Efficiency of Rescue Paramedic Hoist versus Underslung Antenna in Helicopter-Based Avalanche Searches: A Randomized Trial.

Survival for avalanche victims is time-dependent, and survival is often reliant on ground companion rescue. Due to the time-critical nature of burial, remote locations, and high frequency of concomitant severe trauma, helicopters are often dispatched to these incidents. While helicopter-based transceiver searches are standard, the most efficient deployment strategy, either using an underslung antenna or hoisting a rescue paramedic (RP) with a handheld transceiver, remains unknown. This study compared the operational efficiency of these two methods in the Norwegian Search-and-Rescue (SAR) Helicopter Service.

A dual randomized, experimental field trial was conducted with the on-duty SAR helicopter and crew at the Ørland Main Airforce Base (Trøndelag, Norway). A simulated avalanche area of 80 × 150 meters was used, and six avalanche transceivers were buried at approximately 0.5m depth across the area. Only one transceiver was active at each run, and the locations were randomized to prevent crew memorization. The sequence of which procedure to use was also randomized. Four operational timestamps were recorded: First Signal, Optimal Signal, RP on Ground, and Transceiver Found.

Over three days, a total of 25 trial runs were performed, 13 with Antenna Search and 12 with RP Hoist Search. The RP Hoist Search was significantly faster in both time to Optimal Signal, with a difference between the groups of 29 seconds (95% CI, 9 - 50), and time for RP on Ground, with a difference between the groups of 124 seconds (95% CI, 98 - 151). For the total time to Transceiver Found, the difference between the groups was 143 seconds (95% CI, 113 - 172; P <0.001). Furthermore, the RP Hoist Search resulted in significantly faster fine search on the ground.

This randomized, experimental field trial comparing two currently used standard search procedures in the Norwegian SAR service showed that the RP Hoist Search was significantly more efficient than the Antenna Search for localizing buried avalanche victims, reducing total localization time by more than two minutes. Given that survival probability is reduced after 10-15 minutes of burial, this time saving may be clinically significant. The findings support that RP Hoist Search is an effective localization strategy for SAR helicopter services with comparable hoist systems.