June 2002 / Volume 47 / Number 6 / Page 675
Noninvasive Nocturnal Ventilatory Support in Advanced Lung Disease from Cystic Fibrosis
Noninvasive positive-pressure ventilation (NPPV) has been successfully used in patients with chronic respiratory failure secondary to neuromuscular and skeletal disorders. In patients with acute respiratory failure (ARF) from chronic obstructive pulmonary disease (COPD), NPPV reduces the requirement for intubation and mechanical ventilation and may reduce mortality. Experience with NPPV in COPD patients with stable hypercapnic respiratory failure is evolving and was recently extensively reviewed. When combined with domiciliary oxygen, NPPV improves daytime blood gas values and quality of life more than oxygen alone. However, other studies have not shown more benefit from NPPV than from sham ventilation or oxygen therapy alone. Respiratory failure is responsible for the majority of morbidity and mortality in adult cystic fibrosis (CF) patients. Previous studies evaluated the role of NPPV in patients with acute exacerbations of CF. Padman et al reported their experience with NPPV in 15 pediatric patients with ARF (4 with CF). All 4 CF patients were supported through ARF and were maintained on NPPV for 3 weeks to 1.5 years until lung transplantation. Two centers have specifically evaluated the use of NPPV in (a total of 14) CF patients. Both studies found initial improvement in gas exchange and that NPPV could be tolerated for periods of up to 18 months. Hill et al reported that their patients had subjective improvement in sleep, measurable increase in forced vital capacity, and reduced PaCO2. Unfortunately, no formal comparative assessments of sleep, exercise, or quality of life were made before and after NPPV. In addition, those patients were studied during documented deterioration.
Less information is available on the efficacy of NPPV in patients with stable CF. We recently found that NPPV acutely improved gas exchange and breathing pattern in patients with chronic respiratory failure and stable lung function. We also observed that NPPV reduced pleural pressure swings during tidal breathing and concluded that NPPV might reduce patients' effort of breathing. Thus, NPPV is a potentially useful modality to manage CF patients with chronic respiratory failure. We postulated that NPPV would improve sleep architecture, daytime blood gas values, exercise tolerance, and health-related quality of life in patients with advanced CF awaiting lung transplantation. Chronic respiratory failure is the leading cause of death in people with CF, and among those who are appropriate candidates for lung transplantation, many die because of donor shortages and the increasing waiting times to transplantation. Based on experience with NPPV in patients with acute respiratory exacerbations of CF, NPPV may be useful in patients awaiting lung transplantation.