Epidemiology of accidental hypothermia in polytrauma patients: An analysis of 15,230 patients of the TraumaRegister DGU

Development and Internal Validation of a Risk Model to Estimate Probability of Intraoperative Hypothermia in Adult Surgical Patients

Intraoperative hypothermia is associated with various perioperative complications and an increased risk of mortality. This study aims to develop and validate a reliable risk model, the Intraoperative Hypothermia Risk Estimating Model (IHREM), for assessing the likelihood of intraoperative hypothermia in adult patients receiving different types of surgery and anesthesia. Data from 1815 surgical patients were collected, with 1521 used to develop the IHREM training set. Univariate logistic regression was utilized to evaluate the parameters included in the study. For the first time, parameters showing non-linear associations with the risk of intraoperative hypothermia were evaluated and then incorporated into a primary model using restricted cubic splines (RCS), based on the result of multivariate logistic regression. The final model was comprised of 12 risk factors, including body mass index (BMI), fasting time, preoperative heart rate, preoperative tympanic temperature, intravenous fluid administration volume, intraoperative irrigation volume, estimated blood loss, duration of anesthesia, surgical position, intraoperative warming, operation room temperature, and humidity. The IHREM model demonstrated satisfactory performance in the training set, exhibiting reliable discrimination, calibration, overall performance, and clinical utility. In the temporal validation set (n = 294), the c-index, calibration intercept and calibration slope, Brier score, and R2 were determined to be 0.763 (95% CI, 0.710-0.819), 0.394 (95% CI, 0.118-0.680), 0.865 (95% CI, 0.638-1.114), 0.204 (95% CI, 0.180-0.229), and 0.236, respectively. Meanwhile, decision curve analysis and clinical impact curve showed that IHREM provides promising clinical value. In addition, RCS analysis indicated that maintaining the operation room temperature above 20°C is sufficient to prevent hypothermia while increasing or sustaining the preoperative core temperature to around 36.7-36.8°C significantly reduces the risk of hypothermia. IHREM holds promise as a valuable tool for identifying adult patients at risk of intraoperative hypothermia under various types of surgery and anesthesia, thereby supporting clinical decision-making.

Maintenance of normothermia in the out-of-hospital setting: A pilot comparative crossover study of a foil blanket versus self-warming blanket

INTRODUCTION

Hypothermia can increase mortality in certain patients. Paramedics apply cotton and foil "space" blankets for warming, yet their effectiveness remains uncertain. This pilot study aimed to evaluate combining cotton blankets with a self-warming blanket versus a combination of cotton blankets and a foil blanket in an out-of-hospital simulation.

METHODS

Eight participants were allocated to warming with either two cotton blankets and one foil blanket, or two cotton blankets and one self-warming blanket, with the alternate method applied in a subsequent session. Participants were cooled using an ice-vest and fan until shivering onset, after which the warming method was applied. Simulation involved transitioning through three environments: baseline (22 °C), cooling/warming (16 °C), and "ambulance" (27 °C). Core temperature was monitored via oesophageal probe, skin temperature via thermistors (recorded every minute), and tympanic temperature and thermal sensation and comfort were recorded five minutely.

RESULTS

There were minor differences in thermal sensation. For the primary outcome there was no significant difference between blanket methods (core: foil 36.98 ± 0.08 °C vs. self-warming 36.95 ± 0.10 °C, P > 0.05).

CONCLUSION

The combination of cotton and self-warming blankets did not exhibit superiority compared to cotton and foil blankets in out-of-hospital simulation. Future research should explore alternative warming methodologies to optimise normothermia maintenance.

Hypothermia on admission predicts poor outcomes in adult trauma patients

BACKGROUND

Hypothermia is known to contribute to poor outcomes in trauma patients during acute phases. The aim of our study is to evaluate the effect of hypothermia on admission, upon in-hospital complications and mortality in adult trauma patients.

