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

Introduction: 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.

Methods: 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).

Results: 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.

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