 0 °C and - 20 °C in a climatic chamber. We calculated the heat balance for two simulated clinical scenarios with both a shivering and non-shivering victim and measured the heat gain from gel, electrical, and chemical warming systems for 3.5 h. The heat balance in the simulated shivering patient was positive. In the non-shivering patient, we found a negative heat balance for both simulated weather conditions (- 429.53 kJ at 0 °C and - 1469.78 kJ at - 20 °C). Each warming system delivered about 300 kJ. The efficacy of the gel and electrical systems was higher within the first hour than later (p < 0.001). We conclude that none of the tested warming systems is able to compensate for heat loss in a simulated model of a non-shivering patient whose physiological heat production is impaired during a prolonged mountain evacuation. Additional thermal insulation seems to be required in these settings.

Cold weather is independently associated with hypothermia in severely injured trauma patients

Introduction

Hypothermia at admission in trauma patients has been significantly associated with worse outcomes and increased blood usage. Previous studies have found variably significant associations between ambient temperatures and incidence of hypothermia in trauma patients.

Methods

The trauma quality improvement registry was queried for data on trauma patients admitted direct from the scene over a 5-year period. This database was matched to daily weather data taken from the nearest National Oceanic and Atmospheric Administration land-based climate monitoring center, and further combined with blood usage data from the laboratory information system.

Results

Multivariate logistic regression models predicted significant associations between ambient temperature and patient admission temperature for severely injured patients. No significant direct associations were predicted between ambient temperature and in-hospital mortality or blood usage. Models predicted a significant association between decreased admission temperature and increased likelihood of both blood transfusion and mortality for a severely injured subgroup.

Conclusions

Ambient temperature is a significant contributor to the rate of admission hypothermia in trauma patients. Most of the variability in admission temperatures for severely injured trauma patients remains unaccounted for by models using standard markers of anatomic and physiologic severity. Decreasing admission temperature is significantly associated with increased mortality and likelihood of blood transfusion for severely injured patients.

The Impact of Accidental Hypothermia on Mortality in Trauma Patients Overall and Patients with Traumatic Brain Injury Specifically: A Systematic Review and Meta-Analysis

Background

Accidental hypothermia is a known predictor for worse outcomes in trauma patients, but has not been comprehensively assessed in a meta-analysis so far. The aim of this systematic review and meta-analysis was to investigate the impact of accidental hypothermia on mortality in trauma patients overall and patients with traumatic brain injury (TBI) specifically.

Methods

This is a systematic review and meta-analysis using the Ovid Medline/PubMed database. Scientific articles reporting accidental hypothermia and its impact on outcomes in trauma patients were included in qualitative synthesis. Studies that compared the effect of hypothermia vs. normothermia at hospital admission on in-hospital mortality were included in two meta-analyses on (1) trauma patients overall and (2) patients with TBI specifically. Meta-analysis was performed using a Mantel–Haenszel random-effects model.

Results

Literature search revealed 264 articles. Of these, 14 studies published 1987–2018 were included in the qualitative synthesis. Seven studies qualified for meta-analysis on trauma patients overall and three studies for meta-analysis on patients with TBI specifically. Accidental hypothermia at admission was associated with significantly higher mortality both in trauma patients overall (OR 5.18 [95% CI 2.61–10.28]) and patients with TBI specifically (OR 2.38 [95% CI 1.53–3.69]).

Conclusions

In the current meta-analysis, accidental hypothermia was strongly associated with higher in-hospital mortality both in trauma patients overall and patients with TBI specifically. These findings underscore the importance of measures to avoid accidental hypothermia in the prehospital care of trauma patients.

Electronic supplementary material

The online version of this article (10.1007/s00268-020-05750-5) contains supplementary material, which is available to authorized users.

Cabin temperature during prehospital patient transport - a prospective observational study

Background

Few studies have investigated the patient compartment temperatures during ambulance missions or its relation to admission hypothermia. Still hypothermia is a known risk factor for increased mortality and morbidity in both trauma and disease. This has special relevance to our sub-arctic region’s pre-hospital services, and we prospectively studied the environmental temperature in the patient transport compartment in both ground and air ambulances.

