A Comparative Study on the Effectiveness of Evaporative and Phase Change Material Cooling Vests for People With Paraplegia

Abstract

Abstract Personal cooling vests to alleviate thermal strain in persons with thoracic spinal cord injury (SCI), named paraplegia, were tested. Mainly, phase change material (PCM) cooling vests were the most frequent type applied at different exercises and ambient conditions. Published results of PCM cooling vests indicated its significant effect in reducing body core temperature for persons having more than 50% of their trunk skin as sensate. Nevertheless, preferences of persons with SCI obtained from subjective voting during experimental studies revealed that the use of PCM cooling vests caused additional burden weight on the body and sometimes restricted the movement. It is of interest to investigate the effect of an alternative personal evaporative cooling vest (ECV), characterized by light weight and practical use without hindering body movement of persons with SCI. In this study, it is aimed to compare the effect of ECV on the physiological and psychological responses of persons with SCI compared to that of PCM cooling vests under the same ambient conditions and metabolic rates. The research methodology included human subject experiments for persons with mid-thoracic (T4-T8) and low-thoracic (T9-T12) injury where the sensate skin of the trunk is at least 50% of its area. Thirteen participants were recruited to perform an arm-crank exercise at a constant load of 30 W for 30-min while using ECV inside a controlled climatic chamber of hot conditions (30°C, 4 0% RH). Measurements of body core and skin temperatures as well as thermal comfort and sensation, perceived exertion and skin wettedness were done. Furthermore, Multi-way ANOVA test was conducted to analyse the results of three tests: no vest (NV), with ECV, and with PCM. Findings of mid- and low-thoracic groups showed similar effectiveness of ECV compared to PCM cooling vest in reducing core temperature, yet the change in perceived exertion was better with the use of ECV due to its light weight.