外来通院可能な高度呼吸不全患者（PaO2<45 Torr）の病態の解析—"慣れ"の現象の背景因子の検討

Analysis ofpathophysiology in stable out-patients with severe respiratory failure (PaO2<45 Torr):Backgrounds of Accomodation

　在宅酸素療法は，長期酸素療法を必要とする慢性呼吸不全患者に対し，1985年春以来の医療費の保険適用により全国的な普及をみせ，患者のquality of lifeの向上に大きく寄与している。このため慢性呼吸不全症例の予後にも大きな変貌が期待されるが，一方我々はそのために外来診療に際してPa_CO2が40台，ときには30台の患者に遭遇するようになった。慢性の低酸素血症は案外臨床症状に乏しく，今回検討した症例の中にはPa_O2が29.5　Torrで再び帰宅して行った症例を経験し生体の"慣れ"という現象に驚かされたことがある。今回我々はそう言った"慣れ"にはどのような背景があるのかに興味を感じ，当院に外来通院している慢性呼吸不全患者についてretrospectiveに検討を行った。

For investigation of "accomodation" in stable patients with chronic respiratory failure, the back-grounds of ten out-patients with severe hypoxemia (Pa_O2<45 Torr) were analysed. The patients ex-amined were four with pulmonary tuberculosis-related disorders, four with chronic obstructive lung diseases and two with interstitial pneumonias. Home oxygen therapy, performed in all cases, was started at arterial oxygen levels of 46.1±3.0 Torr. Low levels of arterial oxygen have been continued with-out change for several years. The forced vital capacity was 52.7±4.7% and was maintained or improved over several years. Furthermore, acute exercerbations, usually induced by infectious diseases rarely occurred and these patients did not show multi-organ failures, such as renal failure or heart failure. The patients also maintained good nutri-tional conditions, showing a serum albumin concen-tration of 3.9±0. 1 g/dl and 1. 3±5. 0% of the stan-dard body weight.

In general, in the control of chronic respiratory failure it is important to prevent acute exercerba-tions and the multi-organ failures. In our patients, stable clinical courses could be maintained by pre-venting severe complications. Our findings suggest that a good nutritional status is important in pre-venting undesirable complications.

We conclude that control of nutritional is impor-tant, as well as early diagnosis of infectious diseases, congestive heart failures or multi-organ failures.