Effect of Phase Change Material Cooling Vests on Body Thermoregulation and Thermal Comfort of Patients With Paraplegia: A Human Subject Experimental Study

STUDY DESIGN: Randomized experimental study. OBJECTIVE: Compared to able-bodied people, patients with paraplegia due to thoracic spinal cord injury (SCI) are at an increased risk of heat illnesses during exercise due to impaired thermoregulatory responses. To overcome this limitation, we investigated the performance of three phase change material (PCM) cooling vests of different melting temperatures (Eijsvogels, #49) and coverage area of the trunk. METHODS: Sixteen participants were divided into three groups according to their injury level. All were tested for V20 full vest (20°C Tm, 75% coverage). Mid-thoracic and high-thoracic groups were tested for V14 vest (14°C T(m), 75% coverage). The mid-thoracic group was tested for V20 half vest (20°C T(m), 50% coverage). The participants performed a 30-min arm-crank exercise followed by a recovery period inside a controlled hot climatic chamber. The heart rate, segmental skin (T(skin)), and core temperature (T(core)) values were recorded, and subjective questionnaires were taken. RESULTS: Compared to no vest (NV) test, all the vests showed an effective decrease in T(skin) values of the trunk. However, the decrease in T(skin) was not enough to induce a significant decrease in T(core) in all three groups. Mid-thoracic and low-thoracic groups showed a reduction in the increasing T(core) by the end of the exercise and recovery period. Finally, the level of thermal comfort was enhanced for the three groups. CONCLUSION: The effectiveness of cooling vests for persons with paraplegia is dependent on injury level and thus the ratio of sensate to insensate skin. Future studies necessitate the investigation of the cooling effects of PCM vests at a lower Tm with a larger sample size.