METHODS

We performed a 5-year analysis of ACS-TQIP database (2017-2021). Patients with incomplete data, burns, inter-facility transfers, or documented as dead on arrival were excluded. Hypothermia (HT) was defined as a temperature of <35 degrees Celsius (°C), and Normothermia (NT) as ≥35 °C to≤40 °C measured at the time of patient arrival. Data were collected including demographic variables, mechanism of injury, injury severity, injury patterns, and shock index. Outcome variables were mortality, ICU length of stay (LOS), duration of mechanical ventilation, hospital LOS, and in-hospital complications. Multivariable regression analysis was performed.

RESULTS

A total of 3,043,030 patients were included and 1 % were hypothermic. HT patients were severely injured, developed in-hospital complications (17.1 %vs.4.5 %), had longer ICU LOS (4 (2-9) vs. 3 (2-5) days), hospital LOS (5 (2-12) vs. 4 (2-6) days), and higher mortality (23.4 % vs. 2.3 %). Hypothermia was independently associated with higher odds of mortality (OR:1.934 [1.858-2.013]). Subgroup analysis of patients with isolated traumatic brain injury revealed pre-hospital hypothermia to still be an independent predictor of mortality (OR: 1.728[1.600-1.867]). HT who underwent rewarming had a lower mortality, shorter hospital and ICU LOS.

CONCLUSION

Pre-hospital hypothermia is independently associated with higher resource utilization, in-hospital complications, and mortality. Even in patients with isolated TBI, pre-hospital hypothermia increases the odds of mortality. Rewarming interventions can potentially improve outcomes among patients, even with mild hypothermia.

LEVEL OF EVIDENCE

Level III retrospective study.

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.

Effect of wet clothing removal on skin temperature in subjects exposed to cold and wrapped in a vapor barrier: a human, randomized, crossover field study

BACKGROUND

Prehospital care for cold-stressed and hypothermic patients focuses on effective insulation and rewarming. When encountering patients wearing wet clothing, rescuers can either remove the wet clothing before isolating the patient or isolate the patient using a vapor barrier. Wet clothing removal increases skin exposure but avoids the need to heat the wet clothing during rewarming. Leaving wet clothing on will avoid skin exposure but is likely to increase heat loss during rewarming. This study aimed to evaluate the effect of wet clothing removal compared to containing the moisture using a vapor barrier on skin temperature in a prehospital setting.

METHODS

This randomized crossover experimental field study was conducted in a snow cave in Hemsedal, Norway. After an initial cooling phase of 30 min while wearing wet clothes, the participants were subjected to one of two rewarming scenarios: (1) wet clothing removal and wrapping in a vapor barrier, insulating blankets, and windproof outer shell (dry group) or (2) wrapping in a vapor barrier, insulating blankets, and windproof outer shell (wet group). The mean skin temperature was the primary outcome whereas subjective scores for both thermal comfort and degree of shivering were secondary outcomes. Primary outcome data were analyzed using the analysis of covariance (ANCOVA).

RESULTS

After an initial decrease in temperature during the exposure phase, the dry group had a higher mean skin temperature compared to the wet group after only 2 min. The skin-rewarming rate was highest in the initial rewarming stages for both groups, but increased in the dry group as compared to the wet group in the first 10 min. Return to baseline temperature occurred significantly faster in the dry group (mean 12.5 min [dry] vs. 28.1 min [wet]). No intergroup differences in the subjective thermal comfort or shivering were observed.

CONCLUSION

Removal of wet clothing in combination with a vapor barrier increases skin rewarming rate compared to encasing the wet clothing in a vapor barrier, in mild cold and environments without wind.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT05996757, retrospectively registered 18/08/2023.

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.

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.

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.

Prevention of Hypothermia in the Aftermath of Natural Disasters in Areas at Risk of Avalanches, Earthquakes, Tsunamis and Floods

Throughout history, accidental hypothermia has accompanied natural disasters in cold, temperate, and even subtropical regions. We conducted a non-systematic review of the causes and means of preventing accidental hypothermia after natural disasters caused by avalanches, earthquakes, tsunamis, and floods. Before a disaster occurs, preventive measures are required, such as accurate disaster risk analysis for given areas, hazard mapping and warning, protecting existing structures within hazard zones to the greatest extent possible, building structures outside hazard zones, and organising rapid and effective rescue. After the event, post hoc analyses of failures, and implementation of corrective actions will reduce the risk of accidental hypothermia in future disasters.

