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

Prevalence of airway patency and air pocket in critically buried avalanche victims - a scoping review

INTRODUCTION

Survival of critically buried avalanche victims is directly dependent on the patency of the airway and the victims' ability to breathe. While guidelines and avalanche research have consistently emphasized on the importance of airway patency, there is a notable lack of evidence regarding its prevalence.

OBJECTIVE

The aim of this review is to provide insight into the prevalence of airway patency and air pocket in critically buried avalanche victims.

METHODS

A scoping review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline extension for scoping reviews. MEDLINE and Cochrane databases, as well as additional manual searching was performed to identify literature reporting data on airway patency and the presence of an air pocket in critically buried avalanche victims. After eliminating duplicates, we screened abstracts and main texts to identify eligible studies.

RESULTS

Of 4,109 studies identified 154 were eligible for further screening. Twenty-four publications and three additional data sources with a total number of 566 cases were included in this review. The proportion of short-term (< 35 min) to long-term burial (≥ 35 min) in the analysed studies was 19% and 66%, respectively. The burial duration remained unknown in 12% of cases. The prevalence of airway patency in critically buried avalanche victims was 41% while that of airway obstruction was 12%, with an overall rate of reporting as low as 50%. An air pocket was present in 19% of cases, absent in 46% and unknown in 35% of the cases.

CONCLUSION

The present study found that in critically buried avalanche victims patent airways were more than three times more prevalent than obstructed, with the airway status reported only in half of the cases. This high rate of airway patency supports the ongoing development and the effectiveness of avalanche rescue systems which oppose asphyxiation in critically buried avalanche victims. Further effort should be done to improve the documentation of airway patency and the presence of an air pocket in avalanche victims and to identify factors affecting the rate of airway obstruction.

Wilderness Medical Society Clinical Practice Guidelines for Prevention and Management of Avalanche and Nonavalanche Snow Burial Accidents: 2024 Update

To provide guidance to the general public, clinicians, and avalanche professionals about best practices, the Wilderness Medical Society convened an expert panel to revise the evidence-based guidelines for the prevention, rescue, and resuscitation of avalanche and nonavalanche snow burial victims. The original panel authored the Wilderness Medical Society Practice Guidelines for Prevention and Management of Avalanche and Nonavalanche Snow Burial Accidents in 2017. A second panel was convened to update these guidelines and make recommendations based on quality of supporting evidence.

Surviving 20 Hours of Critical Avalanche Burial and a Core Temperature of 22.5 °C

A 24-year-old male snowboarder was buried in an avalanche for 20 h and rescued on the next day at a depth of 2.3 m below the snow surface. A large air pocket was noted in front of his mouth and nose. He was responsive but moved restlessly and uncoordinatedly. The epitympanic temperature was 22.5 °C. He was bradycardic (35/min), and a right bundle branch block with Osborn waves was noted. Rewarming (1 °C/h) was initiated with continuous hemodialysis; core temperature raised to 29.8 °C within 4 h. At 30 °C he became conscious. With rewarming, the heart rate increased to 90 beats per minute and the ECG changes disappeared; nonfreezing cold injuries were noted. On the next day, his pulmonary function deteriorated-fluid overload of 9 L since admission was diagnosed. With spontaneous diuresis, the situation improved. On Day 4, the neurologist reported subtle polyneuropathy in both legs secondary to hypothermia, without tendency to regress. This case occurred more than 20 years ago but has not been reported yet. To this day, this is the third-longest critical avalanche burial ever reported. We discuss the circumstances of this accident, the clinical course, and how treatment has changed since 2000.

Hypothermic cardiac arrest patients admitted to hospital who were not rewarmed with extracorporeal life support: A retrospective study

Aims

Our goal was to study hypothermic cardiac arrest (CA) patients who were not rewarmed by Extracorporeal Life Support (ECLS) but were admitted to a hospital equipped for it. The focus was on whether the decisions of non-rewarming, meaning termination of resuscitation, were compliant with international guidelines based on serum potassium at hospital admission.

Methods

We retrospectively included all hypothermic CA who were not rewarmed, from three Swiss centers between 1st January 2000 and 2nd May 2021. Data were extracted from medical charts and assembled into two groups for analysis according to serum potassium. We identified the criteria used to terminate resuscitation. We also retrospectively calculated the HOPE score, a multivariable tool predicting the survival probability in hypothermic CA undergoing ECLS rewarming.

Results

Thirty-eight victims were included in the study. The decision of non-rewarming was compliant with international guidelines for 12 (33%) patients. Among the 36 patients for whom the serum potassium was measured at hospital admission, 24 (67%) had a value that - alone - would have indicated ECLS. For 13 of these 24 (54%) patients, the HOPE score was <10%, meaning that ECLS was not indicated. The HOPE estimation of the survival probabilities, when used with a 10% threshold, supported 23 (68%) of the non-rewarming decisions made by the clinicians.

Conclusions

This study showed a low adherence to international guidelines for hypothermic CA patients. In contrast, most of these non-rewarming decisions made by clinicians would have been compliant with current guidelines based on the HOPE score.

The role of explainable Artificial Intelligence in high-stakes decision-making systems: a systematic review

A high-stakes event is an extreme risk with a low probability of occurring, but severe consequences (e.g., life-threatening conditions or economic collapse). The accompanying lack of information is a source of high-stress pressure and anxiety for emergency medical services authorities. Deciding on the best proactive plan and action in this environment is a complicated process, which calls for intelligent agents to automatically produce knowledge in the manner of human-like intelligence. Research in high-stakes decision-making systems has increasingly focused on eXplainable Artificial Intelligence (XAI), but recent developments in prediction systems give little prominence to explanations based on human-like intelligence. This work investigates XAI based on cause-and-effect interpretations for supporting high-stakes decisions. We review recent applications in the first aid and medical emergency fields based on three perspectives: available data, desirable knowledge, and the use of intelligence. We identify the limitations of recent AI, and discuss the potential of XAI for dealing with such limitations. We propose an architecture for high-stakes decision-making driven by XAI, and highlight likely future trends and directions.

Effects of Seawater Immersion on Lethal Triad and Organ Function in Healthy and Hemorrhagic Shock Rats

INTRODUCTION

Marine casualties are increasing, and mortality from trauma associated with immersion in seawater is high. However, the associated pathophysiological characteristics remain unclear, limiting research into the early emergency treatment strategy.

METHODS

Healthy and 50% hemorrhagic shock rats were soaked in 15°C and 21°C seawater for 2 h, 4 h and 6 h, respectively, and the effects on vital signs, internal environment, tissue metabolism, lethal triad, vital organ functions and survival were observed.

RESULTS

Immersion in seawater can cause death in healthy rats. Rats with hemorrhagic shock in 15°C seawater showed a lower survival rate than the corresponding groups in 21°C seawater. Moreover, compared with 21°C seawater, 15°C seawater played a more remarkable role in decreasing mean arterial pressure, heart rate, and respiration rate, increasing water content and decreasing Na⁺/K⁺-ATPase activity in the brain and lung; increase in plasma osmolality, Na⁺, K⁺, Cl^-, and the occurrence of the lethal triad manifested by a decrease in core body temperature, pH, lactate, and an increase in coagulation parameters, as well as damage to cardiac, intestinal, hepatic, and renal functions in rats with hemorrhagic shock.

