Mortality rates in Norwegian HEMS-a retrospective analysis from Central Norway.

BACKGROUND: Helicopter Emergency Medical Services (HEMS) provide rapid and specialized care to critically ill or injured patients. Norwegian HEMS in Central Norway serves an important role in pre-hospital emergency medical care. To grade the severity of patients, HEMS uses the National Advisory Committee for Aeronautics' (NACA) severity score. The objective of this study was to describe the short- and long term mortality overall and in each NACA-group for patients transported by HEMS Trondheim using linkage of HEMS and hospital data. METHODS: The study used a retrospective cohort design, aligning with the STROBE recommendations. Patient data from Trondheim HEMS between 01.01.2017 and 31.12.2019 was linked to mortality data from a hospital database and analyzed. Kaplan Meier plots and cumulative mortality rates were calculated for each NACA group at day one, day 30, and one year and three years after the incident. RESULTS: Trondheim HEMS responded to 2224 alarms in the included time period, with 1431 patients meeting inclusion criteria for the study. Overall mortality rates at respective time points were 10.1% at day one, 13.4% at 30 days, 18.5% at one year, and 22.3% at three years. The one-year cumulative mortality rates for each NACA group were as follows: 0% for NACA 1 and 2, 2.9% for NACA 3, 10.1% for NACA 4, 24.7% for NACA 5 and 49.5% for NACA 6. Statistical analysis with a global log-rank test indicated a significant difference in survival outcomes among the groups (p < 2⋅10- 16). CONCLUSION: Among patients transported by Trondheim HEMS, we observed an incremental rise in mortality rates with increasing NACA scores. The study further suggests that a one-year follow-up may be sufficient for future investigations into HEMS outcomes.

Hydration status during commercial saturation diving measured by bioimpedance and urine specific gravity.

Excessive fluid loss triggered by hyperbaric pressure, water immersion and hot water suits causes saturation divers to be at risk of dehydration. Dehydration is associated with reductions in mental and physical performance, resulting in less effective work and an increased risk of work-related accidents. In this study we examined the hydration status of 11 male divers over 19 days of a commercial saturation diving campaign to a working depth of 74 m, using two non-invasive methods: Bioelectrical impedance analysis (BIA) and urine specific gravity (USG). Measurements were made daily before and after bell runs, and the BIA data was used to calculated total body water (TBW). We found that BIA and USG were weakly negatively correlated, probably reflecting differences in what they measure. TBW was significantly increased after bell runs for all divers, but more so for bellmen than for in-water divers. There were no progressing changes in TBW over the 19-day study period, indicating that the divers' routines were sufficient for maintaining their hydration levels on short and long term.