Evaluation of gastric emptying in severe, burn-injured patients

Objective: The aim of this study was to evaluate the possible effect of a severe burn on gastric emptying by determining the absorption kinetics of orally administered acetaminophen. Design: A prospective, controlled study. Setting: A ten-bed burn center in a 1,300-bed university hospital. Patients: Ten adult patients suffering from second-degree burn involving >20% of total body surface area and 20 normal, healthy volunteers who acted as controls. Interventions: Patients received routine treatment such as nutritional support and cimetidine. However, opiates were stopped for at least 12 hrs before the start of the study, and nonsteroidal anti-inflammatory drugs as alternatives were used. After an 8-hr fast, the subjects ingested 0.5 g acetaminophen with 200 mL of water. The plasma concentrations of acetaminophen were determined by high-performance liquid chromatography, and the absorption kinetics was estimated from determination of time to reach the maximum plasma concentration, the maximum plasma concentration, and the area under the plasma concentration-time curve. Measurements and Main Results: The mean time for reaching the maximum plasma concentration was 33 ± 24 (SD) mins in patients and 39 ± 24 mins in the healthy volunteers. The mean area under the plasma concentration-time curve from time 0 to 120 mins and the mean maximum plasma concentration were 556 ± 190 μg/mL/min and 9.5 ± 3.5 μg/mL in patients, and 539 ± 131 μg/mL/min and 7.8 ± 2.8 μg/mL in volunteers, respectively. There was no statistical difference between groups in the time to reach the maximum plasma concentration, the area under the plasma concentration-time curve from time 0 to 120 mins, and the maximum plasma concentration. The time for reaching the maximum plasma concentration was not correlated with the severity of the burn (% area of burn) and the duration of healing (days) after burn. Conclusions: We conclude that severe burn injury does not affect the kinetics of gastric emptying, and that 200 mL of water ingested 2 hrs before anesthesia is quite safe in severely burned patients. Also, the absorption kinetics of acetaminophen was not altered by burn injury.