CONCLUSIONS

Immersion in seawater at low temperatures could be lethal to healthy rats, causing the occurrence of a lethal triad and damage to vital organs. Furthermore, 15°C-seawater had a more significant effect than 21°C-seawater on aggravating the imbalance of internal environment and tissue metabolism, resulting in a higher incidence of the lethal triad and thus aggravating the dysfunctions of vital organs, which eventually resulted in higher mortality in rats with hemorrhagic shock.

On-site treatment of avalanche victims: Scoping review and 2023 recommendations of the international commission for mountain emergency medicine (ICAR MedCom)

INTRODUCTION

The International Commission for Mountain Emergency Medicine (ICAR MedCom) developed updated recommendations for the management of avalanche victims.

METHODS

ICAR MedCom created Population Intervention Comparator Outcome (PICO) questions and conducted a scoping review of the literature. We evaluated and graded the evidence using the American College of Chest Physicians system.

RESULTS

We included 120 studies including original data in the qualitative synthesis. There were 45 retrospective studies (38%), 44 case reports or case series (37%), and 18 prospective studies on volunteers (15%). The main cause of death from avalanche burial was asphyxia (range of all studies 65-100%). Trauma was the second most common cause of death (5-29%). Hypothermia accounted for few deaths (0-4%).

CONCLUSIONS AND RECOMMENDATIONS

For a victim with a burial time ≤ 60 minutes without signs of life, presume asphyxia and provide rescue breaths as soon as possible, regardless of airway patency. For a victim with a burial time > 60 minutes, no signs of life but a patent airway or airway with unknown patency, presume that a primary hypothermic CA has occurred and initiate cardiopulmonary resuscitation (CPR) unless temperature can be measured to rule out hypothermic cardiac arrest. For a victim buried > 60 minutes without signs of life and with an obstructed airway, if core temperature cannot be measured, rescuers can presume asphyxia-induced CA, and should not initiate CPR. If core temperature can be measured, for a victim without signs of life, with a patent airway, and with a core temperature < 30 °C attempt resuscitation, regardless of burial duration.

Electromagnetic Interference from Heated Gloves May Compromise Avalanche Transceiver Function

INTRODUCTION

Rapid location of avalanche victims by companions using avalanche transceivers is of utmost importance to prevent asphyxiation. The objective was to determine whether electromagnetic interference from heating elements in gloves worn by rescuers or victims can impair the receiving or transmitting function of avalanche beacons.

METHODS

Commercially available heated gloves from 3 different manufacturers were examined during a simulated search with 3 common brands of avalanche transceivers. Distance to target beacon at first signal detection and accuracy of direction to target, as indicated by the arrow from the direction indicator, were evaluated.

RESULTS

Preliminary tests showed that transmitting and receiving signals are degraded by electromagnetic interference caused by rectangular pulses emitted by activated heating elements. Field tests revealed significantly reduced distances of first signal detection when heated gloves were turned on near receiving avalanche transceivers (P<0.001; Wilcoxon signed-rank test). Decreased distance to target beacon ranged between 1.9 m (5%) and 41.5 m (94%) at first detection, depending on the avalanche transceiver used.

CONCLUSIONS

Avalanche transceivers are susceptible to electromagnetic interference from gloves with electric heating elements. We do not recommend using heated gloves when performing a transceiver search for avalanche victims because it can lead to a delay in rescue.

Avalanche survival depends on the time of day of the accident: A retrospective observational study

INTRODUCTION

We aimed to investigate the relationship between the time of the day and the probability of survival of completely buried avalanche victims. We explored the frequency of avalanche burials occurring after sunset, and described victims' characteristics, duration of burial and rescue circumstances compared to daytime avalanches.

METHODS

In this retrospective, observational study, we analysed avalanche data from the registry of the Swiss Institute for Snow and Avalanche Research, from 1998 to 2020.

RESULTS

A total of 3,892 avalanche victims were included in the analysis, with 72 of the accidents (1.85%) occurring in the nighttime. Nearly 50% of the victims involved in nighttime avalanche accidents were completely buried, compared to about 25% of victims in daytime avalanches. Completely buried victims were rescued by a companion less often at night than in the daytime (15% vs. 51%, p<.001). The search and rescue of completely buried avalanche victims took longer during the nighttime compared to the daytime (median 89 min vs 20 min, p=.002). The probability of survival decreased as the day progressed; it was highest at around midday (63.0%), but decreased at sunset (40.4%) and was the lowest at midnight (28.7%).

CONCLUSIONS

Avalanche accidents at night are a rare event, and probability of survival after complete burial is lower during the nighttime compared to the daytime. The most relevant reason for this is the longer duration of burial, which is explained in part by the lower rate of companion rescue and the lower rate of victim localisation with an avalanche transceiver.

Physiological Changes in Subjects Exposed to Accidental Hypothermia: An Update

Background

Accidental hypothermia (AH) is an unintended decrease in body core temperature (BCT) to below 35°C. We present an update on physiological/pathophysiological changes associated with AH and rewarming from hypothermic cardiac arrest (HCA).

Temperature Regulation and Metabolism

Triggered by falling skin temperature, Thyrotropin-Releasing Hormone (TRH) from hypothalamus induces release of Thyroid-Stimulating Hormone (TSH) and Prolactin from pituitary gland anterior lobe that stimulate thyroid generation of triiodothyronine and thyroxine (T4). The latter act together with noradrenaline to induce heat production by binding to adrenergic β3-receptors in fat cells. Exposed to cold, noradrenaline prompts degradation of triglycerides from brown adipose tissue (BAT) into free fatty acids that uncouple metabolism to heat production, rather than generating adenosine triphosphate. If BAT is lacking, AH occurs more readily.

Cardiac Output

Assuming a 7% drop in metabolism per °C, a BCT decrease of 10°C can reduce metabolism by 70% paralleled by a corresponding decline in CO. Consequently, it is possible to maintain adequate oxygen delivery provided correctly performed cardiopulmonary resuscitation (CPR), which might result in approximately 30% of CO generated at normal BCT.

Liver and Coagulation

AH promotes coagulation disturbances following trauma and acidosis by reducing coagulation and platelet functions. Mean prothrombin and partial thromboplastin times might increase by 40–60% in moderate hypothermia. Rewarming might release tissue factor from damaged tissues, that triggers disseminated intravascular coagulation. Hypothermia might inhibit platelet aggregation and coagulation.

Kidneys

Renal blood flow decreases due to vasoconstriction of afferent arterioles, electrolyte and fluid disturbances and increasing blood viscosity. Severely deranged renal function occurs particularly in the presence of rhabdomyolysis induced by severe AH combined with trauma.

Conclusion

Metabolism drops 7% per °C fall in BCT, reducing CO correspondingly. Therefore, it is possible to maintain adequate oxygen delivery after 10°C drop in BCT provided correctly performed CPR. Hypothermia may facilitate rhabdomyolysis in traumatized patients. Victims suspected of HCA should be rewarmed before being pronounced dead. Rewarming avalanche victims of HCA with serum potassium > 12 mmol/L and a burial time >30 min with no air pocket, most probably be futile.

Solid Organ Donation From Brain-dead Donors With Cardiorespiratory Arrest After Snow Avalanche Burial: A Retrospective Single-center Study

BACKGROUND

Complete snow avalanche burial is associated with high mortality. The aim of this study was to assess the feasibility and incidence of organ retrieval in brain-dead donors following cardiorespiratory arrest due to avalanche burial and to evaluate the function of transplanted organs.

