A randomised, cross-over trial of upright sitting versus alternate side lying during nebulised delivery of medication to improve the pattern of aerosol deposition in healthy participants

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Participants will inhale a 4mL radioaerosol in two positions in random order throughout the nebulisation period of 20 minutes: 1. Upright sitting: or 2. Alternate Side Lying: (alternated between left and right at each minute) After each nebulisation a gamma camera will perform a 20-minute deposition scan incorporating a 2-minute transmission scan to outline the three-dimensional margin of the lung fields. This data will be reconstructed to determine the distribution of the deposited radioaerosol in the lungs. A 15% improvement in uniformity of deposition is the proposed minimum difference that would make further investigation of the alternate side lying strategy worthwhile in patient populations. Significance of project: In many patient populations (eg, cystic fibrosis, HIV and bronchiectasis), the pattern of deposition of inhaled medication is poor and non-uniform. Typically the upper lobes receive a reduced dose compared to the rest of the lung. The ability to deliver a drug more uniformly to the lung using a strategy of side lying may have a significant impact on treatment efficacy for people with lung disease. Data from healthy participants will aid interpretation of subsequent studies in patients.