Ultrasonography of Diaphragm Can Predict Pulmonary Function in Spinal Cord Injury Patients: A Pilot Case-Control Study

BACKGROUND: Ultrasonography of the diaphragm is an under-utilized instrument in cervical spinal cord injury patients. We conducted a pilot study to first compare the difference of diaphragm thickness and the excursion between patients with cervical spinal cord injury and healthy volunteers, and second to correlate diaphragmic ultrasonography and pulmonary function in cervical spinal cord injury patients. MATERIAL/METHODS: Thirty patients with C4–C5 cervical spinal cord injury of more than 1 year and thirty healthy volunteers were included in this study. All demographic data were evaluated. All participants underwent diaphragmic ultrasonography evaluation and pulmonary function test. Diaphragm thickness of both sides and diaphragm excursions of the right hemi-diaphragm were obtained at the end of quiet tidal breathing and maximal inspiration. We compared diaphragmatic thickness and excursions, and we analyzed the relationship between diaphragmatic ultrasonography and pulmonary function. RESULTS: All spinal cord injury patients had restrictive pulmonary dysfunction compared to the control group of healthy volunteers. Diaphragm thickness on both sides was significantly increased in spinal cord injury patients. Diaphragmatic excursion in spinal cord injury patients was increased on the right hemi-diaphragm during tidal breathing. However, the right hemi-diaphragmatic excursion was no difference in both groups during maximal inspiration. Right hemi-diaphragmatic excursion during deep breathing correlated positively with expiratory volume in 1 second (P<0.01) and forced vital capacity (P<0.01). Right hemi-diaphragm thickness at end of maximum inspiration correlated positively with expiratory volume in 1 second (P<0.01) and forced vital capacity (P<0.01). Left hemi-diaphragm thickness at end of maximum inspiration correlated positively with expiratory volume in 1 second (P<0.01) and forced vital capacity (P<0.01). CONCLUSIONS: Diaphragm thickness and motion of the cervical spinal cord injury patients were different from controls. Pulmonary function was impaired in spinal cord injury patients. Ultrasonography of the diaphragm as a non-invasive method that is correlated with pulmonary function.