A 15-year study of the changing demographics and infection risk in a new UK cardiac surgery unit

OBJECTIVES: National trends in cardiac surgery show a shift towards a higher preoperative risk profile and factors that might also be expected to increase the risk of postoperative infective complications. We document the changing patient demographics in the first 15 years of a new cardiac surgery unit and examine the impact of these and other changes in estate, staffing and clinical protocols, on the risks of common postoperative infections. METHODS: Data recorded included patient age, sex and body mass index, type and number of operations, logistic EuroSCORE, mortality rate, urgency of operation, reoperation rate, requirement for intra-aortic balloon pump, incidence of diabetes and the incidence of common postoperative infections. RESULTS: A total of 8449 cardiac operations were undertaken. The mean patient age increased from 62.71 to 65.82 years; procedural complexity increased with the proportion of isolated coronary artery bypass procedures falling from 72.8 to 54%; there were increases in the urgency of operation (11.3-26.9%), average patient body mass index (27.01-28.67), the incidence of diabetes (12.3-21.2%), logistic EuroSCORE (5.36-7.74) and intra-aortic balloon pump usage (6.4-15.6%). The incidence of superficial sternal infection reduced (3.9-1.4%); other wound infection rates were low and showed no overall trend with time. Urinary tract infection varied between 0 and 1.7%, but did show a significant increase over the last 3 years (P < 0.01). CONCLUSIONS: This study demonstrates a change in the patient profile, yet despite an increase in infection risk factors, no increase in actual infection rates. The importance of non-patient factors in influencing the outcomes after cardiac surgery is discussed.