Risk factors for onset of hypothermia in trauma victims: the HypoTraum study

Thermal insulation does not hamper assessment of injuries in trauma CT scans

PURPOSE

The use of thermal insulations reduces the risk of hypothermia, therefore decreases the risk of death in trauma victims. The aim of the study was to assess whether thermal insulations cause artifacts, which may hinder the diagnosis of injuries, and how the used thermo-systems alter the radiation dose in polytrauma computed tomography.

METHODS

Computed tomography scans were made using the road accident victim body wrapped consecutively with 7 different covers. 14 injury areas were listed and evaluated by 22 radiologists. The radiation dose was measured using a dosimeter placed on the victim in the abdominal area.

RESULTS

No significant artifacts in any of the tested covers were observed. The presence of few minor artifacts did not hinder the assessment of injuries. Certain materials increased (up to 19,1%) and some decreased (up to -30,3%) the absorbed radiation dose.

CONCLUSIONS

Thermal insulation systems tested in this study do not cause significant artifacts hindering assessment of injuries in CT scans. Concern for artifacts and increased radiation dose should not be a reason to remove patients' thermal insulation during performing trauma CT-scanning.

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.

Prehospital Active and Passive Warming in Trauma Patients

OBJECTIVE

Hypothermia is common among trauma patients and can lead to a serious rise in morbidity and mortality. This study was performed to investigate the effect of active and passive warming measures implemented in the prehospital phase on the body temperature of trauma patients.

METHODS

In a multicenter, multinational prospective observational design, the effect of active and passive warming measures on the incidence of hypothermia was investigated. Adult trauma patients who were transported by helicopter emergency medical services (HEMS) or ground emergency medical services with an HEMS physician directly from the scene of injury were included. Four HEMS/ground emergency medical services programs from Canada, the United States, and the Netherlands participated.

RESULTS

A total of 80 patients (n = 20 per site) were included. Eleven percent had hypothermia on presentation, and the initial evaluation occurred predominantly within 60 minutes after injury. In-line fluid warmers and blankets were the most frequently used active and passive warming measures, respectively. Independent risk factors for a negative change in body temperature were transportation by ground ambulance (odds ratio = 3.20; 95% confidence interval, 1.06-11.49; P = .03) and being wet on initial presentation (odds ratio = 3.64; 95% confidence interval, 0.99-13.36; P = .05).

CONCLUSION

For adult patients transported from the scene of injury to a trauma center, active and passive warming measures, most notably the removal of wet clothing, were associated with a favorable outcome, whereas wet patients and ground ambulance transport were associated with an unfavorable outcome with respect to temperature.

Traumatisme et température

Le patient traumatisé est exposé à l’hypothermie. La mortalité des traumatisés hypothermes est multipliée par quatre ou cinq. Les interactions de l’hypothermie avec l’hémostase et le système cardiovasculaire sont délétères. Les effets sur la coagulation sont multiples et concourent directement à la surmortalité faisant de l’hypothermie une composante majeure de la « triade létale ». Les causes d’hypothermie chez le patient traumatisé sont multiples : 1) environnementales, le risque augmente quand la température ambiante diminue ; 2) cliniques, le risque augmente avec la gravité ; et aussi 3) thérapeutiques, par exemple par la perfusion de solutés à température ambiante. Une prise en charge optimale repose sur une mesure précoce et un monitorage continu de la température corporelle. L’objectif thérapeutique est de maintenir une température corporelle au moins égale à 36 °C. Limiter le déshabillage du patient, le protéger du froid avec une couverture de survie, l’installer rapidement dans une ambulance chauffée, recourir à des dispositifs de réchauffement actifs, perfuser des solutés réchauffés sont les éléments fondamentaux de la prise en charge d’un patient traumatisé, potentiellement hypotherme.

Prehospital body temperature measurement in trauma patients: A literature review

OBJECTIVES

Accidental hypothermia in trauma patients can contribute to cardiorespiratory dysfunction, acidosis, and coagulopathy, causing increased morbidity and mortality. The early recognition of the clinical signs of hypothermia and the accurate measurement of body temperature by prehospital care providers are essential to avoid deterioration. This review provides an overview of studies that examine the reliability of different core temperature measurement options, with a focus on the prehospital setting.

