Baroreceptor reflex response in paraplegia during head-up tilt position.

ABSTRACT

Paraplegia is one of the most common spinal cord lesions seen in spinal cord injury patients below 4th thoracic vertebra and is associated with autonomic loss below the level of lesion with intact vagal cardiac nerves. It occurs due to lesion of spinal cord at an appropriate level. i.e., sparing superior extremities and involving inferior extremities. The common causes of paraplegia are accidents such as gunshot injuries, spinal cord injuries, autonomic injuries and dislocation of spine. The degree of cardiovascular control impairment is related to the level and severity of the lesion. This study was to investigate the autonomic control of cardio vascular functions in paraplegia patients in response to head up tilt following spinal cord injury. The parameter studies were in head up tilt response on resting heart rate and blood pressure changes in paraplegic subjects. The results show an abnormal response to head – up tilt in paraplegia patients with decrease in diastolic blood pressure but the heart rate showed normal response. Thus, in patients of paraplegia, sympathetic reflexes below the level of the lesion induce vasoconstriction. These results indicate that increased sympathetic activity in controls during Head up tilt and decreased sympathetic activity in paraplegia. This suggests that patients with paraplegia maintain cardiovascular homeostasis during Head up tilt without increase in sympathetic activity.