Contamination of nebulisers and surrounding air at the bedside of mechanically ventilated patients

Abstract

Background . The delivery of aerosolised medication, as performed by nurses and physiotherapists in intensive care units (ICUs), forms an important component of patient care. Objectives. To determine the presence of contamination of nebulisers used within a ventilator circuit; to describe the protocol and clinical practice regarding decontamination and storage of these devices; and to identify micro-organisms colonising contaminated nebulisers and the surrounding air at patients’ bedsides. Methods . A cross-sectional multicentre observational study was conducted, including site and equipment sampling to determine contamination. ICU managers were interviewed to determine the decontamination and storage protocols used for nebulisers in their units. Swabs were taken from nebuliser chambers and streaked onto blood agar plates (BAPs). An air sampler was used to collect air samples from the surrounding bedside environment. The BAPs were incubated for bacterial and fungal contamination. Species of colonies observed in these samples were identified. Results. Sixty-one nebulisers from seven ICUs were sampled (Micro Mist n =37; Aeroneb n =24). Half of the nebulisers (Micro Mist ( n =19, 51.4%));Aeroneb ( n =12, 50%)) and most air samples ( n =60, 98%)) presented with contamination. All participating ICUs reported decontamination and storage protocols, but visual inspection of nebulisers suggested that the protocols were not observed. Nebulisers rinsed with alcohol and left open to the environment to dry had the lowest contamination rates. Coagulase-negative Staphylococcus species (spp.) were mostly found in the surrounding air and Aeroneb samples, and Enterococcus spp. were mostly found in the Micro Mist nebulisers. Conclusion . Although decontamination and storage protocols for nebulisers were in place, nebuliser and air contamination was high, possibly due to poor staff adherence