Accidental hypothermia

Extracorporeal membrane oxygenation rewarming in the ED: an opportunity for success

On average, approximately 1300 Americans die of hypothermia each year. Although accidental hypothermia is commonly associated with severely cold regions or mountain accident victims, hypothermia also commonly occurs in urban centers. Contributing factors often include homelessness, mental illness, and substance abuse. Hypothermia can profoundly affect the cardiovascular system. As the myocardium cools, the conduction system slows down,which results in prolongation of the QT interval as well as propensity for arrhythmias. Eventually, bradycardia, atrial fibrillation, and ventricular fibrillation (VF) can develop. The risk of cardiac arrest increases as the core temperature drops below 32°C and increases substantially when less than 28°C.

Is body temperature an independent predictor of mortality in hip fracture patients?

INTRODUCTION

Admission body temperature is a critical parameter in all trauma patients. Low admission temperature is strongly associated with adverse outcomes. We have previously shown, in a prospective study that low admission body temperature is common and associated with high mortality in hip fracture patients (Uzoigwe et al., 2014). However, no previous studies have evaluated whether admission temperature is an independent predictor of mortality in hip fracture patients after adjustment for the 7 recognised independent prognostic indicators (Maxwell et al., 2008).

METHODS

We retrospectively collated data on all patients presenting to our institution between June 2011 and February 2013 with a hip fracture. This included patients involved in the original prospective study (Uzoigwe et al., 2014). Admission tympanic temperature, measured on initial presentation at triage, was recorded. The prognosticators of age, gender, source of admission, abbreviated mental test score, haemoglobin, co-morbid disease and the presence or absence of malignancy were also recorded. Using multiple logistic regression, adjustment was made for these potentially confounding prognostic indicators of 30-day mortality, to determine if admission low body temperature were independently linked to mortality.

RESULTS

1066 patients were included. 781 patients, involved in the original prospective study (Uzoigwe et al., 2014), presented in the relevant time frame and were included in the retrospective study. The mean age was 81. There were 273 (26%) men and 793 (74%) women. 407 (38%) had low body temperature (<36.5 °C). Adjustment was made for age, gender, source of admission, abbreviated mental test score, haemoglobin, co-morbid disease and the presence or absence of malignancy. Those with low body temperature had an adjusted odds ratio of 30-day mortality that was 2.1 times that of the euthermic (36.5–37.5 °C).

CONCLUSIONS

Low body temperature is strongly and independently associated with 30-day mortality in hip fracture patients.

Epidemiology and mortality of glacier crevasse accidents

INTRODUCTION

Crevasse accidents can lead to severe injuries and even death, but little is known about their epidemiology and mortality.

METHODS

We retrospectively reviewed helicopter-based emergency services rescue missions for crevasse victims in Switzerland between 2000 and 2010. Demographic and epidemiological data were collected. Injury severity was graded according to the National Advisory Committee for Aeronautics (NACA) score.

RESULTS

A total of 415 victims of crevasse falls were included in the study. The mean victim age was 40 years (SD 13) (range 6-75), 84% were male, and 67% were foreigners. The absolute number of victims was much higher during the months of March, April, July, and August, amounting to 73% of all victims; 77% of victims were practicing mountaineering or ski touring. The mean depth of fall was 16.5m (SD 9.0) (range 1-35). Overall on-site mortality was 11%, and it was higher during the ski season than the ski offseason (14% vs. 7%; P=0.01), for foreigners (14% vs. 5%; P=0.01), and with higher mean depth of fall (22 vs. 15m; P=0.01). The NACA score was ≥4 for 22% of the victims, indicating potential or overt vital threatening injuries, but 24% of the victims were uninjured (NACA 0). Multivariable analyses revealed that depth of the fall, summer season, and snowshoeing were associated with higher NACA scores, whereas depth of the fall, snowshoeing, and foreigners but not season were associated with higher risk of death.

CONCLUSION

The clinical spectrum of injuries sustained by the 415 patients in this study ranged from benign to life-threatening. Death occurred in 11% of victims and seems to be determined primarily by the depth of the fall.

Hypothermia in victims of the great East Japan earthquake: a survey in Miyagi prefecture

OBJECTIVE

A survey was conducted to describe the characteristics of patients treated for hypothermia after the Great East Japan Earthquake.

