An important aspect of quality assurance in cardiac surgery covers the
epidemiological analysis of patient data. After an 8 year period of c
linical experience with quality assurance, we summarize and evaluate c
urrent concepts and actual experiences regarding a special type of dat
abase application and organisation (''feedback-control-system'') for q
uality assurance. It had been developed to meet and solve the problems
related to the data acquisition process, that are typically present i
n the clinical routine of quality assurance. In 1988 the ''feedback-co
ntrol-system'' was designed and implemented in the Department of Cardi
ac Surgery at Heidelberg University. Since then it had been countinuou
sly improved and adapted to satisfy current needs in cardiac surgery.
More than 1500 items are now recorded routinely per patient. At presen
t, detailed information of more than 10,000 patients is available for
the specific methods of analysis in the field of quality assurance. Th
e basic concept included 1. the integration of the data aquisition in
the daily clinical routine, 2. the evaluation and improvement of colle
cted data material by means of ''output-functions'', that require prev
iously recorded reliable data (that is automatically computer generate
d operation reports, letters, statistics, accounting etc.), and 3. to
ensure that the medical and non-medical staff members participate in t
he advantages and the responsibilities of the data-base system for qua
lity assurance. Analyses of perioperative risks and results, early dis
covery of trends, identification of special subpopulations receiving s
pecial types of treatment in cardiac surgery etc. have now become a re
gularly performed tool in clinical routine. This includes the availabi
lity of ''problem profiles'', ''trend analysis'', the use of simple co
ncluding statistics as well as the calculation of multivariable models
. This internal quality assurance is completed by ''multicentric'' com
parisons with further hospitals already using the same data-base syste
m (external quality assurance). Within 8 years, the feedback-control-s
ystem has become a reliable and valuable tool for quality assurance in
daily routine. The high acceptance of the database system is related
to the advantages it provides for every participant. We conclude that
the concept of data evaluation and improvement by means of ''output fu
nctions'' and ''integration of data acquisition in clinical routines''
has proved to be efficient in everyday practice. The sensitivity and
specifity of such a feedback controlled system as a tool for measuring
surgical quality, however, still remains a matter requiring further r
esearch.