Does Rescue Collapse Mandate a Paradigm Shift in the Field Management of Avalanche Victims?

It is with great interest that we read the publication of Peter Mair et al., reporting the poor survival of avalanche victims with unwitnessed hypothermic cardiac arrest (Mair et al., 2014). These results are in agreement with another recent publication, which highlighted the more favorable outcome of the subgroup of hypothermic victims who sustained a witnessed arrest (i.e., “rescue collapse”) (Boué et al., 2014a). Two case reports also supported the excellent survival and neurological outcome of rescue collapse victims (Boué et al., 2014b). Rescue collapse is defined as “the occurrence of cardiac arrest related to the patient's extrication or transfer in profound hypothermia” (Boué et al., 2014a), and was mentioned in the CISA-IKAR guidelines on resuscitation of avalanche victims in 2013 (Brugger et al., 2013).

The current guidelines recommend that cardiac monitoring is to be established in avalanche victims “prior to transport” or “applied upon extrication” (Brugger et al., 2011; 2013), but fails to mention rescue collapse specifically, where early monitoring is critical as cardiac arrest may go unnoticed by rescuers busy with the extrication. We suggest changing our extrication practice: with a burial time >35 min early ECG monitoring and prolonged search for vital signs should be emphasized in order to improve the detection of rescue collapse in the field.

Management of avalanche victims in cardiac arrest with no apparent traumatic cause of arrest should be guided by burial time. Burial times under 35 minutes imply asphyxia as the probable cause of arrest, and mandate prompt ventilation, whereas victims buried for >35 minutes should be assumed to be in hypothermia-induced arrest (Brugger et al., 2013).

Based on the 35-minutes cut-off, we propose to emphasize two strategies to maximize the probability of detecting and treating rescue collapse, namely immediate cardiac monitoring and prolonged check of vital signs. First, rescuers should monitor the heart rate as soon as the torso is exposed when a victim has been buried for more than 35 minutes and in any case before extrication. This was proposed in 2012 by Strappazon et al. (2012), but has not been incorporated in the guidelines yet. Second, vital signs should be carefully sought for 1 minute. In deeply hypothermic patients, pulse may not be palpable due to the hypothermia-associated hypotension, and respiration may be nearly undetectable, unless sought methodically. Otherwise, patients may be erroneously pronounced dead on site, rescue collapse may be missed, or unnecessary chest compressions may be performed in a stage III hypothermic victim, which may precipitate ventricular fibrillation (Brugger et al., 2011; Pasquier et al., 2014). The thorough 1-minute check may delay CPR, but is a worthy investment considering that survival of deeply hypothermic patients is possible even with prolonged periods without CPR (Althaus et al., 1982; Oberhammer et al., 2008; Zafren et al., 2014).

Our helicopter-based emergency medical service Air-Glaciers rescues 10 to 15 fully buried avalanche victims every year. After reviewing these recent publications (Boué et al., 2014a; 2014b; Mair et al., 2014), we changed our practical field approach: in an unconscious avalanche victim fully buried for more than 35 minutes and found with a patent airway, cardiac monitoring with multifunction defibrillator electrodes is applied as soon as the torso is exposed; then vital signs are sought for 1 minute, paying particular attention to respiration. This pragmatic approach was presented and tested during our annual pre-winter season field training in December 2014, and will now be applied in the field.

In conclusion, early ECG monitoring and prolonged search for vital signs for burial duration greater than 35 minutes should be emphasized and implemented in the field as soon as possible, so as to improve the detection of rescue collapse.