METHODS

Written questionnaires were distributed to 72 emergency medical hospitals in Miyagi Prefecture. Data were requested regarding inpatients with a temperature less than 36ºC admitted within 72 hours after the earthquake. The availability of functional heating systems and the time required to restore heating after the earthquake were also documented.

RESULTS

A total of 91 inpatients from 13 hospitals were identified. Tsunami victims comprised 73% of the patients with hypothermia. Within 24 hours of the earthquake, 66 patients were admitted. Most patients with a temperature of 32ºC or higher were treated with passive external rewarming with blankets. Discharge without sequelae was reported for 83.3% of patients admitted within 24 hours of the earthquake and 44.0% of those admitted from 24 to 72 hours after the earthquake. Heating systems were restored within 3 days of the earthquake at 43% of the hospitals.

CONCLUSIONS

Hypothermia in patients hospitalized within 72 hours of the earthquake was primarily due to cold-water exposure during the tsunami. Many patients were successfully treated in spite of the post-earthquake disruption of regional social infrastructure.

Defibrillation in rural areas

AIM OF THE STUDY

Automated external defibrillation (AED) and public access defibrillation (PAD) have become cornerstones in the chain of survival in modern cardiopulmonary resuscitation. Most studies of AED and PAD have been performed in urban areas, and evidence is scarce for sparsely populated rural areas. The aim of this review was to review the literature and discuss treatment strategies for out-of-hospital cardiac arrest in rural areas.

METHODS

A Medline search was performed with the keywords automated external defibrillation (617 hits), public access defibrillation (256), and automated external defibrillator public (542). Of these 1415 abstracts and additional articles found by manually searching references, 92 articles were included in this nonsystematic review.

RESULTS

Early defibrillation is crucial for survival with good neurological outcome after cardiac arrest. Rapid defibrillation can be a challenge in sparsely populated and remote areas, where the incidence of cardiac arrest is low and rescuer response times can be long. The few studies performed in rural areas showed that the introduction of AED programs based on a 2-tier emergency medical system, consisting of Basic Life Support and Advanced Life Support teams, resulted in a decrease in collapse-to-defibrillation times and better survival of patients with out-of-hospital cardiac arrest.

CONCLUSIONS

In rural areas, introducing AED programs and a 2-tier emergency medical system may increase survival of out-of-hospital cardiac arrest patients. More studies on AED and PAD in rural areas are required.

Peripheral thermosensation in mammals

Our ability to perceive temperature is crucial: it enables us to swiftly react to noxiously cold or hot objects and helps us to maintain a constant body temperature. Sensory nerve endings, upon depolarization by temperature-gated ion channels, convey electrical signals from the periphery to the CNS, eliciting a sense of temperature. In the past two decades, we have witnessed important advances in our understanding of mammalian thermosensation, with the identification and animal-model assessment of candidate molecular thermosensors - such as types of transient receptor potential (TRP) cation channels - involved in peripheral thermosensation. Ongoing research aims to understand how these miniature thermometers operate at the cellular and molecular level, and how they can be pharmacologically targeted to treat pain without disturbing vital thermoregulatory processes.

Survival after avalanche-induced cardiac arrest

AIM

Criteria to prolong resuscitation after cardiac arrest (CA) induced by complete avalanche burial are critical since profound hypothermia could be involved. We sought parameters associated with survival in a cohort of victims of complete avalanche burial.

METHODS

Retrospective observational study of patients suffering CA on-scene after avalanche burial in the Northern French Alps between 1994 and 2013. Criteria associated with survival at discharge from the intensive care unit (ICU) were collected on scene and upon admission to Level-1 trauma center. Neurological outcome was assessed at 3 months using cerebral performance category score.

RESULTS

Forty-eight patients were studied. They were buried for a median time of 43 min (25-76 min; 25-75th percentiles) and had a pre-hospital body core temperature of 28.0°C (26.0-30.7). Eighteen patients (37.5%) had pre-hospital return of spontaneous circulation and 30 had refractory CA. Rewarming of 21 patients (43.7%) was performed using extracorporeal life support. Eight patients (16.7%) survived and were discharged from the ICU, three (6.3%) had favorable neurological outcome at 3 months. Pre-hospital parameters associated with survival were the presence of an air pocket and rescue collapse. On admission, survivors had lower serum potassium concentrations than non-survivors: 3.2 mmol/L (2.7-4.0) versus 5.6 mmol/L (4.2-8.0), respectively (P<0.01). They also had normal values for prothrombin and activated partial thromboplastin compared to non-survivors.

