Propofol is an intravenous agent used commonly for the induction and maintenance of anesthesia, procedural, and critical care sedation in children. The mechanisms of action on the central nervous system involve interactions at various neurotransmitter receptors, especially the gamma-aminobutyric acid A receptor. Approved for use in the USA by the Food and Drug Administration in 1989, its use for induction ofanesthesia in children less than 3 years of age still remains off-label. Despite its wide use in pediatric anesthesia, there is conflicting literature about its safety and serious adverse effects in particular subsets of children. Particularly as children are not "little adults", in this review, we emphasize the maturational aspects of propofol pharmacokinetics. Despite the myriad of propofol pharmacokinetic-pharmacodynamic studies and the ability to use allometrical scaling to smooth out differences due to size and age, there is no optimal model that can be used in target controlled infusion pumps for providing closed loop total intravenous anesthesia in children. As the commercial formulation of propofol is a nutrient-rich emulsion, the risk for bacterial contamination exists despite the Food and Drug Administration mandating addition of antimicrobial preservative, calling for manufacturers' directions to discard open vials after 6 h. While propofol has advantages over inhalation anesthesia such as less postoperative nausea and emergence delirium in children, pain on injection remains a problem even with newer formulations. Propofol is known to depress mitochondrial function by its action as an uncoupling agent in oxidative phosphorylation. This has implications for children with mitochondrial diseases and the occurrence of propofol-related infusion syndrome, a rare but seriously life-threatening complication of propofol. At the time of this review, there is no direct evidence in humans for propofol-induced neurotoxicity to the infant brain; however, current concerns of neuroapoptosis in developing brains induced by propofol persist and continue to be a focus of research.
OBJECTIVES: Emergence agitation (EA) is a common and troublesome problem in pediatric patients recovering from general anesthesia. The incidence of EA is reportedly higher after general anesthesia maintained with sevoflurane, a popular inhalational anesthetic agent for pediatricpatients. We conducted this prospective, randomized, double-blind study to test the effect of an intravenous ultra-short-acting barbiturate, thiamylal, administered during induction of general anesthesia on the incidence and severity of EA in pediatric patients recovering from Sevoflurane anesthesia. METHODS: Fifty-four pediatric patients (1 to 6 years of age) undergoing subumbilical surgeries were randomized into 2 groups. Patients received either intravenous thiamylal 5mg/kg (Group T) or inhalational Sevoflurane 5% (Group S) as an anesthetic induction agent. Following induction, general anesthesia was maintained with Sevoflurane and nitrous oxide (N2O) in both groups. To control the intra- and post-operative pain, caudal block or ilioinguinal/iliohypogastric block was performed. The incidence and severity of EA were evaluated by using the Modified Objective Pain Scale (MOPS: 0 to 6) at 15 and 30 min after arrival in the post-anesthesia care unit (PACU). RESULTS: Fifteen minutes after arrival in the PACU, the incidence of EA in Group T (28%) was significantly lower than in Group S (64%; p = 0.023) and the MOPS in Group T (median 0, range 0 to 6) was significantly lower than in Group S (median 4, range 0 to 6; p = 0.005). The interval from discontinuation of Sevoflurane to emergence from anesthesia was not significantly different between the 2 groups. CONCLUSIONS: Thiamylal induction reduced the incidence and severity of EA in pediatric patients immediately after Sevoflurane anesthesia.
BACKGROUND: This study was performed to compare the incidence of emergence agitation (EA) between inhalation and intravenous anesthesiainduction in children after sevoflurane anesthesia. METHODS: In this prospective and double-blind study, 100 children aged 3 to 7 years were enrolled. Subjects were randomly assigned to the sevoflurane (Group S) or thiopental (Group T) anesthesia induction groups. Anesthesia was induced using 8% sevoflurane and 4-6 mg/kg thiopental in Groups S and T, respectively. Anesthesia was maintained with nitrous oxide and sevoflurane. The children were evaluated at 5 and 20 min after arrival in the postanesthesia care unit (PACU) with a four-point agitation scale and the Pediatric Anesthesia Emergence Delirium scale. The incidence of EA and administration of the rescue agent were recorded. RESULTS: The incidence of EA was significantly lower in Group T compared to Group S at 5 min after PACU arrival (3/49 patients, 6% vs. 12/47 patients, 26%, P = 0.019). However, there was no difference between the two groups at 20 min after PACU arrival (23/49 vs. 19/47 patients in Group T vs. Group S, P = 0.425). The overall incidence of EA was 60% (28/47 patients) in Group S and 41% (20/49 patients) in Group T (P = 0.102). The number of children who received propofol as a rescue agent was significantly lower in Group T (Group S: 14/47 vs. Group T: 5/49, P = 0.031). CONCLUSIONS: Intravenous anesthesia induction with thiopental reduced the incidence of EA in the early PACU period compared to inhalation induction with sevoflurane in 3- to 7-year-old children undergoing sevoflurane anesthesia.