Emily Procter

Adherence of backcountry winter recreationists to avalanche prevention and safety practices in northern Italy.

Backcountry recreationists account for a high percentage of avalanche fatalities, but the total number of recreationists and relative percentage of different recreation types are unknown. The aim of this study was to collect the first comprehensive survey of backcountry skiers and snowshoers in a region in the European Alps to quantify adherence to basic prevention and safety practices. Over a 1‐week period in February 2011 in South Tyrol, Italy, 5576 individuals (77.7% skiers, 22.3% snowshoers) in 1927 groups were surveyed. Significantly more skiers than snowshoers could report the avalanche danger level (52.5% vs 28.0% of groups) and carried standard rescue equipment (transceiver, probe, and shovel) (80.6% vs 13.7% of individuals). Complete adherence to minimum advisable practices (i.e., an individual being in a group with one member correctly informed about the danger level and carrying personal standard rescue equipment) was 41.5%, but was significantly higher in skiers (51.1% vs 8.7% snowshoers) and in individuals who were younger, reported more tours per season, traveled in larger groups, and started earlier. A transnational survey over a complete winter season would be required to obtain total participation prevalence, detect regional differences, and assess the influence of prevention and safety practices on relative reduction in mortality.

Electrical Heart Activity Recorded During Prolonged Avalanche Burial

A man in his midthirties triggered an avalanche at an elevation of 2750 m (9022 ft) while ski touring and sustained complete avalanche burial for 253 minutes before being located with an avalanche transceiver device, probed, and extricated by a rescue team. The burial depth (ie, depth of the head) was 30 cm (1 ft). The victim was in a supine position with a patent airway and a clearly visible air space in front of the mouth and nose with a size of 15×15×5 cm (0.5×0.5×0.2 ft) and frozen inner surface, which was not reported to the emergency physician on site. The victim had a Glasgow Coma Scale of 3 (E1V1M1), no vital signs, and no obvious traumatic fatal injuries. Extrication proceeded without reading the core body temperature or ECG. Because of severe weather conditions and the impending risk for the rescue team, the emergency physician withheld an on-site attempt of resuscitation. The victim was evacuated down to the valley by helicopter and declared dead. While the victims body was being handled in the mortuary, it was revealed that the victim was equipped with a multifunction sport watch and transmitter chest belt. The recorded dataset included heart rate, …

The effectiveness of avalanche airbags

AIM Asphyxia is the primary cause of death among avalanche victims. Avalanche airbags can lower mortality by directly reducing grade of burial, the single most important factor for survival. This study aims to provide an updated perspective on the effectiveness of this safety device. METHODS A retrospective analysis of avalanche accidents involving at least one airbag user between 1994 and 2012 in Austria, Canada, France, Norway, Slovakia, Switzerland and the United States. A multivariate analysis was used to calculate adjusted absolute risk reduction and estimate the effectiveness of airbags on grade of burial and mortality. A univariate analysis was used to examine causes of non-deployment. RESULTS Binomial linear regression models showed main effects for airbag use, avalanche size and injuries on critical burial, and for grade of burial, injuries and avalanche size on mortality. The adjusted risk of critical burial is 47% with non-inflated airbags and 20% with inflated airbags. The adjusted mortality is 44% for critically buried victims and 3% for non-critically buried victims. The adjusted absolute mortality reduction for inflated airbags is -11 percentage points (22% to 11%; 95% confidence interval: -4 to -18 percentage points) and adjusted risk ratio is 0.51 (95% confidence interval: 0.29 to 0.72). Overall non-inflation rate is 20%, 60% of which is attributed to deployment failure by the user. CONCLUSION Although the impact on survival is smaller than previously reported, these results confirm the effectiveness of airbags. Non-deployment remains the most considerable limitation to effectiveness. Development of standardized data collection protocols is encouraged to facilitate further research.

Basic life support trained nurses ventilate more efficiently with laryngeal mask supreme than with facemask or laryngeal tube suction-disposable—A prospective, randomized clinical trial