CONCLUSIONS

Our findings indicate that survival after avalanche burial and on-scene CA is rarely associated with favorable neurological outcome. Among criteria associated with survival, normal blood coagulation on admission warrants further investigation.

High-altitude mountaineering made safer

Mountains all over the world are attracting a steadily growing number of visitors due to the increasing number of cheap flights; the construction of new roads, railways, and cable cars; and commercial offers of trekking tours and expeditions to attempt even the world's highest peaks. However, one must not forget that mountains are typically inhospitable areas characterised by cold and hypoxic environments and rapidly changing weather and track conditions associated with a relatively high risk of accidents and emergencies. Beside the objective hazards, subjective hazards, for example physical fitness and health status, mountaineering skills, and equipment, contribute substantially to the risk. Whereas in some regions, for example the Alps, rescue operations and medical emergency interventions can be performed rapidly and effectively, this is absolutely not the case in most of the very remote areas and on very high mountains. Therefore, the understanding of the risk associated with the various modes of mountaineering as well as knowledge about how to optimise prevention is of the utmost importance. Ultimately, it is the informed mountaineer who has to decide whether the risks are acceptable or not. Continuing joint efforts of scientists, medical and alpine institutions, expedition organisers, and mountaineers will help to make high-altitude mountaineering safer.

[Publication performances of university clinics for anesthesiology: Germany, Austria and Switzerland from 2001 to 2010]

AIM

This study assessed the publication performance of university departments of anesthesiology in Austria, Germany and Switzerland. The number of publications, original articles, impact factors and citations were evaluated.

MATERIAL AND METHODS

A search was performed in PubMed to identify publications related to anesthesiology from 2001 to 2010. All articles from anesthesiology journals listed in the fields of anesthesia/pain therapy, critical care and emergency medicine by the "journal citation report 2013" in Thomson Reuters ISI web of knowledge were included. Articles from non-anaesthesiology journals, where the stem of the word anesthesia (anes*, anaes*, anäst*, anast*) appears in the affiliation field of PubMed, were included as well. The time periods 2001-2005 and 2006-2010 were compared. Articles were allocated to university departments in Austria, Germany and Switzerland via the affiliation field.

RESULTS

A total of 45 university departments in Austria, Germany and Switzerland and 125,979 publications from 2,863 journals (65 anesthesiology journals, 2,798 non-anesthesiology journals) were analyzed. Of the publications 23 % could not be allocated to a given university department of anesthesiology. In the observation period the university department of anesthesiology in Berlin achieved most publications (n = 479) and impact points (1,384), whereas Vienna accumulated most original articles (n = 156). Austria had the most publications per million inhabitants in 2006-2010 (n=50) followed by Switzerland (n=49) and Germany (n=35). The number of publications during the observation period decreased in Germany (0.5 %), Austria (7 %) and Switzerland (8 %). Tables 2 and 4-8 of this article are available at Springer Link under Supplemental.

CONCLUSIONS

The research performance varied among the university departments of anesthesiology in Germany, Austria and Switzerland whereby larger university departments, such as Berlin or Vienna published most. Publication output in Germany, Austria and Switzerland has decreased. Data processing in PubMed should be improved.

Surviving two hours of ventricular fibrillation in accidental hypothermia

BACKGROUND

Cardiac arrest as a consequence of deep accidental hypothermia is associated with high mortality. Standardized prehospital management as well as rewarming with extracorporeal circulation (ECC) are important factors to improve survival. The objective of this case report is to illustrate the importance of effective cardiopulmonary resuscitation (CPR) and ECC in a cardiac arrest following deep accidental hypothermia.