METHODS

The transplant registry of the Medical University of Innsbruck was searched for organ donors with a history of avalanche burial, and the function and survival of transplanted organs were assessed.

RESULTS

Thirty-three organs were procured from eight donors and 31 organs (13 kidneys, 6 livers, 3 pancreases, 5 hearts, and 4 lungs) were ultimately transplanted. Allograft and recipient 1-y survival were 100% and both initial and long-term graft function were good. Only one-third of all avalanche victims who died in the intensive care unit with signs of irreversible hypoxic brain injury became organ donors.

CONCLUSIONS

Initial experience from this retrospective study suggests that organs from brain-dead avalanche victims can be transplanted with good results. Starting a Donation after Circulatory Determination of Death program might be an option for increasing the number of organ donations from avalanche victims with irreversible hypoxic brain injury.

Perlite is a suitable model material for experiments investigating breathing in high density snow

Outdoor breathing trials with simulated avalanche snow are fundamental for the research of the gas exchange under avalanche snow, which supports the development of the international resuscitation guidelines. However, these studies have to face numerous problems, including unstable weather and variable snow properties. This pilot study examines a mineral material perlite as a potential snow model for studies of ventilation and gas exchange parameters. Thirteen male subjects underwent three breathing phases—into snow, wet perlite and dry perlite. The resulting trends of gas exchange parameters in all tested materials were similar and when there was a significant difference observed, the trends in the parameters for high density snow used in the study lay in between the trends in dry and wet perlite. These findings, together with its stability and accessibility year-round, make perlite a potential avalanche snow model material. Perlite seems suitable especially for simulation and preparation of breathing trials assessing gas exchange under avalanche snow, and potentially for testing of new avalanche safety equipment before their validation in real snow.

The study was registered in ClinicalTrials.gov on January 22, 2018; the registration number is NCT03413878.

ACSM Expert Consensus Statement: Injury Prevention and Exercise Performance during Cold-Weather Exercise

ABSTRACT

Cold injury can result from exercising at low temperatures and can impair exercise performance or cause lifelong debility or death. This consensus statement provides up-to-date information on the pathogenesis, nature, impacts, prevention, and treatment of the most common cold injuries.

Rewarming With Closed Thoracic Lavage Following 3-h CPR at 27°C Failed to Reestablish a Perfusing Rhythm

Introduction: Previously, we showed that the cardiopulmonary resuscitation (CPR) for hypothermic cardiac arrest (HCA) maintained cardiac output (CO) and mean arterial pressure (MAP) to the same reduced level during normothermia (38°C) vs. hypothermia (27°C). In addition, at 27°C, the CPR for 3-h provided global O₂ delivery (DO₂) to support aerobic metabolism. The present study investigated if rewarming with closed thoracic lavage induces a perfusing rhythm after 3-h continuous CPR at 27°C.

Materials and Methods: Eight male pigs were anesthetized, and immersion-cooled. At 27°C, HCA was electrically induced, CPR was started and continued for a 3-h period. Thereafter, the animals were rewarmed by combining closed thoracic lavage and continued CPR. Organ blood flow was measured using microspheres.

Results: After cooling with spontaneous circulation to 27°C, MAP and CO were initially reduced by 37 and 58% from baseline, respectively. By 15 min after the onset of CPR, MAP, and CO were further reduced by 58 and 77% from baseline, respectively, which remained unchanged throughout the rest of the 3-h period of CPR. During CPR at 27°C, DO₂ and O₂ extraction rate (VO₂) fell to critically low levels, but the simultaneous small increase in lactate and a modest reduction in pH, indicated the presence of maintained aerobic metabolism. During rewarming with closed thoracic lavage, all animals displayed ventricular fibrillation, but only one animal could be electro-converted to restore a short-lived perfusing rhythm. Rewarming ended in circulatory collapse in all the animals at 38°C.

Conclusion: The CPR for 3-h at 27°C managed to sustain lower levels of CO and MAP sufficient to support global DO₂. Rewarming accidental hypothermia patients following prolonged CPR for HCA with closed thoracic lavage is not an alternative to rewarming by extra-corporeal life support as these patients are often in need of massive cardio-pulmonary support during as well as after rewarming.

On-Site Medical Management of Avalanche Victims-A Narrative Review

Avalanche accidents are common in mountain regions and approximately 100 fatalities are counted in Europe each year. The average mortality rate is about 25% and survival chances are mainly determined by the degree and duration of avalanche burial, the patency of the airway, the presence of an air pocket, snow characteristics, and the severity of traumatic injuries. The most common cause of death in completely buried avalanche victims is asphyxia followed by trauma. Hypothermia accounts for a minority of deaths; however, hypothermic cardiac arrest has a favorable prognosis and prolonged resuscitation and extracorporeal rewarming are indicated. In this article, we give an overview on the pathophysiology and on-site management of avalanche victims.

Quality Indicators for Avalanche Victim Management and Rescue

Decisions in the management and rescue of avalanche victims are complex and must be made in difficult, sometimes dangerous, environments. Our goal was to identify indicators for quality measurement in the management and rescue of avalanche victims. The International Commission for Mountain Emergency Medicine (ICAR MedCom) convened a group of internal and external experts. We used brainstorming and a five-round modified nominal group technique to identify the most relevant quality indicators (QIs) according to the National Quality Forum Measure Evaluation Criteria. Using a consensus process, we identified a set of 23 QIs to measure the quality of the management and rescue of avalanche victims. These QIs may be a valuable tool for continuous quality improvement. They allow objective feedback to rescuers regarding clinical performance and identify areas that should be the foci of further quality improvement efforts in avalanche rescue.

CPR with restricted patient access using alternative rescuer positions: a randomised cross-over manikin study simulating the CPR scenario after avalanche burial

Background

The aim of this manikin study was to evaluate the quality of cardiopulmonary resuscitation (CPR) with restricted patient access during simulated avalanche rescue using over-the-head and straddle position as compared to standard position.

Methods

In this prospective, randomised cross-over study, 25 medical students (64% male, mean age 24) performed single-rescuer CPR with restricted patient access in over-the-head and straddle position using mouth-to-mouth ventilation or pocket mask ventilation. Chest compression depth, rate, hand position, recoil, compression/decompression ratio, hands-off times, tidal volume of ventilation and gastric insufflation were compared to CPR with unrestricted patient access in standard position.

Results

Only 28% of all tidal volumes conformed to the guidelines (400–800 ml), 59% were below 400 ml and 13% were above 800 ml. There was no significant difference in ventilation parameters when comparing standard to atypical rescuer positions. Participants performed sufficient chest compressions depth in 98.1%, a minimum rate in 94.7%, correct compression recoil in 43.8% and correct hand position in 97.3% with no difference between standard and atypical rescuer positions. In 36.9% hands-off times were longer than 9 s.

Conclusions

Efficacy of CPR from an atypical rescuer position with restricted patient access is comparable to CPR in standard rescuer position. Our data suggest to start basic life-support before complete extrication in order to reduce the duration of untreated cardiac arrest in avalanche rescue. Ventilation quality provided by lay rescuers may be a limiting factor in resuscitation situations where rescue ventilation is considered essential.

Survivors of avalanche accidents: posttraumatic stress disorder symptoms and quality of life: a multicentre study

BACKGROUND

As any traumatic event, avalanches could trigger psychological disorders on survivors. Our objectives were to determine the prevalence of post-traumatic stress disorder among avalanche survivors and to evaluate post-traumatic stress disorder risks factors as well as the impact on quality of life.

