Rationale for the use of non-invasive ventilation in chronic ventilatory failure

Evidence base for the use of NIV in chronic ventilatory failure

SLOWLY PROGRESSIVE NEUROMUSCULAR DISEASE AND CHEST WALL DISORDERS

Several uncontrolled studies have shown benefit from nocturnal NIV in terms of improvement in daytime arterial blood gas tensions, relief of the symptoms of nocturnal hypoventilation, and improved survival compared with that which would be expected without treatment in patients with neuromuscular and chest wall diseases.1-5In a large case series Leger et al 6 reported on 276 patients with chronic ventilatory failure. In patients with kyphoscoliosis or sequelae of previous tuberculosis (usually thoracoplasty) they found a significant improvement in diurnal arterial oxygen and carbon dioxide tensions (Pao ₂ and Paco ₂) and a reduction in the need for hospitalisation for respiratory illness following the introduction of NIV; 62% of the patients reported improvement in their quality of sleep and 70% reported improvements in activities of daily living. NIV was continued for two years by 80% of the kyphoscoliosis group, 76% of the patients who had sequelae of previous tuberculosis, and 56% of the patients with Duchenne-type muscular dystrophy (DMD). In a further uncontrolled study Simonds and Elliott7 reported the five year actuarial probability of continuing NIV in patients with scoliosis, previous polio, post tuberculous lung disease, and generalised neuromuscular disorders to be 79%, 100%, 94%, and 81%, respectively. After one year of NIV arterial blood gas tensions recorded during spontaneous breathing by day showed that, compared with the pretreatment value, Pao ₂ increased by a mean (SD) of 1.8 (1.9) kPa and Paco ₂ decreased by 1.4 …