CASE REPORT

A 42-year-old man was found unresponsive to external stimuli and pulseless at an outdoor temperature of 1°C. CPR was started at the scene by laypersons, and the emergency medical services (EMS) arrived 5 minutes after the emergency call. Resuscitation according to International Liaison Committee on Resuscitation (ILCOR) guidelines was initiated by EMS. The first recorded rhythm was ventricular fibrillation (VF), which persisted, despite repeated defibrillation. The patient showed signs of severe hypothermia and, during ongoing CPR, was transported to hospital where on arrival the patient's rectal temperature was measured at 22°C. Resuscitation measures were continued and warming was started at the emergency room. Due to persistent VF and deep hypothermia, the patient was transferred to a cardiothoracic surgical unit for rewarming with ECC. At commencement of ECC, CPR had been going for approximately 130 minutes and a total of 38 defibrillations had been made. During this time interval the patients was pulseless. At a core temperature of 30°C, one defibrillation restored sinus rhythm and subsequently stable circulation was achieved. The patient received a further 24 hours of hypothermia treatment at 32-34°C. He was discharged to rehabilitation facilities after 3 weeks of hospital care. Three months after the cardiac arrest the patient was fully recovered, was back to work, and had resumed normal activities.

CONCLUSIONS

We demonstrate a case of cardiac arrest due to deep accidental hypothermia that stresses the importance of effective CPR and early-stage consideration of the use of ECC for safe and effective rewarming.

Neurologic recovery from profound accidental hypothermia after 5 hours of cardiopulmonary resuscitation

OBJECTIVE

To describe the successful neurologic recovery from profound accidental hypothermia with cardiac arrest despite the longest reported duration of cardiopulmonary resuscitation.

DESIGN

Case report.

SETTING

Mountain.

PATIENT

A 57-year-old woman experienced profound accidental hypothermia (16.9°C) in a mountainous region of Grenoble. She was unconscious and had extreme bradycardia (6 beats/min) at presentation. A cardiac arrest occurred at the mobilization that was not responsive to electrical shocks or epinephrine.

INTERVENTION

Cardiopulmonary resuscitation was continued for 307 minutes after rescue until venoarterial extracorporeal membrane oxygenation blood flow had been established at the emergency department.

MEASUREMENTS AND MAIN RESULTS

At a 3-month follow-up, the patient showed good physical and mental recovery.

CONCLUSION

With no evidence of trauma or asphyxia, profound accidental hypothermia with cardiac arrest represents a specific condition for which successful neurologic recovery is feasible despite prolonged cardiopulmonary resuscitation.

Mechanical chest compressions in an avalanche victim with cardiac arrest: an option for extreme mountain rescue operations

Mountain rescue operations often present helicopter emergency medical service crews with unique challenges. One of the most challenging problems is the prehospital care of cardiac arrest patients during evacuation and transport. In this paper we outline a case in which we successfully performed a cardiopulmonary resuscitation of an avalanche victim. A mechanical chest-compression device proved to be a good way of minimizing hands-off time and providing high-quality chest compressions while the patient was evacuated from the site of the accident.

Accidental cold-related injury leading to hospitalization in northern Sweden: an eight-year retrospective analysis

BACKGROUND

Cold injuries are rare but important causes of hospitalization. We aimed to identify the magnitude of cold injury hospitalization, and assess causes, associated factors and treatment routines in a subarctic region.

METHODS

In this retrospective analysis of hospital records from the 4 northernmost counties in Sweden, cases from 2000-2007 were identified from the hospital registry by diagnosis codes for accidental hypothermia, frostbite, and cold-water drowning. Results were analyzed for pre-hospital site events, clinical events in-hospital, and complications observed with mild (temperature 34.9 - 32°C), moderate (31.9 - 28°C) and severe (<28°C), hypothermia as well as for frostbite and cold-water drowning.

RESULTS

From the 362 cases, average annual incidences for hypothermia, frostbite, and cold-water drowning were estimated to be 3.4/100,000, 1.5/100,000, and 0.8/100,000 inhabitants, respectively. Annual frequencies for hypothermia hospitalizations increased by approximately 3 cases/year during the study period. Twenty percent of the hypothermia cases were mild, 40% moderate, and 24% severe. For 12%, the lowest documented core temperature was 35°C or higher, for 4% there was no temperature documented. Body core temperature was seldom measured in pre-hospital locations. Of 362 cold injury admissions, 17 (5%) died in hospital related to their injuries. Associated co-factors and co-morbidities included ethanol consumption, dementia, and psychiatric diagnosis.

