Air-borne contamination hazard in open heart surgery. Efficiency of HEPA air filtration and laminar flow.

Since 1975 we have reinforced all measures to prevent post-operative infection in open heart surgery. The environment where we worked has been gradually improved first in our old Hospital and later in the new University unit. It was, therefore, possible to relate post-operative infection to our surroundings and four groups of patients operated upon under different stages of asepsis in the operating theatre were examined. We conclude that air-borne contamination during the operation is a definite hazard, and that HEPA filtration is quite efficient in reducing this risk.