Methods

We recorded cabin temperature during patient transport in two ground ambulances and one ambulance helicopter in the catchment area of the University Hospital of North Norway using automatic temperature loggers. The data were collected for one month in each of the four seasons. We calculated the sum of degrees Celsius below 18 min by minute to describe the patient exposure to unfavourably low cabin temperature, and present the data as box plots. The statistical differences between transport mode and season were analysed with ANCOVA.

Results

The recorded cabin temperatures were higher during the summer than the other three seasons. However, we also found that helicopter transports were performed at lower cabin temperatures and with significantly more exposure to unfavourably low temperatures than the ground ambulance transports. Furthermore, the helicopter cabin reached the final temperature much slower than the ground ambulance cabins did or remained at a lower than comfortable temperature.

Conclusions

Helicopter cabin temperature during ambulance missions should be monitored closer, particularly for patients at risk for developing admission hypothermia.

The impact of hypothermia on outcomes in massively transfused patients

BACKGROUND

Hypothermia is associated with poor outcomes after injury. The relationship between hypothermia during contemporary large volume resuscitation and blood product consumption is unknown. We evaluated this association, and the predictive value of hypothermia on mortality.

METHODS

Patients predicted to receive massive transfusion at 12 level 1 trauma centers were randomized in the Pragmatic Randomized Optimal Platelet and Plasma Ratios (PROPPR) trial and were grouped into those who were hypothermic (<36°C) or normothermic (36-38.5°C) within the first 6 hours of emergency department arrival. The impact of hypothermia or normothermia on the volume of blood product required during the first 24 hours was determined via negative binomial regression, adjusting for treatment arm, injury severity score, mechanism, demographics, pre-emergency department fluid volume, blood administered before becoming hypothermic, pulse and systolic blood pressure on arrival, and the time exposed to hypothermic or normothermic temperatures.

RESULTS

Of 680 patients, 590 had a temperature measured during the first 6 hours in hospital, and 399 experienced hypothermia. The mean number of red blood cell (RBC) units given to all patients in the first 24 hours of admission was 8.8 (95% confidence interval [CI], 7.9-9.6). In multivariable analysis, every 1°C decrease in temperature below 36.0°C was associated with a 10% increase (incidence rate ratio, 0.90; 95% CI, 0.89-0.92; p < 0.00) in consumption of RBCs during the first 24 hours of admission. There was no association between RBC administration and a temperature above 36°C. Hypothermia on arrival was an independent predictor of mortality, with an adjusted odds ratio of 2.7 (95% CI, 1.7-4.5; p < 0.00) for 24-hour mortality and 1.8 (95% CI, 1.3-2.4; p < 0.00) for 30-day mortality.

CONCLUSION

Hypothermia is associated with increase in blood product consumption and mortality. These findings support the maintenance of normothermia in trauma patients and suggest that further investigation on the impact of cooling or rewarming during massive transfusion is warranted.

LEVEL OF EVIDENCE

Prognostic, level III.

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.

Wilderness Medical Society Clinical Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia: 2019 Update

To provide guidance to clinicians, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and a balance between benefits and risks/burdens according to the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations. This is the 2019 update of the Wilderness Medical Society Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia: 2014 Update.

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.

Impact of Accidental Hypothermia on Pulmonary Complications in Multiply Injured Patients With Blunt Chest Trauma - A Matched-pair Analysis

BACKGROUND/AIM

Blunt chest trauma is one of the major injuries in multiply injured patients and is associated with an increased risk of acute respiratory distress syndrome (ARDS) and ventilator-associated pneumonia (VAP). Accidental hypothermia is a common accompaniment of multiply injured patients. The objective of this study was to analyze the influence of accidental hypothermia on pulmonary complications in multiply injured patients with blunt chest trauma.

PATIENTS AND METHODS

Multiply injured patients [injury severity score (ISS) ≥16] with severe blunt chest trauma [abbreviated injury scale of the chest (AISchest) ≥3] were analyzed. Hypothermia was defined as body core temperature <35°C. The primary endpoint was the development of ARDS and VAP. Propensity score matching was performed.

