Drowning incidents treated by the Danish Royal Air Force's Search and Rescue helicopters: a 10-year nationwide registry-based cohort study

BACKGROUND: The primary objective of this study was to estimate the incidence and describe the characteristics of non-fatal and fatal drowning incidents treated by the Royal Danish Air Force's Search And Rescue (SAR) helicopters from 2014 to 2023.

METHODS: This nationwide registry-based cohort study identified drowning patients treated by the SAR helicopters from January 1, 2014, through December 31, 2023. The medical records within the SAR database were used for patient identification and data extraction. We reported the annual number of fatal and non-fatal drowning incidents stratified for prehospital survival and assessed prognostic factors associated with fatal drowning using Fisher's Exact Test.

RESULTS: During the 10-year study period from 2014 to 2023, 247 drowning incidents treated by SAR helicopters were recorded, corresponding to an incidence rate of 0.43 cases per 100,000 person-years [95% CI: 0.38-0.49]. After exclusion of patients with irreversible signs of death, 229 patients were analysed. Males accounted for 89%, and most patients were treated from June to August (42%). The prehospital survival rate was 55%. Significantly higher fatal drowning rates were observed for male vs. female patients (39% vs. 5%), patients aged 50-70 years vs. <20 years (approx. 50% vs. 8%), submersion vs. immersion (86% vs. 1%) and low GCS score < 14 vs. 14-15 at SAR arrival 85% vs. 0%). The fatal group received prehospital critical care interventions more frequently, as part of advanced life support.

CONCLUSIONS: The SAR helicopters rescue and treat a significant number of drowning patients every year. The overall prehospital survival rate was 55%, and significant prognostic factors associated with fatal drowning included male sex, increasing age, submersion injury, and a GCS score < 14 at SAR arrival.