Respiratory function in hoist rescue: comparing slings, stretcher, and rescue basket

Some types of equipment used in helicopter hoist rescue have the potential to cause respiratory embarrassment due to chest compression and/or body positioning. This study compared the respiratory effects of four commonly used devices.

A randomized crossover trial was undertaken in 27 healthy adults while suspended in single sling (SSling), double sling (DSling), supine in a rescue stretcher, and in a rescue basket (RB) of the type used by the U.S. Coast Guard. Primary variables measured were 1-s forced expiratory volume (FEVI), forced vital capacity (FVC), FEV1/FVC ratio, and inspiratory capacity (IC) in each modality versus control. Secondary measurements were peripheral oxygen saturation (SpO2), heart rate (HR), and respiratory rate (RR).

Data meeting repeatability standards was obtained from at least 24 subjects in each position. The SSling was associated with significant mean decreases from control of 17% in FEV1, 19.8% in FVC, and 28.3% in IC, together with increases in HR and RR and a decrease in SpO2. The DSling and stretcher were associated with smaller decreases in expiratory spirometry; the DSling was associated with a >10% decrease in IC and the stretcher was associated with a >10% increase in IC. The values for RB did not vary from control for any outcome measure. There was no decrease in FEV1/FVC ratios in any modality.

The RB was not associated with any change in measured outcomes. Other methods tested, especially SSling, have detrimental effects on respiratory function.