Inspiratory flows through dry powder inhaler in chronic obstructive pulmonary disease: age and gender rather than severity matters

Background: Dry powder inhalers (DPIs) are inspiratory flow driven and hence flow dependent. Most patients with chronic obstructive pulmonary disease (COPD) are elderly and have poor lung function. The factors affecting their inspiratory flows through inhalers are unclear. Objective: To study peak inspiratory flows (PIFs) and their determinants through a DPI in COPD patients of varying age and severity. Methods: Flow-volume spirometry was performed in 93 COPD patients. Maximum PIF rates were recorded through an empty Easyhaler® (PIFEH; Orion Corporation, Espoo, Finland), a DPI that provides consistent dose delivery at inhalation rates through the inhaler of 28 L/min or higher. Results: The mean PIFEH was 54 L/min (range 26–95 L/min) with a coefficient of variation of 7%. All but two patients were able to generate a flow of ≥28 L/min. In a general linear model, the independent determinants for PIFEH were age (P = 0.02) and gender (P = 0.01), and forced expiratory volume in 1 s (FEV1) expressed as percent predicted was not a significant factor. The regression model accounted only for 18% of the variation in PIFEH. Conclusion: In patients with COPD, age and gender are more important determinants of inspiratory flow through DPIs than the degree of expiratory airway obstruction. Most COPD patients with varying age and severity are able to generate inspiratory flows through the test inhaler that is sufficient for optimal drug delivery to the lower airways.

[1]  M. Decramer.  Hyperinflation and respiratory muscle interaction. , 1997, The European respiratory journal.

[2]  R. Schultz,et al.  Effect of inhalation flow rate on the dosing characteristics of dry powder inhaler (DPI) and metered dose inhaler (MDI) products. , 1996, Journal of aerosol medicine : the official journal of the International Society for Aerosols in Medicine.

[3]  R. Sorva,et al.  Application and efficacy of the multi‐dose powder inhaler, Easyhaler®, in children with asthma , 1999, Pediatric allergy and immunology : official publication of the European Society of Pediatric Allergy and Immunology.

[4]  W. Hop,et al.  Inhalation profiles in asthmatics and COPD patients: reproducibility and effect of instruction. , 2003, Journal of aerosol medicine : the official journal of the International Society for Aerosols in Medicine.

[5]  M. Silvasti,et al.  Efficacy of salbutamol via Easyhaler unaffected by low inspiratory flow. , 2000, Respiratory medicine.

[6]  R. Pauwels,et al.  Lung deposition and efficacy of inhaled formoterol in patients with moderate to severe COPD. , 2007, Respiratory medicine.

[7]  Henry Chrystyn,et al.  Can all patients with COPD use the correct inhalation flow with all inhalers and does training help? , 2007, Respiratory medicine.

[8]  L. Corbetta,et al.  The need to improve inhalation technique in Europe: a report from the Aerosol Drug Management Improvement Team. , 2006, Respiratory medicine.

[9]  R. Woodhouse,et al.  A critical comparison of the dose delivery characteristics of four alternative inhalation devices delivering salbutamol: pressurized metered dose inhaler, Diskus inhaler, Diskhaler inhaler, and Turbuhaler inhaler. , 1999, Journal of aerosol medicine : the official journal of the International Society for Aerosols in Medicine.

[10]  P. Korhonen,et al.  Easyhaler® Multiple Dose Powder Inhaler—Practical and Effective Alternative to the Pressurized MDI , 1995 .

[11]  M. Decramer,et al.  Inspiratory flow rates at different levels of resistance in elderly COPD patients , 2008, European Respiratory Journal.

[12]  A. Hollingworth,et al.  The relationship between powder inhaler resistance and peak inspiratory conditions in healthy volunteers--implications for in vitro testing. , 1993, Journal of aerosol medicine : the official journal of the International Society for Aerosols in Medicine.

[13]  H. Chen,et al.  Relationship between respiratory muscle function and age, sex, and other factors. , 1989, Journal of applied physiology.

[14]  L. Borgström,et al.  On the use of dry powder inhalers in situations perceived as constrained. , 2001, Journal of aerosol medicine : the official journal of the International Society for Aerosols in Medicine.

[15]  C. Lenfant,et al.  Global Initiative for chronic obstructive lung disease. Global strategy for the diagnosis, management and prevention of chronic obstructive pulmonary disease , 2006 .

[16]  G. Crompton,et al.  Peak inspiratory flow through Turbuhaler in chronic obstructive airways disease. , 1999, Respiratory medicine.

[17]  W. Hop,et al.  The course of inhalation profiles during an exacerbation of obstructive lung disease. , 2004, Respiratory medicine.

[18]  W. Bailey,et al.  Editorial: Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2023 Guidelines for COPD, Including COVID-19, Climate Change, and Air Pollution , 2023, Medical science monitor : international medical journal of experimental and clinical research.

[19]  K. P. Van de Woestijne,et al.  Maximal Inspiratory Flow Rates in Patients with COPD. , 2000, Chest.

[20]  T. Mattila,et al.  In vitro Comparison of Three Salbutamol-Containing Multidose Dry Powder Inhalers , 2000 .

[21]  H. Chrystyn,et al.  Is inhalation rate important for a dry powder inhaler? Using the In-Check Dial to identify these rates. , 2003, Respiratory medicine.