title: Large and small airway responses to procaterol hydrochloride administered through different extension devices in asthmatic patients.
abstract: The effects of spacer devices on the magnitude and velocity of large and small airway bronchodilator responses in asthmatic patients who can correctly operate a metered dose inhaler (MDI) remain unclear. According to a double-blinded, randomized, crossover protocol, 14 asthmatic patients were studied on seven separate occasions. On each occasion, patients inhaled doubling methacholine concentrations until forced expiratory volume in 1 second (FEV1) had fallen by 20% of baseline. Changes in forced expiratory flow between 25% and 75% of vital capacity (FEF25-75) were also evaluated. Subsequently, patients were administered 20 or 50 micrograms of procaterol from an MDI either alone or in conjunction with a small- or large-volume spacer device. Changes in FEV1 and FEF25-75 corrected for baseline forced vital capacity (isoFEF25-75) were assessed at 3-minute intervals for 15 minutes and at 30 minutes. Spontaneous recovery was similarly evaluated. The time required to attain significant increases in both FEV1 and isoFEF25-75 was calculated in bronchodilator trials. With 20 micrograms of procaterol, both spacers allowed larger and faster FEV1 increases than the MDI alone (P < 0.01); with 50 micrograms, the velocity and magnitude of FEV1 increases were further enhanced in trials with the MDI alone. The lower procaterol dose via the large-volume spacer determined larger and faster isoFEF25-75 increases than the higher dose via both the small-volume spacer and the MDI alone (P < 0.01). Spacers enhance bronchodilation even in patients using MDIs optimally. Compared with both the small-volume device and the MDI alone, the large-volume spacer allows faster and larger small airway dilation with less than half of the procaterol dose.
authors.affiliation: Dipartimento di Fisiopatologia Clinica, Università di Firenze, Florence, Italy. g.fontana@dfc.unifi.it
authors.forename: G A
authors.initials: GA
authors.lastname: Fontana
authors.forename: F
authors.initials: F
authors.lastname: Lavorini
authors.forename: M
authors.initials: M
authors.lastname: Chiostri
authors.forename: W
authors.initials: W
authors.lastname: Castellani
authors.forename: V
authors.initials: V
authors.lastname: Boddi
authors.forename: M
authors.initials: M
authors.lastname: Pistolesi
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy*; D001980:Bronchi / Q000187:drug effects*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D002648:Child; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D009330:Nebulizers and Vaporizers; D017265:Procaterol / Q000008:administration & dosage*; D012044:Regression Analysis; D012129:Respiratory Function Tests; D016896:Treatment Outcome
chemical_list: D001993:Bronchodilator Agents; D017265:Procaterol