RESULTS

Data were analyzed for 238 patients, with a median ISS of 26 (interquartile range=12). A total of 67 patients (28%) were hypothermic on admission. Hypothermic patients were injured more severely (median ISS 34 vs. 24, p<0.001) and had a higher transfusion requirement (p<0.001). Their mortality rate was consequently increased (10% vs. 1%, p=0.002); After propensity score matching, the mortality rate was still higher (10% vs. 2%, p=0.046). However, hypothermia was not an independent predictor of mortality. Hypothermic patients had to be ventilated longer (p=0.02). However, there were no differences in occurrence of ARDS and VAP. Hypothermia was not identified as an independent predictor of ARDS and VAP.

CONCLUSION

Among multiply injured patients with severe blunt chest trauma, accidental hypothermia is not an independent predictor of ARDS and VAP and is more likely to be an accompaniment of injury severity and hemorrhage.

Time course of platelet counts in relation to the neurologic outcome in patients undergoing targeted temperature management after cardiac arrest

BACKGROUND

Thrombocytopenia is common and associated with mortality in critically ill patients. However, the time course of platelet counts and its association with the neurologic outcome after out-of-hospital cardiac arrest (OHCA) are not well known. The purpose of this study is to describe the time course of platelet counts in relation to the neurologic outcome in patients undergoing targeted temperature management (TTM) after CA.

METHODS

Review of consecutive patients receiving TTM after out-of-hospital CA between 2009 and 2016. The blood sample was collected daily until 7 days. The primary outcome was poor neurologic outcome at 6 months after CA defined as Cerebral Performance Category of 3-5 and secondary outcome was mortality at 6 months.

RESULTS

A total of 261 consecutive patients treated with TTM after OHCA between 2009 and 2016. One hundred seventy-five patients (67.0%) had poor neurologic outcomes 6 months after CA. The changes in the platelet counts over time between the good and poor outcome groups were statistically significant (p < 0.001). The platelet counts declined during TTM in both groups. The platelet counts recovered to the normal range at the end of the first week in the good neurologic outcome group. However, the platelet counts remained low in the poor outcome group. Low platelet counts on the 7th day were associated with poor neurologic outcomes (aOR 0.975, 95% CI, 0.961-0.989) and mortality at 6 months (aOR 0.986, 95% CI, 0.975-0.997) after adjusting for covariates.

CONCLUSION

The changes in platelet counts in OHCA patients have a biphasic pattern that is significantly different in patients with good neurologic outcomes and those with poor neurologic outcomes at 6 months. A low platelet count 7 days after CA was associated with a poor neurologic outcome and mortality at 6 months.

Mild hypothermia is associated with improved outcomes in patients undergoing microvascular head and neck reconstruction

OBJECTIVE

Microvascular free tissue transfer has become the standard for reconstruction for large defects. With long operative times and an increased surface area exposed, transient hypothermia is common, but it is unclear how this impacts surgical outcomes. This study evaluated the impact of core body temperature on free tissue flap outcomes in patients undergoing microvascular reconstruction.

STUDY DESIGN

Retrospective data analysis.

SETTING

Mount Sinai Hospital; NYC, NY; 2007-2016.

SUBJECTS AND METHODS

Demographic information, mean/minimum/maximum body temperatures, and the presence of flap complications (venous thrombosis, arterial insufficiency, flap death, wound infection/dehiscence, fistula, chyle leak, hematoma/seroma) of 519 free tissue transfer patients were documented. Binomial logistic regression was used to examine associations between the presence of flap complications and mean temperature. Statistical analysis used SPSS, with p-values ≤0.05 deemed statistically significant.

RESULTS

393 soft-tissue and 125 osteocutaneous flaps were included. 19.8% (n = 103) patients had the presence of ≥1 flap complication, while 80.2% (n = 416) did not. Average temperature for all patients was 36.12 ± 0.84 °C, with minimum at 34.43 ± 0.97 °C and maximum at 37.24 ± 1.23 °C. After controlling for several factors including: tumor stage, radiation, diabetes, BMI, age, sex, and flap type, there was a significant association between flap complications and mean intraoperative temperature (Exp(B) = 1.559, p = 0.004).

CONCLUSION

Higher intraoperative temperatures were associated with worse outcomes. A mild relative hypothermia may improve flap outcomes in this population. This represents the largest study to date evaluating the impact of intraoperative temperature on free tissue transfer outcomes.

