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.

Correction to: Suspension syndrome: a potentially fatal vagally mediated circulatory collapse-an experimental randomized crossover trial.

The original version of this article unfortunately contained a mistake. Information was missing in the acknowledgements section. The correct information is given below.

Suspension syndrome: a potentially fatal vagally mediated circulatory collapse-an experimental randomized crossover trial.

PURPOSE: Suspension syndrome describes a potentially life-threatening event during passive suspension on a rope. The pathophysiological mechanism is not fully understood and optimal treatment unknown. We aimed to elucidate the pathophysiology and to give treatment recommendations. METHODS: In this experimental, randomized crossover trial, 20 healthy volunteers were suspended in a sit harness for a maximum of 60 min, with and without prior climbing. Venous pooling was assessed by measuring the diameter of the superficial femoral vein (SFV), lower leg tissue oxygenation (StO2) and by determining localized bioelectrical impedance. Hemodynamic response was assessed by measuring heart rate, blood pressure, stroke volume, and left ventricular diameters. Signs and symptoms of pre-syncope were recorded. RESULTS: Twelve (30%) out of 40 tests were prematurely terminated due to pre-syncopal symptoms (mean 44.7 min, minimum 13.4, maximum 59.7). SFV diameter increased, StO2 and the capacitive resistance of the cells decreased indicating venous pooling. Heart rate and blood pressure did not change in participants without pre-syncope. In contrast, in participants experiencing pre-syncope, heart rate and blood pressure dropped immediately before the event. All symptoms dissolved and values returned to normal within 5 min with participants in a supine position. CONCLUSIONS: Sudden pre-syncope during passive suspension in a harness was observed in 30% of the tests. Blood pools in the veins of the lower legs; however, a vagal mechanism finally leads to loss of consciousness. Time to pre-syncope is unpredictable and persons suspended on a rope should be rescued and put into a supine position as soon as possible.

The Crohn's disease-associated polymorphism in ATG16L1 (rs2241880) reduces SHIP gene expression and activity in human subjects.

Crohn's disease (CD) is a polygenic immune-mediated disease characterized by gastrointestinal inflammation. Mice deficient in the hematopoietic-restricted SH2 domain-containing inositolpolyphosphate 5'-phosphatase (SHIP) develop spontaneous CD-like ileal inflammation. Intriguingly, SHIP mRNA is not upregulated in biopsies from patients with ileal CD despite immune cell infiltration, but SHIP's role in human CD remains unknown. We analyzed SHIP mRNA expression and activity in biopsies and peripheral blood mononuclear cells (PBMCs) from control and treatment-naive subjects with ileal CD, and demonstrated that SHIP mRNA and activity were lower in hematopoietic cells in ileal biopsies and PBMCs from subjects with CD. In all tissues from our patient cohort and in PBMCs from a second healthy control cohort, subjects homozygous for the autophagy-related 16-like protein (ATG16L1) CD-associated gene variant (rs2241880), had low SHIP mRNA expression and activity. SHIP protein expression increased during autophagy and SHIP upregulation was dependent on ATG16L1 and/or autophagy, as well as the ATG16L1 CD-associated gene variant. Finally, homozygosity for the ATG16L1 risk variant and low SHIP mRNA expression is inversely related to increased (LPS+ATP)-induced IL-1ß production by PBMCs in our cohorts and was regulated by increased transcription of ILIB. These data suggest a novel mechanism by which the ATG16L1 CD-associated gene variant may predispose people to develop intestinal inflammation.

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.

[Accidental hypothermia]. / Akzidentelle Hypothermie.

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.

[Life-saving air supported avalanche mission at night in high alpine terrain]. / Lebensrettender luftgestützter lawineneinsatz bei nacht im hochalpinen gelände.

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.

Retention of mouth-to-mouth, mouth-to-mask and mouth-to-face shield ventilation.

BACKGROUND: Retention of mouth-to-mouth, mouth-to-mask and mouth-to-face shield ventilation techniques is poorly understood. METHODS: A prospective randomised clinical trial was undertaken in January 2004 in 70 candidates randomly assigned to training in mouth-to-mouth, mouth-to-mask or mouth-to-face shield ventilation. Each candidate was trained for 10 min, after which tidal volume, respiratory rate, minute volume, peak airway pressure and the presence or absence of stomach inflation were measured. 58 subjects were reassessed 1 year later and study parameters were recorded again. Data were analysed with ANOVA, chi(2) and McNemar tests. RESULTS: Tidal volume, minute volume, peak airway pressure, ventilation rate and stomach inflation rate increased significantly at reassessment with all ventilation techniques compared with the initial assessment. However, at reassessment, mean (SD) tidal volume (960 (446) vs 1008 (366) vs 1402 (302) ml; p<0.05), minute volume (12 (5) vs 13 (7) vs 18 (3) l/min; p<0.05), peak airway pressure (14 (8) vs 17 (13) vs 25 (8) cm H(2)O; p<0.05) and stomach inflation rate (63% vs 58% vs 100%; p<0.05) were significantly lower with mouth-to-mask and mouth-to-face shield ventilation than with mouth-to-mouth ventilation. The ventilation rate at reassessment did not differ significantly between the ventilation techniques. CONCLUSIONS: One year after a single episode of ventilation training, lay persons tended to hyperventilate; however, the degree of hyperventilation and resulting stomach inflation were lower when a mouth-to-mask or a face shield device was employed. Regular training is therefore required to retain ventilation skills; retention of skills may be better with ventilation devices.

