Short-Term Effect of Nasal Intermittent Positive-Pressure Ventilation in Patients with Restrictive Thoracic Disease

Abstract

Background: The use of nasal intermittent positive pressure ventilation (NIPPV) would be expected to ameliorate dyspnea, ventilatory capacity and exercise tolerance durably in individuals with hypercapnic respiratory failure secondary to restrictive thoracic disease. Objectives: The purpose of this study was to determine the short-term effect of NIPPV on respiratory muscle endurance, exercise capacity and respiratory functions in patients with chronic respiratory failure due to restrictive thoracic disease. Methods: Twelve patients with chronic ventilatory failure due to restrictive thoracic disease underwent nasal bilevel positive airway pressure (BiPAP) ventilation for 2 h a day during 15 consecutive days. The effects were assessed by spirometry, arterial blood gas analysis, 6-min walking test, sensation of dyspnea according to the American Thoracic Society dyspnea scoring scales (ATS) and surface electromyogram of the diaphragm (EMGdi) before and after the study (on day 15). Results: Nasal BiPAP reduced the ATS dyspnea score from 2.5 ± 0.9 to 1.6 ± 0.4 (p < 0.01). Distances walked in 6 min increased from 320.66 ± 93.56 to 382.41 ± 121.20 m (p < 0.05). Comparison of baseline with levels after nasal BiPAP ventilation showed a statistically significant improvement in PaCO₂ (p < 0.05). Forced vital capacity increased from 35 to 50% of the predicted value (p < 0.01). There were no statistically significant reductions in the amplitude of EMGdi after the therapy. Conclusion: These results indicate that NIPPV delivered via nasal BiPAP improves respiratory functions, exercise capacity, and reduces dyspnea in the short term in patients with chronic respiratory failure due to restrictive thoracic disease. Whether such short-term improvements can be sustained merits further study.