A smal l proportion of patients in chronic Type II (hypoxaemic, hypercapnic) respi ratory fai lure wi l l develop apnoea i f their central hypoxic drive is removed by supplemental oxygen. However, this is seldom (if ever) abrupt and a period of deterioration and increasing drowsiness wi l l alert medical and nursing staff to consider ei ther (i) FIO2 reduction if overal l condition al lows, (i i) non-invasive or invasive mechanical ventilation if fatiguing or (i i i) use of respiratory stimulants such as doxepram. The corol lary is that close supervision and moni toring is necessary in al l critically.