METHODS

A search was performed in PubMed, Embase, Cochrane Library, and CINAHL using combinations of the Medical Subject Headings terms "ambulances," "emergency medical services," "thermometers," "body temperature," "hypothermia," and "body temperature regulation." Studies up to October 2021 were included, and different measurement options were listed and discussed. Eligible studies included those that identified the specific type of thermometer and focused on the out-of-hospital environment.

RESULTS

The search strategy yielded 521 studies, five of which met the eligibility criteria. Four studies focused on tympanic temperature measurement, and one focused on temporal artery temperature measurement. Among the noninvasive options, tympanic temperature measurement was most frequently identified as a reliable option for out-of-hospital use.

CONCLUSION

A thermistor-based tympanic thermometer that features insulation of the ear and a temperature probe with a cap is likely the most suitable option for prehospital body temperature measurement in trauma patients. These results are based on outdated literature with currently more novel temperature measurement devices available. Future studies are necessary to provide strong recommendations regarding temperature measurement due to emerging technology, the lack of studies, and the heterogeneity of existing studies.

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

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

A simple improvised prehospital method to warm intravenous fluid

STUDY OBJECTIVE

Use of warmed intravenous fluid by emergency medical services (EMS) for prehospital injured patients is recommended to avoid iatrogenic hypothermia. We hypothesized that an improvised heating method would significantly increase the temperature of an intravenous fluid bag in a simulated prehospital environment.

METHODS

The change from baseline in the temperature of a 1-L intravenous fluid bag positioned above the vehicle windshield defroster vent was measured for 30 minutes using a thermocouple probe. Temperature changes were compared with a control fluid bag positioned on the vehicle console armrest. A total of 10 independent experiments were performed.

RESULTS

The defroster vent method increased intravenous fluid bag temperature from a mean starting temperature of 19.4°C (95% confidence interval [CI], 17.4°C-21.4°C) to a mean end temperature of 32.6°C (95% CI, 30.6°C-34.6°C) after 30 minutes. The temperature of a control intravenous fluid bag (mean starting temperature of 20.1°C; 95% CI, 19.0°C-21.2°C) exposed to a warmed (mean 33.2°C) passenger compartment changed little during the same time period (mean end temperature of 22.3°C; 95% CI, 19.4°C-25.2°C).

CONCLUSIONS

Convective warming of an intravenous fluid bag using the dashboard defroster vent significantly raised the fluid temperature. Such a method should be readily available to EMS or first responders.

Prevention of hypothermia in trauma victims - the HYPOTRAUM 2 study

INTRODUCTION

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

AIM

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

DESIGN

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

DISCUSSION

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

IMPACT

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

Association of body temperature with in-hospital mortality among paediatric trauma patients: an analysis of a nationwide observational trauma database in Japan

OBJECTIVES

To examine the association between body temperature (BT) on hospital arrival and in-hospital mortality among paediatric trauma patients.

DESIGN

A retrospective cohort study.

SETTING

Japan Trauma Data Bank (JTDB, which is a nationwide, prospective, observational trauma registry with data from 235 hospitals).

PARTICIPANTS

Paediatric trauma patients <16 years old who were transferred directly from the scene of injury to the hospital and registered in the JTDB from January 2004 to December 2017 were included. We excluded patients >16 years old and those who developed cardiac arrest before or on hospital arrival.

PRIMARY OUTCOME

The association between BT on hospital arrival and in-hospital mortality. We conducted multivariate logistic regression analyses to calculate the adjusted ORs, with their 95% CIs, of the association between BT and in-hospital mortality.

RESULTS

A total of 9012 patients were included (median age: 9 years (IQR, 6.0-13.0 years), mortality: 2.5% (mortality number was 226 in total 9012 patients)). In the multivariate logistic regression analysis, the corresponding adjusted ORs of BT <36.0°C and BT ≥37.0°C, relative to a BT of 36°C-36.9°C, for in-hospital mortality were 2.83 (95% CI: 1.85 to 4.33) and 0.93 (95% CI: 0.53 to 1.63), respectively.

