The utility of traditional prehospital interventions in maintaining thermostasis

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.

Prehospital Use of Ultrathin Reflective Foils

Ultrathin reflective foils (URFs) are widely used to protect patients from heat loss, but there is no clear evidence that they are effective. We review the physics of thermal insulation by URFs and discuss their clinical applications. A conventional view is that the high reflectivity of the metallic side of the URF is responsible for thermal protection. In most circumstances, the heat radiated from a well-clothed body is minimal and the reflecting properties of a URF are relatively insignificant. The reflection of radiant heat can be impaired by condensation and freezing of the moisture on the inner surface and by a tight fit of the URF against the outermost layer of insulation. The protection by thermal insulating materials depends mostly on the ability to trap air and increases with the number of covering layers. A URF as a single layer may be useful in low wind conditions and moderate ambient temperature, but in cold and windy conditions a URF probably best serves as a waterproof outer covering. When a URF is used to protect against hypothermia in a wilderness emergency, it does not matter whether the gold or silver side is facing outward.

Perioperative Hypothermia-A Narrative Review

Unintentional hypothermia (core temperature < 36 °C) is a common side effect in patients undergoing surgery. Several patient-centred and external factors, e.g., drugs, comorbidities, trauma, environmental temperature, type of anaesthesia, as well as extent and duration of surgery, influence core temperature. Perioperative hypothermia has negative effects on coagulation, blood loss and transfusion requirements, metabolization of drugs, surgical site infections, and discharge from the post-anaesthesia care unit. Therefore, active temperature management is required in the pre-, intra-, and postoperative period to diminish the risks of perioperative hypothermia. Temperature measurement should be done with accurate and continuous probes. Perioperative temperature management includes a bundle of warming tools adapted to individual needs and local circumstances. Warming blankets and mattresses as well as the administration of properly warmed infusions via dedicated devices are important for this purpose. Temperature management should follow checklists and be individualized to the patient's requirements and the local possibilities.

Cardiac Arrest Secondary to Accidental Hypothermia: Rewarming Strategies in the Field

Hypothermic cardiac arrest is rare and poses a challenge to prehospital responders. Standard cardiac arrest protocols advise treating reversible causes of arrest; however, rewarming the cold casualty is not easily achieved in the field. This article aimed to review the literature on hypothermia in order to produce evidence-based recommendations on rewarming that could realistically be applied to hypothermic cardiac arrest patients.

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

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

Human Responses to 5 Heated Hypothermia Wrap Systems in a Cold Environment

INTRODUCTION

We compared the effectiveness of 5 heated hypothermia wrap systems.

METHODS

Physiologic and subjective responses were determined in 5 normothermic subjects (1 female) for 5 heated hypothermia wraps (with vapor barrier and chemical heat sources) during 60 min of exposure to a temperature of -22°C. The 5 systems were 1) user-assembled; 2) Doctor Down Rescue Wrap; 3) hypothermia prevention and management kit (HPMK); 4) MARSARS Hypothermia Stabilizer Bag; and 5) Wiggy's Victims Casualty Hypothermia Bag. Core and skin temperature, metabolic heat production, skin heat loss, and body net heat gain were determined. Subjective responses were also evaluated for whole body cold discomfort, overall shivering rating, overall temperature rating, and preferential ranking.

RESULTS

The Doctor Down and user-assembled systems were generally more effective, with higher skin temperatures and lower metabolic heat production; they allowed less heat loss, resulting in higher net heat gain (P<0.05). HPMK had the lowest skin temperature and highest shivering heat production and scored worse than the other 4 systems for the "whole body cold discomfort" and "overall temperature" ratings (P<0.05).

CONCLUSIONS

The user-assembled and Doctor Down systems were most effective, and subjects were coldest with the HPMK system. However, it is likely that any of the tested systems would be viable options for wilderness responders, and the choice would depend on considerations of cost; volume, as it relates to available space; and weight, as it relates to ability to carry or transport the system to the patient.

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.

The European guideline on management of major bleeding and coagulopathy following trauma: fifth edition

Background

Severe traumatic injury continues to present challenges to healthcare systems around the world, and post-traumatic bleeding remains a leading cause of potentially preventable death among injured patients. Now in its fifth edition, this document aims to provide guidance on the management of major bleeding and coagulopathy following traumatic injury and encourages adaptation of the guiding principles described here to individual institutional circumstances and resources.

Methods

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma was founded in 2004, and the current author group included representatives of six relevant European professional societies. The group applied a structured, evidence-based consensus approach to address scientific queries that served as the basis for each recommendation and supporting rationale. Expert opinion and current clinical practice were also considered, particularly in areas in which randomised clinical trials have not or cannot be performed. Existing recommendations were re-examined and revised based on scientific evidence that has emerged since the previous edition and observed shifts in clinical practice. New recommendations were formulated to reflect current clinical concerns and areas in which new research data have been generated.

