[Respiratory failure and its care in Duchenne muscular dystrophy]

Respiratory failure is the major cause of death in patients with Duchenne muscular dystrophy (DMD). In this report we retrospectively examined the clinical courses, pulmonary function, progression of scoliosis and the time of assisted ventilation. Forty nine patients, aged 2 to 27 years were studied and thirty eight patients of them were examined twice in some intervals. The subjects of examinations included pulmonary function studies consisting of spirometry, measurement of the thoracic scoliosis measured according to the method of Cobb and room air arterial blood gas values. The results were the following; 1) The decline in percentage values of vital capacity (%VC) began at age 8 or 9 and decreased consistently with age. Finally %VC reached under 10 percent at mean age of 21.53 with respiratory failure. 2) Thoracic scoliosis measured according to the method of Cobb increased further with advancing age. The greater the angle of curvature, the more likely the development of respiratory failure. 3) Sixteen patients received negative pressure ventilator (chest respirator: CR) between 16.5 and 25.1 years of age. Twelve patients used part-time (mainly night-time) ventilator and four patients used it in full-time. The average PaCO2 and PaO2 before administration of ventilator were 67.49 mmHg and 71.46 mmHg, respectively. The levels after ventilation were 58.01 mmHg (PaCO2) and 82.09 mmHg (PaO2).