CONCLUSIONS

In paediatric patients with hypothermia (BT <36.0°C) on hospital arrival, a clear association with in-hospital mortality was observed; no such association was observed between higher BT values (≥37.0°C) and outcomes.

Body temperature and in-hospital mortality in trauma patients: analysis of a nationwide trauma database in Japan

PURPOSE

Avoiding body temperature (BT) abnormalities has been emphasized in trauma care, and BT correction in the initial treatment period may improve patient outcome. However, the effect of hyperthermia at hospital arrival on mortality in trauma patients is unclear. This study aimed to identify the association between BT and in-hospital mortality among adult trauma patients.

METHODS

This was a retrospective analysis of a multi-centre prospective cohort study. Data were obtained from the Japan Trauma Data Bank (JTDB). Adult trauma patients who were transferred directly from the scene of injury to the hospital and registered in the JTDB between January 2004 and December 2017 were included. The primary outcome was the association between BT at hospital arrival and in-hospital mortality. BT at hospital arrival was classified by 1 °C strata. We conducted multivariable logistic regression analyses to calculate the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for in-hospital mortality for each BT group using 36.0-36.9 °C as a reference.

RESULTS

Overall, 153,117 patients were included. The total mortality rate was 7% (n = 10,118). The adjusted OR for in-hospital mortality for < 35.0 °C was 1.65 (95% CI 1.51-1.79, p < 0.001), 35.0-35.9 °C was 1.33 (95% CI 1.25-1.41, p < 0.001), 37.0-37.9 °C was 0.99 (95% CI 0.91-1.07, p = 0.639), 38.0-38.9 °C was 1.30 (95% CI 1.08-1.56, p = 0.007) and > 39.0 °C was 1.62 (95% CI 1.18-2.22, p = 0.003) compared to that for normothermia.

CONCLUSIONS

Our results reveal that hypothermia and hyperthermia at hospital arrival are associated with increased in-hospital mortality in adult trauma patients.

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.

Impact of Prehospital Hypothermia on the Outcomes of Severely Burned Patients

When treating burn injuries, to date, there still remains significant disagreement whether presence of hypothermia (HT) on burn centers' intensive care unit (BICU) admission improves or worsens outcomes. The presented single burn center experiences set out to further evaluate the incidence, cause, and potential effects of HT on outcomes in severely burned patients. Between January 2015 and February 2017, 142 severely burned patients were admitted to a BICU. Temperature at BICU admission of <36.0°C was defined as HT and ≥36.0°C as normothermia (NT). The cases were divided into two groups: HT vs NT. Fifty-four patients met inclusion criteria and were analyzed retrospectively regarding encountered complications, time of hospitalization, and overall survival. The overall incidence of HT on arrival was 62.9%. Mean duration from burn accident to BICU admission did not differ significantly, but the groups showed significant differences regarding total body surface area (TBSA; P < .05). Both groups showed a similar distribution, regarding number of surgeries, duration until first burn excision, length of ventilation, and mortality rate of patients (P > .05). However, time until death was significantly shorter in the HT group. HT at admission remains a common problem following burn injury. Main risk factors include inappropriate temperature management after injury and during transport, extent of TBSA burn, and quantity of resuscitation. Given the high incidence, the involved health care and, especially, also prehospital providers should be further educated about existing recommendations and guidelines to prevent HT.

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.

The changes of intraoperative body temperature in adult liver transplantation: A retrospective study

BACKGROUND

Body temperature is poorly regulated in patients with end-stage liver disease. Due to the prolonged surgery time and anhepatic time as well as the complex surgical procedures performed in liver transplantation, the body temperature fluctuates greatly. This study investigated the effect of intraoperative body temperature fluctuations on the prognosis of liver recipients.

METHODS

The body temperatures of liver recipients recorded from the induction of anesthesia (T₀) until the end of surgery (T₁₄) were retrieved. The patients were divided into two groups: the hypothermia group (< 35 °C and ≥ 5 min) and the normothermia group (≥ 35 °C or < 35 °C but < 5 min). Intraoperative and postoperative variables were compared between the two groups, and the correlations between the duration of hypothermia and the medical variables were analyzed.

