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.

[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.

The determination of the myocardial extracellular space in the cat in vivo: a comparative methodological study.

The myocardial extracellular space (ECS) was determined in cats in vivo by means of the ECS indicators, inulin and sulfanilic acid and, additionally, as glucose space. Experiments were carried out in cats subjected to bilateral kidney ligation (single injection) and in intact cats (single injection or infusion of indicator). The heart was clamped by instant deep-freezing in situ; this technique was compared, in renally-ligated cats, with excision and subsequent freezing of the heart in liquid nitrogen. The myocardial blood content was significantly decreased, and the myocardial lactate concentration significantly increased in excised, as compared with in situ-clamped hearts. Renally-ligated cats showed marked hypotension. The mean myocardial blood content was also significantly lower than in intact animals. A highly significant correlation was found between myocardial blood content and blood pressure for all experiments with instant deep-freezing. The mean inulin ECS value in renally-ligated cats was 22.7 +/- 1.5 ml. In accordance with the fact that the ECS is dependent on the tissure blood content, the corresponding values in intact animals were significantly higher, 25.9 +/- 2.5 ml (single injection) and 26.3 +/- 3.9 ml (infusion), calculated per 100 g tissue wet weight. Similar values were obtained for the glucose and sulfanilic acid ECS. If the interstitial space, an expression independent of the tissue blood content is used as space parameter, no significant differences were found under any of the present experimental conditions.