Adverse events of conscious sedation using midazolam for gastrointestinal endoscopy

Background: This study was conducted to identify the types and incidence of adverse events associated with midazolam, which is the most widely used drug to induce conscious sedation during gastrointestinal endoscopy, and to analyze the factors associated with hypoxemia and sedation failure. Methods: Of 87,740 patients who underwent gastrointestinal endoscopy between February 2015 and May 2017, the electronic medical records of 335 who reportedly developed adverse events were retrospectively reviewed, and analysis was performed to determine the risk factors for hypoxemia and sedation failure, the two most frequent adverse events among those manifested during gastrointestinal endoscopy. Results: The overall adverse event rate was 0.38% (n = 335); hypoxemia was most frequent, accounting for 40.7% (n = 90), followed by sedation failure (34.8%, n = 77), delayed discharge from the recovery room (22.1%, n = 49), and hypotension (2.2%, n = 5). Compared with the control group, the hypoxemia group did not show any significant differences in sex and body weight, but mean age was significantly older (P < 0.001) and a significantly lower dose of midazolam was administered (P < 0.001). In the group with sedation failure, the mean rate was higher in men (P < 0.001) and a significantly higher dose of midazolam was administered (P < 0.001), but no age difference was found. Conclusions: Midazolam-based conscious sedation during gastrointestinal endoscopy can lead to various adverse events. In particular, as elderly patients are at higher risk of developing hypoxemia, midazolam dose adjustment and careful monitoring are required in this group. Keywords: Conscious sedation; Gastrointestinal endoscopy; Hypoxemia; Midazolam