METHODS

A multicentre study was conducted in victims included in the North Alpine Avalanche Registry from 2014 to 2018. Data were collected through a standard questionnaire during semi-directed phone interviews. The primary outcome was the total score on the Impact of Event Scale Revised. Secondary outcomes were the Mental Component Scale and the Physical Component Scale scores of the Short Form 12 questionnaire.

RESULTS

During the study period, 132 of 211 victims survived. Among the 107 victims included, 55 (51.4%) phone interviews were obtained. Six patients (10.9, 95% CI 1.76-20.05) had an Impact of Event Scale Revised score ≥ 33 indicating a strong probability for post-traumatic stress disorder. Median Mental Component Scale score was 39.0 (IQR 30.5-46.3) for post-traumatic stress disorder patients and 40.1 (IQR 36.5-43.4) for non post-traumatic stress disorder (p = 0.76). Median Physical Component Scale score was 39.4 (37.2-44.3) for post-traumatic stress disorder patients and 44.2 (39.1-46.8) for non post-traumatic stress disorder (p = 0.39). No significant difference in the quality of life in both populations was observed, and no independent risk factors of post-traumatic stress disorder was identified.

CONCLUSION

Avalanche accidents may induce post-traumatic stress disorders among survivors in a comparable prevalence to the most traumatic event already studied. Early recognition and preventive measures should be set up in order to reduce the psychological burden in these victims.

TRIAL REGISTRATION

NCT03936738 .

[Cardiac arrest under special circumstances]

These guidelines of the European Resuscitation Council (ERC) Cardiac Arrest under Special Circumstances are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required for basic and advanced life support for the prevention and treatment of cardiac arrest under special circumstances; in particular, specific causes (hypoxia, trauma, anaphylaxis, sepsis, hypo-/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), specific settings (operating room, cardiac surgery, cardiac catheterization laboratory, dialysis unit, dental clinics, transportation [in-flight, cruise ships], sport, drowning, mass casualty incidents), and specific patient groups (asthma and chronic obstructive pulmonary disease, neurological disease, morbid obesity, pregnancy).

Survival probability in avalanche victims with long burial (≥60 min): A retrospective study

BACKGROUND

The survival of completely buried victims in an avalanche mainly depends on burial duration. Knowledge is limited about survival probability after 60 min of complete burial.

AIM

We aimed to study the survival probability and prehospital characteristics of avalanche victims with long burial durations.

METHODS

We retrospectively included all completely buried avalanche victims with a burial duration of ≥60 min between 1997 and 2018 in Switzerland. Data were extracted from the registry of the Swiss Institute for Snow and Avalanche Research and the prehospital medical records of the physician-staffed helicopter emergency medical services. Avalanche victims buried for ≥24 h or with an unknown survival status were excluded. Survival probability was estimated by using the non-parametric Ayer-Turnbull method and logistic regression. The primary outcome was survival probability.

RESULTS

We identified 140 avalanche victims with a burial duration of ≥60 min, of whom 27 (19%) survived. Survival probability shows a slight decrease with increasing burial duration (23% after 60 min, to <6% after 1400 min, p = 0.13). Burial depth was deeper for those who died (100 cm vs 70 cm, p = 0.008). None of the survivors sustained CA during the prehospital phase.

CONCLUSIONS

The overall survival rate of 19% for completely buried avalanche victims with a long burial duration illustrates the importance of continuing rescue efforts. Avalanche victims in CA after long burial duration without obstructed airway, frozen body or obvious lethal trauma should be considered to be in hypothermic CA, with initiation of cardiopulmonary resuscitation and an evaluation for rewarming with extracorporeal life support.

[Paediatric Life Support]

The European Resuscitation Council (ERC) Paediatric Life Support (PLS) guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations of the International Liaison Committee on Resuscitation (ILCOR). This section provides guidelines on the management of critically ill or injured infants, children and adolescents before, during and after respiratory/cardiac arrest.

Rewarming From Hypothermic Cardiac Arrest Applying Extracorporeal Life Support: A Systematic Review and Meta-Analysis

Introduction: This systematic review and meta-analysis aims at comparing outcomes of rewarming after accidental hypothermic cardiac arrest (HCA) with cardiopulmonary bypass (CPB) or/and extracorporeal membrane oxygenation (ECMO). Material and Methods: Literature searches were limited to references with an abstract in English, French or German. Additionally, we searched reference lists of included papers. Primary outcome was survival to hospital discharge. We assessed neurological outcome, differences in relative risks (RR) of surviving, as related to the applied rewarming technique, sex, asphyxia, and witnessed or unwitnessed HCA. We calculated hypothermia outcome prediction probability score after extracorporeal life support (HOPE) in patients in whom we found individual data. P < 0.05 considered significant. Results: Twenty-three case observation studies comprising 464 patients were included in a meta-analysis comparing outcomes of rewarming with CPB or/and ECMO. One-hundred-and-seventy-two patients (37%) survived to hospital discharge, 76 of 245 (31%) after CPB and 96 of 219 (44 %) after ECMO; 87 and 75%, respectively, had good neurological outcomes. Overall chance of surviving was 41% higher (P = 0.005) with ECMO as compared with CPB. A man and a woman had 46% (P = 0.043) and 31% (P = 0.115) higher chance, respectively, of surviving with ECMO as compared with CPB. Avalanche victims had the lowest chance of surviving, followed by drowning and people losing consciousness in cold environments. Assessed by logistic regression, asphyxia, unwitnessed HCA, male sex, high initial body temperature, low pH and high serum potassium (s-K+) levels were associated with reduced chance of surviving. In patients displaying individual data, overall mean predictive surviving probability (HOPE score; n = 134) was 33.9 ± 33.6% with no significant difference between ECMO and CPB-treated patients. We also surveyed 80 case reports with 96 victims of HCA, who underwent resuscitation with CPB or ECMO, without including them in the meta-analysis. Conclusions: The chance of surviving was significantly higher after rewarming with ECMO, as compared to CPB, and in patients with witnessed compared to unwitnessed HCA. Avalanche victims had the lowest probability of surviving. Male sex, high initial body temperature, low pH, and high s-K+ were factors associated with low surviving chances.

Effects of Climate Change on Avalanche Accidents and Survival

Avalanches are major natural hazards in snow-covered mountains, threatening people and infrastructure. With ongoing climate change, the frequency and types of snow avalanches may change, affecting the rates of avalanche burial and survival. With a wetter and warmer snow climate, consequences of burial may become more severe. In this review, we assess the potential effects of climate change on the frequency and characteristics of avalanches. We then discuss how these changes might affect the survival rates of subjects buried by avalanches and might influence the responses of search and rescue (SAR) teams and health care providers. While climate change is inevitable, the effects on avalanches remain elusive. The frequency of human triggered avalanches may not change, because this depends largely on the number and behavior of winter recreationists. Blunt trauma and secondary injuries will likely become more frequent as terrain roughness is expected to rise and snow cover to become thinner. Higher snow densities in avalanche debris will likely interfere with the respiration of completely buried victims. Asphyxia and trauma, as causes of avalanche death, may increase. It is unlikely that SAR and health care providers involved in avalanche rescue will have to change their strategies in areas where they are already established. The effects of climate change might foster the expansion of mitigation strategies and the establishment of mountain rescue services in areas subject to increased avalanche hazards caused by changes in snow cover and land use.

