IngentaConnect Dehydration Effects on the Risk of Severe Decompression Sickness ...

Abstract:

Fahlman A, Dromsky DM. Dehydration effects on the risk of severe decompression sickness in a swine model. Aviat Space Environ Med 2006; 77:102–6.

Background: Several physiological factors have been suspected of affecting the risk of decompression sickness (DCS), but few have been thoroughly studied during controlled conditions. Dehydration is a potential factor that could increase the risk of DCS. It has been suggested that hydration may enhance inert gas removal or increase surface tension of the blood. Hypothesis: Dehydration increases DCS risk. Methods: Littermate pairs of male Yorkshire swine (n = 57, mean ± 1 SD 20.6 ± 1.7 kg) were randomized into two groups. The hydrated group received no medication and was allowed ad lib access to water during a simulated saturation dive. The dehydrated group received intravenous 2 mg · kg⁻¹ Lasix (a diuretic medication) without access to water throughout the dive. Animals were then compressed on air to 110 ft of seawater (fsw, 4.33 ATA) for 22 h and brought directly to the surface at a rate of 30 fsw · min⁻¹ (0.91 ATA · min⁻¹). Outcomes of death and non-fatal central nervous system (CNS) or cardiopulmonary DCS were recorded. Results: In the hydrated group (n = 31): DCS = 10, cardiopulmonary DCS = 9, CNS DCS = 2, Death = 4. In the dehydrated group (n = 26): DCS = 19, cardiopulmonary DCS = 19, CNS DCS = 6, Death = 9. Dehydration significantly increased the overall risk of severe DCS and death. Specifically, it increased the risk of cardiopulmonary DCS, and showed a trend toward increased CNS DCS. In addition, dehydrated subjects manifested cardiopulmonary DCS sooner and showed a trend toward more rapid death (p < 0.1). Conclusion: Hydration status at the time of decompression significantly influences the incidence and time to onset of DCS in this model.

Dehydration Effects on the Risk of Severe Decompression Sickness in a Swine Model