Predictors of Hypothermia upon Trauma Center Arrival in Severe Trauma Patients Transported to Hospital via EMS

Introduction: Hypothermia in severe trauma patients can increase mortality by 25%. Active warming practices decrease mortality and are recommended in the Advanced Trauma Life Support (ATLS) guidelines. Despite this, many emergency medical services (EMS) vehicles do not carry equipment necessary to perform active warming. The intent of this study was to determine the rate of hypothermia in severe trauma patients upon major trauma center (MTC) arrival, as well as to characterize factors associated with hypothermia in trauma in order to devote potential resources to those at highest risk. Methods: This single-center retrospective chart review included adults (age ≥ 18) in the local trauma registry (trauma team activation or injury severity score ≥12) from January 2009 to June 2016. Logistic regression was used to identify predictors of hypothermia on MTC arrival. Results: A total of 3,070 patient charts were reviewed, of which 159 (5.2%) were hypothermic. Multivariate logistic regression identified 7 factors that were significantly associated with hypothermia on MTC arrival in severe trauma. Risk factors for hypothermia on MTC arrival after severe trauma included: intubation pre-MTC, increased number of co-morbidities, and increased injury severity. Conversely, protective factors against hypothermia were: higher initial systolic blood pressure (SBP), penetrating injury, referral to MTC, and higher ambient outdoor temperatures. Median length of stay in hospital was 7 days for hypothermic patients compared to 4 days for normothermic patients (Δ 3 days; p < 0.001). Only 69.2% of hypothermic patients survived to discharge compared to 93.9% of normothermic patients (Δ 24.7%; χ² = 133.4, p < 0.001). Conclusions: This retrospective study of hypothermia in major trauma patients found a rate of hypothermia of 5%. Factors associated with higher risk of hypothermia include pre-MTC intubation, high ISS, multiple comorbidities, low SBP, non-penetrating mechanism of injury, and being transferred directly to MTC, and colder outdoor temperature. Avoidance of hypothermia is imperative to the management of major trauma patients. Prospective studies are required to determine if prehospital warming in these high-risk patients decreases the rate of hypothermia in major trauma and improves patient outcomes.

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.

Prehospital and Emergency Care in Adult Patients with Acute Traumatic Brain Injury

Traumatic brain injury (TBI) is a major healthcare problem and a major burden to society. The identification of a TBI can be challenging in the prehospital setting, particularly in elderly patients with unobserved falls. Errors in triage on scene cannot be ruled out based on limited clinical diagnostics. Potential new mobile diagnostics may decrease these errors. Prehospital care includes decision-making in clinical pathways, means of transport, and the degree of prehospital treatment. Emergency care at hospital admission includes the definitive diagnosis of TBI with, or without extracranial lesions, and triage to the appropriate receiving structure for definitive care. Early risk factors for an unfavorable outcome includes the severity of TBI, pupil reaction and age. These three variables are core variables, included in most predictive models for TBI, to predict short-term mortality. Additional early risk factors of mortality after severe TBI are hypotension and hypothermia. The extent and duration of these two risk factors may be decreased with optimal prehospital and emergency care. Potential new avenues of treatment are the early use of drugs with the capacity to decrease bleeding, and brain edema after TBI. There are still many uncertainties in prehospital and emergency care for TBI patients related to the complexity of TBI patterns.

Concept of Lethal Triad in Critical Care of Severe Burn Injury

Background

The trinity of hypothermia, acidosis and coagulopathy, the lethal triad in trauma setting is a well-known risk factor associated with high risk of death. Burn is also a pathological situation where inflammatory response, endothelial injury, hypovolemia, reduced end-organ perfusion, cellular hypoxia, and myocardial depression are frequently encountered. This study aimed to study the occurrence and outcome of patients presenting with the ‘triad of death’ in burn population.

Methods

The study population included patients between 18 years and 60 years presenting to the department with thermal and scald burns with total body surface area involving 50–70%. The study was conducted for a period of 180 days and patients were followed up for 30 days. A p value <0.05 was considered statistically significant.

