2. Impact of inhalation flow pattern assessment on inhalation instruction

The present study was conducted in Shiga University of Medical Science Hospital from February to July 2016. Inclusion criteria were the adult patients who were prescribed a combination of DPI and SMI. Exclusion criteria were the patients who refused the informed consent, or age younger than 20 years. A total of 10 participants were measured their inhalation flow patterns via their prescribed devices at their regular clinical visits (1–3 clinical visits in a participant). Peak inhalation flow rate (PIFR) and inhalation duration time (DT) were assessed as parameters of inhalation pattern (Fig 1B). The essential criterion of optimal inhalation pattern for DPI and SMI were (1) higher than the lower limit of PIFR for each device in order to disperse dry powder from the inhalation device and (2) a DT longer than 1.5 sec for soft mist spraying time [15], respectively. The lower limits of PIFR for each device are listed in Table 1 [21–29].

The clinical protocol for instruction of inhalation pattern is as follows. In the case that the participant could not achieve the criterion, participants were received the instruction for inhalation by pharmacists, and measured their inhalation pattern again. The achievement rate of the criterion between pre- and post- instruction were analysed with Chi square test. In addition, the difference of inhalation pattern parameters between pre- and post- instruction were compared and analysed with the paired t-test. A difference was considered significant at P< 0.05. This study was performed in accordance with the Declaration of Helsinki. This human study was approved by the Ethics Boards of Shiga University of Medical Science—approval: 27-14-1. All participants provided written informed consent to participate in this study.