Lauren Chambers, PharmD, BCCCP,
Pediatric Critical Care Pharmacist
Seattle Children's Hospital
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Title: Implementation of a Pharmacist-Led Beta-Lactam Therapeutic Drug Monitoring Protocol in the PICU
Introduction: Critically ill patients demonstrate significant pharmacokinetic (PK) and interpatient variability which necessitates the need for individualized dosing strategies, especially for anti-infectives. There is increasing evidence to support the practice of beta-lactam therapeutic drug monitoring (TDM). Data is limited in pediatric patients, but adult studies suggest optimal efficacy when beta-lactam concentrations target 4–6 times the MIC for the entire dosing interval. To optimize beta-lactam dosing in critically ill pediatric patients, a retrospective review was performed and a pharmacist-led protocol was developed and implemented at a pediatric hospital.
Methods: This was a single-center, retrospective chart review of PICU patients that had cefepime or meropenem trough levels from May 2020-July 2021. Patients received drug monitoring if they had a multi-drug resistant organism (MDRO) or were on continuous renal replacement therapy (CRRT) and/or extracorporeal membrane oxygenation (ECMO). The primary objective was to evaluate whether empiric drug dosing reached therapeutic targets as defined as 100% T > MIC using CLSI breakpoints for Pseudomonas. A pharmacist-driven protocol was developed to capture patients who would benefit from TDM and to facilitate level ordering, processing, and interpretation.
Results: A total of 9 patients were included. The majority were male (56%) with a median age of 2 years (range 3 months-23 years) and median weight of 16.8 kg (range 4.3-120 kg). 7 patients were on CRRT, 3 were on both CRRT and VA ECMO, and 2 patients were monitored due to MDRO. A total of 12 levels were drawn; 7 cefepime troughs in 5 patients and 5 meropenem troughs in 4 patients. The median cefepime and meropenem levels were 51.9 mcg/mL (range 5.3-143) and 27 mcg/mL (range 5-143), respectively. According to the protocol 5 levels (42%) were in goal range and 6 (50%) were supratherapeutic. Five patients (56%) had dose adjustments.
Conclusions: Only 42% of patients achieved therapeutic drug targets and most required dose adjustments while on extracorporeal therapies. Due to the small sample size, further studies are needed to validate these findings and to guide optimal beta-lactam targets. A pharmacist-driven protocol is one approach to ensure PK target attainment in critically ill pediatric patients.