Early clinical outcomes of two regimens of prophylactic antibiotics in cardiac surgical patients with delayed sternal closure.

Background: Delayed sternal closure (DSC) can be a lifesaving approach for certain patients who have undergone cardiac surgery. The value of the type of prophylactic antibiotics in DSC is still debatable.

Aim: To investigate clinical outcomes of different prophylactic antibiotic regimens in patients who had DSC after cardiac surgery.

Methods: This was a retrospective observational single-center study. Fifty-three consecutive patients who underwent cardiac surgery and had an indication for DSC were included. Patients were subjected to two regimens of antibiotics: Narrow-spectrum and broad-spectrum regimens.

Results: The main outcome measures were length of hospital and intensive care unit (ICU) stay, duration of mechanical ventilation, and mortality. Of the 53 patients, 12 (22.6%) received narrow-spectrum antibiotics, and 41 (77.4%) received broad-spectrum antibiotics. The mean age was 59.0 ± 12.1 years, without significant differences between the groups. The mean duration of antibiotic use was significantly longer in the broad-spectrum than the narrow-spectrum group (11.9 ± 8.7 vs 3.4 ± 2.0 d , P < 0.001). The median duration of open chest was 3.0 (2.0-5.0) d for all patients, with no difference between groups (P = 0.146). The median duration of mechanical ventilation was significantly longer in the broad-spectrum group [60.0 (Δ interquartile range (IQR) 170.0) h vs 50.0 (ΔIQR 113.0) h, P = 0.047]. Similarly, the median length of stay for both ICU and hospital were significantly longer in the broad-spectrum group [7.5 (ΔIQR 10.0) d vs 5.0 (ΔIQR 5.0) d, P = 0.008] and [27.0 (ΔIQR 30.0) d vs 19.0 (ΔIQR 21.0) d, P = 0.031]. Five (9.8%) patients were readmitted to the ICU and 18 (34.6%) patients died without a difference between groups.

Conclusion: Prophylactic broad-spectrum antibiotics did not improve clinical outcomes in patients with DSC post-cardiac surgery but was associated with longer ventilation duration, length of ICU and hospital stays vs narrow-spectrum antibiotics.