(986) The Impact of Extending Beta-Lactam Infusions on Intravenous Access Requirements

Introduction: As time-dependent antimicrobials, delivery of beta-lactams via extended infusion (EI; over >3 hours) has been recommended over traditional dosing (TD; over 30-minutes) to optimize outcomes in the critically ill. EI beta-lactam delivery may occupy an intravenous line for 12 or more hours per day, rather than the traditional 2 hours or less. We hypothesized that transitioning beta-lactam delivery from TD to EI would increase the number of IV access sites needed.

Methods: This was a retrospective cohort study of patients at a single academic medical center treated with cefepime, piperacillin-tazobactam, or meropenem from 2021 to 2024 who underwent therapeutic drug monitoring (TDM) as part of routine clinical care. All patients were initially on TD. Patients who transitioned from TD to EI in response to TDM results (EI group) were matched 1:1 to patients who remained on TD after TDM results (TD group). Matching criteria included drug, gender, vasopressor use, and ICU subtype. The primary analysis compared IV access (total number of available lumens for medication administration) in the 24-hours before TDM to the 48-hours after TDM. Between group comparisons used Wilcoxon-rank Sum test. Within group change used paired methods.

Results: 86 patients were included (43 TD and 43 EI). Most patients were hospitalized in the cardiothoracic surgical (N = 20; 23%) or medical ICUs (N = 20; 23%) and 44 (51%) were on vasopressors. The median (IQR) total number of available lumens in the 24-hours before and in the 48-hours after TDM were similar between groups [24-hours before: TD 3 (2, 5) vs EI 4 (3, 5); P = 0.22; 48-hours after: TD 3 (2, 4) vs EI 4 (3, 5); P = 0.05]. There was no difference in the intra-individual change in the total number of lumens between group [TD: 0, (-1,0), EI: 0, (0,0); P = 0.26]. Secondary analyses indicated no difference in the number of antibiotic doses delayed between groups (P = 0.14 ), nor the number of drug incompatibilities (P = 0.91).

Conclusions: The delivery of beta-lactams via EI in a critically ill population was not associated with a need for more IV access compared to TD. IV access should not be a primary concern limiting the use of EI beta-lactams when clinically indicated.