Results

One hundred and ninety-six patients were admitted during study period. Fifty patients out of them were eligible and were included in the study. The average abbreviated burns score index was 11 in lethal triad subgroup when compared to eight in the subgroup without the lethal triad. The mortality in the subgroup with lethal triad was higher (68.8% vs 17.6%, p = 0.0009). The “on admission” acidosis, hypothermia, and coagulopathy were independently associated with significantly increased mortality. The overall relative risk of mortality in the presence of lethal triad was 3.896.

Conclusion

This study reiterates the fact that the lethal triad is seen in burn patient. Burn associated with on admission lethal triad has significantly higher mortality rates. There are only countable studies addressing this issue in burn setting.

How to cite this article

Muthukumar V, Karki D, Jatin B. Concept of Lethal Triad in Critical Care of Severe Burn Injury. Indian J Crit Care Med 2019;23(5):206-209.

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.

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.

Guiding Management in Severe Trauma: Reviewing Factors Predicting Outcome in Vastly Injured Patients

Trauma is one of the leading causes of death worldwide, with road traffic collisions, suicides, and homicides accounting for the majority of injury-related deaths. Since trauma mainly affects young age groups, it is recognized as a serious social and economic threat, as annually, almost 16,000 posttrauma individuals are expected to lose their lives and many more to end up disabled. The purpose of this research is to summarize current knowledge on factors predicting outcome - specifically mortality risk - in severely injured patients. Development of this review was mainly based on the systematic search of PubMed medical library, Cochrane database, and advanced trauma life support Guiding Manuals. The research was based on publications between 1994 and 2016. Although hypovolemic, obstructive, cardiogenic, and septic shock can all be seen in multi-trauma patients, hemorrhage-induced shock is by far the most common cause of shock. In this review, we summarize current knowledge on factors predicting outcome - more specifically mortality risk - in severely injured patients. The main mortality-predicting factors in trauma patients are those associated with basic human physiology and tissue perfusion status, coagulation adequacy, and resuscitation requirements. On the contrary, advanced age and the presence of comorbidities predispose patients to a poor outcome because of the loss of physiological reserves. Trauma resuscitation teams considering mortality prediction factors can not only guide resuscitation but also identify patients with high mortality risk who were previously considered less severely injured.

Reanimating Patients After Traumatic Cardiac Arrest: A Practical Approach Informed by Best Evidence

Resuscitation of traumatic cardiac arrest is typically considered futile. Recent evidence suggests that traumatic cardiac arrest is survivable. In this article key principles in managing traumatic cardiac arrest are discussed, including the importance of rapidly seeking prognostic information, such as signs of life and point-of-care ultrasonography evidence of cardiac contractility, to inform the decision to proceed with resuscitative efforts. In addition, a rationale for deprioritizing chest compressions, steps to quickly reverse dysfunctional ventilation, techniques for temporary control of hemorrhage, and the importance of blood resuscitation are discussed. The best available evidence and the authors' collective experience inform this article.

The Evolving Science of Trauma Resuscitation

This review summarizes the evolution of trauma resuscitation from a one-size-fits-all approach to one tailored to patient physiology. The most dramatic change is in the management of actively bleeding patients, with a balanced blood product-based resuscitation approach (avoiding crystalloids) and surgery focused on hemorrhage control, not definitive care. When hemostasis has been achieved, definitive resuscitation to restore organ perfusion is initiated. This approach is associated with decreased mortality, reduced duration of stay, improved coagulation profile, and reduced crystalloid/vasopressor use. This article focuses on the tools and methods used for trauma resuscitation in the acute phase of trauma care.

Protection against cold - a survey of available equipment in Swedish pre-hospital services

BACKGROUND

The aim of this study was to survey the current equipment used for prevention, treatment and monitoring of accidental hypothermia in Swedish pre-hospital services.

METHODS

A questionnaire was sent to all road ambulance services (AS), the helicopter emergency medical services (HEMS), the national helicopter search and rescue service (SAR) and the municipal rescue services (RS) in Sweden to determine the availability of insulation, active warming, fluid heating, and low-reading thermometers.