European Resuscitation Council Guidelines 2021: Paediatric Life Support

These European Resuscitation Council Paediatric Life Support (PLS) guidelines, are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the management of critically ill infants and children, before, during and after cardiac arrest.

European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances

These European Resuscitation Council (ERC) Cardiac Arrest in Special Circumstances guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required to basic and advanced life support for the prevention and treatment of cardiac arrest in special circumstances; specifically special causes (hypoxia, trauma, anaphylaxis, sepsis, hypo/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), special settings (operating room, cardiac surgery, catheter laboratory, dialysis unit, dental clinics, transportation (in-flight, cruise ships), sport, drowning, mass casualty incidents), and special patient groups (asthma and COPD, neurological disease, obesity, pregnancy).

Clinical staging of accidental hypothermia: The Revised Swiss System: Recommendation of the International Commission for Mountain Emergency Medicine (ICAR MedCom)

Clinical staging of accidental hypothermia is used to guide out-of-hospital treatment and transport decisions. Most clinical systems utilize core temperature, by measurement or estimation, to stage hypothermia, despite the challenge of obtaining accurate field measurements. Recent studies have demonstrated that field estimation of core temperature is imprecise. We propose a revision of the original Swiss Staging system. The revised system uses the risk of cardiac arrest, instead of core temperature, to determine the staging level. Our revised system simplifies assessment by using the level of responsiveness, based on the AVPU scale, and by removing shivering as a stage-defining sign.

Witnessed Cardiac Arrest in a Hypothermic Avalanche Victim Completely Buried for 2 Hours

A 34-y-old skier triggered a wind slab avalanche and was completely buried for over 2 h. After extrication by rescuers, the victim was breathing and conscious. Despite directions from the rescuers against standing up, the victim struggled to free himself and ultimately stood upright before collapsing in cardiac arrest. The rescuers performed cardiopulmonary resuscitation during transport to a nearby trailhead, where a helicopter emergency medical services crew found that the victim was in ventricular fibrillation. After further resuscitative efforts, including advanced life support, the victim was declared dead at the scene. Afterdrop and circumrescue collapse were the most likely triggers of cardiac arrest. This case highlights a need for rescuers, emergency medical services, and hospitals to be prepared to care for victims with hypothermia. To prevent circumrescue collapse, victims with hypothermia should be extricated gently, should not be allowed to stand, and should be placed flat. This may be difficult or impossible, as in this case. Hypothermic victims in cardiac arrest may require prolonged cardiopulmonary resuscitation, preferably with mechanical compressions, during transport to a hospital that has protocols for rewarming using extracorporeal life support. Resuscitation from hypothermic cardiac arrest should not be terminated before the victim has been rewarmed.

Determination of Death in Mountain Rescue: Recommendations of the International Commission for Mountain Emergency Medicine (ICAR MedCom)

Determination of death requires specific knowledge, training, and experience in most cases. It can be particularly difficult when external conditions, such as objective hazards in mountains, prevent close physical examination of an apparently lifeless person, or when examination cannot be accomplished by an authorized person. Guidelines exist, but proper use can be difficult. In addition to the absence of vital signs, definitive signs of death must be present. Recognition of definitive signs of death can be problematic due to the variability in time course and the possibility of mimics. Only clear criteria such as decapitation or detruncation should be used to determine death from a distance or by laypersons who are not medically trained. To present criteria that allow for accurate determination of death in mountain rescue situations, the International Commission for Mountain Emergency Medicine convened a panel of mountain rescue doctors and a forensic pathologist. These recommendations are based on a nonsystematic review of the literature including articles on determination of death and related topics.

Total TauProtein as Investigated by Cerebral Microdialysis Increases in Hypothermic Cardiac Arrest: A Pig Study

The understanding and neurological prognostication of hypoxic ischemic encephalopathy (HIE) after hypothermic cardiac arrest (CA) is limited. Recent data suggest that the protein tau (total tau) might be a useful marker for outcome in patients with HIE. This translational porcine study aimed to analyze brain physiology in relation to total tau protein release during hypothermic CA. Eight domestic pigs were studied as part of a prospective porcine study using cerebral microdialysis (CMD). CMD samples for tau analysis were collected at baseline, after reaching the targeted core temperature of 28°C (hypothermia), after hypoxic hypercapnia (partial asphyxia), and finally 20 minutes after cardiopulmonary resuscitation. CMD-total tau-protein was analyzed using enzyme-linked immunosorbent essay. Cerebral tau protein was slightly elevated at baseline most likely due to an insertion trauma, remained stable during hypercapnic hypoxia, and significantly (p = 0.009) increased in 8/8 pigs during resuscitation to 1335 pg/mL (interquartile range: 705-2100). CMD-tau release was associated with lower levels of brain tissue oxygen tension (p = 0.011), higher CMD-lactate/pyruvate ratio, higher CMD-lactate, CMD-glutamate, and CMD-glycerol levels (p < 0.001, respectively), but not with cerebral perfusion pressure, intracranial pressure, or CMD-glucose levels. This study demonstrates an immediate tau protein release accompanied by deranged cerebral metabolism and decreased brain tissue oxygen tension during mechanical resuscitation in hypothermic CA. Understanding tau physiology and release kinetics is important for the design and interpretation of studies investigating tau as a biomarker of HIE.

Systematic Review of Evidence-Based Guidelines for Prehospital Care

Introduction: Multiple national organizations have identified a need to incorporate more evidence-based medicine in emergency medical services (EMS) through the creation of evidence-based guidelines (EBGs). Tools like the Appraisal of Guidelines for Research and Evaluation (AGREE) II and criteria outlined by the National Academy of Medicine (NAM) have established concrete recommendations for the development of high-quality guidelines. While many guidelines have been created that address topics within EMS medicine, neither the quantity nor quality of prehospital EBGs have been previously reported. Objectives: To perform a systematic review to identify existing EBGs related to prehospital care and evaluate the quality of these guidelines using the AGREE II tool and criteria for clinical guidelines described by the NAM. Methods: We performed a systematic search of the literature in MEDLINE, EMBASE, PubMED, Trip, and guidelines.gov, through September 2018. Guideline topics were categorized based on the 2019 Core Content of EMS Medicine. Two independent reviewers screened titles for relevance and then abstracts for essential guideline features. Included guidelines were appraised with the AGREE II tool across 6 domains by 3 independent reviewers and scores averaged. Two additional reviewers determined if each guideline reported the key elements of clinical practice guidelines recommended by the NAM via consensus. Results: We identified 71 guidelines, of which 89% addressed clinical aspects of EMS medicine. Only 9 guidelines scored >75% across AGREE II domains and most (63%) scored between 50 and 75%. Domain 4 (Clarity of Presentation) had the highest (79.7%) and domain 5 (Applicability) had the lowest average score across EMS guidelines. Only 38% of EMS guidelines included a reporting of all criteria identified by the NAM for clinical practice guidelines, with elements of a systematic review of the literature most commonly missing. Conclusions: EBGs exist addressing a variety of topics in EMS medicine. This systematic review and appraisal of EMS guidelines identified a wide range in the quality of these guidelines and variable reporting of key elements of clinical guidelines. Future guideline developers should consider established methodological and reporting recommendations to improve the quality of EMS guidelines.