RESULTS

Of the 107 patients, 67 patients were in the normothermia group, and 40 in the hypothermia group. The lowest body temperature was at 5 min after reperfusion for the whole cohort. Compared with the normothermia group, patients in the hypothermia group were more prone to bleeding, had a longer intubation time and increased rates of bacterial infection and acute pulmonary edema after liver transplantation (P < 0.05). Hypothermia time was positively correlated with bleeding volume, intubation time, units of blood transfusions and intensive care stay, but negatively correlated with urine output.

CONCLUSIONS

The intraoperative body temperature exhibited a graphical "V" trend, and the lowest temperature was at 5 min after reperfusion. The longer the duration of hypothermia, the more unfavourable the prognosis.

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.

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.

Accidental hypothermia: factors related to long-term hospitalization. A retrospective study from northern Finland

Accidental hypothermia has a low incidence, but is associated with a high mortality rate. Knowledge about concomitant factors, complications, and length of hospital stay is limited. A retrospective cohort study on patients with accidental hypothermia admitted to Oulu University Hospital in Finland, over a 5-year period. Patients were categorized as short-stay patients (7 days or less) and long-stay patients (more than 7 days) according to their length of stay in hospital. From a total of 105 patients, 67 patients were included in the analyses. Alcohol abuse was the most common concomitant factor (54 %). Median length of hospital stay was 4 days, and 16 patients (24 %) stayed in hospital over 7 days (median 15 days). Thirty-day mortality was low (14/105, 13 %). Patients with long-term hospitalization had a lower initial temperature (28.4 versus 31.2 °C, p = 0.011), a lower level of consciousness (GCS score 8.4 versus 12.8, p = 0.003), more severe acidosis (pH 7.08 versus 7.28, p = 0.005, and lactate 7.2 versus 3.9, p = 0.043), and a lower level of platelets (183 versus 242, p = 0.041) on admission compared with short-stay patients. Thirty-six patients (54 %) had at least one complication, and this prolonged median hospital treatment for 2.5 days (p < 0.001). Alcohol is the most common concomitant factor and every fourth patient spends more than 7 days in hospital. Long-term hospitalization is related to a lower core temperature, lower consciousness, more severe lactic acidosis, lower platelet level and infections, rhabdomyolysis, and renal failure.

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.

Screening for carbapenem-resistant Enterobacteriaceae: Who, When, and How?

The global spread of carbapenem-resistant Enterobacteriaceae (CRE) has been fostered by the lack of preemptive screening of patients in healthcare facilities that could prevent patient-to-patient transmission. Outbreaks of CRE infections have led some institutions to implement rigorous screening programs, although controlled comparative data are frequently lacking. Resource limitations and uncertainty regarding the optimal approach has kept many facilities from enacting more active routine surveillance policies that could reduce the prevalence of CRE. The ideal population to target for screening, the frequency of testing, and the preferred test method are components of surveillance programs that remain open to debate. This review discusses the rationale for different screening policies in use and the performance characteristics of laboratory methods available to detect CRE carriage.

A Novel Cooling Method and Comparison of Active Rewarming of Mildly Hypothermic Subjects

OBJECTIVE

To compare the effectiveness of arteriovenous anastomosis (AVA) vs heated intravenous fluid (IVF) rewarming in hypothermic subjects. Additionally, we sought to develop a novel method of hypothermia induction.

METHODS

Eight subjects underwent 3 cooling trials each to a core temperature of 34.8±0.6 (32.7 to 36.3°C [mean±SD with range]) by 14°C water immersion for 30 minutes, followed by walking on a treadmill for 5 minutes. Core temperatures (Δtes) and rates of cooling (°C/h) were measured. Participants were then rewarmed by 1) control: shivering only in a sleeping bag; 2) IVF: shivering in sleeping bag and infusion of 2 L normal saline warmed to 42°C at 77 mL/min; and 3) AVA: shivering in sleeping bag and circulation of 45°C warmed fluid through neoprene pads affixed to the palms and soles of the feet.

