Augmented creatinine clearance in traumatic brain injury.

Area of Science:

• Nephrology
• Critical Care Medicine
• Trauma Surgery

Background:

• Traumatic brain injury (TBI) management often involves interventions like hypertonic saline and norepinephrine infusions to maintain cerebral perfusion pressure (CPP).
• The impact of these interventions on renal function, specifically creatinine clearance (CrCl), in TBI patients is not fully understood.

Purpose of the Study:

• To investigate whether creatinine clearances (CrCls) are significantly augmented in patients with TBI undergoing active management of CPP.
• To determine the persistence of augmented CrCls after cessation of CPP-directed therapy.

Main Methods:

• An observational cohort study included TBI patients over 16 years old with normal baseline serum creatinine.
• Eight-hour urinary collections were performed to measure CrCl during and after active CPP management.
• Augmented CrCl was defined using sex-specific thresholds (>150 mL/min/1.73 m² in women, >160 mL/min/1.73 m² in men).

Main Results:

• Seventeen out of 20 (85%) TBI patients demonstrated augmented CrCls during CPP therapy, with a mean maximum CrCl of 179 mL/min/1.73 m².
• CrCl returned to a mean of 111 mL/min/1.73 m² after intensive care unit (ICU) discharge (P < 0.001).
• Norepinephrine, saline loading, mean arterial pressure, and central venous pressure were associated with augmented CrCl.

Conclusions:

• Augmented CrCl is a frequent finding in TBI patients receiving active CPP management.
• Elevated CrCl levels can persist even after the discontinuation of CPP-directed therapies.
• Further research is necessary to understand the clinical implications of these augmented CrCls on the pharmacokinetics of renally excreted drugs in TBI patients.