Results

Advances in our understanding of the pathophysiology of post-traumatic coagulopathy have supported improved management strategies, including evidence that early, individualised goal-directed treatment improves the outcome of severely injured patients. The overall organisation of the current guideline has been designed to reflect the clinical decision-making process along the patient pathway in an approximate temporal sequence. Recommendations are grouped behind the rationale for key decision points, which are patient- or problem-oriented rather than related to specific treatment modalities. While these recommendations provide guidance for the diagnosis and treatment of major bleeding and coagulopathy, emerging evidence supports the author group’s belief that the greatest outcome improvement can be achieved through education and the establishment of and adherence to local clinical management algorithms.

Conclusions

A multidisciplinary approach and adherence to evidence-based guidance are key to improving patient outcomes. If incorporated into local practice, these clinical practice guidelines have the potential to ensure a uniform standard of care across Europe and beyond and better outcomes for the severely bleeding trauma patient.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2347-3) contains supplementary material, which is available to authorized users.

Patient-centred outcomes for prehospital trauma trials: A systematic review and patient involvement exercise

Introduction

Outcome measures are used in clinical trials to determine efficacy of interventions. We aimed to determine which outcome measures in prehospital major trauma trials have been reported in the literature, and which of these are most patient-centred.

Methods

A systematic review identified outcomes reported in prehospital clinical trials of major trauma patients. A search was undertaken using Medline, Embase, clinicaltrials.gov, Web of Science and Google Scholar. Data were summarised by dividing outcomes into common themes which were presented to a Patient and Public Involvement group consisting of trauma survivors and their relatives. This group ranked the categories of outcomes in order of most importance, and agreed consensus statements regarding these outcome measures.

Results

There were 27 eligible studies, including 9,537 patients. Outcome measures were divided into nine categories: quality of life; length of stay; mortality/survival; physiological parameters; fluid/blood product requirements; complications; health economics; safety and feasibility; and intervention success. Of these, mortality/survival was the most commonly reported category, but over multiple timescales. The Patient and Public Involvement group agreed that the most important category was quality of life, and that mortality/survival should only be reported if concurrently reported with longer term quality of life. Length of stay and health economics were not considered important.

Conclusions

Outcome measures in prehospital clinical trials in major trauma have been heterogeneous, inconsistent, and not necessarily patient-centred. Trauma survivors considered quality of life and mortality most important when combined. Consensus is required for consistent, patient-centred, outcome measures in order to investigate interventions of meaningful impact to patients.

Benefits of Passive Warming on Surgical Patients Undergoing Regional Anesthetic Procedures

PURPOSE

The purpose of this quality improvement project was to determine if application of preoperative passive warming methods would maintain body temperature in patients receiving regional anesthetic procedures (RAPs).

DESIGN

A nonrandomized quasi-experimental design was used.

METHODS

A passive warming trial using a convenience sample of 53 RAP patients warmed with passive measures was compared with data collected from 67 retrospective chart reviews of RAP patients warmed per standard unit policy-typically active forced warm air. Passive measures included a thermal reflective surgical cap and an activated chemical warmer.

FINDINGS

Passive warming methods maintained temperatures throughout the perioperative process. No significant variations in mean temperatures were noted. As age increased, the difference in temperature from admit to transfer to operating room also increased (P = .0182).

CONCLUSIONS

Passive warming is a suitable cost-effective alternative when forced-air warming is not feasible. Additional inquiry into the use of passive warming is warranted.

Managing accidental hypothermia: a UK-wide survey of prehospital and search and rescue providers

AIM

The management of hypothermic casualties is a challenge faced by all prehospital and search and rescue (SAR) teams. It is not known how the practice of these diverse teams compare. The aim of this study was to review prehospital hypothermia management across a wide range of SAR providers in the UK.

METHODS

A survey of ground ambulances (GAs), air ambulances (AAs), mountain rescue teams (MRTs, including Ministry of Defence), lowland rescue teams (LRTs), cave rescue teams (CRTs), and lifeboats and lifeguard organisations (LLOs) across the UK was conducted between May and November 2017. In total, 189 teams were contacted. Questions investigated packaging methods, temperature measurement and protocols for managing hypothermic casualties.

RESULTS

Response rate was 59%, comprising 112 teams from a wide range of organisations. Heavyweight (>3 kg) casualty bags were used by all CRTs, 81% of MRTs, 29% of LRTs, 18% of AAs and 8% of LLOs. Specially designed lightweight (<0.5 kg) blankets or wraps were used by 93% of LRTs, 85% of LLOs, 82% of GAs, 71% of AAs and 50% of MRTs. Bubble wrap was used mainly by AAs, with 35% of AAs reporting its use. Overall, 94% of packaging methods incorporated both insulating and vapour-tight layers. Active warming by heated pads or blankets was used by 65% of AAs, 60% of CRTs, 54% of MRTs, 29% of LRTs and 9% of GAs, with no LLO use. Temperature measurement was reported by all AAs and GAs, 93% of LRTs, 80% of CRTs, 75% of MRTs and 31% of LLOs. The favoured anatomical site for temperature measurement was tympanic. Protocols for packaging hypothermic casualties were reported by 73% of services.

