Analysis and assessment of factors affecting air inflow from areas adjacent to operating rooms due to door opening and closing

Abstract

Operating rooms usually work with positive differential pressure in order to prevent the entry of contaminated air from adjacent areas and so maintain asepsis. Nevertheless, the opening of doors causes this pressure difference to disappear and means that contaminating agents can enter from adjacent areas. As a result, a knowledge of air flow pattern behaviour during the door opening and closing cycle is key to understanding the risk of infection and contamination in the operating room. The objective of this study is to quantify the air flow that enters the operating room during a complete door opening and closing cycle. We specifically study two operating rooms equipped with a heating ventilating air conditioning system: one with turbulent air flow and the other with laminar air flow. We assess the influence of the type of door - hinged and sliding – for different origin values of flow exhaust fan regulation. In order to perform the measurements, a threedimensional ultrasonic anemometer that measures the magnitude and direction of the instant air velocity on the doorway of the door was used. Analysis of the results shows that the door opening and closing process leads to air entering the operating room from the adjacent areas in all of the cases studied, regardless of the ventilation system used. Sliding doors are seen to reduce the amount of air entering from the adjacent area in all the scenarios tested. Sliding doors are thus considered the preferred option in operating rooms.