Long-term non-invasive ventilation to manage persistent ventilatory failure after COPD exacerbation

Abstract

Background and objective: Patients with ventilatory failure at discharge from hospital following an exacerbation of COPD (ECOPD) have increased work of breathing and reduced inspiratory muscle strength compared with those with a normal arterial carbon dioxide tension (PaCO(2)). They also have a significantly worse prognosis. Long-term non-invasive positive pressure ventilation (NIPPV) may offer a treatment strategy but benefits have not been established.

Methods: We examined the outcomes of 35 patients, with a PaCO(2) >7.5 kPa and normal pH, following hospital admission with an ECOPD. Patients were initiated on long-term NIPPV. Our aims were to establish if NIPPV was tolerated and to describe the effects on ventilatory parameters.

Results: Daytime arterial blood gases and nocturnal ventilatory parameters improved significantly on NIPPV. Diurnal PaO(2), self-ventilating, rose from (mean (SD)) 7.3 (1.8) to 8.1 (0.9) kPa (P = 0.005) and PaCO(2) fell from 8.8 (1.3) to 7.3 (0.8) kPa (P <or= 0.001). Mean overnight oxygen saturations increased from 82% (7%) to 89% (2%) (P <or= 0.001) and mean overnight transcutaneous carbon dioxide fell from 7.6 (1.3) to 5.6 (1.7) kPa (P <or= 0.001). Similar changes were seen in a group of stable COPD patients, who initiated NIPPV without a preceding exacerbation, suggesting improvements were not solely due to recovery from exacerbation. Acceptance (89%) and compliance (8.4 (3.5) h/day) with domiciliary treatment were good. Median survival was 28.6 months (95% CI: 10.9-46.8).

Conclusions: NIPPV was well tolerated in this group and appears to improve ventilation. Our preliminary data support further investigation of NIPPV in patients who remain hypercapnic after hospital admission with ECOPD.