How to control propofol infusion in pediatric patients undergoing gamma knife radiosurgery.

Abstract

Although Gamma Knife radiosurgery (GKS) is commonly performed under local anesthesia, general anesthesia is sometimes required. The authors previously reported a remote-controlled patient management system consisting of propofol-based general anesthesia with a target-controlled infusion (TCI) that we designed for pediatric GKS. However, a commercially available propofol TCI system has age and weight limitations (<16 years and <30 kg). We examined a manually controlled regimen of propofol appropriate for pediatric GKS. A pharmacokinetic model of the TIVA Trainer© with Paedfusor's parameter was used. A manually controlled infusion scheme to achieve a sufficient level of propofol for pediatric GKS was examined in five models ranging from 10 to 30 kg. Following a loading dose of 3.0 mg/kg, the combination of continuous infusion of 14, 12, 10, and 8 mg/kg/h resulted in a target concentration of 3.0-4.0 μg/ml, the required level for pediatric GKS. Propofol titration is a key issue in GKS. Manual infusion is less accurate than TCI, but the combination of a small bolus and continuous infusion might be a substitute. Considering the characteristics of propofol pharmacokinetics in children, co-administration of opioids is recommended.