Observations of cold-induced vasodilation in persons with spinal cord injuries

Study Design: Acute experimental study Objectives: Cold-induced vasodilation (CIVD) is a local mechanism of protection against frostbite in able-body persons. This study assessed whether CIVD was observed in the sensate and non-sensate area in spinal cord injuries (SCIs) and whether the response patterns were different between the region levels or sites. Setting: Laboratory of Wakayama Medical University, Japan Methods: A local cooler device (diameter 4 cm) was placed on the chest (sensate) and thigh (non-sensate) in persons with cervical (SCIC; n=9) and thoracolumbar spinal cord injuries (SCITL; n=9). After the surface temperature was controlled at 33°C for 10 min (baseline), local cooling (LC) with a rate of 0.045°C/s was applied and the temperature was maintained at 15 and 8°C for 15 min of each stage. Skin blood flow (SkBF; laser Doppler flowmetry) was monitored using a 1-mm needle-type probe inserted into its center. CIVD was observed on the both sites in all participants at 8°C LC. Results: % change in SkBF (%ΔSkBF) on the chest remained unchanged until the end of the 15°C stage in both groups, then it increased at 8°C stage over the baseline. %ΔSkBF on the thigh remained unchanged throughout the measurement in SCIC, but decreased during the periods from 33 to 15°C and from 15 to 8°C, then recovered to around the baseline level at 8°C in SCITL. Conclusions: CIVD was observed both in the sensate and non-sensate areas in SCIs. The magnitudes of the response were different between the both areas.