Prevention of Nebulised Drug Dispersal using an Extractor Tent

Nebulisers convert liquids into a fine mist of suspended particles that are inhalable into the respiratory tract. They are used to deliver drug therapy by the respiratory route, for example bronchodilators, or to aid production of diagnostic sputum samples (sputum induction). On continuous monitoring of biological airborne particles in a respiratory ward over 4 weeks using a biological particle detector (WIBS) the majority of detected particles were attributable to nebuliser therapy. Tents with extractor/filter devices are indicated for infection control purposes in collection of induced sputum from patients with suspected tuberculosis. We tested the efficacy of an extractor tent (Demistifier 2000, Peace Medical) on reducing detectable aerosols from nebulised bronchodilator drugs by continuously monitoring a room outside a tent containing a nebuliser. The mean fluorescent particle count per m3 was 0.63 and 0.31 (equivalent to background levels pre-nebuliser) for nebulised Ventolin and Ipramol, respectively, when they were nebulised within the tent. Removing the tent and nebulising directly into room air resulted in a 2.56×104 and 4.64×104-fold increase in particle concentrations for Ventolin and Ipramol, respectively, over background levels. WIBS monitoring therefore showed 100 % efficacy of the tent in restricting spread of nebulised drug particles. Extractor tents can prevent spread of drug particles from nebulised therapy. The implications of this will be discussed.