Incidence of deep sternal wound infections after tracheostomy in cardiac surgery patients

Background. Tracheostomy after median sternotomy is associated with an increased risk of deep sternal wound infection (DSWI). However, associated comorbidities in these patients make the exact risk of tracheostomy difficult to discern. Therefore, we performed a retrospective review to determine the risk of DSWI in our cardiac surgery patients who underwent postoperative tracheostomy. Methods. Our cardiac surgery database was queried from January 1996 to July 2003. Perioperative morbidities were identified for all patients who underwent tracheostomy after cardiac surgery. Statistical analysis was performed using χ² analysis and Fisher's exact test. Results. During the study period, 16,277 cardiac procedures were performed through a median sternotomy. Tracheostomy was performed in 291 patients (1.8%). Deep sternal wound infections occurred in 0.8% of all patients and in 3.4% of patients (9 of 268) who underwent tracheostomy. Mean number of days to tracheostomy was 14.2 in the DSWI group and 15.8 in the non-DSWI group (p = 0.45). In patients with a tracheostomy, preoperative renal failure was the only perioperative comorbidity found to be significantly associated with DSWI (p = 0.03). Overall operative mortality was 3.6%. Mortality was 16.5% for patients with DSWI, 22.7% for patients requiring tracheostomy, and 55% for patients with DSWI and tracheostomy. Conclusions. The incidence of DSWI after tracheostomy, in our experience, is not as high as previously reported. Tracheostomy can be performed safely after median sternotomy with a low morbidity and mortality rate. However, if DSWI occurs after tracheostomy, mortality is significant.