Aminophylline for acute exacerbations of chronic obstructive pulmonary disease. A controlled trial

To determine the efficacy of intravenous aminophylline in the treatment of patients hospitalized for exacerbation of chronic obstructive pulmonary disease.

Randomized, double-blind, placebo-controlled trial during the first 72 hours of hospitalization.

Thirty patients admitted from the emergency room or walk-in clinic with the primary diagnosis of an exacerbation of chronic obstructive pulmonary disease. Twenty-eight patients completed the study; 2 patients, 1 receiving placebo and 1 receiving aminophylline, were removed from the study because of respiratory failure requiring mechanical ventilation.

PATIENTS received either intravenous aminophylline or placebo, in addition to nebulized, inhaled 0.3 mL of a 5% solution every 6 hours; methylprednisolone, 0.5 mg/kg body weight every 6 hours intravenously; ampicillin, 500 mg orally every 6 hours (tetracycline or trimethoprim-sulfamethoxazole were substituted in penicillin-allergic patients); and supplemental oxygen as needed. Aminophylline infusion rates were adjusted by an unblinded investigator to achieve theophylline levels of 72 to 83 mumol/L. Changes were also made in placebo infusion rates to maintain the double-blind design.

The forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) before and after metaproterenol inhalation were measured twice daily by a blinded investigator, who also administered a verbal dyspnea index with a scale of 1 to 10 and questioned patients regarding possible side effects of treatment (tremor, palpitations, nausea, or vomiting). Arterial blood gas measurements at 72 hours were compared with those obtained on admission. Significant improvements in FEV1 and FVC measured before and after metaproterenol treatment and in dyspnea occurred over time in both treatment groups (p less than 0.05 for all measurements). However, there were no significant differences between the placebo and aminophylline groups in any of the spirometric measurements or the dyspnea indices (p greater than 0.5 in all five analyses). The mean increases (+/- SE) in Po2 of 1.9 (+/- 0.5) kPa with placebo and 1.7 (+/- 0.7) kPa with aminophylline and the mean decreases in PCO2 of 0.5 (+/- 0.4) kPa with placebo and 1.2 (+/- 0.4) kPa with aminophylline were not significantly different (p greater than 0.6 for PO2, p greater than 0.2 for PCO2).(ABSTRACT TRUNCATED AT 400 WORDS)