[Nocturnal hypoxia and treatment in the patients with Duchenne muscular dystrophy]

Overnight monitoring using pulse oximeter was performed on 10 patients with Duchenne muscular dystrophy (mean age, 22; mean %FVC, 26.6%; mean PaCO2, 54.1 Torr; mean PaO2 76.6 Torr). At the same time, spinal deformity and obesity were examined. In 4 patients, the measurement of the chest and abdominal wall movements were performed by using a respisomnograph. In 5 patients, nocturnal desaturation below 95% occurred despite normal daylight blood gas tension. In the other 5 patients with hypercapnea of over 50 Torr, nocturnal desaturation below 85% occurred, and 3 patients required oxygen supplementation treatment using a low concentration of oxygen. In 4 patients with hypercapnea over 50 Torr, cuirass-assisted respirators were used and they prevented mild nocturnal desaturation, but did not have much effect on severe nocturnal desaturation. Nocturnal desaturation was associated not only with hypopnea and hypoventilation, but with normal chest and abdominal wall movement using cuirass-assisted respirators. It seemed that desaturation with normal respiratory pattern can be attributed to ventilation-perfusion mismatching. The severity of the desaturation did not always correlate to the spinal deformity and the obesity.