Beneficial effect of fluid warming in elderly patients with bladder cancer undergoing Da Vinci robotic-assisted laparoscopic radical cystectomy

OBJECTIVES

The enhanced recovery after surgery (ERAS) protocol recommends prevention of intraoperative hypothermia. However, the beneficial effect of maintaining normothermia after radical cystectomy has not been evaluated. This study aimed to investigate the efficacy of fluid warming nursing in elderly patients undergoing Da Vinci robotic-assisted laparoscopic radical cystectomy.

METHODS

A total of 108 patients with bladder cancer scheduled to undergo DaVinci robotic-assisted laparoscopic radical cystectomy were recruited and randomly divided into the control group (n=55), which received a warming blanket (43°C) during the intraoperative period and the warming group (n=53), in which all intraoperative fluids were administered via a fluid warmer (41°C). The surgical data, body temperature, coagulation function indexes, and postoperative complications were compared between the two groups.

RESULTS

Compared to the control group, the warming group had significantly less intraoperative transfusion (p=0.028) and shorter hospitalization days (p<0.05). During the entire intraoperative period (from 1 to 6h), body temperature was significantly higher in the warming group than in the control group. There were significant differences in preoperative fibrinogen level, white blood cell count, total bilirubin level, intraoperative lactose level, postoperative thrombin time (TT), and platelet count between the control and warming groups. Multivariate linear regression analysis demonstrated that TT was the only significant factor, suggesting that the warming group had a lower TT than the control group.

CONCLUSION

Fluid warming nursing can effectively reduce transfusion requirement and hospitalization days, maintain intraoperative normothermia, and promote postoperative coagulation function in elderly patients undergoing Da Vinci robotic-assisted laparoscopic radical cystectomy.

Intra-patient potassium variability after hypothermic cardiac arrest: a multicentre, prospective study

Background

To date, the decision to set up therapeutic extra-corporeal life support (ECLS) in hypothermia-related cardiac arrest is based on the potassium value only. However, no information is available about how the analysis should be performed. Our goal was to compare intra-individual variation in serum potassium values depending on the sampling site and analytical technique in hypothermia-related cardiac arrests.

Methods

Adult patients with suspected hypothermia-related refractory cardiac arrest, admitted to three hospitals with ECLS facilities were included. Blood samples were obtained from the femoral vein, a peripheral vein and the femoral artery. Serum potassium was analysed using blood gas (BGA) and clinical laboratory analysis (CL).

Results

Of the 15 consecutive patients included, 12 met the principal criteria, and 5 (33%) survived. The difference in average potassium values between sites or analytical method used was ≤1 mmol/L. The agreement between potassium values according to the three different sampling sites was poor. The ranges of the differences in potassium using BGA measurement were − 1.6 to + 1.7 mmol/L; − 1.18 to + 2.7 mmol/L and − 0.87 to + 2 mmol/L when comparing respectively central venous and peripheral venous, central venous and arterial, and peripheral venous and arterial potassium.

Conclusions

We found important and clinically relevant variability in potassium values between sampling sites. Clinical decisions should not rely on one biological indicator. However, according to our results, the site of lowest potassium, and therefore the preferred site for a single potassium sampling is central venous blood. The use of multivariable prediction tools may help to mitigate the risks inherent in the limits of potassium measurement.

Trial registration

ClinicalTrials.gov Identifier: NCT03096561.

Sudden Cardiac Arrest and Cardiopulmonary Resuscitation with Automated External Defibrillator in the Austrian Mountains: A Retrospective Study

Background: Few data exist on the likelihood of surviving sudden cardiac arrest in the mountains. The aim of this study was to analyze the epidemiology and outcomes of patients suffering sudden cardiac arrest and undergoing cardiopulmonary resuscitation (CPR) with automated external defibrillator (AED) in the Austrian mountains. Materials and Methods: We analyzed all cardiac arrest cases in the Austrian mountains reported in the nationwide Austrian Alpine Police database from October 26, 2005, to December 31, 2015. To obtain information on outcomes, these patient data were manually merged with patient data from the main Austrian referral center for mountain emergencies, Innsbruck Medical University Hospital. Results: Overall, 781 cases of sudden cardiac arrest in the Austrian mountains were recorded. In 136 cases (17%), CPR with AED was attempted. The most frequent activities at the time of sudden cardiac arrest were hiking (n = 63, 46%) and skiing or snowboarding (n = 44, 32%). In the nationwide Austrian Alpine Police database, only 4 (3%) patients survived, whereas in the Innsbruck Medical University Hospital database, there were seven survivors who received CPR and AED. All survivors had received immediate CPR with an AED. Five patients had good neurological outcome (cerebral performance category 1-2). Conclusions: In the Austrian mountains, CPR was attempted in less than 20% of sudden cardiac arrest cases. The few that survived had received immediate CPR with an AED. To better understand the circumstances and outcome of sudden cardiac arrest in the mountains, out-of hospital and in-hospital data should be linked.

Cut-off values of serum potassium and core temperature at hospital admission for extracorporeal rewarming of avalanche victims in cardiac arrest: A retrospective multi-centre study

AIM

Evidence of existing guidelines for the on-site triage of avalanche victims is limited and adherence suboptimal. This study attempted to find reliable cut-off values for the identification of hypothermic avalanche victims with reversible out-of-hospital cardiac arrest (OHCA) at hospital admission. This may enable hospitals to allocate extracorporeal life support (ECLS) resources more appropriately while increasing the proportion of survivors among rewarmed victims.

METHODS

All avalanche victims with OHCA admitted to seven centres in Europe capable of ECLS from 1995 to 2016 were included. Optimal cut-off values, for parameters identified by logistic regression, were determined by means of bootstrapping and exact binomial distribution and served to calculate sensitivity, rate of overtriage, positive and negative predictive values, and receiver operating curves.

RESULTS

In total, 103 avalanche victims with OHCA were included. Of the 103 patients 61 (58%) were rewarmed by ECLS. Six (10%) of the rewarmed patients survived whilst 55 (90%) died. We obtained optimal cut-off values of 7 mmol/L for serum potassium and 30 °C for core temperature.

CONCLUSION

For in-hospital triage of avalanche victims admitted with OHCA, serum potassium accurately predicts survival. The combination of the cut-offs 7 mmol/L for serum potassium and 30 °C for core temperature achieved the lowest overtriage rate (47%) and the highest positive predictive value (19%), with a sensitivity of 100% for survivors. The presence of vital signs at extrication is strongly associated with survival. For further optimisation of in-hospital triage, larger datasets are needed to include additional parameters.

Management of accidental hypothermia: an established extracorporeal membrane oxygenation centre experience

Introduction:

Data on management of severe accidental hypothermia published from an established high-volume extracorporeal membrane oxygenation centre are scarce.

Methods:

A total of 28 patients with intravesical temperature lower than 28°C on admission were either treated with veno-arterial extracorporeal membrane oxygenation or rewarmed conservatively.