CONCLUSIONS

The incidence of accidental hypothermia seems to be increasing in this studied sub-arctic region. Likely associated factors are recognized (ethanol intake, dementia, and psychiatric diagnosis).

Vital signs, QT prolongation, and newly diagnosed cardiovascular disease during severe hypoglycemia in type 1 and type 2 diabetic patients

OBJECTIVE To assess vital signs, QT intervals, and newly diagnosed cardiovascular disease during severe hypoglycemia in diabetic patients. RESEARCH DESIGN AND METHODS From January 2006 to March 2012, we conducted a retrospective cohort study to assess type 1 and type 2 diabetic patients with severe hypoglycemia at a national center in Japan. Severe hypoglycemia was defined as the presence of any hypoglycemic symptoms that could not be resolved by the patients themselves in prehospital settings. RESULTS A total of 59,602 cases that visited the emergency room by ambulance were screened, and 414 cases of severe hypoglycemia were analyzed. The median (interquartile range) blood glucose levels were not significantly different between the type 1 diabetes mellitus (T1DM) (n = 88) and type 2 diabetes mellitus (T2DM) (n = 326) groups (32 [24-42] vs. 31 [24-39] mg/dL, P = 0.59). During severe hypoglycemia, the incidences of severe hypertension (≥180/120 mmHg), hypokalemia (<3.5 mEq/L), and QT prolongation were 19.8 and 38.8% (P = 0.001), 42.4 and 36.3% (P = 0.30), and 50.0 and 59.9% (P = 0.29) in the T1DM and T2DM groups, respectively. Newly diagnosed cardiovascular disease during severe hypoglycemia and death were only observed in the T2DM group (1.5 and 1.8%, respectively). Blood glucose levels between the deceased and surviving patients in the T2DM group were significantly different (18 [14-33] vs. 31 [24-39] mg/dL, P = 0.02). CONCLUSIONS T1DM and T2DM patients with severe hypoglycemia experienced many critical problems that could lead to cardiovascular disease, fatal arrhythmia, and death.

Wilderness medicine

BACKGROUND

Human activity in wilderness areas has increased globally in recent decades, leading to increased risk of injury and illness. Wilderness medicine has developed in response to both need and interest.

METHODS

The field of wilderness medicine encompasses many areas of interest. Some focus on special circumstances (such as avalanches) while others have a broader scope (such as trauma care). Several core areas of key interest within wilderness medicine are discussed in this study.

RESULTS

Wilderness medicine is characterized by remote and improvised care of patients with routine or exotic illnesses or trauma, limited resources and manpower, and delayed evacuation to definitive care. Wilderness medicine is developing rapidly and draws from the breadth of medical and surgical subspecialties as well as the technical fields of mountaineering, climbing, and diving. Research, epidemiology, and evidence-based guidelines are evolving. A hallmark of this field is injury prevention and risk mitigation. The range of topics encompasses high-altitude cerebral edema, decompression sickness, snake envenomation, lightning injury, extremity trauma, and gastroenteritis. Several professional societies, academic fellowships, and training organizations offer education and resources for laypeople and health care professionals.

CONCLUSIONS

THE FUTURE OF WILDERNESS MEDICINE IS UNFOLDING ON MULTIPLE FRONTS: education, research, training, technology, communications, and environment. Although wilderness medicine research is technically difficult to perform, it is essential to deepening our understanding of the contribution of specific techniques in achieving improvements in clinical outcomes.

Validity and reliability of the Cold Discomfort Scale: a subjective judgement scale for the assessment of patient thermal state in a cold environment

Complementary measures for the assessment of patient thermoregulatory state, such as subjective judgement scales, might be of considerable importance in field rescue scenarios where objective measures such as body core temperature, skin temperature, and oxygen consumption are difficult to obtain. The objective of this study was to evaluate, in healthy subjects, the reliability of the Cold Discomfort Scale (CDS), a subjective judgement scale for the assessment of patient thermal state in cold environments, defined as test–retest stability, and criterion validity, defined as the ability to detect a difference in cumulative cold stress over time. Twenty-two healthy subjects performed two consecutive trials (test–retest). Dressed in light clothing, the subjects remained in a climatic chamber set to −20 °C for 60 min. CDS ratings were obtained every 5 min. Reliability was analysed by test–retest stability using weighted kappa coefficient that was 0.84 including all the 5-min interval measurements. When analysed separately at each 5-min interval the weighted kappa coefficients were was 0.48–0.86. Criterion validity was analysed by comparing median CDS ratings of a moving time interval. The comparison revealed that CDS ratings were significantly increased for every interval of 10, 15, and 30 min (p < 0.001) but not for every interval of 5 min. In conclusion, in a prehospital scenario, subjective judgement scales might be a valuable measure for the assessment of patient thermal state. The results of this study indicated that, in concious patients, the CDS may be both reliable and valid for such purpose.