CONCLUSIONS

This survey describes current practice in prehospital hypothermia management, comparing the various methods used by different teams, and provides a basis to direct further education and research.

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.

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.

The opinions of ambulance personnel regarding using a heated mattress for patients being cared for in a cold climate - An intervention study in ambulance care

The purpose of the study was to describe the opinions of ambulance personnel regarding differences between using a heated mattress and a standard ambulance mattress. This study was an intervention study with pre- and post-evaluation. Evaluations of the opinions of personnel regarding the standard unheated mattress were conducted initially. After the intervention with new heated mattresses, follow-up evaluations were conducted. Ambulance personnel (n=64) from an ambulance station in northern Sweden took part in the study, which ran from October 2014 until February 2016. There were differences in opinions regarding the standard unheated mattress and the new heated mattress. The evaluation of the proxy ratings by the personnel showed that the heated mattress was warmer than the standard mattress, more pleasant to lie on and that patients were happier and more relaxed than when the standard mattress was used. The ambulance personnel in this study rated the experience of working with the heated mattress as very positive and proxy rated that it had a good effect on patient comfort. A heated mattress can be recommended for patients in ambulance care, even if more research is needed to receive sufficient evidence.

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.

Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia

Accidental hypothermia is an unintentional drop in core temperature to 35°C or below. Core temperature is best measured by esophageal probe. If core temperature cannot be measured, the degree should be estimated using clinical signs. Treatment is to protect from further heat loss, minimize afterdrop, and prevent cardiovascular collapse during rescue and resuscitation. The patient should be handled gently, kept horizontal, insulated, and actively rewarmed. Active rewarming is also beneficial in mild hypothermia but passive rewarming usually suffices. Cardiopulmonary resuscitation should be performed if there are no contraindications to resuscitation. CPR may be delayed or intermittent.

A prospective observational study of the association between cabin and outside air temperature, and patient temperature gradient during helicopter transport in New South Wales

The prevalence of hypothermia in patients following helicopter transport varies widely. Low outside air temperature has been identified as a risk factor. Modern helicopters are insulated and have heating; therefore outside temperature may be unimportant if cabin heat is maintained. We sought to describe the association between outside air, cabin and patient temperature, and having the cabin temperature in the thermoneutral zone (18-36°C) in our helicopter-transported patients. We conducted a prospective observational study over one year. Patient temperature was measured on loading and engines off. Cabin and outside air temperature were recorded for the same time periods for each patient, as well as in-flight. Previously identified risk factors were recorded. Complete data was obtained for 133 patients. Patients' temperature increased by a median of 0.15°C (P=0.013). There was no association between outside air temperature or cabin temperature and patient temperature gradient. The best predictor of patient temperature on landing was patient temperature on loading (R2=0.86) and was not improved significantly when other risk factors were added (P=0.63). Thirty-five percent of patients were hypothermic on loading, including those transferred from district hospitals. No patient loaded normothermic became hypothermic when the cabin temperature was in the thermoneutral zone (P=0.04). A large proportion of patients in our sample were hypothermic at the referring hospital. The best predictor of patient temperature on landing is patient temperature on loading. This has implications for studies that fail to account for pre-flight temperature.

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.

The European guideline on management of major bleeding and coagulopathy following trauma: fourth edition

BACKGROUND

Severe trauma continues to represent a global public health issue and mortality and morbidity in trauma patients remains substantial. A number of initiatives have aimed to provide guidance on the management of trauma patients. This document focuses on the management of major bleeding and coagulopathy following trauma and encourages adaptation of the guiding principles to each local situation and implementation within each institution.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma was founded in 2004 and included representatives of six relevant European professional societies. The group used a structured, evidence-based consensus approach to address scientific queries that served as the basis for each recommendation and supporting rationale. Expert opinion and current clinical practice were also considered, particularly in areas in which randomised clinical trials have not or cannot be performed. Existing recommendations were reconsidered and revised based on new scientific evidence and observed shifts in clinical practice; new recommendations were formulated to reflect current clinical concerns and areas in which new research data have been generated. This guideline represents the fourth edition of a document first published in 2007 and updated in 2010 and 2013.

RESULTS

The guideline now recommends that patients be transferred directly to an appropriate trauma treatment centre and encourages use of a restricted volume replacement strategy during initial resuscitation. Best-practice use of blood products during further resuscitation continues to evolve and should be guided by a goal-directed strategy. The identification and management of patients pre-treated with anticoagulant agents continues to pose a real challenge, despite accumulating experience and awareness. The present guideline should be viewed as an educational aid to improve and standardise the care of the bleeding trauma patients across Europe and beyond. This document may also serve as a basis for local implementation. Furthermore, local quality and safety management systems need to be established to specifically assess key measures of bleeding control and outcome.

