Circulatory reflexes in spinal man

Abstract

Three normal controls and eight tetraplegic patients with complete transverse spinal cord syndromes between C6 and T3 were studied. Five of the patients had complete lesions above C8. Hand and forearm blood flows were measured with water filled venous occlusion plethysmographs maintained at 30°-32°C. and 34°-36°C. respectively. Skin temperature and heart rate were also recorded. The effects of the Valsalva manœuvre, passive elevation of the legs and indirect heating were studied. It was found that the blood flow of the tetraplegic patients did not increase in response to indirect heating which raised the oral temperature nearly two degrees centigrade, and failed to alter following the Valsalva manœuvre. In contrast, there was an increase in the forearm blood flow in response to passive elevation of the legs which returned to normal when the legs were restored to the horizontal position. This was accompanied in some cases by a bradycardia. It was concluded that this was a spinal reflex. The significance of these findings is discussed in relation to the central and peripheral control of the blood vessels, and the pathways involved. © 1965, International Spinal Cord Society. All rights reserved.