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Three backcountry skiers are getting ready for their descent down the summit slope. Just as the last one is about to ski down, a slab avalanche releases. His two colleagues are caught in it and completely buried. He immediately begins searching for them and soon finds the first victim with his avalanche transceiver. He digs him out, but he shows no sign of life. He begins cardiopulmonary resuscitation (CPR) and tries to resuscitate him – without success. The minutes tick by – and the second victim is still lying under the snow. Should the rescuer nevertheless keep trying to resuscitate the first victim? Or should he rescue the second buried person instead before it is too late for her to be saved?
This fictive example illustrates the kind of dilemmas helpers face if they cannot rescue all the victims in an avalanche accident at the same time. “Such situations are rather rare, but still happen,” says Jürg Schweizer, Head of SLF and the Research Unit ‘Snow Avalanches and Prevention’. In avalanche-rescue training courses, the question about what best to do in such a situation is often raised.
According to an official recommendation of the International Commission for Alpine Rescue (ICAR), you should try to resuscitate victims of avalanche accidents who are not responsive for at least 20 minutes. “But if another person is buried, their chances of survival go down drastically in this time,” says Jürg. When should you stop performing CPR on the first victim and start searching for the second to maximise the survival chances of both?
It is exactly this question that has preoccupied the Swiss avalanche-rescue specialist Manuel Genswein for some time. He and Jürg Schweizer, together with other avalanche researchers and emergency medicine specialists, carried out a study to try to find a solution for such a scenario where two people are buried and another is trying to rescue them. As no data from case studies exists, the researchers performed a so-called Monte-Carlo simulation on the computer – a new approach in emergency medicine. The model estimates, with the help of calculated probabilities, the best moment to end trying to revive the first victim and to rescue the second. As a basis for the simulation, the researchers used existing data on the probability that buried people survive an avalanche burial and on functional outcome after out-of-hospital cardiac arrest in relation to time spent on resuscitation.
Reconsidering current recommendations
The results show that the chances that both victims will survive are greatest if CPR is performed on the first victim for a few minutes before starting to search for the second. “This means the official recommendation of 20 minutes for CPR duration is too long in this case,” says Jürg. He is therefore keen for new recommendations to be drawn up. To ensure they are well-based, further research and better medical data are needed to substantiate the results of this study.
“Performing a triage in an emergency situation is, of course, always ethically tricky,” says Jürg. “Such decisions cannot, however, be avoided, which means making sure they are as good as possible.” The principle of maximising survival chances is already applied today when several rescuers use probes to search for a buried person. This involves probing in such a way that the speed and precision of the search are balanced to ensure the chances of finding the victim alive are as great as possible. (Claudia Hoffmann, Diagonal 2/18)