[Analysis of withdrawal from noninvasive mechanical ventilation in patients with obesity-hypoventilation syndrome. Medium term results].

OBJECTIVE

To evaluate the possibility of cessation of noninvasive mechanical ventilation or noninvasive positive pressure ventilation (NPPV) treatment in patients with obesity-hypoventilation syndrome (OHS).

METHODS

A study was carried out on 22 OHS patients who had received NPPV for a minimum of 1 year. Prior to evaluation of the cessation of ventilatory support, all patients underwent the following tests: diurnal and nocturnal arterial blood gases, nocturnal oximetry, nocturnal cardiorespiratory polygraphy, and lung function tests. Based on the results obtained, 12 patients who met the NPPV cessation criteria were selected. This group was liberated from ventilatory support for 3 months. At the end of this period, all of the tests initially carried out were repeated on all patients and the results were compared with those obtained at the time of NPPV cessation.

RESULTS

Three months after liberation from NPPV, no significant variations were observed in arterial blood gases or in lung function tests in comparison with the values found at the time of cessation. In terms of individual development, only 1 patient showed blood gas deterioration requiring a return to NPPV. In 7 cases, a polygraph showed obstructive sleep apnea syndrome (OSAS), 4 at the time of cessation and 3 at the follow-up examination carried out at the end of the 3 months. Finally, in 4 patients the respiratory situation remained stable, with no significant variations in the tests done before or after cessation of NPPV.

CONCLUSIONS

The majority of the OHS patients who receive prolonged treatment with NPPV continue to be stable 3 months after liberation from ventilatory support. A high percentage of these patients can be seen to have OSAS once the hypercapnia situation is corrected.