RESULTS

Cold water immersion resulted in a decrease of 0.5±0.5°C Δtes and 1±0.3°C with exercise (P < .01); with an immersion cooling rate of 0.9±0.8°C/h vs 12.6±3.2°C/h with exercise (P < .001). Temperature nadir reached 35.0±0.5°C. There were no significant differences in rewarming rates between the 3 conditions (shivering: 1.3±0.7°C/h, R² = 0.683; IVF 1.3±0.7°C/h, R² = 0.863; and AVA 1.4±0.6°C/h, R² = 0.853; P = .58). Shivering inhibition was greater with AVA but was not significantly different (P = .07).

CONCLUSIONS

This study developed a novel and efficient model of hypothermia induction through exercise-induced convective afterdrop. Although there was not a clear benefit in either of the 2 active rewarming methods, AVA rewarming showed a nonsignificant trend toward greater shivering inhibition, which may be optimized by an improved interface.

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.

Accidental hypothermia in severe trauma

Hypothermia, along with acidosis and coagulopathy, is part of the lethal triad that worsen the prognosis of severe trauma patients. While accidental hypothermia is easy to identify by a simple measurement, it is no less pernicious if it is not detected or treated in the initial phase of patient care. It is a multifactorial process and is a factor of mortality in severe trauma cases. The consequences of hypothermia are many: it modifies myocardial contractions and may induce arrhythmias; it contributes to trauma-induced coagulopathy; from an immunological point of view, it diminishes inflammatory response and increases the chance of pneumonia in the patient; it inhibits the elimination of anaesthetic drugs and can complicate the calculation of dosing requirements; and it leads to an over-estimation of coagulation factor activities. This review will detail the pathophysiological consequences of hypothermia, as well as the most recent principle recommendations in dealing with it.

A recommended early goal-directed management guideline for the prevention of hypothermia-related transfusion, morbidity, and mortality in severely injured trauma patients

Hypothermia is present in up to two-thirds of patients with severe injury, although it is often disregarded during the initial resuscitation. Studies have revealed that hypothermia is associated with mortality in a large percentage of trauma cases when the patient's temperature is below 32 °C. Risk factors include the severity of injury, wet clothing, low transport unit temperature, use of anesthesia, and prolonged surgery. Fortunately, associated coagulation disorders have been shown to completely resolve with aggressive warming. Selected passive and active warming techniques can be applied in damage control resuscitation. While treatment guidelines exist for acidosis and bleeding, there is no evidence-based approach to managing hypothermia in trauma patients. We synthesized a goal-directed algorithm for warming the severely injured patient that can be directly incorporated into current Advanced Trauma Life Support guidelines. This involves the early use of warming blankets and removal of wet clothing in the prehospital phase followed by aggressive rewarming on arrival at the hospital if the patient's injuries require damage control therapy. Future research in hypothermia management should concentrate on applying this treatment algorithm and should evaluate its influence on patient outcomes. This treatment strategy may help to reduce blood loss and improve morbidity and mortality in this population of patients.

Infection control implications of heterogeneous resistance mechanisms in carbapenem-resistant Enterobacteriaceae (CRE)

The Centers for Disease Control and Prevention (CDC) defines carbapenem-resistant Enterobacteriaceae (CRE) based upon a phenotypic demonstration of carbapenem resistance. However, considerable heterogeneity exists within this definitional umbrella. CRE may mechanistically differ by whether they do or do not produce carbapenemases. Moreover, patients can acquire CRE through multiple pathways: endogenously through antibiotic selective pressure on intestinal microbiota, exogenously through horizontal transmission or through a combination of these factors. Some evidence suggests that non-carbapenemase-producing CRE may be more frequently acquired by antibiotic exposure and carbapenemase-producing CRE via horizontal transmission, but definitive data are lacking. This review examines types of CRE resistance mechanisms, antibiotic exposure and horizontal transmission pathways of CRE acquisition, and the implications of these heterogeneities to the development of evidence-based CRE healthcare epidemiology policies. In our Expert Commentary & Five-Year View, we outline specific nosocomial CRE knowledge gaps and potential methodological approaches for their resolution.

The impact of environmental factors in pre-hospital thermistor-based tympanic temperature measurement: a pilot field study

BACKGROUND

Few pre-hospital services have the possibility to accurately measure core temperature (T core). Non-invasive estimation of T core will improve pre-hospital decision-making regarding the triage and management of hypothermic patients. Thermistor-based tympanic temperature (T tymp) correlates well with T core in controlled studies; however, little is known about the feasibility of using T tymp under field conditions. This study assessed the impact of pre-hospital environmental factors on the accuracy of T tymp . Deep rectal temperature (T rect) was used as a substitute for T core .

