A bacteriological study of the effect on the environment of using a one- or two-trolley system in theatre.

In a survey of 53 hospitals, 62% still had a transfer zone in theatre, involving the use of two trolleys. Reluctance to use one trolley without patient transfer was probably because of concerns about excessive bacterial contamination of the theatre. In an attempt to see if these concerns were justified, air in the operating theatre was sampled for bacterial content, as were the surfaces and wheels of trolleys and the floor in the theatre, anaesthetic room and at the 'red line' in the transfer zone. Samples were taken during the first and second cases on the list of each session in one plenum-ventilated theatre over a four-week period, alternating each week between a one- and two-trolley system. Using one trolley did not significantly influence the bacterial counts in the theatre and anaesthetic room. There were significant differences between counts from the trolley wheels and from the floor of the transfer zone, with counts being higher for one trolley than two. These differences were greatly diminished after the trolleys were washed half way through the study. We conclude that there is no deleterious effect on the environment of the operating theatre, the most sensitive area, if only one trolley is used. If it is considered desirable to decrease the contamination of less important areas when using a one-trolley system, trolleys should be washed regularly, particularly the wheels.