Revisiting respiratory muscle strength and pulmonary function in spinal cord injury: The effect of body positions

OBJECTIVES: In the subjects with high cervical spinal cord injury (SCI), The difference of respiratory muscle strength and pulmonary function according to supine and sitting position were investigated whether there are changes in the tendency. METHODS: Twenty-three subjects with high cervical SCI and 23 subjects with low cervical and thoracic SCI were evaluated. The reference neurological level of injury for dividing the groups was fifth cervical vertebrae (C5). SCI severity was classified as motor-complete SCI. The supine and sitting forced vital capacity (FVC), percent of the predicted FVC (FVC%), maximal expiratory pressure (MEP), maximal inspiratory pressure (MIP), MEP / MIP ratio, and peak cough flow (PCF) were compared. RESULTS: The significantly higher FVC, FVC% in the low cervical and thoracic SCI group was identified in the supine position than the sitting position. The same tendency was observed in the high cervical SCI group. In the comparison of respiratory muscle strength, higher values of supine MEP and MIP were found only in the high cervical SCI group. PCF is more positively correlated with MIP than with MEP in all groups. CONCLUSION: We found that the supine position is more advantageous for the strong breathing and larger lung capacity in patients with high cervical SCI. The positive correlation between PCF and MIP in the patients with high cervical SCI was also confirmed. These results may be used to establish a pulmonary rehabili- tation strategy for patients with high cervical SCI.