Assessing the ideal microwave duration for disinfection of sinus irrigation bottles-A quantitative study

Objectives: Saline irrigation of the nasal cavity and paranasal sinuses has a recognised role in the management of chronic rhinosinusitis. However, bacterial recontamination of irrigation bottles through backflow from the sinonasal cavity is a concern in recurrent sinus cavity infections. While patients are encouraged to clean the irrigation bottles regularly, there remains significant concern that the use of contaminated bottles may perpetuate chronic rhinosinusitis. This study assesses the optimal microwave duration to achieve decontamination for each irrigation bottle component part (reservoir, tube and nozzle) using a standard, commercially available microwave. In addition, the irrigation fluid was also tested for contamination after each microwave cycle. Study Design: Laboratory-based experimental study. Participants: No patients were involved in this study. Main outcome measures: The percentage in vitro decontamination of the bottles' components was determined following 30, 60, 90, 120, 150 seconds of microwave cycles. Results: Complete decontamination of the bottles was not achieved at any of the tested microwave cycles. Levels of decontamination differed for the different bottle components, and the greatest degree of decontamination for all bottle components occurred at 90 seconds. Although higher levels of decontamination were observed at microwave durations exceeding 90 seconds, this was at the expense of thermal degradation and deformation of the reservoir plastic component of the irrigation bottle. Similarly, lowest contamination of irrigation fluid was observed at 120 seconds. Conclusions: This study highlights the importance of establishing precise decontamination procedures and recommends a microwave cycle of 90 seconds for optimal decontamination.