Capsaicin provocation using two different inhalation devices

SummaryBackgroundSensory hyperreactivity (SHR) has been suggested as one explanation for chemically induced airway symptoms; it can be diagnosed with a capsaicin inhalation test. Previous capsaicin inhalation studies of SHR have used a Pari Boy® device. This model of inhalator device has become outdated, hence it is necessary to abandon it in favour of a new device. The aim of this study was to transfer the capsaicin inhalation test using the Pari Boy® device to a corresponding model using the Maxin MA3® device.MethodsTwenty-one patients with SHR and 44 healthy controls visited the clinic twice and underwent a randomised protocol. The participants were provoked with saline and capsaicin using one of two devices, Pari Boy® and Maxin MA3®. Eight patients also underwent two additional capsaicin provocations with Maxin MA3®. A new series of capsaicin concentrations was chosen for Maxin MA3®. The results from each device were analysed, the agreement between the two devices and the repeatability of the Maxin MA3® were evaluated.ResultsAmong all participants, the mean number of coughs with the Pari Boy® was 5.5 (95% CI: 2.7; 8.2) after inhalation of 0.4 μmol/L capsaicin and 20.0 (95% CI: 14.1; 25.9) after 2.0 μmol/L. With the Maxin MA3®, the mean number of coughs was 3.6 (95% CI: 1.3; 4.0) after 0.06 μmol/L capsaicin, and 17.8 (95% CI: 12.0; 23.6) after 0.3 μmol/L. The Maxin MA3® showed good repeatability and the agreement between the devices with the capsaicin concentrations chosen for each device was considered to be good.