Hyperthermia and Hypohydration in a Disabled Pressurized Rescue Module

Principal Investigator: Dave Hostler, PhD

Funding Agency: Naval Sea Systems Command

Abstract: In the event of a disabled submarine, a Pressurized Rescue Module (PRM) may be deployed. The PRM is a small pressurized vehicle capable of holding the rescued sailors and safely delivering them to the surface. Safe deployment of the PRM is dependent on understanding and mitigating the possible challenges if failures were to occur. If the PRM were to become disabled, the environmental conditions could quickly challenge the health and safety of those inside the PRM. For instance, because of the high number of sailors in a small space, the magnitude of increases in humidity and air temperature during a blower failure are predicted to rise to upwards of 35°C (95°F) and the air will quickly become saturated with water, raising humidity to >95% relative humidity. Such conditions will hinder temperature regulation and potentially overwhelm the capacity for heat loss. As a result, the thermal environment in the disabled PRM can become dangerous very quickly. However, to our knowledge there are no models supported by data that are capable of accurately predicting the magnitude of increases in core body temperature or reductions in body fluids occurring subsequent to sweating in an environment in which humidity exceeds 95% relative humidity and air temperatures are in excess of 33°C (92°F) for up to 24 h. Furthermore, there are no models capable of accurately predicting these variables in a hyperbaric, humid and warm environment for up to 24 h. This project will determine the magnitude of increases in core body temperature or reductions in body fluids incurred in a warm and humid disabled PRM scenario at sea level and at depth (20 feet of seawater) for up to 24 h.