The administration of sedatives during gastrointestinal (GI) endoscopy is considered a standard practice at many centers. Sedation during endoscopic procedures can improve patient comfort and practice efficiency, especially during therapeutic procedures [1]. However, sedation is a major contributor to complications during endoscopy [2–4]. Clinically insignificant complications, including transient hypotension, bradycardia, and microaspiration, can occur, but serious complications, such as sedation-induced death, neurologic sequelae, and aspiration pneumonia, may also occur. Many sedative agents are used in endoscopy, and combinations of low-dose benzodiazepine with opiates are traditionally used to achieve moderate levels of sedation [1, 2, 4]. The incidence of adverse events for these standard sedatives is very low [2, 5–8]. For instance, a large-scale retrospective study (21,011 patients) of midazolam for endoscopic sedation showed that the complication rate was only 1.35 % [2]. Over the past decade, propofol has become an increasingly popular agent for endoscopic sedation and has replaced standard sedation regimens largely because of its rapid onset and short duration of effect [9, 10]. Although propofol is an attractive sedative for endoscopic procedures, its adverse effects are more serious than those of benzodiazepines used with or without opiates. Debate also continues regarding its safe administration by non-anesthesiologists. However, the safety and efficacy of propofol for routine endoscopic procedures when administered by endoscopists as well as anesthesiologists have been reported in multiple trials [11– 13]. In addition, there are data supporting the safe use of propofol for advanced endoscopic procedures such as endoscopic retrograde cholangiopancreatography (ERCP) and/or endoscopic ultrasound (EUS) [14–19]. The incidences of complications, such as hypoxemia, bradycardia, and the need for airway intervention were not different between propofol and standard sedatives in previous studies. Rex et al. [20] reported complication rates for a very large sample of patients (646,080) who underwent endoscopist-directed propofol sedation, and found that endotracheal intubations, permanent neurologic injuries, and deaths only affected 11, 0, and four patients, respectively, while the proportion of cases requiring mask ventilation was a mere 0.1 %. The four deaths in this large cohort of patients occurred in patients with American Society of Anesthesiologists (ASA) [21] statuses of 3 or higher who were undergoing non-routine medical procedures, and three of the patients had serious underlying illnesses. These results indicate that the safety of propofol administration by endoscopists is comparable or superior to the published safety records of opioids and benzodiazepines administered by endoscopists for GI endoscopy [5–8]. The low incidence of complications may be attributed to new technologies such as computer-assisted personalized sedation. Additionally, high levels of monitoring may standardize the use of propofol by non-anesthesiologists in endoscopy [22–25]. The American College of Gastroenterology and the American Society for Gastrointestinal Endoscopy have published a joint statement supporting the safe use of non-anesthesiologist-administered propofol for GI endoscopy [26]. Even though the complication rates associated with the increasing use of propofol for endoscopic sedation are very low, it is important to identify patients and procedures at the highest risk of sedation-related complications. Several C. H. Choi (&) Department of Internal Medicine, Chung-Ang University College of Medicine, 224-1 Heukseok-dong, Dongjak-gu, Seoul 156-755, Republic of Korea e-mail: gicch@cau.ac.kr