5 ERS Practical Handbook Noninvasive Ventilation Introduction provides the rationale for NIV to be available in every acute unit that admits res- piratory patients, and for NIV to be used post-operatively in high-risk patients and for weaning. An additional major change in the past 30–40 years has been the increasing indications for long-term, chronic NIV and, of course, long-term appli- cation of CPAP in OSA. For patients with a range of causes of ventilatory failure, the natural history pro- gresses from normal breathing, to a gradual loss in lung volumes and then, ini- tially, changes in blood gases are seen at night due to hypoventilation, and if that is not addressed, ultimately, progression to daytime respiratory failure, cardiac decompensation and premature death. The interval between the onset of respira- tory failure and death may be as short as a few years. In Duchenne muscular dys- trophy, once a patient has developed a raised carbon dioxide level during the day, there is a 90% chance that they will be dead within a year. Figure 4 shows the long-term outcome of different groups of patients treated with NIV having developed severe ventilatory failure or progressed to cor pulmo- nale pretreatment. In post-polio patients, 5-year survival with NIV is 100% and it appears that these individuals will live to their normal life expectancy. 5-year survival is ∼80% in the other restrictive conditions. Results are less good in COPD and bronchiectasis for two reasons: these are intrinsic lung disease conditions rather than being restrictive disorders with normal lungs, and the patients were severely end-stage when treated – with some being on the transplant waiting list. In COPD, recent trials have shown NIV may be of benefit in stable hypercapnic patients, as discussed further in the section entitled “Chronic NIV in COPD”. In Duchenne patients, median survival is now nearly 30 years, and around a third of our Duchenne patients are living into their late thirties and early forties. NIV has been extended to the paediatric age range, with the feasibility of using NIV to control nocturnal hypoventilation in children initially being demonstrated 80 100 60 40 20 0 Years 1 0 2 3 4 5 6 Neuromuscular COPD Bronchiectasis TB Kyphoscoliosis Polio Figure 4. Probability of continuing NIV long term, which is equivalent to survival in most cases. Reproduced from Simonds et al. (1995) with permission from the publisher. Continuing NIV %