What is New in Augmented Renal Clearance in Septic Patients?

Abstract

Purpose of Review In this narrative review encompassing relevant scientific publications regarding critically ill patients in the last 5 years, we discuss key questions regarding the concept, pathophysiology, identification, epidemiology, and implications of augmented renal clearance (ARC) in the treatment of sepsis. Recent Findings Mathematical estimates of renal function show low accuracy when evaluating renal function in the intensive care unit, jeopardizing the correct dosing of antimicrobials. The description of ARC in critically ill patients in several, distant geographical areas worldwide reveals that this condition is more frequent than anticipated. Several new risk factors have been recently reported, needing future confirmation. Pathophysiology is still largely unknown; however, intact kidney physiology, inflammatory mediators, and tubular secretion seem to play a role. Several studies have demonstrated the association between ARC and subtherapeutic levels of several β-lactams, vancomycin, and fluconazole. Lately, there have been recommendations of dosage regimen adjustments for patients with ARC, namely, through increases in total daily dose or prolonged infusion for various antimicrobials. Literature is scarce describing the influence of ARC on clinical outcomes of patients receiving antibiotics, and results are contradictory. Summary Growing body of evidence supports that measured creatinine clearance based on time-defined urine output is strongly recommended for the identification of ARC and for reliable evaluation of its prevalence and risk factors. Clinicians should be alert for the need to use off-label dosing of antimicrobials in septic patients showing ARC. Concise recommendations for antibiotic dosage regimens, based on clinical data, are still needed.

Comparative analysis of two-hour creatinine clearance and the C-G formula for renal function assessment in critically ill patients

“…Moreover, in critically ill patients with ARC, both the CG formula and MDRD formula tend to underestimate GFR when compared to 8-h or 24-h creatinine clearance [ 3 ]. Baptista elucidated in the most recent review that, for critically ill patients, the estimated GFR derived from formulas exhibits a tenuous correlation with measured GFR, emphasizing the superior accuracy of utilizing measured GFR within the ICU context [ 29 ].…”

“…The incidence of ARC is notably high, predominantly manifesting in patients experiencing trauma, severe infection, or major surgery, consistent with findings from prior investigations. Earlier research has demonstrated ARC incidence rates ranging from 22.1 % to 65.1 %, with identified risk factors encompassing age, male gender, trauma, severe infection, and vasopressor usage [ 29 ]. Notably, in Udy's study, GFR was estimated using 8-h creatinine clearance.…”