Sternal wound infections (SWI) in delayed sternal closure (DSC) patients are a healthcare burden after congenital heart surgery. There are no guidelines specific for pediatric DSC patients to prevent this costly complication. The hypothesis was that the modifications to a bundled approach for DSC patients would decrease the SWI rate. For this prospective cohort study, DSC patients were postoperatively admitted to a pediatric cardiac care unit from February 2017 to January 2018. Using a modified protocol for prevention of SWI, the infection rates pre- and post-modified protocol were compared. The primary outcome measure was SWI. Secondary outcome measures were compliance with modifications. Retrospective review of cases in pre-protocol modification era from January 1, 2014 to December 31, 2016 showed 377 pediatric cardiopulmonary bypass cases and 39 (10.4%) underwent DSC. During the post-protocol modification era, there were 129 cardiopulmonary bypass cases and 17 (13%) DSC cases. The SWI rate in DSC were 7.7% and 0% for pre-intervention and post-intervention, respectively (p = 0.52). The Bayesian confidence interval with Jeffreys prior gives a 95% confidence interval of 1.5% to 18.3% for pre-intervention and 0 to 13.5% for post-intervention. Compliance with the protocol bundle during the post protocol era was 93–100%. Although preliminary results are not statistically significant due to cohort size, the economic burden and increased LOS for each SWI is clinically significant. The early results of reduced infections for DSC patients using a modified bundle approach appear promising. Continued study and a multicenter project would be beneficial.