COMPARISON OF ONE VERSUS 2 BRONCHODILATORS IN VENTILATED COPD PATIENTS

Objective: To compare the bronchodilating effect of a single drug, ipr atropium bromide (IBr), with that of its combination with fenoterol (I Br+F). Design: The study was triple blind and randomized. Setting: Med ical-surgical intensive care unit. Patients. 12 patients with acute ex acerbation of chronic obstructive pulmonary disease (COPD) requiring m echanical ventilation for severe respiratory failure. Interventions: B efore administering each drug, peak airway pressure (Ppeak), end inspi ratory pressure (Pei), resistive pressure (Pres), and auto positive - end expiratory pressure (auto-PEEP) were measured. Inspiratory system resistance (Rins) and dynamic respiratory system compliance (C) were c alculated. Arterial pH and blood gas determinations were made. These m easurements were repeated 60 min after administration of each therapeu tic regimen. For ipratropium bromide alone the dose was 0.04 mg. When the combination of drugs was used, the doses were 0.04 mg for ipratrop ium bromide and 0.1 mg for fenoterol. Measurements and results: With t he combination of both drugs, all the pressures in the airway, as well as the auto-PEEP and the Rins were significantly reduced (p < 0.05) w ith respect to baseline values. With ipratropium bromide alone, no sig nificant changes were observed either in the pressures or in the inspi ratory resistance. No significant changes were observed either in the pH or blood gases with any of the treatments. The combination of both drugs produced significantly reduction in Pei and auto-PEEP when compa red with ipratropium bromide alone. Conclusions: The combination of bo th drugs is more effective than ipratropium bromide alone at the doses used in this study.