Diagnostic Stewardship to Optimize Blood Culture in a Pediatric Cardiac Intensive Care Unit

The threshold for ordering blood cultures and initiating empiric broad-spectrum antibiotic therapy is often low in pediatric cardiac intensive care units (CICUs). However, excessive blood cultures carry risks, including anemia, false-positive results, and contamination related to vascular access. Overuse of broad-spectrum antibiotics can lead to the development of multidrug-resistant bacteria.

In this quality improvement initiative focused on diagnostic stewardship, a blood culture algorithm was developed to reduce unnecessary blood culture sampling in patients with low sepsis probability. All patients admitted to the CICU were included in the study. The preimplementation observation period spanned from January 2022 to June 2023, and the postimplementation observation period lasted from July 2023 to December 2025.

There were 5,958 CICU admissions during the study period, with no statistically significant difference in the baseline clinical characteristics. The number of blood culture samples declined by 26% in the postimplementation period, from 111.9 to 82.8 per 1,000 patient-days (P < 0.001), and a centerline shift was observed after the 5-month mark in the statistical process control U-chart. No statistically significant change was observed in the central line-associated bloodstream infection rate per 1,000 line-days (1.7 versus 1.3, P = 0.26).

A structured algorithm to support clinicians' decision-making for blood culture testing resulted in a statistically significant reduction in the number of blood cultures sent. The delayed centerline shift indicated that lasting change required complete practice adoption rather than mere intervention launch. This intervention was not associated with any safety concerns in clinical outcomes.