The effects of withdrawing long-term nocturnal non-invasive ventilation in COPD patients.

Patients with ventilatory failure due to chronic obstructive pulmonary disease (COPD) are increasingly managed with long-term non-invasive positive pressure ventilation (NIPPV) and this may improve survival. NIPPV can frequently be interrupted but there are few data detailing the short-term effects and none on the longer-term consequences of treatment withdrawal. Ten patients withdrew from NIPPV for 1 week and were randomised to restart NIPPV or to continued withdrawal for up to 6 months. Outcomes assessed included daytime blood gases, nocturnal ventilation, lung function, exercise capacity and health status. After 1 week of withdrawal PaO(2), PaCO(2), nocturnal oximetry, lung function and exercise capacity did not change, but mean nocturnal transcutaneous CO(2) (6.3 (1) vs. 7.6 (1.1) kPa p = 0.04) and daytime blood gas bicarbonate (30.3 (4.5) vs. 31.2 (3.9) mmol/L p = 0.04) rose. During a 6-month period of withdrawal of nocturnal NIPPV, daytime PaCO(2) (6 (1.1) vs. 7.5 (1.3) kPa p = 0.002) increased and health status (total St George's Respiratory Questionnaire score 55.5 (6.3) vs. 65.6 (10) p = 0.006) worsened. Three out of five patients met a priori criteria to restart NIPPV in the continued withdrawal group. Short interruptions to domiciliary NIPPV used to manage chronic ventilatory failure as a consequence of COPD do not cause a rapid clinical deterioration but nocturnal ventilation worsens and daytime bicarbonate levels increase following 1 week's cessation. Thereafter, daytime PaCO(2) rises and health status worsens, supporting the role of long-term NIPPV in the management of such patients.

A randomised crossover trial comparing volume assured and pressure preset noninvasive ventilation in stable hypercapnic COPD.

Recent randomised controlled trials suggest non-invasive ventilation may offer benefit in the long-term management of ventilatory failure in stable COPD. The best mode of ventilation is unknown and newer volume assured modes may offer advantages by optimising ventilation overnight when treatment is delivered. This study compares volume assured with pressure preset non-invasive ventilation. Randomised crossover trial including twenty five subjects previously established on long-term non-invasive ventilation to manage COPD with chronic ventilatory failure. Two 8-week treatment periods of volume assured and pressure preset non-invasive ventilation. The primary outcomes were daytime arterial blood gas tensions and mean nocturnal oxygen saturation. Secondary outcomes included lung function, exercise capacity, mean nocturnal transcutaneous carbon dioxide, health status and compliance. No significant differences were seen in primary or secondary outcomes following 8 weeks of treatment when comparing volume assured and pressure preset ventilation. Primary outcomes assessed: mean (standard deviation) PaO(2) 7.8 (1.2) vs 8.1(1) kPa, PaCO(2) 6.7 (1.1) vs 6.3 (1.2) kPa and mean nocturnal oxygenation 90 (4) vs 91 (3)% volume assured versus pressure preset, respectively. Volume assured and pressure preset non-invasive ventilation appear equally effective in the long-term management of ventilatory failure associated with stable COPD.