P232 Patient lungpower and inhalation maneuver quality with inhalers of different resistance

• Published in: Thorax Vol. 74; no. Suppl 2; p. A216
• Main Authors: Haikarainen, J, Vahteristo, M, Jõgi, R, Lähelmä, S, Vartiainen, V, Malmberg, LP
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group LTD 01.12.2019
• Subjects: Asthma; Chronic obstructive pulmonary disease; Inhalers; Patients
• ISSN: 0040-6376; 1468-3296
• DOI: 10.1136/thorax-2019-BTSabstracts2019.375

Patient’s adherence and ability to correctly perform the inhalation maneuver are challenges often discussed when sufficient control over asthma or COPD is not achieved. Dry powder inhalers (DPIs) rely on patient generated energy to aerosolize the formulation. Inspiratory flow rate is used to evaluate whether the patient is able to use DPIs. However, the power generation is a function of both flow rate and inhaler resistance and hence flow rate alone does not describe the physics involved in the powder deagglomeration nor does it describe the patients ability to inhale sufficiently.We used modified ‘Inhalation Manouvre Quality’ –requirements1 to assess how asthma (n=724) and COPD (n=244) patients performed with various DPIs. The airflow profiles of asthma and COPD were assessed for lungpower, flow acceleration and inspiratory volume after peak flow rate. The unit conversion from peak inspiratory flow rate to lungpower was conducted using device resistances found in literature.96.1% (n=383), 92.6% (n=202), 89.5% (n=202) and 84.6% (n=181) of the patients met the requirements for successful inhalation for Easyhaler combi (for combination therapy), Easyhaler mono (for monotherapy), Diskus and Turbuhaler respectively (figure 1). The mean lungpower values varied between 7.18W and 9.65W for the four devices while the minimum power threshold calculated from the minimum flow rate was 0.58W, 1.15W, 0.29W and 4.36W for Easyhaler combi, Easyhaler mono, Diskus and Turbuhaler, respectively. In terms of lungpower, the poorest performing patients were COPD patients using Diskus. In this patient group 10th percentile cut off was 1.29W, which is sufficient for all the studied DPIs except for Turbuhaler.For large majority of respiratory patients DPIs provide a feasible treatment option. The Turbuhaler requires largest lungpower and performed worst likely due to its built-in deagglomeration system that requires large flow rates to operate properly.1 As for other inhalers, the lungpower requirement did not significantly limit the performance in any patient group.ReferenceHaidl P, Heindl S, Siemon K, Bernacka M, Cloes RM. Inhalation device requirements for patients’ inhalation maneuvers. Respir Med 2016;118:65–75. doi:10.1016/j.rmed.2016.07.013Abstract P232 Figure 1The success rate of inhalations according to criteria presented by Kamin and Haidl for patients with asthma and COPD with Easyhaler (combi and mono), Diskus and Turbuhaler. Error bars represent 95% confidence interval.Pairwise comparsion by McNemar’s test. *p<0.0001