Efficacy of coughing in tetraplegic patients

A randomized cross-over design study in six tetraplegic patients.

To investigate the efficacy of coughing in tetraplegic patients.

In tetraplegic patients, pulmonary complications due to insufficient clearance of bronchial mucus frequently are described. Coughing in tetraplegic patients is thought to be insufficient because of severely impaired expiratory muscle function. More recently, however, it has been reported that many tetraplegic patients may have dynamic airway compression and thus a more or less effective cough.

Mucus clearance was measured using a radioactive aerosol tracer technique during 45 minutes on 2 days: once without intervention, and once with voluntary coughing in the period 15 to 30 minutes (once every 30 seconds). Measurements were done in a randomized order. For each day, individual slopes for the decrease in radioactivity were calculated, reflecting mucus transport in the peripheral, central, and the whole lung region.

Significant differences in slopes were found between the control day and the cough day in the peripheral lung region for the interval 0 to 30 minutes and in the whole lung region for the interval 0 to 30 minutes and 0 to 45 minutes. The improvement of mucus clearance due to coughing, however, was relatively small in these patients, only 3% after 45 minutes: from 4% whole lung clearance during quiet breathing to 7% whole lung clearance during coughing.

Tetraplegic patients may achieve a statistically significant increase in their bronchial mucus transport by voluntary coughing.