The effect on delivered dose when using and misusing nebuliser face masks

Anna Gyllenstrand¹, Ellinor Nilsson¹ & Gunilla Petersson¹

¹AstraZeneca R&D Gothenburg, Pepparedsleden 1, Mölndal, 43183, Sweden

Summary

The effect on delivered dose when using nebuliser and face masks was studied for a range of nebulisers, face mask brands and patient simulation scenarios. It was found that the dose to a patient may vary substantially for the same drug product, depending on the combination of nebuliser, mask type and size, breathing pattern and user handling. The terbutaline dose varied for adult mask and adult breathing pattern between 332-1361 µg and for children between 138-801 µg. Adding a face mask reduced the patient dose by about 50%. Interestingly the dose increased more than two times when a small dead volume mask, intended for a younger patient, was used. The impact of simulated air leakages varied not only for different nebulisers and face masks, but also for different face model types used. It is clear that there is no mask fitting all face shapes, not even when the mask is of the intended age design. Face mask design, mask volume, breathing pattern and leakages were shown critical for the patient dose. Flexible mask materials seemed more efficient in maintaining the skin contact and hence more efficiently preventing leakages, also if the mask is somewhat moved during treatment.

Key Message

Even for nebulisers with high drug delivery efficiency, face mask properties and handling have a substantial impact on patient dose. Important mask features are shape, volume, material, inlet orientation, air vents and one-way inhalation valves.  Breathing patterns, incorrect handling and a poor face fit also affect the dose.