VENTILATORY FUNCTION IN CERVICAL AND HIGH THORACIC SPINAL-CORD INJURY- RELATIONSHIP TO LEVEL OF INJURY AND TONE

Weakness and spasticity of chest wall muscles are known to adversely a ffect pulmonary function in spinal cord-injured patients. To test the assertion that impaired strength and increased tone contribute to vent ilation deficits, 52 patients with recent acute traumatic cervical and high thoracic spinal cord injury underwent complete pulmonary functio n testing. Regression analyses were performed to determine relationshi ps between spinal cord injury level and pulmonary function test result s and between Ashworth scale tone ratings and pulmonary function test results. Level of injury was found to be significantly correlated with expiratory reserve volume (and percent predicted expiratory reserve v olume), residual volume/total lung capacity ratio, and negative inspir atory pressure but not with vital capacity, forced expiratory volume i n one second, forced expiratory volume in one second/vital capacity ra tio, inspiratory capacity, total lung capacity, functional residual ca pacity, residual volume, or positive expiratory pressure. There were s ignificant correlations between Ashworth Scale tone ratings and negati ve inspiratory pressure but not between tone ratings and any of the ot her pulmonary function test results. It appears that muscle strength m ay be a more important factor than muscle tone in determining pulmonar y function in spinal cord-injured patients and that both strength and tone are closely related to negative inspiratory pressure.