The effect of ventilation system design on air contamination with halothane in operating theatres.

By measuring the halothane concentrations in samples of air from three different operating theatres during routine operating lists the pattern of spread of the waste anaesthetic gases has been demonstrated. The results show that in all the theatres there was a spread of halothane from its point of escape from the anaesthetic circuit to all parts of the theatre air. A turbulent flow ventilation system produced an uneven spread with the greatest concentrations in the zone of air breathed by standing personnel. A downward displacement system produced a more even spread throughout the theatre but with a much reduced general level of pollution.