Emergency-use spacers improve salbutamol delivery in asthmatics compared to pMDI alone

BACKGROUND: Pressurized metered dose inhalers (pMDIs) spacers improve delivery by reducing hand-breath coordination requirements. OBJECTIVES: This study aimed to assess the efficacy of emergency-use and conventional spacers. METHOD: a multi-arm, parallel-group, randomized trial in which 108 asthmatics were randomized to 9 groups (pMDI alone and various spacers); each received 400 µg salbutamol. Emitted dose on the ex vivo filter was quantified using high-performance liquid chromatography. Pulmonary absorption was assessed via urinary salbutamol at 0.5 h post-dose (USAL0.5) and spirometry changes was assessed via forced expiratory volume in 1 second (FEV₁) and its percent of predicted (∆FEV₁ and ∆FEV₁% predicted), and forced vital capacity (∆FVC). RESULTS: While the pMDI alone group yielded the highest ex vivo deposition (325.4 µg, P ˂0.001), it showed the lowest USAL0.5 (4.13 µg, P ˂0.001-0.032) and ∆FEV₁ (0.12 L, P ˂0.001). Among all tested devices, the Aerochamber, Able, and Tips-Haler spacers demonstrated superior performance (ex vivo filter: 207.1, 181.1, 167.5 µg, P ˂0.001-0.02; USAL0.5: 11.61, 11.15, 10.73 µg, P ˂0.001-0.09), ∆FEV₁: 0.32, 0.29, 0.31 L, respectively, P ˂0.001-0.06), with no significant difference between the three spacers, except the Aerochamber showed a significantly higher ex vivo result (P ˂0.001-0.02). DispozABLE and Lite-Air showed moderate efficacy, whereas the Atomizer, showed the lowest pulmonary function performance with varied significance across devices. CONCLUSION: This study emphasizes the significance of spacer design. It supports the use of validated emergency-use spacers in low-resource or emergency settings where conventional devices are not available. The trial was registered at ClinicalTrials.gov, identifier: NCT06816342.