Glomerular filtration rate is increased in burn patients

Area of Science:

• Nephrology
• Trauma Medicine
• Pharmacokinetics

Background:

• Urinary output is a common but insufficient indicator of kidney function in burn patients.
• Assessing glomerular filtration rate (GFR) accurately is crucial for managing burn trauma.

Purpose of the Study:

• To evaluate glomerular filtration rate (GFR) using iohexol clearance in adult burn patients during the first week post-injury.
• To compare GFR measurements between a one-compartment and a two-compartment kinetic model.
• To compare GFR in burn patients to healthy controls.

Main Methods:

• Nineteen adult burn patients received intravenous iohexol injections every other day.
• Plasma iohexol concentrations were measured over 4 hours post-injection.
• Clearance (CL) was calculated using a one-compartment kinetic model and compared to a two-compartment model and healthy controls.

Main Results:

• Early after burn (day 1), median iohexol CL was significantly higher in burn patients (155 mL/min/1.73 m²) compared to controls (117 mL/min/1.73 m²).
• By day 7, CL values in burn patients approached the expected baseline (mean 122 mL/min/1.73 m²).
• A correction factor of 0.9 was established for one-compartment model calculations to align with two-compartment model results.

Conclusions:

• Iohexol clearance indicates an early increase in GFR following major burn injury.
• This elevated GFR may be associated with the period of vascular dysfunction and increased cardiac output characteristic of early burn trauma.
• The precise mechanisms driving this early hyperfiltration require further investigation.