Wilderness and Rescue Medicine 7th Edition Jeffrey Isaac, PA-C and David E. Johnson, MD

Chapter 20: Medical Aspects of Avalanche Rescue

Most avalanche fatalities are caused by asphyxia. Since snow is mostly air and is very porous, the victimmay be able to breathe for a period of time. Eventually, the victim’s exhaled breath condenses and freezes into a nonporous ice mask around the airway. Although it seems like the cold would play a major role in death by burial in snow, very few victims actually survive long enough to die from hypothermia. The most important factor in survival of ava- lanche burial is the speed of recovery. In the first 15 minutes, between 80% and 90% of victims are found alive. This drops to about 30% at 35 minutes and around 3% at 130 minutes. It makes sense that most of the victims that survive are dug out by the people traveling with them, not by rescue teams arriving hours later. If the victim is wearing an avalanche beacon, other members of the group may be able to find and recover him or her within minutes. The Recco system, used in many ski areas, is a device that broadcasts a directional radio wave that excites a small metallic tag or sticker sewn into the skier’s clothing. The return signal is picked up by the unit’s receiver and can be followed directly back to the victim. The device has been known to detect a reflected signal off cell phones, radios, and other metallic objects. In the absence of either

technology, the most efficient tool for locating a buried victim is a well-trained avalanche search dog team. If neither the technology nor dog is available, a quick find is unlikely unless some part of the victim is projecting above the surface of the snow. The backup plan consists of a probe line of rescu- ers working slowly through the debris field. A live find is far less likely. Nevertheless, survival of prolonged burial is possible, especially in cases where the victim has come to rest in an air space around a tree or boul- der or has been partially protected by building debris. User deployed airbag devices, designed to keep a victim afloat during an avalanche, can also create an airspace around a victim who is com- pletely buried. Another device, called the Avalung, can allow victims to continue breathing under the snow for an hour or more if the user has managed to retain the mouthpiece in place during the slide. The possibility of a prolonged survival makes avalanche search and recovery a high-priority time sensitive mission. If a live patient is recov- ered, the primary problem addressed by the medi- cal practitioner is likely to be respiratory arrest due to asphyxiation. This can occur because of snow packed into the nose and mouth, the for- mation of an ice mask, or restricted respiratory excursion due to the pressure of the snow pack