[Measurement of aerial bacterial in operation theaters].

The numbers of aerial bacteria in the conventionally aerated theaters of the department Balgrist show the chances of contamination. The required low values of 30-70 bacterial/m-3 of air almost always been exceeded during operation, even though the surgical team was well trained. Comparative measurements in the operation-box with vertical air flow, introduced in 1972, showed germ-figures smaller than 1/m-3 close to the wound, independently from whether surgeon and first assistant worked with breath-suction and helmet or without. The number of wounds contaminated at the end of the operation by germs of any source fell from 50 per cent to 5 per cent which is probably the reason for the fall of post-operative infection. Experience so far shows that one can count on reduction of, particularly of early, infection. Since the patient-material changed -there were far more cases at risk- it is impossible to compare present rates of infection with earlier ones.