CONCLUSIONS

A multidisciplinary approach and adherence to evidence-based guidance are key to improving patient outcomes. The implementation of locally adapted treatment algorithms should strive to achieve measureable improvements in patient outcome.

Effect evaluation of a heated ambulance mattress-prototype on thermal comfort and patients' temperatures in prehospital emergency care--an intervention study

Background

The ambulance milieu does not offer good thermal comfort to patients during the cold Swedish winters. Patients’ exposure to cold temperatures combined with a cold ambulance mattress seems to be the major factor leading to an overall sensation of discomfort. There is little research on the effect of active heat delivered from underneath in ambulance care. Therefore, the aim of this study was to evaluate the effect of an electrically heated ambulance mattress-prototype on thermal comfort and patients’ temperatures in the prehospital emergency care.

Methods

A quantitative intervention study on ambulance care was conducted in the north of Sweden. The ambulance used for the intervention group (n=30) was equipped with an electrically heated mattress on the regular ambulance stretcher whereas for the control group (n=30) no active heat was provided on the stretcher. Outcome variables were measured as thermal comfort on the Cold Discomfort Scale (CDS), subjective comments on cold experiences, and finger, ear and air temperatures.

Results

Thermal comfort, measured by CDS, improved during the ambulance transport to the emergency department in the intervention group (p=0.001) but decreased in the control group (p=0.014). A significant higher proportion (57%) of the control group rated the stretcher as cold to lie down compared to the intervention group (3%, p<0.001). At arrival, finger, ear and compartment air temperature showed no statistical significant difference between groups. Mean transport time was approximately 15 minutes.

Conclusions

The use of active heat from underneath increases the patients’ thermal comfort and may prevent the negative consequences of cold stress.

Wilderness Medical Society practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia: 2014 update

To provide guidance to clinicians, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations. This is an updated version of the original Wilderness Medical Society Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia published in Wilderness & Environmental Medicine 2014;25(4):425-445.

Wilderness Medical Society practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia

To provide guidance to clinicians, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations.

Evaluating cold, wind, and moisture protection of different coverings for prehospital maritime transportation-a thermal manikin and human study

INTRODUCTION

Prehospital maritime transportation in northern areas sets high demands on hypothermia prevention. To prevent body cooling and hypothermia of seriously-ill or injured casualties during transportation, casualty coverings must provide adequate thermal insulation and protection against cold, wind, moisture, and water splashes.

OBJECTIVE

The aim of this study was to determine the thermal protective properties of different types of casualty coverings and to evaluate which would be adequate for use under difficult maritime conditions (cold, high wind speed, and water splashes). In addition, the study evaluated the need for thermal protection of a casualty and verified the optimum system for maritime casualty transportation.

METHODS

The study consisted of two parts: (1) the definition and comparison of the thermal protective properties of different casualty coverings in a laboratory; and (2) the evaluation of the chosen optimum protective covering for maritime prehospital transportation. The thermal insulations of ten different casualty coverings were measured according to the European standard for sleeping bags (EN 13537) using a thermal manikin in a climate chamber (-5°C) with wind speeds of 0.3 m/s and 4.0 m/s, and during moisture simulations. The second phase consisted of measurements of skin and core temperatures, air temperature, and relative humidity inside the clothing of four male test subjects during authentic maritime prehospital transportation in a partially-covered motor boat.

RESULTS

Wind (4 m/s) decreased the total thermal insulation of coverings by 11%-45%. The decrement of thermal insulation due to the added moisture inside the coverings was the lowest (approximately 22%-29%) when a waterproof reflective sheet inside blankets or bubble wrap was used, whereas vapor-tight rescue bags and bubble wrap provide the most protection against external water splashes. During authentic maritime transportation lasting 30 minutes, mean skin temperature decreased on average by 0.5°C when a windproof and water-resistant rescue bag was used over layered winter clothing.

CONCLUSION

The selected optimum rescue bag consisted of insulating and water-resistant layers providing sufficient protection against cold, wind, and water splashes during prehospital transportation lasting 30 minutes in the uncovered portion of a motor boat. The minimum thermal insulation for safe maritime transportation (30 minutes) is 0.46 m²K/W at a temperature of -5°C and a wind speed of 10 m/s.

Effect evaluation of a heated ambulance mattress-prototype on body temperatures and thermal comfort--an experimental study

Background

Exposure to cold temperatures is, often, a neglected problem in prehospital care. One of the leading influences of the overall sensation of cold discomfort is the cooling of the back. The aim of this study was to evaluate the effect of a heated ambulance mattress-prototype on body temperatures and thermal comfort in an experimental study.

Method

Data were collected during four days in November, 2011 inside and outside of a cold chamber. All participants (n = 23) participated in two trials each. In one trial, they were lying on a stretcher with a supplied heated mattress and in the other trial without a heated mattress. Outcomes were back temperature, finger temperature, core body temperature, Cold Discomfort Scale (CDS), four statements from the state-trait anxiety – inventory (STAI), and short notes of their experiences of the two mattresses. Data were analysed both quantitatively and qualitatively. A repeated measure design was used to evaluate the effect of the two mattresses.

