[Use of home mechanical ventilation in patients with high grade chronic obstructive lung disease (COPD)]

Nasal intermittent positive pressure ventilation (NIPPV) ist well established in the treatment of chronic hypercapnic ventilatory failure in patients with scoliosis or neuromuscular diseases. It has been introduced in acute respiratory failure in patients with COPD. The role of NIPPV in the long term treatment in severe stable hypercapnic COPD patients has not been well established (Thorax 1996; 51: 455-7).

We analysed the results of blood gases and lung function in all stable chronic hypercapnic COPD patients (PaCO2 59 +/- 6 mmHg), who underwent a trial of NIPPV from 11/95 to 1/98 (n = 25; 12 f/13 m; mean age 62 +/- 10 years). Patients with acute respiratory failure or an additional obstructive sleep apnoea syndrome were excluded. NIPPV was performed over an individual hand-molded nasal mask in the assisted/controlled mode (4 volume-, 21 pressure-cycled). At the time of discharge (25 +/- 15 days after the initiation of NIPPV) patients were able to apply the ventilator during night for al least 6 h. At the time PaCO2 during NIPPV was 43 +/- 6 mmHg.

5 patients failed to continue NIPPV for long-term treatment, so it was discontinued after a period of 6 weeks. 20 patients (80%) continued NIPPV for 13 +/- 8 months (range 1-27 months), 2 patients died during NIPPV (after 1 and 13 months). NIPPV had no significant influence on lung function (FEV1 predicted 28 +/- 13 vs. 30 +/- 11%; intrathoracic lung volume 6.9 +/- 2.5 vs. 6.2 +/- 1.7 l) or respiratory muscle strength (Pimax 4.2 +/- 0.9 vs. 4.5 +/- 1.6 kPa). However, we observed a significant improvement in PaCO2 during spontaneous breathing (59 +/- 6 vs. 48 +/- 8 mmHg; p < 0.001) and in case of base excess (7.4 +/- 4.1 vs. 3.4 +/- 2.4 mmol/l; p < 0.003).

NIPPV can improve hypercapnic ventilatory failure in a subgroup of severe stable COPD, provided patients are motivated and home mechanical ventilation is adequately performed.