RESULTS

The response rate was 77% (n = 255). All units carried woollen or polyester blankets for basic insulation. Specific windproof insulation materials were common in the HEMS, SAR and RS units but only present in about half of the AS units. Active warming equipment was present in all the SAR units, but only in about two-thirds of the HEMS units and about one-third of the AS units. About half of the RS units had the ability to provide a heated tent or container. Low-reading thermometers were present in less than half of the AS and HEMS units and were non-existent in the SAR units. Pre-warmed intravenous fluids were carried by almost all of the AS units and half of the HEMS units but infusion heaters were absent in most units.

CONCLUSION

Basic insulation capabilities are well established in the Swedish pre-hospital services. Specific wind and waterproof insulation materials, active warming devices, low-reading thermometers and IV fluid heating systems are less common. We suggest the development and implementation of national guidelines on accidental hypothermia that include basic recommendations on equipment requirements.

Epidemiology and outcomes of children with accidental hypothermia: A propensity-matched study

BACKGROUND

The purpose of this study was to explore the epidemiology and outcomes of hospitalized children with a diagnosis of accidental hypothermia.

METHODS

The 2012 Kids' Inpatient Database, detailing discharge diagnoses in children admitted to US hospitals, was analyzed using International Classification of Diseases, Ninth Revision, Clinical Modification codes to filter out relevant patients. Children ages 1 month to 17 years were included in the analysis. Demographic and outcome variables in the hypothermia group were compared with the rest of the patients. In a separate analysis, children with hypothermia were matched 1:1 using a correlative propensity score using sex, age, hospital region, income quartiles, race, ventilation status, coagulopathy, drowning, and All Patient Refined Diagnosis Related Groups severity score and their outcomes were compared with controls. The sample data were weighted to get a national estimate.

RESULTS

Accidental hypothermia was present in 1,028 cases out of 1,915,435 discharges. Children with hypothermia were more likely to be males (54.7% vs. 50.9%; p < 0.05) and infants (32.6% vs. 17.5%); they were less likely to be teens (30% vs. 37.8%). Children with hypothermia were more likely to be admitted in the Southern region (48.3% vs. 38.4%; p < 0.05) and have a higher mortality rate compared to all other discharges (8.5% vs. 0.3%; p < 0.05) or when compared with the matched controls (8.9% vs. 4.4%).

CONCLUSIONS

The diagnosis of accidental hypothermia significantly increased mortality in hospitalized children. Interestingly, accidental hypothermia was more common in Southern states compared to the other areas of the United States.

LEVEL OF EVIDENCE

Prognostic/epidemiological study, level III.

Body Temperature after EMS Transport: Association with Traumatic Brain Injury Outcomes

INTRODUCTION

Low body temperatures following prehospital transport are associated with poor outcomes in patients with traumatic brain injury (TBI). However, a minimal amount is known about potential associations across a range of temperatures obtained immediately after prehospital transport. Furthermore, a minimal amount is known about the influence of body temperature on non-mortality outcomes. The purpose of this study was to assess the correlation between temperatures obtained immediately following prehospital transport and TBI outcomes across the entire range of temperatures.

METHODS

This retrospective observational study included all moderate/severe TBI cases (CDC Barell Matrix Type 1) in the pre-implementation cohort of the Excellence in Prehospital Injury Care (EPIC) TBI Study (NIH/NINDS: 1R01NS071049). Cases were compared across four cohorts of initial trauma center temperature (ITCT): <35.0°C [Very Low Temperature (VLT)]; 35.0-35.9°C [Low Temperature (LT)]; 36.0-37.9°C [Normal Temperature (NT)]; and ≥38.0°C [Elevated Temperature (ET)]. Multivariable analysis was performed adjusting for injury severity score, age, sex, race, ethnicity, blunt/penetrating trauma, and payment source. Adjusted odds ratios (aORs) with 95% confidence intervals (CI) for mortality were calculated. To evaluate non-mortality outcomes, deaths were excluded and the adjusted median increase in hospital length of stay (LOS), ICU LOS and total hospital charges were calculated for each ITCT group and compared to the NT group.

