title: Clarifying the dilemmas about inhalation techniques for dry  powder inhalers: integrating science with clinical practice.
abstract: This review integrates pharmaceutical science with routine clinical practice to explain why inhalation manoeuvres through a dry powder  inhaler (DPI) should start with a gentle exhalation, away from the inhaler. Place the inhaler in the mouth and ensure the lips form a tight  seal. This should be followed by an immediate forceful inhalation that is as fast as possible and continued for as long as the patient can  comfortably achieve. Although this is universally accepted, there has been a lot of attention on inhalation flow as an indicator of  adequate inspiratory effort. This has led to the wrong assumption that inhalation flows through each DPI should be the same, and that  low flows through some DPIs suggest that dose delivery is impaired. Most miss the concept that inhalation flow together with the  resistance of the DPI combine to create a turbulent energy which de-aggregates the formulation and provides an effective emitted dose.  A low flow through a DPI with high resistance generates the same turbulent energy as fast flow with low resistance. Therefore,  depending on the device, different inhalation flows are compatible with potentially effective use. Flow measurements should be a guide  to train patients to inhale faster. The focus of inhaler technique training should be the use of the above generic inhalation manoeuvre.
authors.affiliation: Division of Pharmacy and Pharmaceutical Sciences, School of Applied Sciences, University of Huddersfield, Huddersfield, West Yorkshire HDI 3DH, UK. h.chrystyn@hud.ac.uk
authors.forename: Wahida
authors.initials: W
authors.lastname: Azouz
authors.forename: Henry
authors.initials: H
authors.lastname: Chrystyn
mesh_terms: D000280:Administration, Inhalation; D058995:Dry Powder Inhalers / Q000379:methods*; D006801:Humans; D015656:Respiratory Mechanics