OBJECTIVE In some emergency situations resuscitation and ventilation may have to be performed by basic life support trained personnel, especially in rural areas where arrival of advanced life support teams can be delayed. The use of advanced airway devices such as endotracheal intubation has been deemphasized for basically-trained personnel, but it is unclear whether supraglottic airway devices are advisable over traditional mask-ventilation. METHODS In this prospective, randomized clinical single-centre trial we compared airway management and ventilation performed by nurses using facemask, laryngeal mask Supreme (LMA-S) and laryngeal tube suction-disposable (LTS-D). Basic life support trained nurses (n=20) received one-hour practical training with each device. ASA 1-2 patients scheduled for elective surgery were included (n=150). After induction of anaesthesia and neuromuscular block nurses had two 90-second attempts to manage the airway and ventilate the patient with volume-controlled ventilation. RESULTS Ventilation failed in 34% of patients with facemask, 2% with LMA-S and 22% with LTS-D (P<0.001). In patients who could be ventilated successfully mean tidal volume was 240±210 ml with facemask, 470±120 ml with LMA-S and 470±140 ml with LTS-D (P<0.001). Leak pressure was lower with LMA-S (23.3±10.8 cm H2O, 95% CI 20.2-26.4) than with LTS-D (28.9±13.9 cm·H2O, 95% CI 24.4-33.4; P=0.047). CONCLUSIONS After one hour of introductory training, nurses were able to use LMA-S more effectively than facemask and LTS-D. High ventilation failure rates with facemask and LTS-D may indicate that additional training is required to perform airway management adequately with these devices. High-level trials are needed to confirm these results in cardiac arrest patients.

Factors associated with optic nerve sheath diameter during exposure to hypobaric hypoxia

Objective: To monitor the changes in optic nerve sheath diameter (ONSD) induced by acute exposure to hypobaric hypoxia and to investigate factors associated with these changes, including development of acute mountain sickness. Methods: In this cohort study, neurologic signs and symptoms, cardiovascular parameters, and ultrasonography of ONSD were prospectively assessed in 19 healthy lowlanders at baseline and after ascent to 3,830 m (3 hours, 9 hours, 24 hours, 48 hours, 72 hours, and 8 days) by blinded investigators. Potential confounding factors (e.g., altitude variations, physical effort) were minimized. A multivariate analysis of factors associated with ONSD was performed by means of generalized estimating equations. Results: ONSD increased with exposure to altitude in all participants (p < 0.001). The increase between 9 and 24 hours was larger in patients who developed acute mountain sickness (p = 0.001). There was no influence of sex, oxygen saturation, or acclimatization on ONSD. Conclusion: Both physiologic and pathologic responses to hypobaric hypoxia were independently associated with changes in ONSD. Studies on a larger cohort, at a range of altitudes, and with baseline neuroimaging techniques are necessary to further understand the clinical significance of increased ONSD during exposure to hypobaric hypoxia.

Burial duration, depth and air pocket explain avalanche survival patterns in Austria and Switzerland

AIM To calculate the first Austrian avalanche survival curve and update a Swiss survival curve to explore survival patterns in the Alps. METHODS Avalanche accidents occurring between 2005/06 and 2012/13 in Austria and Switzerland were collected. Completely buried victims (i.e. burial of the head and chest) in open terrain with known outcome (survived or not survived) were included in the analysis. Extrication and survival curves were calculated using the Turnbull algorithm, as in previous studies. RESULTS 633 of the 796 completely buried victims were included (Austria n=333, Switzerland n=300). Overall survival was 56% (Austria 59%; Switzerland 52%; p=0.065). Time to extrication was shorter in Austria for victims buried ≤60min (p<0.001). The survival curves were similar and showed a rapid initial drop in survival probability and a second drop to 25-28% survival probability after burial duration of ca. 35min, where an inflection point exists and the curve levels off. In a logistic regression analysis, both duration of burial and burial depth had an independent effect on survival. Victims with an air pocket were more likely to survive, especially if buried >15min. CONCLUSION The survival curves resembled those previously published and support the idea that underlying survival patterns are reproducible. The results are in accordance with current recommendations for management of avalanche victims and serve as a reminder that expedient companion rescue within a few minutes is critical for survival. An air pocket was shown to be a positive prognostic factor for survival.

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.

Oxidative stress response to acute hypobaric hypoxia and its association with indirect measurement of increased intracranial pressure: a field study

High altitude is the most intriguing natural laboratory to study human physiological response to hypoxic conditions. In this study, we investigated changes in reactive oxygen species (ROS) and oxidative stress biomarkers during exposure to hypobaric hypoxia in 16 lowlanders. Moreover, we looked at the potential relationship between ROS related cellular damage and optic nerve sheath diameter (ONSD) as an indirect measurement of intracranial pressure. Baseline measurement of clinical signs and symptoms, biological samples and ultrasonography were assessed at 262 m and after passive ascent to 3830 m (9, 24 and 72 h). After 24 h the imbalance between ROS production (+141%) and scavenging (−41%) reflected an increase in oxidative stress related damage of 50–85%. ONSD concurrently increased, but regression analysis did not infer a causal relationship between oxidative stress biomarkers and changes in ONSD. These results provide new insight regarding ROS homeostasis and potential pathophysiological mechanisms of acute exposure to hypobaric hypoxia, plus other disease states associated with oxidative-stress damage as a result of tissue hypoxia.

