CONTAMINATION AND CURRENT PRACTICE IN DECONTAMINATION OF NEBULISERS IN VENTILATED PATIENTS

¹University of the Witwatersrand, Physiotherapy, Johannesburg, South Africa

Background: Aerosol therapy is often used by physiotherapists and nursing staff in intensive care units (ICU) for the management of patients receiving mechanical ventilation. A range of aerosol devices are used for administration of medication within a ventilator circuit. The methods used to store these nebulisers and the pathogens in the surrounding air may contribute to the contamination of these devices. Nebulisers have been identified as a possible source of ventilator-associated pneumonia (VAP).

Purpose: To determine the incidence of contamination of nebulisers used within a ventilator circuit; the practice regarding decontamination and storage of these devices and to identify the micro-organisms that colonise contaminated nebulisers and the surrounding air.

Methods: A cross-sectional multi-centre observational study was done with site and equipment sampling to determine contamination. ICU managers were interviewed to identify which decontamination and storage protocols were 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. Descriptive analysis was used to analyse the data in SPSS version 24.

Results: Sixty-one nebulisers from seven ICUs were sampled (n=37 Micro Mist; n=24 Aeroneb). The incidence of nebuliser contamination was high [n=19 (51.4%) Micro Mist; n=12 (50%) Aeroneb]. All participating ICUs had decontamination and storage protocols in place. Observed staff adherence to protocols was low. Nebulisers rinsed with alcohol and left open to the environment to dry had the lowest contamination rates. Coagulase-negative Staphylococcus species (spp.) was mostly found in air and Aeroneb samples and Enterococcus spp. was mostly found in Micro Mist nebulisers.

Conclusion(s): Decontamination and storage protocols for nebulisers used within a ventilator circuit were in place but the incidence of nebuliser contamination was high as staff adherence to protocols was low. The micro-organisms identified in nebulisers and air samples are associated with the development of VAP as described in the literature. Suggestions for future work include audit of clinical practice in ICU in order to reduce the risk of infection to patients, and investigation into associations between newly diagnosed cases of VAP and surrounding air and nebuliser contamination.

Implications: Findings from this study suggest that nebulisers used within a ventilator circuit should be wiped dry after use and stored open to the environment to ensure the least amount of contamination occurs. Unit managers should ensure that physiotherapists and ICU nurses are educated on nebuliser decontamination and storage protocols in place in their units.

Funding acknowledgements: South African Society of Physiotherapy and the Wits University faculty of Health Sciences Research Committee.

Topic: Critical care

Ethics approval: University of the Witwatersrand Human Research Ethics Committee.

All authors, affiliations and abstracts have been published as submitted.