Controlling infectious airborne particle dispersion during surgical procedures: Why mobile air supply units matter?

Abstract

The ventilation system in an operating room (OR) plays a vital role in reducing the risk of patients contracting an infection while undergoing a surgical procedure. The clean air supplied from the ceiling-mounted diffuser removes the airborne particles from the surgical site. The clean air, however, is often obstructed by the medical staff and other objects. Hence, some sterile instruments might remain outside the protected area. The present study aims to examine the effectiveness of a mobile air supply (MAS) unit in reducing the particle settlement on a patient under different airflow velocities supplied from the MAS unit. A simplified computational fluid dynamics (CFD) model of the OR was developed and validated based on published data. An RNG k-epsilon turbulence model, based on the Reynolds-Averaged Navier-Stokes (RANS) equations, was used to simulate the airflow, while a discrete phase model (DPM) was used to simulate the movement of the infectious airborne particles. The MAS unit was evaluated as an extension of unidirectional airflow ventilation. Results showed that the MAS unit successfully reduced the settlement of airborne particles by 78% from 45 particles/m3 to 10 particles/m3. However, the operation of the MAS unit showed a reverse effect on the particle settlement (~7 particles/m3) on the patient when the MAS unit supplied air at a velocity of 0.6 m/s. The present study showed that air supply at a velocity of 0.5 m/s provided an optimum wiping effect that removed the airborne particles from the surgical zone.