The quest for evidence-based medicine in mountain areas.

Emergency medical services operating in remote and mountainous areas have to negotiate extremely adverse environmental, topographical, and logistical conditions. A further challenge stems from the fact that making clinical decisions in an evidence-based manner ‘‘can be a particularly difficult area because of the paucity of data’’ (West, 2010), and this represents the primary limitation at present to decision-making in mountain rescue. In March 2011, the Institute of Mountain Emergency Medicine hosted an international conference in Bolzano, Italy, entitled ‘‘New Insights in Emergency Medicine: How Can We Apply Evidence-Based Medicine in European Mountain Areas?’’ with the participation of 19 experts from Europe. The introductory discussions focused on the epidemiology and treatment of cardiovascular emergencies, cold injuries, and trauma; however, the challenges of reporting on the epidemiology of pathologies in remote settings stems from a paucity of field-specific data, and for this reason we hosted a discussion on the technical and logistical aspects of creating transnational data collection systems. Until such registries accumulate sufficient entries, an epidemiological overview of alpine accidents and treatment outcomes is preliminary and the field remains at the mercy of primarily case reports and case series. This fact motivated discussions on the feasibility and ethical considerations of conducting field-specific research and the applicability of existing treatment guidelines in adverse conditions. A final consensus was formulated regarding the most urgent topics and the research strategies required in order to reach the next milestones in the field. Throughout the discussions it was reiterated that mountain emergency medicine can be differentiated from emergency medicine in other settings in a number of aspects. There are specific pathologies, for example, frostbite (Cauchy et al, 2011), suspension trauma (Mortimer, 2011), the triple H syndrome (hypothermia, hypercapnia, and hypoxia) (Brugger et al, 2003), and high-altitude illness (Basnyat and Murdoch, 2003) that are not seen in other environments. Furthermore, trauma accounts for up to 90% of all cases in mountain rescue operations (Marsigny et al, 1999; McIntosh et al, 2010), and although the incidence of trauma is higher in urban areas, the relative mortality may be higher in rural cases (Fatovich et al, 2011). In this setting, patient outcome ultimately depends on innumerable factors (e.g., type and severity of injury, accident location, environmental conditions), but two factors seem to unavoidably play a major role: the time granted by the specific situation and the skills of the medical and rescue team in extreme conditions. Without extensive training and practice in adverse conditions the emergency physician is not adequately prepared to make case-specific decisions and lacks the flexibility required of emergency situations. Thus, it is crucial that in-field decisions are supported by existing treatment guidelines (Brugger and Durrer, 2002; Durrer et al, 2003; Ellerton et al, 2009; Elsensohn et al, 2006; Morrison et al, 2010; Paal et al, 2007; Soar et al, 2010; Sumann et al, 2009; Tomazin et al, 2003; and Zafren et al, 2005). However, as these are based primarily on data from in-hospital settings and expert consensus with a low level of evidence, whether these guidelines are always applicable in an adverse, prehospital environment is a matter of debate. The collection of data specific to a prehospital setting by means of multicenter data registries clearly emerges as one of the most urgent issues requiring immediate attention. The International Hypothermia Registry (https://www.hypothermiaregistry.org/) and International Alpine Trauma Registry (http:// traumaregistry.eurac.edu/) are transnational platforms for the collection and storage of hypothermia and trauma data, respectively, and aim to identify potential prognostic factors in the preand in-hospital management of patients exposed to environmental factors. A continued focus on international comparisons, as recently exemplified by the differences in avalanche survival curves in a Canadian and Swiss sample (Haegeli et al, 2011), and a better understanding of different environmental conditions and rescue processes will enable tailoring of treatment recommendations and rescue operations to specific cases. Prehospital data collection is not without limitations and inherent ethical challenges. Studies in the emergency setting require special attention to the impossibility of obtaining informed consent from patients in an unconscious or lifethreatening state and, as more recently highlighted, to the possibility of increasing risk in some situations where informed consent regulations create a delay of treatment (Roberts et al, 2011). In the case of animal testing, one must be aware of the impact of public opinion on research feasibility (Brugger et al, 2010; Paal et al, 2010), even if animal welfare models have been respected. The ‘‘three Rs’’ principle for animal testing is a reminder to continue to seek out new research models and techniques to replace animal with nonanimal designs, reduce the number of animals in a test, and refine the experimental design to enhance animal welfare for those animals still tested (Russell and Burch, 2007). The idea of establishing a laboratory that could simulate standardized and reproducible adverse weather conditions was discussed as an innovative testing alternative for scientific investigations in the field of mountain emergency medicine. With a focus on the future, the expert consensus stated that the most urgent single topics in the field at present include: (i)

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.