Association between post-sternotomy tracheostomy and deep sternal wound infection: a retrospective analysis

Tracheostomy has traditionally been used as a means of facilitated mechanical ventilation in patients requiring respiratory management following cardiac surgery. However in the clinical setting, the advantages of tracheostomy has been questioned by concerns surrounding evidence of its association with increased risk of deep sternal wound infections (DSWI). The present study sought to evaluate retrospectively our experience with post-sternotomy tracheostomy among cardiac surgery patients and association with DSWI.

Between July 2003 and June 2013, 11,795 patients underwent open cardiac surgery via sternotomy in our department. Among these, 225 underwent post-sternotomy tracheostomy. Data were obtained by reviewing and analyzing the Cardiac Surgical and Cardiac Intensive Care Unit (ICU) databases for adult cardiac patients.

Out of the 11,795 sternotomy patients analyzed, 225 (1.9%) underwent tracheostomy. The overall mortality rate for post-sternotomy tracheostomy patients was 21.3%. DSWI developed in 23 patients (10.2%) of the tracheostomy group. Seven of these 23 patients had DSWI after insertion of tracheostomy. DSWI was significantly higher in tracheostomy versus no-tracheostomy patients (10.2% vs. 0.48%; P<0.001). DSWI was also associated with higher mortality rates compared to non-DSWI patients (11.4% vs. 2.3%; P<0.001).

The present study demonstrated that tracheostomy was an independent risk factor for post-sternotomy DSWI, and that DSWI was a predictor of mortality. For tracheostomy patients, coronary artery bypass grafting (CABG) procedures and longer durations of tracheostomy were strong predictors of DSWI. Across all sternotomy patients, tracheostomy, diabetes, urgency status and blood transfusions were significant risk factors for DSWI. As such, the decision for tracheostomy post-sternotomy should be carefully considered on a case by case basis.