Cardiovascular responses to bladder distension in patients with spinal transection

Abstract

Arterial blood pressure, heart rate, and cutaneous volume pulses were recorded during controlled elevation of urinary bladder pressure in a group of seven patients with spinal cord transsection above vertebral level T5 and in another group of four patients below T5. Profound elevations in systolic blood pressure and pulse pressure were induced by bladder distension when the lesion was situated above T5. Lesser elevations occurred in patients with lesions below T5. Marked vasoconstriction characterized skin areas innervated by the "isolated" spinal cord, while passive dilatation occurred in areas supplied by the proximal cord. Only three of seven patients with lesions above T5 level had decreased heart rate during marked elevations in arterial blood pressure. The marked elevations in pulse pressure in patients with lesions above T5 could not be explained solelyby increased vasoconstriction and decreased heart rate, but involves also inotropic cardiac responses. These inotropic responses are mediated by cardiac sympathetic nerves which leave the spinal cord above the T5 level.