Glomerular Hyper- and Hypofiltration During Acute Circulatory Failure: Iohexol-Based Gold-Standard Descriptive Study.

Area of Science:

• Nephrology
• Critical Care Medicine
• Pharmacokinetics

Background:

• Acute circulatory failure commonly leads to kidney dysfunction.
• Accurate assessment of glomerular filtration rate (GFR) is crucial for managing critically ill patients.
• Existing methods for GFR estimation may be unreliable in this population.

Purpose of the Study:

• To evaluate the feasibility of measuring iohexol plasma clearance for estimating GFR in early acute circulatory failure.
• To characterize the prevalence of renal hypofiltration in this patient group.

Main Methods:

• Prospective, interventional, multicenter study in three French ICUs.
• Administered a non-toxic dose of iohexol intravenously to patients within 12 hours of ICU admission.
• Measured plasma iohexol concentrations from serial blood samples over 24 hours and calculated clearance using a population pharmacokinetic model.

Main Results:

• Iohexol clearance was successfully calculated in 85 out of 99 patients.
• Median iohexol clearance was 31 mL/min, indicating significant hypofiltration in 48% of patients.
• Urinary creatinine clearance underestimated renal impairment in 50% of cases, with a bias of -18.1 mL/min compared to iohexol clearance.

Conclusions:

• Iohexol clearance measurement is feasible even in unstable critically ill patients.
• Normal kidney function is rare during the early stages of acute circulatory failure.
• Urinary creatinine clearance is frequently inadequate for detecting renal impairment in this setting.