Results

A statistical difference between the regular mattress and the heated mattress was found in the back temperature. In the heated mattress trial, the statement “I am tense” was fewer whereas the statements “I feel comfortable”, “I am relaxed” and “I feel content” were higher in the heated mattress trial. The qualitative analyses of the short notes showed that the heated mattress, when compared to the unheated mattress, was experienced as warm, comfortable, providing security and was easier to relax on.

Conclusions

Heat supply from underneath the body results in increased comfort and may prevent hypothermia which is important for injured and sick patients in ambulance care.

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.

Terrorism in Peru

Two major domestic terrorist groups have plagued Peru over the past 20 years, the Sendero Luminoso or “Shining Path” (SL) and the Revolutionary Movement Túpac Amaru (MRTA). On 28 August 2003, the Peruvian Truth and Reconciliation Commission reported that an estimated 69,280 persons were killed in the internal conflict in Peru from 1980 to 2000. Most of the victims were farmers (56%), most attacks occurred in rural settings (79%), and the SL was responsible for mostof the deaths (54%). Aggressive anti-terrorism efforts by police and military during this period, often at the expense of basic human rights, also contributed to this large burden of terrorism on Peru. During the 1990s, terrorist attacks in Peru had spread to its urban areas. On 17 December 1996, 22 members of MRTA took over the Japanese ambassador's residence in Lima, holding 72 hostages until the grounds were stormed by Peruvian special forces on 23 April 1997.

Until recently, emergency planning and preparedness for terrorism-related events in Peru were largely underdeveloped. In the last five years, Peru has taken two key steps towards developing a mature emergency response system, with the establishment of the country's first emergency medicine residency training program and the construction of the first dedicated trauma center in Lima.

[Resuscitation damage control in the patient with severe trauma]

Severe trauma is the principle cause of death among young people in developed countries, with the main causes being due to road traffic accidents and accidents at work. The principle cause of death in severe trauma is the massive uncontrolled loss of blood. Most of the severe traumas with a massive haemorrhage develop coagulopathy, with some controversy over what is the best treatment for this. Patients with severe trauma are complex patients; they have a high mortality, they consume a significant amount of sources and can require rapid, intensive and multidisciplinary treatment encompassed within the concept of resuscitation damage control. In this article we attempt to present a current view of the pathophysiology of severe trauma and resuscitation damage control that may be applied to these types of patients.

Being cold when injured in a cold environment--patients' experiences

BACKGROUND

Patients in prehospital care, irrespective of diseases or trauma might experience thermal discomfort because of a cold environment and are at risk for decreasing body temperature which can increase both morbidity and mortality.

OBJECTIVE

To explore patients' experiences of being cold when injured in a cold environment.

METHOD

Twenty persons who had been injured in a cold environment in northern Sweden were interviewed. Active heat supply was given to 13 of them and seven had passive heat supply. The participants were asked to narrate their individual experience of cold and the pre- and post-injury event, until arrival at the emergency department. The interviews were transcribed verbatim, then analyzed with qualitative content analysis.

RESULTS

Patients described that they suffered more from the cold than because of the pain from the injury. Patients who received active heat supply experienced it in a positive way. Two categories were formulated: Enduring suffering and Relief of suffering.

CONCLUSION

Thermal discomfort became the largest problem independent of the severity of the injuries. We recommend the use of active heat supply to reduce the negative experiences of thermal discomfort when a person is injured in a cold environment.

The effect of active warming in prehospital trauma care during road and air ambulance transportation - a clinical randomized trial

Background

Prevention and treatment of hypothermia by active warming in prehospital trauma care is recommended but scientifical evidence of its effectiveness in a clinical setting is scarce. The objective of this study was to evaluate the effect of additional active warming during road or air ambulance transportation of trauma patients.

Methods

Patients were assigned to either passive warming with blankets or passive warming with blankets with the addition of an active warming intervention using a large chemical heat pad applied to the upper torso. Ear canal temperature, subjective sensation of cold discomfort and vital signs were monitored.

Results

Mean core temperatures increased from 35.1°C (95% CI; 34.7-35.5°C) to 36.0°C (95% CI; 35.7-36.3°C) (p < 0.05) in patients assigned to passive warming only (n = 22) and from 35.6°C (95% CI; 35.2-36.0°C) to 36.4°C (95% CI; 36.1-36.7°C) (p < 0.05) in patients assigned to additional active warming (n = 26) with no significant differences between the groups. Cold discomfort decreased in 2/3 of patients assigned to passive warming only and in all patients assigned to additional active warming, the difference in cold discomfort change being statistically significant (p < 0.05). Patients assigned to additional active warming also presented a statistically significant decrease in heart rate and respiratory frequency (p < 0.05).

