TREATMENT OF ACUTE BRONCHOSPASM WITH BETA-ADRENERGIC AGONIST AEROSOLSDELIVERED BY A NASAL BILEVEL POSITIVE AIRWAY PRESSURE CIRCUIT

Study objective: To determine whether beta-adrenergic agonist aerosols are more effective in treating acute bronchospasm if delivered by nas al bilevel positive airway pressure (BiPAP) than by a small-volume neb ulizer (SVN). We hypothesized that BiPAP would reduce the work of brea thing in asthmatic patients and thereby hasten improvement of bronchos pasm from beta-agonist therapy. Previous trials with aerosols given by intermittent positive-pressure breathing were unrewarding, but BiPAP is unique in that inspiratory (IPAP) and expiratory (EPAP) support pre ssures may be set separately. Design: Convenience-randomized prospecti ve clinical study. Setting: Emergency department of an urban tertiary care teaching hospital. Participants: Afebrile, wheezing patients betw een 18 and 40 years of age. Interventions: Patients were randomly assi gned to receive two doses of aerosolized albuterol (2.5 mg in 3 mi nor mal saline solution), 20 minutes apart, delivered by either SVN (n=40) or BiPAP (n=60) by nosemask or facemask (IPAP, 10 cm H2O; EPAP, 5 cm H2O). Results: Peak expiratory flow rate (PEEP), arterial blood oxygen saturation (by pulse oximetry), and pulse and respiratory rates were measured at baseline and after each treatment. The two treatment group s had similar values for pulse oximetry, pulse rate, respiratory rate, and percent of predicted peak expiratory flow rate (%PPEFR) at entry, and all patients experienced similar changes in the first three of th ese variables through the course of treatment. BiPAP patients had a si gnificantly greater increase in %PPEFR after each treatment (P=.0011) and from baseline to completion (P=.0013). Increase in absolute PEEP w as greater in the BiPAP group (from 211+/-89 [mean+/-SD] to 357+/-108 L/minute for BiPAP, from 183+/-60 to 280+/-87 L/minute for SVN; P=.000 1).