Head position for opening the upper airway.

Inexperienced rescuers may encounter severe problems in an unconscious patient with opening and maintaining a patent upper airway. Designing a ventilating device that could indicate how to open an upper airway correctly may be beneficial. The heads of 102 volunteers were randomly placed in different head positions by one investigator. A pocket mask was then pressed gently on the volunteer's face followed by measurement of the head position angles. Mean (SD) flexion was - 4 degrees (8 degrees) (95% CI - 5.9 to - 2.9); the mean neutral position was 21 degrees (6 degrees) (95% CI, 19.9 to 22.3); extension was 42 degrees (6 degrees) (95% CI 40.8 to 43.0 degrees) and differed significantly between each position (p < 0.001). The flexion and neutral position angles were significantly greater in men than in women: - 2 (7 degrees) vs. -8 (7 degrees) and 22 (7 degrees) vs 20 (5 degrees); p < 0.001 and p = 0.03, respectively. Maximum extension of the head in both supine men and women was 42 degrees, which could be utilised to optimise assisted ventilation of an unprotected upper airway.

[Avalanche emergencies. Review of the current situation]. / Der Lawinennotfall. Eine aktuelle Ubersicht.

In North America and Europe around 140 persons die every year due to avalanches, approximately 35 in North America, 100 in the European Alps, and 5 in other parts of Europe. Most of the victims are skiers and snowboarders. This article outlines the specific pathophysiology of avalanche burials, such as hypoxia, hypercapnia, and hypothermia and also other factors which influence survival. Strategies to minimize the mortality due to avalanches and the on-site treatment of buried persons are discussed. Finally, possibilities to reduce the number of avalanche deaths are pointed out.

Field management of avalanche victims.

The median annual mortality from snow avalanches registered in Europe and North America 1981-1998 was 146 (range 82-226); trend stable in Alpine countries (r=-0.29; P=0.24), increasing in North America (r=0.68; P=0.002). Swiss data over the same period document 1886 avalanche victims, with an overall mortality rate of 52.4% in completely-buried, versus 4.2% in partially-, or non-buried, persons. Survival probability in completely-buried victims in open areas (n=638) plummets from 91% 18 min after burial to 34% at 35 min, then remains fairly constant until a second drop after 90 min. Likewise, survival probability for completely-buried victims in buildings or on roads (n=97) decreases rapidly following burial initially, but as from 35 min it is significantly higher than that for victims in open areas, with a maximum difference in respective survival probability (31% versus 7%) from 130 to 190 min (P<0.001). Standardised guidelines are introduced for the field management of avalanche victims. Strategy by rescuers confronted with the triad hypoxia, hypercapnia and hypothermia is primarily governed by the length of snow burial and victim's core temperature, in the absence of obviously fatal injuries. With a burial time < or =35 min survival depends on preventing asphyxia by rapid extrication and immediate airway management; cardiopulmonary resuscitation for unconscious victims without spontaneous respiration. With a burial time >35 min combating hypothermia becomes of paramount importance. Thus, gentle extrication, ECG and core temperature monitoring and body insulation are mandatory; unresponsive victims should be intubated and pulseless victims with core temperature <32 degrees C (89.6 degrees F) (prerequisites being an air pocket and free airways) transported with continuous cardiopulmonary resuscitation to a specialist hospital for extracorporeal re-warming.

Distinct thyroid hormone-dependent expression of TrKB and p75NGFR in nonneuronal cells during the critical TH-dependent period of the cochlea.

Analyzing the thyroid hormone (TH)-dependent period of the inner ear, we observed that the presence of triiodothyronine (T3) between postnatal day 3 (P3) and P12 is sufficient for functional maturation of the auditory system. Within this short time period, an unusual transient TH-dependent expression of nonneuronal neurotrophin receptors (NT-R) trkB and p75(NGFR) was observed in correlation with neuronal and morphogenetic processes. The availability of thyroid hormone was revealed to be invariably correlated with (a) a transient expression of full-length trkB in TRalpha1-, TRalpha2- and TRbeta1-expressing hair cells concomitant to the segregation of afferent fibers and the synaptogenesis of efferent fibers; and (b) a transient expression of p75(NGFR) in TRalpha1- and TRbeta1-expressing great epithelia ridge cells in direct spatiotemporal correlation with the appearance of apoptotic cells and morphogenetic maturation of the organ. For the first time, these data suggest a TH dependency of the expression of neurotrophin receptors in nonneuronal cells. A potential role of these peculiar neurotrophin receptor expression for the conversion of the biological function of TH on innervation patterning and morphogenesis during the critical TH-dependent period of the inner ear may be considered.

