TREATMENT OF ACUTE BRONCHOSPASM WITH BETA-ADRENERGIC AGONIST AEROSOLS DELIVERED 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 nasal bilevel positive airway pressure (BiPAP) than by a small-volume nebulizer (SVN). We hypothesized that BiPAP would reduce the work of breathing in asthmatic patients and thereby hasten improvement of bronchospasm 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 pressures may be set separately. Design: Convenience-randomized prospective clinical study. Setting: Emergency department of an urban tertiary care teaching hospital. Participants: Afebrile, wheezing patients between 18 and 40 years of age. Interventions: Patients were randomly assigned to receive two doses of aerosolized albuterol (2.5 mg in 3 mi normal 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 groups 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 these variables through the course of treatment. BiPAP patients had a significantly greater increase in %PPEFR after each treatment (P=.0011) and from baseline to completion (P=.0013). Increase in absolute PEEP was 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=.0001).