Improvement of Peak Cough Flow After the Application of a Mechanical In-exsufflator in Patients With Neuromuscular Disease and Pneumonia: A Pilot Study

OBJECTIVE: To investigate and demonstrate persistent increase of peak cough flow after mechanical in-exsufflator application, in patients with neuromuscular diseases and pneumonia. METHODS: A mechanical in-exsufflator was applied with patients in an upright or semi-upright sitting position (pressure setting, +40 and −40 cmH2O; in-exsufflation times, 2–3 and 1–2 seconds, respectively). Patients underwent five cycles, with 20–30 second intervals to prevent hyperventilation. Peak cough flow without and with assistive maneuvers, was evaluated before, and 15 and 45 minutes after mechanical in-exsufflator application. RESULTS: Peak cough flow was 92.6 L/min at baseline, and 100.4 and 100.7 L/min at 15 and 45 minutes after mechanical in-exsufflator application, respectively. Assisted peak cough flow at baseline, 15 minutes, and 45 minutes after mechanical in-exsufflator application was 170.7, 179.3, and 184.1 L/min, respectively. While peak cough flow and assisted peak cough flow increased significantly at 15 minutes after mechanical in-exsufflator application compared with baseline (p=0.030 and p=0.016), no statistical difference was observed between 15 and 45 minutes. CONCLUSION: Increased peak cough flow after mechanical in-exsufflator application persists for at least 45 minutes.

Correlation of Serum Creatine Kinase Level With Pulmonary Function in Duchenne Muscular Dystrophy

OBJECTIVE: To investigate the relationship between serum creatine kinase (CK) level and pulmonary function in Duchenne muscular dystrophy (DMD). METHODS: A total of 202 patients with DMD admitted to the Department of Rehabilitation Medicine, Gangnam Severance Hospital were enrolled from January 1, 1999 to March 31, 2015. Seventeen patients were excluded. Data collected from the 185 patients included age, height, weight, body mass index, pulmonary function tests including forced vital capacity (FVC), peak cough flow, maximal expiratory pressure (MEP), and maximal inspiratory pressure (MIP), and laboratory measurements (serum level of CK, CK-MB, troponin-T, and B-type natriuretic peptide). FVC, MEP, and MIP were expressed as percentages of predicted normal values. RESULTS: Serum CK activities were elevated above normal levels, even in the oldest DMD group. Serum CK level was strongly correlated with pulmonary functions of sitting FVC (p<0.001), supine FVC (p<0.001), MIP (p=0.004), and MEP (p<0.001). CONCLUSION: Serum CK level is a reliable screening test even in patients with advanced DMD, and is a strong predictor of pulmonary functions.