A totally implantable drug delivery system for local therapy of the middle and inner ear.

Local therapy of middle and inner ear diseases is being used, but is restricted to cases of ear drum perforation or to repeated invasive intratympanic drug application by the physician. In accordance with the Medical Device Directive (class III), a bone-anchored, totally implantable drug delivery system (TI-DDS) has been developed. It includes a micropump for subcutaneous, patient-controlled activation, a drug reservoir and a septum port. A thin guide-wired catheter leads from the pump outlet to the point of application in the mastoid or middle ear cavities. Local inner ear therapy with suitable drugs is possible by positioning the catheter's end near the round window membrane. The system requires no battery and will offer a wide range of patient-controlled bolus applications (25 microliters per activation). We first analyzed the three-dimensional implantation geometry of the mastoid cavity. Basic micromechanical problems have been solved in order to create several prototypes. The TI-DDS has already undergone extensive in vitro testing. Recent results of pump rate precision and digital pressure force testing are promising. Local drug treatment for conditions such as lidocaine-sensitive tinnitus, secretory otitis media, Meniere's disease, localized pain and intralesional cancer is under discussion. Furthermore, local application of future biotechnological trophic factors for inner ear treatment is anticipated. The basic engineering is completed and initial animal tests are in preparation.

[Avalanche emergency. New aspects of the pathophysiology and therapy of buried avalanche victims]. / Der Lawinennotfall. Neue Aspekte zur Pathophysiologie und Therapie von Lawinenverschütteten.

A series of investigations on the pathophysiology and management of persons buried in an avalanche has been undertaken over the past few years in response to increased awareness of the importance of emergency medical treatment of avalanche victims and the fact that the high mortality rate has not decreased in spite of the improvement in rescue techniques. This paper is the very first review of the problems encountered in avalanche disasters. The developments over the past 20 years, in particular, are summarized and discussed. Furthermore, current opinions and recommendations on optimal rescue procedure, as well as the prevention of such emergencies are presented. Precise assessment of the survival probability after burial under an avalanche and recognition of the prognostic importance of an air pocket, but only limited role of hypothermia, provide the basis for new concepts governing therapy and triage by the emergency doctor. Resulting guidelines have been endorsed by the Emergency Medicine Subdivision of the International Commission of the Alpine Rescue Services (ICAR) and these recommendations are intended for implementation by organised rescue teams in order to reduce secondary deaths following successful extrication of victims from the avalanche masses. However, the chance of being rescued alive depends primarily on the rapidity of extrication, i.e. how quickly the rescue teams are alerted and transported to the disaster area in the first instance, then how quickly the victims are located and extricated. In order to reduce the mortality additional preventive measures must be introduced to avoid complete burial if possible, or appreciably hasten the rescue procedure. The very steep drop ("fatal kink") in survival probability as from 15 minutes after burial underlines the absolute necessity of the mastery of efficient rescue procedure by uninjured companions. Improvement of the technical developments for the avoidance of total burial (avalanche air bag) and optimization of the electronic location (transceiver) of buried skiers by uninjured companions are essential future requirements. Nonetheless, primary prevention remains of paramount importance in governing decision making by offpiste skiers. Correct assessment of the inherent risks according to the prevailing circumstances and strict adherence to safety rules take precedence over all other considerations.

On-site triage of avalanche victims with asystole by the emergency doctor.

Asystole in avalanche victims is generally due to asphyxia and not primarily to hypothermia. Hence, on-site establishment of death by asphyxiation would avoid evacuation risks to the rescue party, as well as high costs of transport to, and treatment at, frequently distant specialist centres in cases with a hopeless prognosis. This paper presents a novel differential diagnosis scheme based on burial duration (critical time 45 min) and core temperature (critical level 32 degrees C) of the person on extrication, as well as the presence or absence of an air pocket, facilitating on-site identification of asphyxiated victims. When information regarding an air pocket is uncertain in victims buried longer than 45 min, determination of serum potassium (critical level 10 mmol/l) at the nearest hospital becomes an alternative criterion for triage. The proposed guidelines aim to clarify field decision-making for the emergency doctor with respect to discontinuation of resuscitation and limitation of transferral for cardiopulmonary bypass core rewarming to those patients with presumptive reversible hypothermia.