Results:

A total of 10 patients rewarmed on veno-arterial extracorporeal membrane oxygenation (age: 37 ± 12.6 years) and 18 conservatively (age: 55.2 ± 11.2 years) were collected over a course of 5 years. The dominant cause was alcohol intoxication with exposure to cold (39%), 12 patients were resuscitated prior to admission. The admission temperature in the extracorporeal membrane oxygenation group (23.8 ± 2.6°C) was lower than in the non–extracorporeal membrane oxygenation group (26.0 ± 1.5°C, p = 0.01). The peripheral percutaneous veno-arterial extracorporeal membrane oxygenation was always cannulated in malignant arrhythmias causing refractory cardiac arrest. The typical extracorporeal membrane oxygenation blood flow was 3-4 L/minute and sweep gas flow 2 L/minute, the median extracorporeal membrane oxygenation duration was 48.3 (28.1-86.7) hours. The median rates of rewarming did not differ (0.41 (0.35-0.7)°C/hour in extracorporeal membrane oxygenation and 0.77 (0.54-0.98)°C/hour in non–extracorporeal membrane oxygenation, p = 0.46) as well as the admission arterial lactate, pH and potassium. Their development was not different between the groups except for higher pH between the third and ninth hour of rewarming in the extracorporeal membrane oxygenation group. The hospital mortality was 10% in the extracorporeal membrane oxygenation group and 11.1% in the non–extracorporeal membrane oxygenation group with the median last Glasgow Coma Scale 15 and Cerebral Performance Score 1.

Conclusion:

Veno-arterial extracorporeal membrane oxygenation for severe hypothermia shows promising outcome data collected in an extracorporeal membrane oxygenation/extracorporeal cardiopulmonary resuscitation centre located in a European urban area. Except for presence of refractory cardiac arrest, the established hypothermia-related prognostic indicators did not differ between patients in need for extracorporeal membrane oxygenation and those rewarmed without extracorporeal membrane oxygenation.

Beyond the limits - ECPR in putative fatal circumstances

The eligibility criteria for applying extracorporeal cardiopulmonary resuscitation (ECPR) in patients with cardiac arrest are currently unclear. For those patients with hypothermic cardiac arrest, the European Resuscitation Council (ERC) Guidelines recommend considering ECPR only for patients with potassium <8 mmol/L and a body temperature below 32°C, whereas the American Heart Association Guidelines (AHA) do not express this in a specific manner.

We report the case of an urban unwitnessed out-of-hospital cardiac arrest patient found with her head immersed in water at a temperature of 23°C. The patient presented an unclear history and a dire combination of clinical and laboratory parameters (asystole, arterial blood gas: pH 6.8, potassium 8.3 mmol/L, lactate 16.0 mmol/L). Despite these poor prognostic indicators, ECPR was initiated after 95 minutes of CPR and the patient survived with a good neurological outcome.

This case highlights the uncertainty in ECPR eligibility and prognostication, especially in those with hypothermia and water immersion for whom aggressive therapies may be warranted. Further data and improved strategies are required to delineate candidacy for this resource-intensive procedure better.

On-Site Treatment of Snow Avalanche Victims: From Bench to Mountainside

The number of avalanche accidents involving winter recreationists has notably increased in recent decades due to the increasing popularity of outdoor winter activities. The International Liaison Committee on Cardiopulmonary Resuscitation, the International Commission for Mountain Emergency Medicine (ICAR Medcom), and the Wilderness Medical Society have recently published evidenced-based recommendations for the on-site treatment of snow avalanche victims. Despite these recommendations, recent studies found poor knowledge and compliance by both healthcare providers and laypersons. The aim of this nonsystematic review is to provide an updated overview of avalanche accident epidemiology, to present recent advances in snow avalanche pathophysiology, and to discuss recent advancements in on-site treatment of snow avalanche victims.

Prehospital management and outcome of avalanche patients with out-of-hospital cardiac arrest: a retrospective study in Tyrol, Austria

AIM

The aim of this study is to describe the prehospital management and outcome of avalanche patients with out-of-hospital cardiac arrest in Tyrol, Austria, for the first time since the introduction of international guidelines in 1996.

PATIENTS AND METHODS

This study involved a retrospective analysis of all avalanche accidents involving out-of-hospital cardiac arrest between 1996 and 2009 in Tyrol, Austria.

RESULTS

A total of 170 completely buried avalanche patients were included. Twenty-eight victims were declared dead at the scene. Of 34 patients with short burial, cardiopulmonary resuscitation (CPR) was performed in 27 (79%); 15 of these patients (56%) were transported to hospital with ongoing CPR and four patients were rewarmed with extracorporeal circulation; no patient survived. Of 108 patients with long burial, 49 patients had patent or unknown airway status; CPR was performed in 25 of these patients (51%) and 14 patients (29%) were transported to hospital. Four patients were rewarmed, but only one patient with witnessed cardiac arrest survived. Since the introduction of guidelines in 1996, there has been a marginally significant increase in the rate of documenting airway assessment, but no change in documenting the duration of burial or CPR.

CONCLUSION

CPR is continued to hospital admission in patients with short burial and asphyxial cardiac arrest, but withheld or terminated at the scene in patients with long burial and possible hypothermic cardiac arrest. Insufficient transfer of information from the accident site to the hospital may partially explain the poor outcome of avalanche victims with out-of-hospital cardiac arrest treated with emergency cardiac care.

Identification of the technical and medical requirements for HEMS avalanche rescue missions through a 15-year retrospective analysis in a HEMS in Switzerland: a necessary step for quality improvement

BACKGROUND

Avalanche rescues mostly rely on helicopter emergency medical services (HEMS) and include technical rescue and complex medical situations under difficult conditions. The adequacy of avalanche victim management has been shown to be unexpectedly low, suggesting the need for quality improvement. We analyse the technical rescue and medical competency requirements of HEMS crewmembers for avalanche rescue missions, as well as their clinical exposure. The study aims to identify areas that should be the focus of future quality improvement efforts.

METHODS

This 15-year retrospective study of avalanche rescue by the Swiss HEMS Rega includes all missions where at least one patient had been caught by an avalanche, found within 24 h of the alarm being raised, and transported.

RESULTS

Our analyses included 422 missions (596 patients). Crews were frequently confronted with technical rescue aspects, including winching (29%) and patient location and extrication (48%), as well as multiple casualty accidents (32%). Forty-seven percent of the patients suffered potential or overt vital threat; 29% were in cardiac arrest. The on-site medical management of the victims required a large array of basic and advanced medical skills. Clinical exposure was low, as 56% of the physicians were involved in only one avalanche rescue mission over the study period.

CONCLUSIONS

Our data provide a solid baseline measure and valuable starting point for improving our understanding of the challenges encountered during avalanche rescue missions. We further suggest QI interventions, that might be immediately useful for HEMS operating under similar settings. A coordinated approach using a consensus process to determine quality indicators and a minimal dataset for the specific setting of avalanche rescue would be the logical next step.

Causes of Death Among Avalanche Fatalities in Colorado: A 21-Year Review

INTRODUCTION

A better understanding of the nature of morbidity and mortality in avalanche accidents helps direct both rescue efforts as well as preventive strategies to reduce fatalities.

METHODS

We reviewed all avalanche fatalities from the avalanche years beginning in 1994 to 2015 in the state of Colorado, United States, using the database maintained by the Colorado Avalanche Information Center. For each fatality, we obtained the coroner's official determination of cause of death, and autopsy records if one was performed. We used these records to determine cause of death. Injury severity scores (0-75 scale) were calculated for those victims who underwent autopsy.

RESULTS

Mortality information was available for 110 fatalities occurring during the 21-year study period. Of these, 64 underwent autopsy. Asphyxia was the cause of death in 65% of fatalities (72/110). Trauma was the cause of death in 29% of the fatalities (32/110). Of these, the primary cause was multiple system trauma in 38% (12/32), head trauma in 31% (10/32), and spinal injuries in 19% (6/32). Of the victims who died of asphyxia and had autopsy, only 10% (4/42) also had significant trauma, defined as an injury severity score greater than 15. There were 6 fatalities from other causes, including hypothermia, drowning, and primary cardiac arrest. There was no correlation between trauma and mode of travel, avalanche type, or starting zone elevation.