Oxidative stress and antioxidant activity in hypothermia and rewarming: can RONS modulate the beneficial effects of therapeutic hypothermia?

Hypothermia is a condition in which core temperature drops below the level necessary to maintain bodily functions. The decrease in temperature may disrupt some physiological systems of the body, including alterations in microcirculation and reduction of oxygen supply to tissues. The lack of oxygen can induce the generation of reactive oxygen and nitrogen free radicals (RONS), followed by oxidative stress, and finally, apoptosis and/or necrosis. Furthermore, since the hypothermia is inevitably followed by a rewarming process, we should also consider its effects. Despite hypothermia and rewarming inducing injury, many benefits of hypothermia have been demonstrated when used to preserve brain, cardiac, hepatic, and intestinal function against ischemic injury. This review gives an overview of the effects of hypothermia and rewarming on the oxidant/antioxidant balance and provides hypothesis for the role of reactive oxygen species in therapeutic hypothermia.

Classic Osborn waves and incessant ventricular fibrillation in severe hypothermia

Cardiac arrhythmias in severe hypothermia are common and are managed primarily by re-warming techniques. A 64-year-old male presented with alcohol associated aspiration pneumonia, sepsis and severe hypothermia and was noted to have classic ECG changes of hypothermia, i.e. Osborn waves. The patient had a tumultuous clinical course with prolonged resuscitative measures. Ultimately, an early focus on invasive core temperature re-warming with cardio-pulmonary bypass resulted in a favorable outcome.

Hemodynamic observations of tumo yoga practitioners in a Himalayan environment

BACKGROUND

Few attempts have been made to evaluate the physiology of traditional Eastern health practices. The goal of this study was to evaluate the hemodynamic effects of the mysterious Buddhist practice of tumo. Tumo is a meditative practice that produces inner heat through the alleged cultivation of body energy-channels.

METHODS

This study was performed by members of an international expedition to the Himalayan Mountains in the Republic of India. The study was performed in an unpopulated outdoor mountainous area at an altitude of 16,400 ft with ambient temperatures between -10 and -15(°)C. Two (2) cohorts of subjects were studied: healthy non-yogi volunteers and tumo practitioners. All of the subjects were stripped down to their underclothes and exposed to the subzero atmospheric temperatures for 5 minutes. The volunteers were then passively rewarmed while the tumo practitioners performed tumo for up to 10 minutes. Blood pressure, heart rate, and stroke volume index (SVI) and cardiac index were measured noninvasively using a NICOM™ hemodynamic monitor, while carotid blood flow and biventricular performance were determined echocardiographically at each stage of the experiment. The total peripheral resistance index (TPRI), left ventricular ejection fraction (LVEF), and tricuspid annular plane systolic excursion (TAPSE) were determined using standard formula.

RESULTS

Fourteen (14) subjects (six volunteers and eight tumo practitioners) completed the study. There was one female subject in each group. With cold exposure, the SVI and carotid blood flow decreased while the TPRI increased significantly in both groups. In the volunteer group, these changes retuned to baseline with rewarming. Following tumo, the cardiac index (4.8±0.6 versus 4.0±0.5 l/m(2); p<0.01), carotid blood flow (445±127 versus 325±100 mL/min/m(2), p<0.01), LVEF (68±5 versus 64±7%; p<0.05) and TAPSE (2.9±0.4 versus 2.4±0.5 cm; p<0.01) were significantly higher when compared with baseline, while the TPRI was significantly lower (1786±189 versus 2173±281; p<0.01).

CONCLUSIONS

Tumo was associated with a hyperdynamic vasodilated state with increased biventricular performance. We postulate that tumo results in a massive increase in sympathetic activity with activation of brown adipose tissue and marked heat production. The increased heat production may explain the paradoxical vasodilatation in tumo practitioners exposed to subzero temperatures.

