ObjectiveTo determine if increased gut permeability within 48 hrs after burn injury correlates with the extent of injury, before sepsis and pulmonary disorders have complicated the clinical course.DesignNonrandomized, controlled study.PatientsConsecutive patients admitted with burn injuries on >20% of body surface area.InterventionsIntestinal absorption and renal excretion of polyethylene glycol 3350 was used as the macromolecule to determine gut permeability; polyethylene glycol 400 intestinal absorption was used as an internal control for abnormal motility and malabsorption. Polyethylene glycol 3350 (40 g) and polyethylene glycol 400 (5 g) were administered enterally.Measurements and Main ResultsGut permeability was significantly increased early after the injury. The patients excreted 0.56 ± 0.34% (n = 11) of polyethylene glycol 3350, compared with the amount (0.12 ± 0.04%) (p< .05) previously reported in normal volunteers. There was no significant difference in the excretion of polyethylene glycol 400 in the patients (27.0 ± 4.6%, n = 11) vs. the normal volunteers previously reported (26.3 ± 5.1%, n = 12), suggesting normal intestinal motility and absorption. The percentage of excretion of polyethylene glycol 3350 correlated with the percentage body surface burned; patients with smaller injuries excreted 0.32 ± 0.17% (n = 6), which was greater than normal and less than those values from patients with larger injuries, 0.84 ± 0.25% (n = 5) (p< .001 by Tukey test).ConclusionsUsing our newly developed method to separate and quantify polyethylene glycols in urine, gut permeability was found to be increased early after burn injury, which confirms a previous study using lactulose as the permeability probe. Furthermore, this increased gut permeability to polyethylene glycol 3350 correlated with the extent of the burn injury.