CONCLUSIONS

Asphyxia was the primary cause of death in avalanche fatalities in Colorado during our study period. The incidence of fatal trauma was 29% and did not correlate with user group demographics or avalanche characteristics.

Place de l’assistance circulatoire extracorporelle dans l’arrêt cardiaque réfractaire

Le bénéfice d’une réanimation cardiopulmonaire (RCP) extracorporelle en comparaison d’une réanimation conventionnelle sur la survie et le pronostic neurologique à long terme des patients victimes d’un arrêt cardiaque réfractaire reste encore incertain. Il pourrait être très différent selon que la RCP soit considérée dans les arrêts cardiaques extrahospitaliers ou intrahospitaliers, d’origine cardiaque ou pas, en contexte toxicologique ou d’hypothermie. L’objectif de cet article est une mise au point sur l’apport de l’assistance circulatoire extracorporelle dans la prise en charge des arrêts cardiaques réfractaires à partir des recherches cliniques les plus récentes. Ainsi, l’apport d’une RCP extracorporelle dans les arrêts cardiaques réfractaires extrahospitaliers d’origine cardiaque est probablement limité, même au sein de populations hautement sélectionnées. En revanche, son intérêt est probablement plus important dans les arrêts cardiaques réfractaires intrahospitaliers d’origine cardiaque sous réserve d’une bonne sélection des patients. Enfin, si des résultats encourageants ont été rapportés dans les cas d’arrêt cardiaque réfractaire de cause toxique ; en revanche, ils sont plus contrastés concernant les arrêts cardiaques réfractaires associés à une hypothermie profonde suite à une exposition accidentelle au froid, à une noyade ou une avalanche. Des recherches bien conduites sont encore nécessaires pour préciser les contextes et les indications pour lesquels les patients seraient en droit d’attendre un bénéfice médical d’une RCP extracorporelle.

Place de l’assistance circulatoire extracorporelle dans l’arrêt cardiaque réfractaire

Le bénéfice d’une réanimation cardiopulmonaire (RCP) extracorporelle en comparaison d’une réanimation conventionnelle sur la survie et le pronostic neurologique à long terme des patients victimes d’un arrêt cardiaque réfractaire reste encore incertain. Il pourrait être très différent selon que la RCP soit considérée dans les arrêts cardiaques extrahospitaliers ou intrahospitaliers, d’origine cardiaque ou pas, en contexte toxicologique ou d’hypothermie. L’objectif de cet article est une mise au point sur l’apport de l’assistance circulatoire extracorporelle dans la prise en charge des arrêts cardiaques réfractaires à partir des recherches cliniques les plus récentes. Ainsi, l’apport d’une RCP extracorporelle dans les arrêts cardiaques réfractaires extrahospitaliers d’origine cardiaque est probablement limité, même au sein de populations hautement sélectionnées. En revanche, son intérêt est probablement plus important dans les arrêts cardiaques réfractaires intrahospitaliers d’origine cardiaque sous réserve d’une bonne sélection des patients. Enfin, si des résultats encourageants ont été rapportés dans les cas d’arrêt cardiaque réfractaire de cause toxique ; en revanche, ils sont plus contrastés concernant les arrêts cardiaques réfractaires associés à une hypothermie profonde suite à une exposition accidentelle au froid, à une noyade ou à une avalanche. Des recherches bien conduites sont encore nécessaires pour préciser les contextes et les indications pour lesquels les patients seraient en droit d’attendre un bénéfice médical d’une RCP extracorporelle.

Management of Multi-Casualty Incidents in Mountain Rescue: Evidence-Based Guidelines of the International Commission for Mountain Emergency Medicine (ICAR MEDCOM)

Blancher, Marc, François Albasini, Fidel Elsensohn, Ken Zafren, Natalie Hölzl, Kyle McLaughlin, Albert R. Wheeler III, Steven Roy, Hermann Brugger, Mike Greene, and Peter Paal. Management of multi-casualty incidents in mountain rescue: Evidence-based guidelines of the International Commission for Mountain Emergency Medicine (ICAR MEDCOM). High Alt Med Biol. 19:131–140, 2018.

Introduction: Multi-Casualty Incidents (MCI) occur in mountain areas. Little is known about the incidence and character of such events, and the kind of rescue response. Therefore, the International Commission for Mountain Emergency Medicine (ICAR MEDCOM) set out to provide recommendations for the management of MCI in mountain areas.

Materials and Methods: Details of MCI occurring in mountain areas related to mountaineering activities and involving organized mountain rescue were collected. A literature search using (1) PubMed, (2) national mountain rescue registries, and (3) lay press articles on the internet was performed. The results were analyzed with respect to specific aspects of mountain rescue.

Results: We identified 198 MCIs that have occurred in mountain areas since 1956: 137 avalanches, 38 ski lift accidents, and 23 other events, including lightning injuries, landslides, volcanic eruptions, lost groups of people, and water-related accidents.

Discussion: General knowledge on MCI management is required. Due to specific aspects of triage and management, the approach to MCIs may differ between those in mountain areas and those in urban settings.

Conclusions: Mountain rescue teams should be prepared to manage MCIs. Knowledge should be reviewed and training performed regularly. Cooperation between terrestrial rescue services, avalanche safety authorities, and helicopter crews is critical to successful management of MCIs in mountain areas.

The prehospital management of hypothermia - An up-to-date overview

BACKGROUND

Accidental hypothermia concerns a body core temperature of less than 35°C without a primary defect in the thermoregulatory system. It is a serious threat to prehospital patients and especially injured patients, since it can induce a vicious cycle of the synergistic effects of hypothermia, acidosis and coagulopathy; referred to as the trauma triad of death. To prevent or manage deterioration of a cold patient, treatment of hypothermia should ideally begin prehospital. Little effort has been made to integrate existent literature about prehospital temperature management. The aim of this study is to provide an up-to-date systematic overview of the currently available treatment modalities and their effectiveness for prehospital hypothermia management.

DATA SOURCES

Databases PubMed, EMbase and MEDLINE were searched using the terms: "hypothermia", "accidental hypothermia", "Emergency Medical Services" and "prehospital". Articles with publications dates up to October 2017 were included and selected by the authors based on relevance.

RESULTS

The literature search produced 903 articles, out of which 51 focused on passive insulation and/or active heating. The most effective insulation systems combined insulation with a vapor barrier. Active external rewarming interventions include chemical, electrical and charcoal-burning heat packs; chemical or electrical heated blankets; and forced air warming. Mildly hypothermic patients, with significant endogenous heat production from shivering, will likely be able to rewarm themselves with only insulation and a vapor barrier, although active warming will still provide comfort and an energy-saving benefit. For colder, non-shivering patients, the addition of active warming is indicated as a non-shivering patient will not rewarm spontaneously. All intravenous fluids must be reliably warmed before infusion.

CONCLUSION

Although it is now accepted that prehospital warming is safe and advantageous, especially for a non-shivering hypothermic patient, this review reveals that no insulation/heating combinations stand significantly above all the others. However, modern designs of hypothermia wraps have shown promise and battery-powered inline fluid warmers are practical devices to warm intravenous fluids prior to infusion. Future research in this field is necessary to assess the effectiveness expressed in patient outcomes.