[Accidental hypothermia]

Uncertainty exists on how to treat patients suffering from accidental hypothermia and on the optimal transport decisions. The aim of this review is to provide an updated evidence-based reference for the pre-hospital and in-hospital management of patients with accidental hypothermia and for the transport decisions required to facilitate treatment. Advances in the efficiency and availability of rewarming techniques have improved the prognosis for patients presenting with hypothermia. For hypothermic patients with a core body temperature ≥ 28 °C without cardiac instability there is increasing evidence to support the use of active external and minimally invasive rewarming techniques (e.g. chemical, electrical or forced air heating packs, blankets and warm parenteral fluids). Hypothermic patients with cardiac instability (i.e. systolic blood pressure < 90 mmHg, ventricular arrhythmia and core body temperature < 28 °C) should be rewarmed with active external and minimally invasive rewarming techniques in a hospital which also has circulation substituting venous-arterial extracorporeal membrane oxygenation (VA-ECMO) and cardiopulmonary bypass (CBP) facilities. In cardiac arrest patients VA-ECMO may be a better treatment option than CBP and survival rates of 100 % can be achieved compared to ~ 10 % with traditional methods (e.g. body cavity lavage). Early transport to a hospital appropriately equipped for rewarming has the potential to decrease complication rates and improve survival.

Ketamine: use in anesthesia

The role of ketamine anesthesia in the prehospital, emergency department and operating theater settings is not well defined. A nonsystematic review of ketamine was performed by authors from Australia, Europe, and North America. Results were discussed among authors and the final manuscript accepted. Ketamine is a useful agent for induction of anesthesia, procedural sedation, and analgesia. Its properties are appealing in many awkward clinical scenarios. Practitioners need to be cognizant of its side effects and limitations.

Resuscitation of avalanche victims: Evidence-based guidelines of the international commission for mountain emergency medicine (ICAR MEDCOM): intended for physicians and other advanced life support personnel

BACKGROUND

In North America and Europe ∼150 persons are killed by avalanches every year.

METHODS

The International Commission for Mountain Emergency Medicine (ICAR MEDCOM) systematically developed evidence-based guidelines and an algorithm for the management of avalanche victims using a worksheet of 27 Population Intervention Comparator Outcome questions. Classification of recommendations and level of evidence are ranked using the American Heart Association system.

RESULTS AND CONCLUSIONS

If lethal injuries are excluded and the body is not frozen, the rescue strategy is governed by the duration of snow burial and, if not available, by the victim's core-temperature. If burial time ≤35 min (or core-temperature ≥32 °C) rapid extrication and standard ALS is important. If burial time >35 min and core-temperature <32 °C, treatment of hypothermia including gentle extrication, full body insulation, ECG and core-temperature monitoring is recommended, and advanced airway management if appropriate. Unresponsive patients presenting with vital signs should be transported to a hospital capable of active external and minimally invasive rewarming such as forced air rewarming. Patients with cardiac instability or in cardiac arrest (with a patent airway) should be transported to a hospital for extracorporeal membrane oxygenation or cardiopulmonary bypass rewarming. Patients in cardiac arrest should receive uninterrupted CPR; with asystole, CPR may be terminated (or withheld) if a patient is lethally injured or completely frozen, the airway is blocked and duration of burial >35 min, serum potassium >12 mmol L(-1), risk to the rescuers is unacceptably high or a valid do-not-resuscitate order exists. Management should include spinal precautions and other trauma care as indicated.

[Life-saving air supported avalanche mission at night in high alpine terrain]

This is a case report about a helicopter emergency medical service (HEMS) operation during the night in response to an avalanche accident with two completely buried victims. One of the victims was rescued alive after 9.2 h presenting with a patent airway and an air pocket and was successfully rewarmed with forced air from 23°C core temperature without any neurological deficits. After the rescue the patient developed lung edema which resolved spontaneously within 2 days. The second victim was found dead presenting with an air pocket but solid frozen thorax. The special circumstances of the rescue operation and treatment are presented and discussed. The impact of a frozen chest on resuscitation decisions is presented and discussed with an emphasis on the triage of multiple victims.