Accidental Hypothermia: 2021 Update

Accidental hypothermia is an unintentional drop of core temperature below 35 °C. Annually, thousands die of primary hypothermia and an unknown number die of secondary hypothermia worldwide. Hypothermia can be expected in emergency patients in the prehospital phase. Injured and intoxicated patients cool quickly even in subtropical regions. Preventive measures are important to avoid hypothermia or cooling in ill or injured patients. Diagnosis and assessment of the risk of cardiac arrest are based on clinical signs and core temperature measurement when available. Hypothermic patients with risk factors for imminent cardiac arrest (temperature < 30 °C in young and healthy patients and <32 °C in elderly persons, or patients with multiple comorbidities), ventricular dysrhythmias, or systolic blood pressure < 90 mmHg) and hypothermic patients who are already in cardiac arrest, should be transferred directly to an extracorporeal life support (ECLS) centre. If a hypothermic patient arrests, continuous cardiopulmonary resuscitation (CPR) should be performed. In hypothermic patients, the chances of survival and good neurological outcome are higher than for normothermic patients for witnessed, unwitnessed and asystolic cardiac arrest. Mechanical CPR devices should be used for prolonged rescue, if available. In severely hypothermic patients in cardiac arrest, if continuous or mechanical CPR is not possible, intermittent CPR should be used. Rewarming can be accomplished by passive and active techniques. Most often, passive and active external techniques are used. Only in patients with refractory hypothermia or cardiac arrest are internal rewarming techniques required. ECLS rewarming should be performed with extracorporeal membrane oxygenation (ECMO). A post-resuscitation care bundle should complement treatment.

Temperature loss by ventilation in a calorimetric bench model

In intensive care medicine heat moisture exchangers are standard tools to warm and humidify ventilation gases in order to prevent temperature loss of patients or airway epithelia damage. Despite being at risk of hypothermia especially after trauma, intubated emergency medicine patients are often ventilated with dry and in winter probably cold ventilation gases. We tried to assess the amount of temperature-loss due to ventilation with cold, dry medical oxygen in comparison to ventilation with warm and humidified oxygen. We ventilated a 50-kg water-dummy representing the calorimetric capacity of a 60-kg patient over a period of 2 hours (tidal volume 6.6 mL/kg = 400 mL; respiratory rate 13/min). Our formal null-hypothesis was that there would be no differences in temperature loss in a 50 kg water-dummy between ventilation with dry oxygen at 10°C vs. ventilation with humidified oxygen at 43°C. After 2 hours the temperature in the water-dummy using cold and dry oxygen was 29.7 ± 0.1°C compared to 30.4 ± 0.1°C using warm and humidified oxygen. This difference in cooling rates between both ventilation attempts of 0.7 ± 0.1°C after 2 hours represents an increased cooling rate of ~0.35°C per hour. Ventilation with cool, dry oxygen using an automated transport ventilator resulted in a 0.35°C faster cooling rate per hour than ventilation with warm humidified oxygen in a bench model simulating calorimetric features of a 60-kg human body.

Epidemiology, Management, and Outcomes of Accidental Hypothermia: A Multicenter Study of Regional Care

BACKGROUND

Hypothermia is an uncommon, potentially life-threatening condition. We hypothesized (1) advanced rewarming techniques were more frequent with increased hypothermia severity, (2) active rewarming is increasingly performed with smaller intravascular catheters and decreased cardiopulmonary bypass, and (3) mortality was associated with age, hypothermia severity, and type.

METHODS

Trauma patients with temperatures <35°C at 4 ACS-verified trauma centers in Wisconsin and Minnesota from 2006 to 2016 were reviewed. Statistical analysis included chi-square and Fisher's exact tests. A P value < .05 was considered significant.

