Korean J Pediatr 2010;53(9):817-823 • DOI: 10.3345/kjp.2010.53.9.817 819 studies demonstrating the adequacy of a brief fast. Ingebo et al.8) found that the fasting time poorly correlates with the volume of gastric fluid at the time of endoscopy and that clear fluids empty rapidly from the stomach in children. Schriener et al.9) found no difference in gastric volume or pH in children allowed clear liquids 2-3 hours before induction of anesthesia compared with conventional prolonged fasting. The following presedation dietary guidelines were adapted from the American Society of Anesthesiologists (ASA)10). Children should be offered clear liquids (this includes breast milk but not other milk or formula) up to 2-3 hours before sedation to avoid dehydration. Infants less than 6 months may receive formula up to 4-6 hours and clear liquids up to 2 hours before sedation. For patients older than 6 months, solids and nonclear liquids should be held for 6-8 hours before sedation. However, longer periods of fasting may be required for conditions such as achalasia and gastric outlet obstruction, because retained food in the upper gastrointestinal lumen may increase the risk of aspiration. According to the guidelines of the Korean Society of Gastroin- testinal Endoscopy11), the recommended fasting time is 4 hours in infants younger than 5 months old, 6 hours in infants 6-36 months old, and more than 8 hours in children older than 36 months old. Sedation and patient monitoring Nonsedated endoscopic procedures have been documented and assessed to be safe in motivated pediatric patients12). However, 80% of these patients would choose to be sedated if upper endoscopy should be repeated. The goals of sedation are maximal comfort, cooperation, amnesia, and loss of anxiety13). Children may require no sedation (diagnostic sigmoidoscopy in infants), intravenous sedation, or general anesthesia14). The so-called lytic or Toronto cocktail15) (the combination of intramuscular meperidine, promethazine, and chlorpromazine) has been used for many pediatric procedures. Nevertheless, the efficacy of its sedative effect is limited in GIE, and an intravenous sedation must be favored. Intravenous anesthetics are popularly used either with an endo- tracheal tube or with a natural airway. A short-acting agent such as propofol provides the advantage of a low incidence of airway obstruction and postoperative nausea and vomiting, as well as rapid recovery from general anesthesia with a low incidence of emergence delirium. The bolus dose of propofol is 1-3.5 mg/kg of body weight, followed by a titrated infusion of 0.1-0.3 mg/kg body weight/ minute. Powers et al.16) reported the prospective study results of the sedative effects of propofol in painful pediatric procedures. The patients required a mean bolus dose of 2.23 mg/kg and a mean titrating dose of 0.52 mg/kg/minute to achieve good sedation. The mean time until awakening was 14.9 minutes. Alternatively, a combination of ketamine, midazolam, and short-acting opioids also has the advantage of a low incidence of airway obstruction, although laryngospasm and delirium occur occasionally. Nasal oxygen supplementation is recommended17). Other drugs have been proposed, e.g., intramuscular ketamine, especially in children older than 7 years18). Chloral hydrate and atropine are frequently used in addition to a standard regimen of sedation. Midazolam combined with fentanyl produces rapid-onset anxiolysis, hypnosis, amnesia, and analgesia, with a relatively brief duration of action in children as well as in adults. This combination has a comfortable margin of safety against complete loss of consciousness. Following an initial dose, both midazolam and fentanyl are titrated using incremental doses every 3-5 minutes until an adequate level of sedation is achieved. The safety of fentanyl and midazolam intravenous sedation was reported in a prospective study of 1,578 procedures (758 upper endoscopies, 116 colonoscopies, and 352 combined procedures)19). This study noted serious adverse events (apnea) in only 2 children. Mild or moderate adverse events included oxygen desaturation <92% for less than 20 seconds in 100 (9%), vomiting in 64 (5%), agitation in 15 (1%), oxygen desaturation <92% greater than 20 seconds in 12 (0.7%), and rash in 8 (0.7%). No cardiopulmonary resuscitation or sedation reversal was required, and no patient required hospitalization. The authors concluded that intravenous sedation with fentanyl and midazolam is safe and that serious adverse events are rare. Another prospective study on the safety of propofol use in gastrointestinal endoscopy was reported20). Propofol was used as a sedative in 811 pediatric patients. Sedation was achieved in all procedures, and all but 3 (0.4%) were successful. None of the patients required intubation. Stridor with signs of upper airway obstruction occurred in 1.7%. Laryngoscopy was required to manage difficulties in introducing the gastroscope in 2.0%. Major desaturation requiring a short course of ventilation occurred in 0.7%, and transient desaturation that resolved spontaneously occurred in 12%. Administration of propofol by nonanesthesiologists for gastroscopic examinations in children was successful, but there was a small risk of potentially severe complications. A recent study reported that the combination use of propofol and midazolam in pediatric GIE was safe and effective as in adult patients21). The method of sedation for endoscopy in children is really