Does human movement-induced airflow elevate infection risk in burn patient’s isolation ward? A validated dynamics numerical simulation approach

An isolation ward requires a highly controlled and contamination-free environment since the settling of bacteria-carrying particles (shed by medical staff) on patients’ wounds could cause infections. The present study examines the effect of medical staff’s walking movement on airflow distribution and particle dispersion. Three different walking speeds of 0.25 m/s, 0.5 m/s, and 1.0 m/s were assigned to the medical staff. An RNG k-ɛ model based on the Reynolds-Averaged Navier-Stokes (RANS) equation was adopted to predict the airflow, while a Lagrangian tracking approach was selected to track particle dispersion. The reliability of the selected airflow turbulent model and particle tracking approach was validated using published data. The present study showed that the low-pressure region behind the moving medical staff’s body has induced wake. The higher walking speed of 1.00 m/s produced a significant secondary airflow of 1.12 m/s, while 0.25 m/s and 0.5 m/s generated lower secondary airflow of 0.41 m/s and 0.53 m/s, respectively. The number of particles settled on the patient at 0.25 m/s, 0.50 m/s, and 1.00 m/s were 31, 18 and 5, respectively. Present finding indicated that a higher walking speed reduces the number of particles settled on the burn patient, therefore potentially reducing the associated nosocomial infection risk.