各種人工呼吸実施のDuchenne型筋ジストロフィーの予後—特に人工呼吸下の睡眠時周期性低酸素血症について

Prognosis of Duchenne Muscular Dystrophy with Mechanical Ventilation:Periodic hypoxemia during sleep

　人工呼吸下のDuchenne型筋ジストロフィー23例の睡眠時の酸素飽和度を検討した．対象は体外式人工呼吸8例（CR群），鼻マスクによる人工呼吸8例（NIPPV群），気管切開下の人工呼吸7例（TIPPV群）であった．ボランティア7名を対照群とした．酸素飽和度測定はパルスオキシメータにより行った．CR,NIPPV実施例のなかに周期性低酸素血症を来す症例があったが，TIPPV群，対照群には認められなかった．酸素飽和度95％以下となった割合は，CR群（44.6％），NIPPV群（43.0％）が対照群（1.9％）に比較して有意に多かった（p＜0.05）．2年間の観察期間中，4例が死亡した．全例気管切開例で，気管出血による死亡が2例あった．CR,NIPPV群では人工呼吸中にもかかわらず睡眠時低酸素血症を呈する例が認められた．したがって，定期的な睡眠時パルスオキシメータモニタリングが必要である．

Overnight monitoring using a pulse oximeter was performed on 23 Duchenne muscular dystrotphy patients maintained on mechanical ventilation. The patients were comprised of 8 with chest respirator (CR), 8 with nasal intermittent positive pressure ventilation (NIPPV) and 7 with intermittent positive pressure ventilation through a tracheostomy (TIPPV). Seven age-matched volunteers underwent the same monitoring as controls. In the CR and NIPPV groups, there were some patients who demonstrated periodic O₂ desaturation during sleep, whereas there were no such patients in the TIPPV and control groups. The proportions of the period of O₂ desaturation (95%≧) during sleep were 44.6% in the CR group, 43.0% in the NIPPV, 15.3% in the TIPPV and 1.9% in the controls. There were statistically significant differences between the CR and NIPPV groups and the controls (p＜0.05). Four patients belonging to the TIPPV group died during the observation period. All belonged to the TIPPV group and two of them died suddenly due to tracheal bleeding. Therefore regular respiratory func-tion tests, especially sleep monitoring by pulse oximetry, must be continued for patients maintained with NIPPV or CR.