Modeling the Effect of Cooling Vest on Body Thermal Response of People With Paraplegia During Exercise

Abstract

Abstract Persons with thoracic spinal cord injury (SCI), also named as people with paraplegia (PA), are encouraged to participate in sport activities for sake of improving their quality of life and health. Yet, heat strain is a major consequence of SCI after which the body loses its ability to regulate its temperature. Disruption in body temperature regulation and instability in core temperature (Tcr) endangers the patient health especially when subjected to extreme ambient conditions or high level of physical activity. Since thermophysiology is disrupted after SCI, using conventional personal cooling methods may not be effective on PA in a way similar to that of able-bodied people (AB). Experimental studies evaluated the effect of phase change material (PCM) and ice cooling vests on thermal response of PA during exercise. Results showed no change in Tcr values for both types of vest during exercise. This study aims at studying the effectiveness of PCM cooling vest for PA during exercise at intensity level of 6.5 MET within 21.1–23.9 °C room temperature and 50% relative humidity. A multi-segmented bioheat model of PA coupled with PCM cooling vest model (fabric-PCM-PA model) was deployed to predict Tcr values at different design conditions of the vest. Segmental core and skin temperatures profiles and the sensible and latent heat losses were obtained for torso segments to assess the percentage of enhancement in the cooling vest performance. Results showed that Tcr value of the body and Tcr values of the torso segments didn’t change at different design conditions of the vest; yet sensible heat losses were increased for all torso segments and latent heat losses were reduced. Decreases in latent heat losses affected Tsk values at the torso. Simulations were performed using fabric-PCM model integrated with PA bioheat model applying variation of skin coverage area, melting point of PCM and combination of both designs. An effective design of the vest for PA was found when using PCM packet at 10°C melting point and coverage area about 40% of torso because sensible heat losses were the highest compared to the other design cases of the vest.