RESULTS

337 patients met inclusion criteria; primary hypothermia was identified in 127 (38%), secondary in 113 (34%), and mixed primary/secondary in 96 (28%) patients. Hypothermia was mild in 69%, moderate in 26%, and severe in 5% of patients. Intravascular rewarming catheter was the most frequent advanced modality (2%), used increasingly since 2014. Advanced techniques were used for primary (12%) vs. secondary (0%) and mixed (5%) (P = .0002); overall use increased with hypothermia severity but varied by institution. Dysrhythmia, acute kidney injury, and frostbite risk worsened with hypothermia severity (P < .0001, P = .031, and P < .0001, respectively). Mortality was greatest in patients with mixed hypothermia (39%, P = .0002) and age >65 years (33%, P = .03). Thirty-day mortality rates were similar among severe, moderate, and mild hypothermia (P = .44).

CONCLUSION

Advanced rewarming techniques were used more frequently in severe and primary hypothermia but varied among institutions. Advanced rewarming was less common in mixed hypothermia; mortality was highest in this subgroup. Reliance on smaller intravascular catheters for advanced rewarming increased over time. Given inconsistencies in management, implementation of guidelines for hypothermia management appears necessary.

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.

Perioperative cardiac arrest and mortality in trauma patients: A systematic review of observational studies

STUDY OBJECTIVE

Factors that influence the occurrence of perioperative cardiac arrest (CA) and its outcomes in trauma patients are not well known. The novelty of our study lies in the performance of a systematic review conducted worldwide on the occurrence of perioperative CA and/or mortality in trauma patients.

DESIGN

A systematic review was performed to identify observational studies that reported the occurrence of CA and/or mortality due to trauma and CA and/or mortality rates in trauma patients up to 24 h postoperatively. We searched the MEDLINE, EMBASE, LILACS and SciELO databases through January 29, 2020.

SETTING

Perioperative period.

MEASUREMENTS

The primary outcomes evaluated were data on the epidemiology of perioperative CA and/or mortality in trauma patients.

MAIN RESULTS

Nine studies were selected, with the first study being published in 1994 and the most recent being published in 2019. Trauma was an important factor in perioperative CA and mortality, with rates of 168 and 74 per 10,000 anesthetic procedures, respectively. The studies reported a higher proportion of perioperative CA and mortality in trauma patients who were males, young adults and adults, patients with American Society of Anesthesiologists (ASA) physical status ≥ III, patients undergoing general anesthesia, and in abdominal or neurological surgeries. Uncontrolled hemorrhage was the main cause of perioperative CA and mortality after trauma. Survival rates after perioperative CA were low.

CONCLUSIONS

Trauma is an important factor in perioperative CA and mortality, especially in young adult and adult males and in patients classified as having an ASA physical status ≥ III mainly due to uncontrollable bleeding after blunt and perforating injuries. Trauma is a global public health problem and has a strong impact on perioperative morbidity and mortality.

Hypothermie accidentelle

L’hypothermie accidentelle est définie comme une baisse non intentionnelle de la température centrale du corps en dessous de 35 °C. La prévention de l’hypothermie est essentielle. La mesure de la température centrale est nécessaire au diagnostic d’hypothermie et permet d’en juger la sévérité. En présence de signes de vie, et en présence d’une hypothermie pure, l’instabilité hémodynamique apparente ne devrait en principe pas faire l’objet d’une prise en charge spécifique. Un risque d’arrêt cardiaque (AC) est présent si la température chute en dessous de 30–32 °C. En raison du risque d’AC, un patient hypotherme devrait bénéficier de l’application d’un monitoring avant toute mobilisation, laquelle devra être prudente. En cas d’AC, seule la mesure de la température oesophagienne est fiable. Si l’hypothermie est suspectée comme étant potentiellement responsable de l’AC du patient, celui-ci doit être transporté sous réanimation cardiopulmonaire vers un hôpital disposant d’une méthode de réchauffement par circulation extracorporelle (CEC). La valeur de la kaliémie ainsi que les autres paramètres à disposition (âge, sexe, valeur de la température corporelle, durée du low flow, présence d’une asphyxie) permettront de décider de l’indication d’une CEC de réchauffement. Le pronostic des patients victimes d’un AC sur hypothermie est potentiellement excellent, y compris sur le plan neurologique.

