Postoperative infections after heart surgery under extracorporeal circulation

Postoperative infection is still an important cause of mortality and morbidity after cardiac surgery. The aim of this study was to assess its incidence and causes in order to optimise treatment. Between January 1996 and December 1997, 1,000 consecutive patients (253 women and 747 men) were operated for cardiac aortic pathology under cardiopulmonary bypass. The mean age was 66 +/- 11 years. The initial pathology was coronary artery disease (N = 663), valvular heart disease (N = 193), an association of the two (N = 94), thoracic aortic pathology (N = 38) or other pathologies (N = 12). The global postoperative infection rate was 4.9% (N = 49). The incidence of sternal and/or mediastinal infections was 0.7%, of bronchopneumonia 0.9%, urinary infection 2.1%, and septicaemia 1.7%. Nine patients died of the consequences of an infection. The hospital stay was significantly longer in infected patients, irrespective of the site of infection. Statistical analysis of the whole population did not show any predictive factor related to the preoperative clinical status of the patients. The only predictive factor demonstrated was the day on which surgery was performed: the infection rate in patients operated during the first 4 days of the week was 2.2% compared with 7.3% for the patients operated during the last 3 days (p = 0.004, odds ratio (OR) = 3.57). In those patients who had an urinary infection, the two identified risk factors were the female gender (p = 0.006, OR = 3.34) and an operation performed at the end of the week (p = 0.017, OR = 3.77). In patients with sternal and medistinal infections, the only identified predictive factor was combined coronary artery and valvular surgery (p = 0.009, OR = 7.43). With respect to pulmonary infections, the only predictive factor was recent preoperative myocardial infarction (< 1 month) (p = 0.004, OR = 7.5). Finally, no predictive risk factors were identified in those patients who developed septicaemia. In conclusion, this study showed that postoperative infection remains a serious complication of cardiac surgery. The prevention of these complications should be a priority for quality health care.