Inciting Events in the High Risk Post-Operative Pediatric Cardiac Patients – A Novel Three Hit Model for Bacteremia Prediction

Abstract

Background: Blood stream infections (BSI) are well described in pediatric cardiac intensive care units (PCICU). We noted that postoperative high-risk patients may develop BSI after an inciting event. The aim of this study was to investigate whether high risk patients who developed bacteremia experienced more inciting events than a similar group of high-risk patients. Methods: In this retrospective case-control study, we enrolled patients who developed bacteremia from March 2010 to November 2019, after undergoing open-heart surgery at a referral pediatric center. The control group was comprised of case-matched patients with the immediate consecutive same surgery. The following were recorded: operative data, common risk factors, postoperative severity of illness parameters, mortality, and inciting events 72-24 hours before bacteremia emerged. Findings: A total of 200 patients were included (100 with bacteremia, and 100 controls). Main demographic and operative parameters were matched. Bacteremia emerged on average postoperative day (POD) 12·8. Gram-negative bacteria were cultured in 84%, and skin associated gram-positive bacteria in 10% of the patients. Average central-venous lines (CVL) duration was 9·5±8·4 days. Postoperatively (72 hours), severity of illness parameters were significantly worse in patients with bacteremia, with a higher rate of postoperative complications during PCICU length-of-stay (LOS). In the bacteremia group, 72-24 hours prior to development of bacteremia, 92(92%) inciting events were recorded, compared to 21 (21%) in controls during their entire LOS. (OR 43·3,CI 18·2-103·1, p<0·0001). Interpretation: We propose a three hit model demonstrating that high-risk patients undergoing open heart surgery have significant higher risk for bacteremia after an inciting event. Funding Statement: No funding was procured for this work. Declaration of Interests: Mrs· Shochat disclosed work for hire at Rabin Medical Center as a statistical consultant. The remaining authors have disclosed that they do not have any potential conflicts of interest. Ethics Approval Statement: The Institutional Review Board reviewed and approved the study, and waived the need for parental consent.