Conclusions

In mildly hypothermic trauma patients, with preserved shivering capacity, adequate passive warming is an effective treatment to establish a slow rewarming rate and to reduce cold discomfort during prehospital transportation. However, the addition of active warming using a chemical heat pad applied to the torso will significantly improve thermal comfort even further and might also reduce the cold induced stress response.

Trial Registration

ClinicalTrials.gov: NCT01400152

Comparison of three different prehospital wrapping methods for preventing hypothermia--a crossover study in humans

BACKGROUND

Accidental hypothermia increases mortality and morbidity in trauma patients. Various methods for insulating and wrapping hypothermic patients are used worldwide. The aim of this study was to compare the thermal insulating effects and comfort of bubble wrap, ambulance blankets / quilts, and Hibler's method, a low-cost method combining a plastic outer layer with an insulating layer.

METHODS

Eight volunteers were dressed in moistened clothing, exposed to a cold and windy environment then wrapped using one of the three different insulation methods in random order on three different days. They were rested quietly on their back for 60 minutes in a cold climatic chamber. Skin temperature, rectal temperature, oxygen consumption were measured, and metabolic heat production was calculated. A questionnaire was used for a subjective evaluation of comfort, thermal sensation, and shivering.

RESULTS

Skin temperature was significantly higher 15 minutes after wrapping using Hibler's method compared with wrapping with ambulance blankets / quilts or bubble wrap. There were no differences in core temperature between the three insulating methods. The subjects reported more shivering, they felt colder, were more uncomfortable, and had an increased heat production when using bubble wrap compared with the other two methods. Hibler's method was the volunteers preferred method for preventing hypothermia. Bubble wrap was the least effective insulating method, and seemed to require significantly higher heat production to compensate for increased heat loss.

CONCLUSIONS

This study demonstrated that a combination of vapour tight layer and an additional dry insulating layer (Hibler's method) is the most efficient wrapping method to prevent heat loss, as shown by increased skin temperatures, lower metabolic rate and better thermal comfort. This should then be the method of choice when wrapping a wet patient at risk of developing hypothermia in prehospital environments.

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

BACKGROUND

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

AIM

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

METHOD

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

MAIN RESULTS

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

CONCLUSION

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

Management of bleeding following major trauma: an updated European guideline

INTRODUCTION

Evidence-based recommendations are needed to guide the acute management of the bleeding trauma patient, which when implemented may improve patient outcomes.

METHODS

The multidisciplinary Task Force for Advanced Bleeding Care in Trauma was formed in 2005 with the aim of developing a guideline for the management of bleeding following severe injury. This document presents an updated version of the guideline published by the group in 2007. Recommendations were formulated using a nominal group process, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) hierarchy of evidence and based on a systematic review of published literature.

RESULTS

Key changes encompassed in this version of the guideline include new recommendations on coagulation support and monitoring and the appropriate use of local haemostatic measures, tourniquets, calcium and desmopressin in the bleeding trauma patient. The remaining recommendations have been reevaluated and graded based on literature published since the last edition of the guideline. Consideration was also given to changes in clinical practice that have taken place during this time period as a result of both new evidence and changes in the general availability of relevant agents and technologies.

CONCLUSIONS

This guideline provides an evidence-based multidisciplinary approach to the management of critically injured bleeding trauma patients.

Field torso-warming modalities: a comparative study using a human model

OBJECTIVE

To compare four field-appropriate torso-warming modalities that do not require alternating-current (AC) electrical power, using a human model of nonshivering hypothermia.

METHODS

Five subjects, serving as their own controls, were cooled four times in 8 degrees C water for 10-30 minutes. Shivering was inhibited by buspirone (30 mg) taken orally prior to cooling and intravenous (IV) meperidine (1.25 mg/kg) at the end of immersion. Subjects were hoisted out of the water, dried, and insulated and then underwent 120 minutes of one of the following: spontaneous warming only; a charcoal heater on the chest; two flexible hot-water bags (total 4 liters of water at 55 degrees C, replenished every 20 minutes) applied to the chest and upper back; or two chemical heating pads applied to the chest and upper back. Supplemental meperidine (maximum cumulative dose of 3.5 mg/kg) was administered as required to inhibit shivering.

RESULTS

The postcooling afterdrop (i.e., the continued decrease in body core temperature during the early period of warming), compared with spontaneous warming (2.2 degrees C), was less for the chemical heating pads (1.5 degrees C) and the hot-water bags (1.6 degrees C, p < 0.05) and was 1.8 degrees C for the charcoal heater. Subsequent core rewarming rates for the hot-water bags (0.7 degree C/h) and the charcoal heater (0.6 degree C/h) tended to be higher than that for the chemical heating pads (0.2 degree C/h) and were significantly higher than that for spontaneous warming rate (0.1 degrees C/h, p < 0.05).

