Oxygen desaturation during sleep andexercise in patients withinterstitial lungdisease

Therelations between mean andmaximumfall inarterial oxygen saturation (Sao2) during sleep, hypoxaemia during moderate andmaximumexercise, andlungmechanics were studied in16patients withinterstitial lungdisease. MeanandminimumSao2during sleep were significantly related toeachother andtodaytime oxygenation butnottolungmechanics. Although themaximumfall inSao2during sleep was similar tothefall during maximumexercise (alevel seldom achieved during normal daily activities), profound hypoxaemic episodes during sleep were rareandbrief andtherefore contributed little tothemean Sao2. Thefall inmean Sao2during sleep was notsignificant andwas considerably less thanduring moderate exercise (average 05 v an estimated 45%,p < 005). Itistherefore concluded thatinpatients withinterstitial lungdisease oxygendesaturation during sleep ismildandless severethanhypoxaemia during exercise.