Vascular effects of a modified cold pressor test in spinal cord injured and able-bodied men

The vascular reflex responses of the hands of ten spinal cord injured (SCI) men (sensory and motor complete) to a modified cold pressor test were compared to ten age-matched, able-bodied men. The skin temperature of the left index finger was measured before, during, and after the immersion of the feet in ice water for 20 seconds. The heart rate and blood pressure were measured 5 minutes before and 15 minutes after the cold stimulus. The able-bodied subjects showed an immediate vasoconstriction and fall in finger temperature after cold stimulation of the feet, followed by vasodilation and an increase in finger temperature (p < .0001), whereas, the SCI subjects did not show any change in finger temperature during this test. Prior to application of the cold stimulus, the SCI subjects had a significantly low diastolic blood pressure compared with the diastolic blood pressure of able-bodied subjects, which "normalized" after the cold stimulus. These data support the concept that regulation of vascular tone occurs at both spinal and supraspinal levels.