Abstract
BACKGROUND: A study was undertaken to assess the long term physiological and clinical outcome in 79 patients with musculoskeletal disorders (73 neuromuscular, six of the chest wall) who received non-invasive ventilation for chronic respiratory failure over a period of 46 years. METHODS: Vital capacity (VC) and carbon dioxide tension (PCO(2)) before and after initiation of ventilation, type and duration of ventilatory assistance, the need for tracheostomy, and mortality were retrospectively studied in 48 patients who were managed with mouth/nasal intermittent positive pressure ventilation (M/NIPPV) and 31 who received body ventilation. The two largest groups analysed were 45 patients with poliomyelitis and 15 with Duchenne's muscular dystrophy. Twenty five patients with poliomyelitis received body ventilation (for a mean of 290 months) and 20 were supported by M/NIPPV (mean 38 months). All 15 patients with Duchenne's muscular dystrophy were ventilated by NIPPV (mean 22 months). RESULTS: Fourteen patients with poliomyelitis on body ventilation (56%) but only one on M/NIPPV, and 10 of 15 patients (67%) with Duchenne's muscular dystrophy eventually received tracheostomies for ventilatory support. Five patients with other neuromuscular disorders required tracheostomies. Twenty of 29 tracheostomies (69%) were provided because of progressive disease and hypercarbia which could not be controlled by non-invasive ventilation; the remaining nine were placed because of bulbar dysfunction and aspiration related complications. Nine of 10 deaths occurred in patients on body ventilation (six with poliomyelitis), although the causes of death were varied and not necessarily related to respiratory complications. A proportionately greater number of patients on M/NIPPV (67%) reported positive outcomes (improved sense of wellbeing and independence) than did those on body ventilation (29%, p<0.01). However, other than tracheostomies and deaths, negative outcomes in the form of machine/interface discomfort and self-discontinuation of ventilation also occurred at a rate 2.3 times higher than in the group who received body ventilation. None of the six patients with chest wall disorders (all on M/NIPPV) required tracheostomy or died. Hospital admission rates increased nearly eightfold in patients receiving body ventilation (all poliomyelitis patients) compared with before ventilation (p<0.01) while in those supported by M/NIPPV they were reduced by 36%. CONCLUSIONS: Non-invasive ventilation (NIV) in the community over prolonged periods is a feasible although variably tolerated form of management in patients with neuromuscular disorders. While patients who received body ventilation were followed the longest (mean 24 years), the need for tracheostomy and deaths occurred more often in this group (most commonly in the poliomyelitis patients). Despite a number of discomforts associated with M/NIPPV, a larger proportion of patients experienced improved wellbeing, independence, and ability to perform daily activities.