[Effect of parting surfaces on the transmission of airborne organisms at junctions between areas of different hygienic standards]

Abstract

Parting surfaces between areas having different standards of hygienic requirements, represent naturally the weak points in the hygienic conception of operating theatres. These boundary areas between the operation room on the one hand and the adjoining entrance lock for the staff on the other are of specific interest in this connection. While opening the connecting doors, dust particles may be whirled up due to turbulence, thermic, constructional and other effects, which are difficult to be identified and may then settle down directly on the operating area after reaching there from the entrance lock through the airways. Since bacteria are in most cases attached to particles, it may be assumed that each air flow loaded with dust particles is also a potential carrier of air-borne germs (contact germs----contaminated dust particles----air borne germs----settling germs). Therefore, the present paper is to be understood as a contribution towards the application of methods for identifying air-borne routes of infection in the operating area and finding ways and means for their elimination. In comparison with the investigations done by Esdorn and Kanz during simulated and operating activities respectively, the experiments described in this paper have been carried out while the operating theatre was not running. It is to be assumed that even under these tranquil conditions, parting surfaces appear to act as permanent disturbing factors. Transmission of germs from the entrance lock for the staff to the operating room is only then possible, if the doors suffer functional disturbance and the entrance lock is found hygienically in objectionable condition. Functional measures regarding construction aim, therefore, at the principle of clear-cut separation of the clean side from the unclean in the design and running of operating theatres, as specified in the guidelines of the Bundesgesundheitsamt. The constructional conception of entrance lock can contribute to achieving almost automatically the necessary hygienic provisions. One of the principle purposes of air-handling systems in operating theatres is to keep a protecting pressure in areas with very high hygienic requirements in relation to those with lower standards of air cleanliness. Air-flow must always follow the direction from the clean to the less clean areas (2, 4, 9, 22, 24, 26, 30). A British-Scandinavian multi-centre study of ultra-clean air and sepsis following total hip replacement (19) showed that the risk of nosocomial infection increases directly with the air contamination.(ABSTRACT TRUNCATED AT 400 WORDS)