(989) Piperacillin-Tazobactam Levels in Burn Injury and Augmented Renal Clearance

Introduction: Augmented Renal Clearance (ARC) is characterized by a supraphysiologic renal clearance defined as a creatinine clearance (CrCl) of greater than 130 mL/min in men or 120 mL/min in women. Patients with burns, neurologic injuries, and trauma have a well described risk of ARC . Other risk factors for ARC include age < 50 years, male sex, and a serum creatinine (SCr) < 0.7 mg/dL. The burn population is particularly susceptible to dynamic changes in clearance, and the onset, duration, and fluctuations of ARC are not well described. Renally cleared antibiotics require significant dose adjustments in those with ARC to avoid suboptimal dosing and therapeutic failure. Likewise, adjustment is required when ARC is no longer present to avoid undue toxicity. We report two levels of steady state piperacillin (PIP) levels while on continuous infusion piperacillin tazobactam (TZP) in a burn patient with and without ARC during a treatment course.

Description: A 40-year-old female with no past medical history presented with a 22% total body surface area thermal burn and blunt trauma from a gas station explosion. Risk factors for ARC included age, burn injury, trauma, and low SCr. A 12-hour urine collection creatinine clearance value (CrCl-12) of 320 mL/min measured on day 1 (D1) with a SCr of 0.57 mg/dL confirmed ARC. Her hospital course was complicated by Pseudomonas aeruginosa VAP and burn wound cellulitis requiring a continuous infusion of TZP 22.5 g over 24 hours on D3. On D5 of therapy, SCr increased to 0.75 mg/dL triggering a PIP level to be collected with a 12-hour urine collection (CrCl-12) resulting at 96 mL/min. The corresponding piperacillin level was 117 mcg/mL. The patient developed ARC again proven on D11, with a SCr of 0.52 mg/dL, a CrCl-12 of 183 mL/min, and a corresponding PIP level of 32 mcg/mL. No dose adjustments were made during the treatment course and infection resolved with therapy.

Discussion: The prevalence of ARC in burn patients is high but poorly characterized. This unique case highlighted two PIP levels for a patient with fluctuations of ARC during hospitalization and emphasizes the need for repeat CrCl-12 assessments to guide TZP dosing.