NONINVASIVE VENTILATORY SUPPORT DOES NOT FACILITATE RECOVERY FROM ACUTE RESPIRATORY-FAILURE IN CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

This investigation evaluates, in a prospective, randomized and control led manner, whether noninvasive ventilatory support (NIVS) with bileve l positive airway pressure (BiPAP) facilitates recovery from acute res piratory failure (ARF) in patients with chronic obstructive pulmonary disease (COPD). Twenty four patients (mean age (+/-SEM) 68+/-2 yrs) wi th COPD (forced expiratory volume in one second (FEV1) at discharge 33 +/-2% predicted), who attended the emergency room because of ARF (pH 7 .33+/-0.01; arterial oxygen tension (Pa,O-2) 6.0+/-0.2 kPa; arterial c arbon dioxide tension (Pa,CO2 7.9+/-3.3 kPa), were initially randomize d. Four out of the 14 patients (29%) allocated to received NIVS did no t tolerate it. Of the remaining 20 patients, 10 received NIVS with BiP AP in a conventional hospital ward during the first 3 days of hospital ization (two daytime sessions of 3 h duration each). All 20 subjects w ere treated with oxygen, bronchodilators and steroids. On the first an d third hospitalization days, before and 30 min after withdrawing oxyg en therapy and/or BiPAP ventilatory support, we measured peak expirato ry now, arterial blood gas values, ventilatory pattern, occlusion pres sure (P0.1), and maximal inspiratory (MIP) and maximal expiratory (MEP ) pressures. All patients were discharged without requiring tracheal i ntubation and mechanical ventilation. Hospitalization time was similar in both groups (11.3+/-1.3 vs 10.6+/-0.9 days, control vs BiPAP, resp ectively), Arterial oxygenation, respiratory acidosis and airflow obst ruction improved significantly throughout hospitalization in both grou ps. By contrast, the ventilatory pattern, P0.1, MIP and MEP did not ch ange. NIVS with BiPAP did not cause any significant difference between groups. We conclude that noninvasive ventilatory support with bilevel positive airway pressure does not facilitate recovery from acute resp iratory failure in patients with chronic obstructive pulmonary disease . Furthermore, a substantial proportion of patients (29%) do not toler ate noninvasive ventilatory support under these circumstances. From th ese results, we cannot recommend the use of noninvasive ventilatory su pport with bilevel positive airway pressure in the routine management of chronic obstructive pulmonary disease patients recovering from acut e respiratory failure.