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.

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.

Hypothermia indices among severely injured trauma patients undergoing urgent surgery: A single-centred retrospective quality review and analysis

BACKGROUND

Hypothermia (<36°C) exacerbates trauma-induced coagulopathy and worsens morbidity and mortality among severely injured trauma patients; there is a paucity of published data describing how well trauma centres adhere to standards regarding measurement of temperature, and best practices for preventing and treating hypothermia.

METHODS

We completed a retrospective quality audit of all severely injured trauma patients (Injury Severity Score (ISS≥20)) who had urgent surgery at Sunnybrook Health Sciences Centre (SHSC) between 2010 and 2014. Information regarding temperature monitoring was evaluated over the course of the initial resuscitation and admission. Independent risk factors for in-hospital mortality were elucidated through a multivariable regression analysis.

RESULTS

Out of a total of 4492 trauma patients, 495 were severely-injured and went to the operating room (OPR) after being treated in the trauma bay (TB) at SHSC between 2010 and 2014. The majority of the patients were male (n=384, 77.6%) and had a blunt mechanism of injury (n=391, 79.0%). The median ISS score was 29 (interquartile range (IQR) 26, 35). Eighty-nine (17.9%) patients died; 26 (5.2%) of these patients died intra-operatively. Less than one fifth of patients (n=82,16.6%) received a temperature measurement during pre-hospital transport phase. Upon arrival to the TB, almost two-thirds (n=301, 60.8%) of patients had their temperature recorded and a similar proportion (n=175, 58.1%) of those patients were hypothermic (<36°C). In the OPR, close to 80% (n=389, 78.6%) of patients had their temperature measured on both arrival; almost 60% (n=223, 57.3%) were hypothermic on arrival. Almost all patients had their temperature measured upon arrival to the ICU or specialized ward (n=450, 98.3%). Warming initiatives were documented in only 36 (7.3%) patients in the TB, yet documented in almost all patients in OR (n=464, 93.7%). An increased risk of in-hospital mortality was correlated with not taking a temperature measurement in the TB (Odds Ratio (OR) 2.86 (95% Confidence Interval (CI) [1.64-4.99]) or OPR (OR 4.66 (95% CI [2.50-8.69]).

CONCLUSIONS

A majority of severely injured trauma patients are hypothermic well into the perioperative period after initial admission. An absence of having temperature measurement during initial hospitalization is associated with increased in-hospital mortality amongst this patient group. Quality improvement initiatives should aim to strive for ongoing temperature measurement as a key performance indicator and early prevention and treatment of hypothermia during initial resuscitation.

The current understanding of trauma-induced coagulopathy (TIC): a focused review on pathophysiology

The emergency management of acute severe bleeding in trauma patients has changed significantly in recent years. In particular, greater attention is now being devoted to a prompt assessment of coagulation alterations, which allows for immediate haemostatic resuscitation procedures when necessary. The importance of an early trauma-induced coagulopathy (TIC) diagnosis has led physicians to increase the efforts to better understand the pathophysiological alterations observed in the haemostatic system after traumatic injuries. As yet, the knowledge of TIC is not exhaustive, and further studies are needed. The aim of this review is to gather all the currently available data and information in an attempt to gain a better understanding of TIC. A comprehensive literature search was performed using MEDLINE database. The bibliographies of relevant articles were screened for additional publications. In major traumas, coagulopathic bleeding stems from a complex interplay among haemostatic and inflammatory systems, and is characterized by a multifactorial dysfunction. In the abundance of biochemical and pathophysiological changes occurring after trauma, it is possible to discern endogenously induced primary predisposing conditions and exogenously induced secondary predisposing conditions. TIC remains one of the most diagnostically and therapeutically challenging condition.