P71 Peak inspiratory flow measured at different inhaler resistances in patients with asthma

Abstract

<h3></h3> Patients’ peak inspiratory flow rate (PIFR) may help clinicians select a suitable inhaler device. The In-Check® device has gained some status as a simple tool to estimate PIFR (scale reflecting inhaler resistance from R0 to R5). It has been suggested that some patients with asthma may not be able to generate sufficient PIFR with high resistance devices (R5) to satisfy the minimum requirements of 30 L/min. We conducted a prospective service evaluation study to identify what proportion of patients with asthma are able to generate a correct PIFR at In-Check device R0-R5 resistance settings and what the phenotypical features of those patients are. As part of UK general practice asthma review service, sequential patients were recruited from 41 centres by 10 respiratory specialist nurses. Patients had PIFR checked at the resistance corresponding to their current preventer inhaler device, at R5 (high resistance dry powder inhaler (DPI) setting), and, at R0 (no resistance, pressurised metered dose inhaler (pMDI) setting. Correct PIFR (pass) was defined for R5 as 30–90 L/min, and, for R0 as 20–60 L/min. 994 adults (female 64.3%) were included, of whom 90.4% currently used a preventer inhaler (71.5% MDI (R0), 0% R1, 6.3% R2, 14.5% R3, 4.9% R4, 2.8% R5). 93.7% of patients passed at R5 resistance, compared to 70.5% at R0 (p&lt;0.0001). This difference was observed in all age groups: among younger patients (18–24 years) 100% passed at R5 compared to 73.7% at R0, and among the older patients (&gt;71 years) 90.2% passed at R5 compared to 71.0% at R0. <h3>Conclusion</h3> Patients with asthma can achieve adequate inspiratory flow 30–90 L/min with high resistance DPI (R5).