CONCLUSION

In subjects with shivering suppressed, greater sources of external heat were effective in attenuating core temperature afterdrop, whereas sustained sources of external heat effectively established core rewarming. Depending on the scenario and available resources, we recommend the use of charcoal heaters, chemical heating pads, or hot-water bags as effective means for treating cold patients in the field or during transport to definitive care.

Pre-hospital trauma care

The chain of survival in outcome from major trauma is equally as important as its well established concept in survival from cardiac arrest. Preventive measures have been shown to be an effective means of reducing death from trauma, and the standard of pre-hospital care for those surviving the primary injury is improving in many trauma systems. The optimal pre-hospital interventions are still debated, but evidence suggests that patients with severe head injury in particular will benefit significantly from pre-hospital rapid-sequence intubation and field stabilization, whereas those with penetrating injury require rapid evacuation to hospital with minimal intervention. Pre-hospital asystole from trauma has a universally poor outcome. When delivering appropriate care, several helicopter-based systems have shown improvements in outcome compared with ground-based systems. The International Liaison Committee on Resuscitation recently published guidelines on resuscitation, with particular relevance to pre-hospital trauma care. The importance of bystander cardiopulmonary resuscitation, oxygenation, and the avoidance of iatrogenic morbidity are stressed.

Management of bleeding following major trauma: a European guideline

INTRODUCTION

Evidence-based recommendations can be made with respect to many aspects of the acute management of the bleeding trauma patient, which when implemented may lead to improved patient outcomes.

METHODS

The multidisciplinary Task Force for Advanced Bleeding Care in Trauma was formed in 2005 with the aim of developing guidelines for the management of bleeding following severe injury. Recommendations were formulated using a nominal group process and the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) hierarchy of evidence and were based on a systematic review of published literature.

RESULTS

Key recommendations include the following: The time elapsed between injury and operation should be minimised for patients in need of urgent surgical bleeding control, and patients presenting with haemorrhagic shock and an identified source of bleeding should undergo immediate surgical bleeding control unless initial resuscitation measures are successful. A damage control surgical approach is essential in the severely injured patient. Pelvic ring disruptions should be closed and stabilised, followed by appropriate angiographic embolisation or surgical bleeding control, including packing. Patients presenting with haemorrhagic shock and an unidentified source of bleeding should undergo immediate further assessment as appropriate using focused sonography, computed tomography, serum lactate, and/or base deficit measurements. This guideline also reviews appropriate physiological targets and suggested use and dosing of blood products, pharmacological agents, and coagulation factor replacement in the bleeding trauma patient.

CONCLUSION

A multidisciplinary approach to the management of the bleeding trauma patient will help create circumstances in which optimal care can be provided. By their very nature, these guidelines reflect the current state-of-the-art and will need to be updated and revised as important new evidence becomes available.

Nursing and medical staff knowledge regarding the monitoring and management of accidental or exposure hypothermia in adult major trauma patients

Recording a patient's vital signs is a basic requirement that in part informs clinical decision-making. Practice suggests that recording a trauma patient's temperature is occasionally overlooked in the emergency department. A staff survey was undertaken to gain an appreciation of knowledge and understanding of the issues that surround accidental or exposure hypothermia in trauma patients. Results demonstrate that nurses and doctors are unsure of how to define hypothermia and are not conversant with simple ways to prevent heat loss or rewarm patients. Complications from hypothermia such as coagulopathy and metabolic acidosis were seldom identified. Issues that limit staff recording temperature include patient access and acuity, lack of knowledge and confidence and access to temperature-measuring devices. These results emphasize the need for regular education. Implications for clinical practice were considered; an algorithm to guide staff on ways to improve the monitoring and management of temperature in trauma patients was developed. Opportunities for ongoing and further research were identified.

KEY ISSUES IN ADVANCED BLEEDING CARE IN TRAUMA

The incidence of hemostatic abnormalities in the early hours after traumatic incident is high and represents an independent predictor of mortality. Key factors in the development of traumatic coagulopathy include the severity of injury, hypothermia, acidosis, hemorrhagic shock, hemodilution, clotting factor consumption, and fibrinolysis. Assessment of bleeding includes evaluation of the mechanism of injury, vital signs, biochemistry, detection of external and internal bleeding sources, injuries found upon secondary investigation, and response to treatment. Priority in treating the bleeding trauma patient should be given to prevention of further bleeding, hypothermia, acidosis, coagulopathy, and maintenance of tissue oxygenation, achieved by careful physical handling, damage control surgery, analgesia, maintenance of normothermia, correction of coagulopathy, control of blood pH, and serum calcium. Priority during initial treatment is to restore tissue perfusion and achieve hemostasis in vital functions; other nonvital procedures may generally be delayed. This state-of-the-art review aims to address key issues in acute control of bleeding in the trauma patient.

Prehospital management of earthquake casualties buried under rubble

Earthquakes continue to exact a heavy toll on life, injury, and loss of property. Survival of casualties extricated from under the rubble depends upon early medical interventions by emergency teams on site. The objective of this paper is to review the pertinent literature and to analyze the information as a practical guideline for the medical management of casualties accidentally buried alive.