RESULTS

22,925 cases were identified and cases with interfacility transfer (7361, 32%), no EMS transport (1213, 5%), missing ITCT (2083, 9%), or missing demographic data (391, 2%) were excluded. Within this study cohort the aORs for death (compared to the NT group) were 2.41 (CI: 1.83-3.17) for VLT, 1.62 (CI: 1.37-1.93) for LT, and 1.86 (CI: 1.52-3.00) for ET. Similarly, trauma center (TC) LOS, ICU LOS, and total TC charges increased in all temperature groups when compared to NT.

CONCLUSION

In this large, statewide study of major TBI, both ETs and LTs immediately following prehospital transport were independently associated with higher mortality and with increased TC LOS, ICU LOS, and total TC charges. Further study is needed to identify the causes of abnormal body temperature during the prehospital interval and if in-field measures to prevent temperature variations might improve outcomes.

Hypothermia in trauma victims at first arrival of ambulance personnel: an observational study with assessment of risk factors

Background

Hypothermia is common in trauma victims and is associated with increased mortality, however its causes are little known. The objective of this study was to identify the risk factors associated with hypothermia in prehospital management of trauma victims.

Methods

This was an ancillary analysis of data recorded in the HypoTraum study, a prospective multicenter study conducted by the emergency medical services (EMS) of 8 hospitals in France. Inclusion criteria were: trauma victim, age over 18 years, and victim receiving prehospital care from an EMS team and transported to hospital by the EMS team in a medically equipped mobile intensive care unit. The following data were recorded: victim demographics, circumstances of the trauma, environmental factors, patient presentation, clinical data and time from accident to EMS arrival. Independent risk factors for hypothermia were analyzed in a multivariate logistic regression model.

Results

A total of 461 trauma patients were included in the study. Road traffic accidents (N = 261; 57%) and falls (N = 65; 14%) were the main causes of trauma. Hypothermia (<35 °C) was present in 136/461 cases (29%). Independent factors significantly associated with the presence of hypothermia were: a low GCS (Odds Ratio (OR) = 0,87 ([0,81-0,92]; p < 0.0001), a low air temperature (OR = 0,93 [0,91-0,96]; p < 0.0001) and a wet patient (OR = 2,08 [1,08-4,00]; p = 0.03).

Conclusion

The incidence of hypothermia was high on EMS arrival at the scene. Body temperature measurement and immediate thermal protection should be routine, and special attention should be given to patients who are wet.

Level of evidence

Prospective, multicenter, open, observational study; Level IV.

Hypothermia and near-drowning associated with life-threatening injuries: A remarkable recovery: A case report

A young male suffered multiple severe injuries after a fall and near-drowning. On presentation to the emergency department (ED), he was in a critical and unstable condition and his chances of survival were deemed very low. This case illustrates the management of the hypothermic multi-trauma patient and the remarkable recovery made possible by a high standard of care.

Hypothermia as a predictor for mortality in trauma patients at admittance to the Intensive Care Unit

Aims:

To study the impact of hypothermia upon admission to the Intensive Care Unit (ICU) on early and late mortality and to develop a prediction model for late mortality in severely injured trauma patients.

Materials and Methods:

A multicenter retrospective cohort study was performed in adult trauma patients admitted to the ICU of two Level-1 trauma centers between 2007 and 2012. Hypothermia was defined as a core body temperature of ≤35° Celsius. Logistic regression analyses were performed to quantify the effect of hypothermia on 24-hour and 28-day mortality and to develop a prediction model.

Results:

A total of 953 patients were included, of which 354 patients had hypothermia (37%) upon ICU admission. Patients were divided into a normothermic or hypothermic group. Hypothermia was associated with a significantly increased mortality at 24 hours and 28 days (OR 2.72 (1.18-6.29 and OR 2.82 (1.83-4.35) resp.). The variables included in the final prediction model were hypothermia, age, APACHE II score (corrected for temperature), INR, platelet count, traumatic brain injury and Injury Severity Score. The final prediction model discriminated between survivors and non-survivors with high accuracy (AUC = 0.871, 95% CI 0.844-0.898).

Conclusions:

Hypothermia, defined as a temperature ≤35° Celsius, is common in critically ill trauma patients and is one of the most important physiological predictors for early and late mortality in trauma patients. Trauma patients admitted to the ICU may be at high risk for late mortality if the patient is hypothermic, coagulopathic, severely injured and has traumatic brain injury or an advanced age.