Objective: The In Check Dial was developed to evaluate whether a patient is able to generate an adequate peak inspiratory flow (PIF) through a certain inhalation device. The inhalation profile recorder (IPR) is a calibrated instrument that measures flows through Diskus and Turbuhaler in our research setting. The aim of this study was to compare the PIFs of patients when inhaling through a Diskus or Turbuhaler connected with the IPR (PIF_diskus and PIF_TH) to the flows through the corresponding orifices of the In Check Dial (Diskus_In Check and TH_In Check).
Methods: Twenty-four stable asthma and twenty-one chronic obstructive pulmonary disease (COPD) patients inhaled, on two separate occasions, in randomised order, via the Diskus or Turbuhaler connected with the IPR. Subsequently, patients inhaled through the In Check Dial using the orifices of Diskus or Turbuhaler.
Results: The difference between Diskus_In Check and PIF_diskus was 3.9 (11.9)l/min (P=0.038). The difference between TH_In Check and PIF_TH was 3.5 (10.6) l/min (NS). All Diskus- and Turbuhaler-inhalations were performed with the minimum required flow of 30 l/min. However, four COPD patients inhaled with the non-optimal flow (<60 l/min) through the Turbuhaler. The In Check Dial did not indicate two of them.
Conclusion: Measuring PIF through Diskus and Turbuhaler using the IPR and the In Check Dial, respectively shows a disagreement of 3.9l/min. A disagreement of 3.5l/min was found for the Turbuhaler. The In Check Dial did not identify two of four patients as 'non-optimal' users.