Antibiotic dosing in critically-ill patients with bacteremia and ARC versus critically-ill patients without ARC

Author(s):
Martin Gordon; Evan Lantz; Caleb Mentzer; Sarah Frye

Background:

Augmented renal clearance (ARC) is a phenomenon observed in critically-ill patients, leading to supraphysiologic drug clearance and concern for suboptimal antibiotic concentrations. The purpose of this study was to compare the clinical outcomes of our institutional protocolized antibiotic dosing regimen in critically-ill patients with bacteremia and ARC compared to critically-ill patients without ARC.

Hypothesis:

We hypothesized that poorer outcomes would be associated with a renally dosed antibiotic regimen protocol for patients with bacteremia and augmented renal clearance compared to patients with bacteremia and no augmented renal clearance.

Methods:

We performed a retrospective study comparing the efficacy of an institutional protocolized antibiotic dosing regimen in critically-ill patients with bacteremia and ARC compared to critically-ill patients without ARC. The primary endpoint was in-hospital mortality. Secondary outcomes were ICU mortality, days requiring mechanical ventilation, ICU length of stay (LOS), hospital LOS, development of drug resistance to index antibiotic, and documented clearance of blood cultures within 72 hours.

Results:

There were 75 patients included in this study. 20% of patients in the ARC group died in the hospital vs 31% in the non-ARC group (p=0.26). The results for the ARC group versus the non-ARC group for the secondary outcomes of ICU mortality (20% vs 26%, p=0.56), ICU LOS (14.7 days vs 7 days, p=0.07), hospital LOS (28.3 days vs 21.6 days, p=0.03), days requiring mechanical ventilation (14 days vs 12 days, p=0.49), duration of antibiotic therapy (7.5 days vs 9.0 days, p=0.39), documented clearance of blood cultures within 72 hours (41% vs 33%, p=0.56) and the development of drug resistance to the index antibiotic (0% vs 0%, p > 0.99) were also calculated.

Conclusions:

Among critically-ill patients with bacteremia and ARC, there was no significant difference in in-hospital mortality compared to critically-ill patients without ARC. There was a significant difference in hospital LOS, with a shorter duration of stay for the non-ARC group. There was no development of multi-drug resistant organisms in either group.