title: An audit of antiasthmatic drug inhalation technique and understanding.
abstract: Inhaled rather than oral antiasthmatic therapy is accepted as more advantageous but depends on patient technique and understanding. In 74 asthmatic outpatients, technique using metered-dose inhaler (MDI) was poor; in 56 patients inhaling beta-agonist, the mean peak expiratory flow rate (PEFR) increase was only 15 L/min (6%) greater than in 18 controls, p < 0.05, 95% confidence intervals 2-27 L/min or 2-11%. Tilting the head back and actuation "stopping" inspiration produced the least favorable PEFR responses; taken together, regression analysis yielded a statistically significant negative correlation with absolute or percentage PEFR change (R2 = 0.15; p < 0.02). Patients were unclear about which drugs to inhale as required or regularly. Among 19 patients reassessed inhaling beta-agonist, only 8 had baseline PEFR values within 10% of each other during both assessments. In the latter, the mean postinhalation PEFR increase was 36 L/min (or 13%) greater than the corresponding increase (or % change) at first assessment, p = 0.05 (0.08), 95% confidence intervals 0-73 L/min (-2 to 29%). Thus, MDI users should avoid tilting the head back, actuation stopping inhalation, and be more aware of prophylactic (steroid) versus symptomatic (beta-agonist) treatment.
authors.affiliation: Department of Medicine, University of Hong Kong.
authors.forename: C R
authors.initials: CR
authors.lastname: Kumana
authors.forename: S Y
authors.initials: SY
authors.lastname: So
authors.forename: I J
authors.initials: IJ
authors.lastname: Lauder
authors.forename: M S
authors.initials: MS
authors.lastname: Ip
authors.forename: W K
authors.initials: WK
authors.lastname: Lam
authors.forename: M
authors.initials: M
authors.lastname: Kou
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage* / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D010366:Peak Expiratory Flow Rate; D012646:Self Administration
chemical_list: D000318:Adrenergic beta-Agonists