title: Improved metered dose inhaler technique when a coordination cap is used.
abstract: BACKGROUND
  Patients often experience problems using metered dose inhalers (MDIs), particularly poor coordination between inhalation start and dose actuation (TsIn: time difference between the start of an inhalation and the actuation of a dose), and fast peak inspiratory flow (PIF). We investigated if a coordination cap (CAP), with instruction to prolong inhalation, solved these problems.
  
  
  METHODS
  Inhalation profiles [PIF, TsIn, inhalation volume (Vi), inhalation time (Ti)] of patients with stable asthma prescribed an MDI were measured using their real-life technique (MDI). Inhalation profiles were then measured with the cap fitted (MDI+CAP). These patients were then instructed to inhale through the MDI+CAP for 5 sec, and inhalation profiles measured (MDI+CAP+TRAIN). TsIn was only measured for the MDI.
  
  
  RESULTS
  Resistances of MDI and MDI+CAP were 0.0135 and 0.0243 (cm H2O)(½)/(L/min), respectively. Seventy-one patients were evaluated, with mean [standard deviation (SD)] forced expiratory volume over 1 sec % predicted normal of 78.3% (21.0). Following MDI, MDI+CAP, and MDI+CAP+TRAIN: mean (SD) PIF was 155.6 (61.5), 112.3 (48.4), and 73.8 (34.9) L/min, respectively (p<0.001); mean (SD) Ti was 1.60 (0.60), 1.92 (0.80), and 2.99 (1.03) sec, respectively (p<0.001); and Vi was similar between stages. Twelve patients used a slow flow with the MDI alone, but only two of these patients demonstrated good coordination. With the cap in place (which ensures good coordination), the number of patients using a slow flow increased to 25 for MDI+CAP and to 50 following MDI+CAP+TRAIN.
  
  
  CONCLUSIONS
  The cap with its effect of increasing resistance to airflow combined with the instruction to prolong inhalation time significantly decreased the inhalation flow.
authors.affiliation: 1 Division of Pharmacy and Pharmaceutical Sciences, School of Applied Sciences, University of Huddersfield , Huddersfield, HD1 3DH, UK .
authors.forename: Wahida
authors.initials: W
authors.lastname: Azouz
authors.forename: Jessica
authors.initials: J
authors.lastname: Campbell
authors.forename: John
authors.initials: J
authors.lastname: Stephenson
authors.forename: Dinesh
authors.initials: D
authors.lastname: Saralaya
authors.forename: Henry
authors.initials: H
authors.lastname: Chrystyn
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D001249:Asthma / Q000503:physiopathology*; D016503:Drug Delivery Systems / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D005541:Forced Expiratory Volume; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D001239:Inhalation; D008168:Lung / Q000503:physiopathology*; D008297:Male; D036501:Metered Dose Inhalers; D008875:Middle Aged; D010353:Patient Education as Topic; D011446:Prospective Studies; D013647:Task Performance and Analysis; D013997:Time Factors; D014797:Vital Capacity; D055815:Young Adult
keywords: I-Breathe; asthma; device; inhalation flow