<p><strong>BACKGROUND: </strong>Acute kidney injury (AKI) commonly occurs after cardiac arrest. Those subsequently treated with vancomycin are at additional risk for drug-induced kidney injury.</p>

<p><strong>OBJECTIVE: </strong>We aimed to determine whether opportunities exist for improved drug monitoring after cardiac arrest.</p>

<p><strong>METHODS: </strong>This was a retrospective cohort study of children aged 30&nbsp;days-17&nbsp;years treated after cardiac arrest in an intensive care unit from January 2010 to September 2014 who received vancomycin within 24&nbsp;h of arrest. Vancomycin dosing and monitoring were compared between those with and without AKI, with AKI defined as pRIFLE (pediatric risk, injury, failure, loss, end-stage renal disease) stage 2-3 AKI at day 5 using Schwartz formula-calculated estimated glomerular filtration rate (eGFR).</p>

<p><strong>RESULTS: </strong>Of 43 children, 16 (37%) had AKI at day 5. Age, arrest duration, median time to first vancomycin dose, and the number of doses before and time to first vancomycin concentration measurement were similar between groups. Children with AKI had higher initial vancomycin concentrations than those without AKI (median 16 vs. 7&nbsp;mg/L; p = 0.003). A concentration was not measured before the second dose in 44% of children with AKI. Initial eGFR predicted day 5 AKI. In children with AKI, the initial eGFR was lower in those with than those without a concentration measurement before the second dose (29&nbsp;mL/min/1.73&nbsp;m [interquartile range (IQR) 23-47] vs. 52 [IQR 50-57]; p = 0.03) but well below normal in both.</p>

<p><strong>CONCLUSIONS: </strong>In children with AKI after cardiac arrest, decreased vancomycin clearance was evident early, and early monitoring was not performed universally in those with low initial eGFR. Earlier vancomycin therapeutic drug monitoring is indicated in this high-risk population.</p>