A survey of operating theatres in Great Britain and Ireland by postal
questionnaire was undertaken to determine the number of nonventilated
theatres in use, the number of designated theatres for specialist surg
ery and how and when bacterial sampling is conducted. Replies were rec
eived from 147 centres covering 438 operating theatre suites. Eighty-s
even (59%) centres contained three or fewer suites and only 32% did no
t have a designated theatre for any specialist surgery. One hundred an
d seventy-three (40%) theatre suites were built over 20 years ago and
28 nonventilated theatres were identified, mainly used for minor surge
ry (e.g. removal of 'lumps'). Four percent of plenum and 9% of ultracl
ean theatres are never monitored bacteriologically and settle plates a
re used in 72 (49%) centres. This survey suggests there is some confus
ion over the indications for bacteriological monitoring and what const
itutes acceptable standards. The use of non-ventilated theatres, excep
t for the most minor of procedures, is of some concern and should be p
hased out.