Improvement and standardization of disinfection in hospital theatre with ultraviolet-C technology

Abstract

Background: The level of disinfection between operating sessions is important to prevent cross-contamination risk in operating theatres.

Aim: To assess the difference in microbial contamination between different disinfection levels, before (T₀) and after (T₁) application of a UVC device (UVC-D).

Methods: A cross-sectional study was conducted between December 2019 and August 2020 in a clinic. Three disinfection levels - no disinfection after surgery, after in-between cleaning, and after terminal cleaning - were compared to assess the reduction of microbial presence at T₀ and T₁ according to the use of UVC-D for 3-5 min per bedside. A total of 260 Petri dishes, divided into a preliminary phase followed by a probabilistic model-driven experiment, were used in three operating theatres, and colony-forming units (cfu) were counted. The Mann-Whitney test was performed in the preliminary phase to establish UVC exposure time. Using the probabilistic model, descriptive statistics and percentage and log₁₀ reduction were calculated. The multivariate analysis of variance (MANOVA) for repeated measures was performed to verify the 95% statistical difference between T₀ and T₁, combined with the disinfection levels and different operating theatres.

Findings: The Mann-Whitney test showed no cfu difference between 3 and 5 min of UVC exposure time; the MANOVA test showed no significant difference between disinfection levels in T₀ - T₁ cfu reduction with a mean cfu reduction of 72% (95% confidence interval: 61.7-84.9) regardless of the disinfection level applied previously.

Conclusion: UVC-D has improved environmental disinfection in all initial conditions. Together with the classic sanitizing procedures already present, it improves and standardizes the level of environmental hygiene.

Keywords: Hospital disinfection; Infection prevention; UVC.