Studies of Air Cleanliness Levels on Bioclean Operating Room of Tohoku University Hospital

Abstract

It is important to keep dust- and bacteria-free air in an operating room for protection against airborne microbial contamination and inferction during surgery. From this point of view, we examined the number of airborne particles and bacteria in bioclean operating room of Tohoku University hospital. The airborne particles were counted by Royco or Lion particle counter and the bacterial counts were detected using a slit sample model STA-203 before and during surgery. The number of dust particles which having a diameter larger than 5μm were 10-50 particulates per cubic foot of air (average : 26 particulates per cubic foot of air) and bacteria counts were 0.02 colonies per cubic foot of air before surgery.Both dust particles and bacteria counts tended to rise during the preoperative period such as induction of anesthesia, sterilization application of the skin, application of drapes and adhesion of disposable plastic drape in most of the cases. However, after the operation was started, the particle counts gradually fell below 1,000 particulates per cubic foot except when an electro-surgical unit was used. The number of airborne bacteria also decreased between 0 and 0.06 colonies per cubic feet of air during operation. These results suggest that application of good aseptic techniques and adequate usage of bioclean operating room will provide a practical method of achieving control of aerobic contamination during surgery.