Recirculation of air in operating rooms.

A study of two neurosurgical operating rooms indicated a low, airborne, microbial population could be maintained by recirculating filtered air during surgical procedures. The commonly used turbulent system of air delivery was employed, and high-efficiency filters were effective in removing airborne bacteria generated within the operating room. Optimal rates and percent of recirculation were determined. The method of exhaust was confirmed to be important. Exhaust ports 40 in. above the floor were more effective in maintaining low airborne microbial populations than baseboard-level ports. The degree of activity of the surgical team and the number of personnel in the operating room correlated with the airborne bacterial counts.