METHODS

Normothermic volunteers (n = 13) were exposed to four simulated field conditions producing local cooling of the head and ear canal. After exposure, T tymp was recorded every 15 s for 10 min and compared with T rect . Descriptive analysis and Bland-Altman plots were used to assess agreement.

RESULTS

Immediately after exposure mean T tymp was low, but increased rapidly and reached an apparent steady state after 3-5 min. After 5 and 10 min, the mean temperature difference (∆T rect-tymp) ranged from 1.5-3.2 °C (SD = 0.5) and 1.2-2.0 °C, respectively. T rect remained unchanged throughout the study period.

CONCLUSIONS

After surface cooling of head and neck, T tymp did not accurately reflect core temperature within the first 10 min of measurement. The variation of ∆T rect-tymp was low after 10 min, regardless of the initial degree of cooling. With the risk of over-triage, T tymp may at this point provide an indication of T core and also exhibit a trend.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02274597.

[Out-of-hospital equipment of emergency medical services for hemorrhagic shock management: can do better!]

INTRODUCTION

Hemorrhagic shock is an emergency, which may benefit from a medicalized prehospital care. Our goal was to survey the means available in the 370 French prehospital medicalized emergency services (SMUR) for hemorrhagic situations.

METHODS

Multicenter descriptive observational study by email then phone with all the 370 French SMUR leaders. The questionnaire was created by investigators of the project through a Delphi method, and was about service protocols concerning hemorrhagic patient care, hemorrhagic parameters measure equipment available, intravenous solutes and drugs as well as various medical devices useful or perceived to be useful to support prehospital hemorrhagic shock. The results are expressed in numbers and percentages.

RESULTS

The overall response rate was 48% (n=178). Protocols were established in between 43% (n=76) and 47% (n=83) according to etiology, measuring devices were available in 5% (n=9) of the Smur for hemostasis up to 89% (n=158) for hemoglobin measurement. Available intravenous solutes were mainly isotonic salty serum (95%, n=169), hydroxylethylstarch (83%, n=148) and Ringer lactate (73%, n=130). Tranexamic acid was available in 84 (47%) Smur. The teams had access to erythrocytes concentrates, fresh frozen plasma and platelets in 84% (n=150), 44% (n=79) and 23% (n=41) respectively. Eighty-one (46%) Smur had tourniquets and 127 (71%) anti-shock trousers. Finally, 57 (32%) had a pelvic restraint belt.

CONCLUSION

There is a great disparity in the means available in the French Smur for the support of prehospitalization bleeding. The majority the Smur physicians can transfuse in a prehospital setting. On the other hand, a minority of teams can actively warm patients, employ tranexamic acid or use pelvic restraint belts.

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

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

Management of hemorrhage in trauma

Hemorrhage remains one of the leading causes of trauma-related deaths. Uncontrolled diffuse microvascular bleeding in the course of initial care is common, potentially resulting in exsanguination. Early and aggressive hemostatic intervention increases survival and reduces the incidence of massive transfusion. Thus, timely diagnosis of the underlying coagulation disorders is mandatory. It has been shown that standard coagulation tests do not sufficiently characterize trauma-induced coagulopathy (TIC). This has led to increasing interest in alternatives, such as the viscoelastic test, to diagnose TIC and to provide the basis for a goal-directed hemostatic therapy. The concept of damage control resuscitation (DCR) has been introduced widely in trauma patients with severe bleeding. This strategy addresses important confounders of the coagulation process such as hemodilution, hypothermia, and acidosis; DCR is based on a damage control surgical approach, permissive hypotension, and improvement of hemostatic competence. Many studies have shown benefit in mortality when using high ratios of fresh frozen plasma (FFP) to red blood cells (RBC) as early treatment. However, there is increased awareness that coagulation factor concentrate could be beneficial in the treatment of trauma-induced coagulopathy.

