Reducing the particles generated by flushing institutional toilets. Part II: Assessing a portable and reusable toilet cover in U.S. hospitals.

Abstract

Flushing uncovered toilets in hospitals has been shown to produce toilet plume aerosols (TPA) in a wide size ranging from nanometers to micrometers. Studies have shown that TPA can carry infectious pathogens and hazardous drugs used in cancer treatment. To mitigate the risk of exposure, some researchers have recommended covering the toilet during flushing, and guidelines from the Oncology Nursing Society have specifically recommended covering the toilet when flushing excreta from patients receiving chemotherapy. Because existing literature primarily focused on controlled laboratory settings or small case studies, there has been a need for a real-world, multi-center study in clinical settings to measure TPA by flushing both covered and un-covered toilets. To address this gap, the authors initiated a multicenter study to measure TPA in clinical settings and to assess the effectiveness of a commercially available, portable, and reusable toilet cover. The study enrolled 15 hospital centers (145 toilets) in nine U.S. states which included seven National Cancer Institute (NCI)-designated comprehensive cancer centers. The particle number concentrations were measured using a TSI optical particle counter (TSI 9306) with six size bins (0.3 to 25.0 µm) positioned 22 inches above the floor. The results showed that the ambient particle number concentrations in the HEPA-filtered floor bathrooms (376 ± 857#/L) are significantly lower than the non-HEPA-filtered ones (7,432 ± 9,207#/L). The mean particle number concentrations generated by flushing are 3,951 ± 8,606#/L with a median of 1,916#/L, ranging from 136#/L to 71,959#/L. Results with cover demonstrated a reduction in the total number of particles of 101 ± 11% regardless of the HEPA filter usage (p = 0.0002 in the Mann-Whitney U test). Mixed-effects modeling revealed that the overall level of particle reduction is substantial regardless of state (nine total), floor levels, flush volumes, and inpatient versus outpatient. This study provides evidence supporting the use of the tested portable toilet cover as an intervention to reduce healthcare workers', patients', and visitors' exposure to toilet plume aerosols in clinical settings.