Forehead SpO2 monitoring compared to finger SpO2 recording in emergency transport

Continuous peripheral oxygen saturation monitoring using a finger pulse oximeter is standard in prehospital emergency medicine. Forehead peripheral oxygen saturation monitoring has been enhanced for better performance during movement and in cold ambient temperatures, both of which are common during emergency transport. We compared a new forehead monitor with standard finger pulse oximeter. The forehead technique had significantly fewer mean (SD) alarms per patient (3.0 (2.2)) than the finger pulse oximeter (7.8 (4.0)) and shorter durations of malfunction (76 (60) s compared to 333 (170) s) when using the finger pulse oximeter. We conclude that measuring peripheral oxygen saturation monitoring with a forehead sensor provides better monitoring quality in emergency care.

[Evaluation of a new insulating system for infusion solutions in preclinical trauma therapy: a prospective, randomized study]

OBJECTIVE

Infusion of cold fluids in a patient leads to a reduction of core temperature and subsequently worsens hypothermia. We evaluated the efficacy of a newly developed self-warming insulation device for use in pre-hospital rescue.

METHODS

We studied 50 trauma patients with a rescue time of more than one hour. They were randomly assigned to either infusions taken directly from a warming box in the ambulance (Group A, n = 25) or infusions taken from the warming box and packed in an insulation device (Group B, n = 25). We recorded ambient temperatures, infusion temperatures in five-minute-steps and transport duration of the infusions from the ambulance to the site of accident.

RESULTS

Ambient temperatures and transport duration did not differ significantly between both groups. In Group A the infusion temperature decreased from 36.0 +/- 6.4 degrees C to 19.8 +/- 6.8 degrees C during the transport from the ambulance to the site of accident. In Group B infusion temperature decreased only about 1 degree C. In Group A the temperature of the infusion continued to decrease until the end of measurements. In contrast in Group B the infusion temperature even increased by 0.5 degree C over the measurement period. These differences between the two groups were statistically significant.

CONCLUSIONS

Our data show that even pre-warmed infusions from a warming box cool down considerably before they can be given to the patient. A self-warming insulation device can stabilize infusion temperature even under extreme conditions of prehospital trauma care.

Preventing post-injury hypothermia during prolonged prehospital evacuation

INTRODUCTION

Post-injury hypothermia is a risk predictor in trauma patients whose physiology is deranged. The aim of the present study was to examine the effect of simple, in-field, hypothermia prevention to victims of penetrating trauma during long prehospital evacuations.

METHODS

A total of 170 consecutively injured landmine victims were included in a prospective, clinical study in Northern Iraq and Cambodia. Thirty patients were provided with systematic prehospital hypothermia prevention, and for 140 patients, no preventive measures were provided.

RESULTS

The mean value for the time from injury to hospital admission was 6.6 hours (range: 0.2-72). The incidence of hypothermia (oral temperature < 36 degrees C) before prevention/rewarming was 21% (95% confidence interval: 15% to 28%). The Prevention Group had a statistically significant lower rate of hypothermia on hospital admission compared to the control group (95% confidence interval for difference: 6% to 24%).

CONCLUSION

Simple, preventive, in-field measures help to prevent hypothermia during protracted evacuation, and should be part of the trauma care protocol in rural rescue systems.

The development of a register of randomized controlled trials in prehospital trauma care

OBJECTIVES

To establish a register of randomized controlled trials of interventions in the prehospital care of trauma patients.

METHODS

A systematic search was conducted for all randomized controlled trials of interventions in the prehospital care of trauma patients. The search included the Cochrane Controlled Trial Register, the Cochrane Injuries Group Specialised Register, Medline, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), Science Citation Index, National Research Register, Dissertation Abstracts, and PubMed for the time period 1966-2000. There were no language restrictions. In addition, full-text hand searching of a range of relevant journals was done, and the authors of included trials were contacted.

RESULTS

The combined search strategy identified 16,037 potentially eligible records, of which 28 were reports of randomized controlled trials evaluating prehospital trauma care interventions. After excluding duplicate reports, there were 24 separate randomized controlled trials including 6,806 patients. The largest and smallest trials involved 1,309 and 30 trauma patients, respectively.

CONCLUSIONS

This register will facilitate the conduct of systematic reviews of the effectiveness of interventions in prehospital trauma care. However, despite the extensive searching, very few randomized trials in this area were found. In view of the absence of evidence for the effectiveness of many of the interventions that are used in the prehospital care of trauma patients, further randomized controlled trials are required.

Avoiding hypothermia in the trauma patient

Hypothermia may be encountered during the management of severely injured patients, and with exception of deliberate hypothermia for neuroprotection, has been associated with increased morbidity and mortality. This review examines the recent literature with regard to risk factors for developing hypothermia, significance of hypothermia, therapeutic use of hypothermia, and invasive and noninvasive methods to prevent and treat hypothermia.