IN-24-C010 - CFD Analysis of Ventilation Performance of the Hospital Post Anesthesia Care Unit (PACU)

Healthcare workers in post-anesthesia care units (PACU) are at risk of exposure to waste anesthetic gases (WAGs) released by patients in the recovery stage. The airflow patterns in the PACU play a crucial role in determining the spread and concentration of WAGs in the breathing zone of the occupants. A Computational Fluid Dynamics (CFD) study was conducted to evaluate the impact of various combinations of supply and return air locations on ventilation performance in the PACU. The CFD analyses indicate that traditional HVAC layouts with 4-way supply diffusers and ceiling returns create mixing airflow patterns that distribute WAGs throughout the entire PACU, thereby increasing the risk of healthcare workers' exposure. Proposed HVAC layouts with ceiling laminar diffusers and headwall returns can induce a horizontal movement of contaminated air towards the headwall returns, significantly reducing the concentration of WAGs in the breathing zone and limiting their spread in the PACU. These analyses further indicate that the PACU with an optimized HVAC layout can operate at a reduced dilution airflow rate without significantly affecting ventilation.