Inhaler Technique in Chronic Obstructive Pulmonary Disease: Patient Impairments and Bronchodilation

RATIONALE: Despite worldwide use of handheld delivery systems in the treatment of chronic obstructive pulmonary disease (COPD), evidence is limited about how patient factors affect inhaler technique with each device type. OBJECTIVES: To assess whether impairments in cognitive function, manual dexterity, and inhalational ability are independently associated with inhaler technique; and to examine whether inhaler technique affects bronchodilation. METHODS: In this multi-centre, prospective, cohort study, stable out-patients with COPD were enrolled based on use of handheld maintenance bronchodilator inhaler(s). At visit 1, demographic information and inhaled COPD medications/delivery systems were recorded. Subjects returned 2 to 21 days later and were instructed to bring in, but not use their inhaler(s) on the day of Visit 2. Spirometry and peak inspiratory flow against a medium-low resistance (PIFr) were measured. Subjects used their handheld maintenance bronchodilator inhaler(s) "as you do at home" and were observed/critiqued on a standardized checklist. Mini-Mental State Examination (MMSE) and the Functional Dexterity Test (FDT) were measured, and spirometry was repeated 30 minutes after patient inhalation. RESULTS: Of 503 patients, age was 70 ± 6 years, 55% were male, post-bronchodilator forced expiratory volume in one second (FEV1) was 46 ± 15% predicted. 71% had acceptable inhaler technique (4 or 5 items satisfactory). Cognitive impairment (MMSE score < 24; 10.3% prevalence), non-functional manual dexterity (FDT > 50 seconds; 34.8% prevalence), and suboptimal peak inspiratory flow (<60 L/min; 20.5% prevalence) were independently associated with unacceptable inhaler technique (≥2 items unsatisfactory). Compared with baseline, FEV1 increased by 105 ± 7 ml and 69 ± 13 ml in patients with acceptable and unacceptable inhaler technique, respectively. Of the five technique items, only satisfactory performance of "Hold your breath" showed statistical increases in lung function compared with not satisfactory performance. CONCLUSIONS: In stable out-patients with COPD, cognitive impairment, non-functional manual dexterity, and suboptimal PIFr were each associated with unacceptable inhaler technique. Those with acceptable inhaler technique achieved greater increases in lung function at 30 minutes after inhalation of their maintenance handheld bronchodilator inhaler(s). "Hold your breath" was the only technique item associated with bronchodilation and was related to patient cognitive function.