Use of Spacers in Ventilated Patients

In-line spacers have been developed to enhance lung deposition of aerosols from pMDIs into the ventilator setting. The advantage of a spacer inserted in 

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In adults, the lung dose achieved with intermediate- and large-volume spacers is about twice that obtained with the corresponding pMDI alone (i.e., 20-35% of the metered dose) (28,61,90-92). In one study, lung doses from pMDIs with and without a large-volume spacer were similar (93), which may be explained by a lack of priming of the plastic spacer. The small-volume spacer AeroChamber de- 

In addition to the total lung dose, the distribution of aerosol within the lungs may affect the clinical response. The aerosol characteristics are changed in a spacer, resulting in smaller particles that are likely to penetrate into smaller airways. However, little is known about the exact anatomic targets of various drugs within the airways. 

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