Research progress on combat trauma treatment in cold regions

Cold regions are a special combat environment in which low temperatures have a great impact on human metabolism and other vital functions, including the nervous, motion, cardiovascular, circulatory, respiratory, and urinary systems; consequently, low temperatures often aggravate existing trauma, leading to high mortality rates if rapid and appropriate treatment is not provided. Hypothermia is an independent risk factor of fatality following combat trauma; therefore, proactive preventative measures are needed to reduce the rate of mortality. After summarizing the basic research on battlefield environments and progress in the prevention and treatment of trauma, this article concludes that current treatment and prevention measures for combat trauma in cold regions are inadequate. Future molecular biology studies are needed to elucidate the mechanisms and relevant cell factors underlying bodily injury caused by cold environment, a research goal will also allow further exploration of corresponding treatments.

Year in review 2012: Critical Care--Out-of-hospital cardiac arrest and trauma

In 2012 Critical Care published many articles pertaining to the resuscitation of out-of-hospital cardiac arrest and trauma. In this review, we summarize several of these articles, including those regarding advances in resuscitation techniques and methods. We examine articles pertaining to prehospital endotracheal intubation, the use of specialized devices for cardiopulmonary resuscitation and policies regarding transport destinations for both cardiac arrest and trauma patients. Articles on the predictors of outcome in both pediatric and adult populations are evaluated, including articles on the effects of obesity on survival from hemorrhage and pediatric outcomes from traumatic cardiac arrest. The effects of the type and volume of resuscitation fluids for both adult and pediatric patients are discussed, as are the factors contributing to hypothermia in trauma patients.

Equipment to prevent, diagnose, and treat hypothermia: a survey of Norwegian pre-hospital services

Introduction

Hypothermia is associated with increased morbidity and mortality in trauma patients and poses a challenge in pre-hospital treatment. The aim of this study was to identify equipment to prevent, diagnose, and treat hypothermia in Norwegian pre-hospital services.

Method

In the period of April-August 2011, we conducted a survey of 42 respondents representing a total of 543 pre-hospital units, which included all the national ground ambulance services, the fixed wing and helicopter air ambulance service, and the national search and rescue service. The survey explored available insulation materials, active warming devices, and the presence of protocols describing wrapping methods, temperature monitoring, and the use of warm i.v. fluids.

Results

Throughout the services, hospital duvets, cotton blankets and plastic “bubble-wrap” were the most common insulation materials. Active warming devices were to a small degree available in vehicle ambulances (14%) and the fixed wing ambulance service (44%) but were more common in the helicopter services (58-70%). Suitable thermometers for diagnosing hypothermia were lacking in the vehicle ambulance services (12%). Protocols describing how to insulate patients were present for 73% of vehicle ambulances and 70% of Search and Rescue helicopters. The minority of Helicopter Emergency Medical Services (42%) and Fixed Wing (22%) units was reported to have such protocols.

Conclusion

The most common equipment types to treat and prevent hypothermia in Norwegian pre-hospital services are duvets, plastic “bubble wrap”, and cotton blankets. Active external heating devices and suitable thermometers are not available in most vehicle ambulance units.

Trauma and aggressive homeostasis management

Homeostasis refers to the capacity of the human body to maintain a stable constant state by means of continuous dynamic equilibrium adjustments controlled by a medley of interconnected regulatory mechanisms. Patients who sustain tissue injury, such as trauma or surgery, undergo a well-understood reproducible metabolic and neuroendocrine stress response. This review discusses 3 issues that concern homeostasis in the acute care of trauma patients directly related to the stress response: hyperglycemia, lactic acidosis, and hypothermia. There is significant reason to question the "conventional wisdom" relating to current approaches to restoring homeostasis in critically ill and trauma patients.

Hypothermia in trauma patients: predicting the big chill

Physicians commonly ignore hypothermia, an often-underappreciated event associated with mortality in trauma patients, in general due to its prevalence and belief that it is secondary to the injury itself (secondary hypothermia). Over the past several decades, hypothermia in trauma has been studied concerning its effects on mortality; however, very little has been done to identify the major risk factors associated with it. The study by Lapostolle and colleagues has attempted to incorporate environmental risk factors and prehospital care along with more traditional variables for the prediction of hypothermia at admission.