Propofol vs. Midazolam-based Balanced Propofol for Nonanesthesiologist Moderate Sedation in Colonoscopy

Nonanesthesiologist administration of propofol for sedation is actually a field of growing interest for endoscopists, as demonstrated by recent American and European guidelines on this issue. Propofol is a hypnotic drug with rapid onset and offset of action. Used as a single agent, it is commonly titrated to deep sedation, whereas balanced propofol sedation (BPS), which combines propofol with small doses of a benzodiazepine and/or an opioid, can be successfully titrated to moderate sedation. However, nonanesthesiologists propofol administration remains controversial on account of the possibility of deep sedation/general anesthesia related adverse events. On the other hand, the use of longer elimination half-life drugs, such as opioids and benzodiazepines, may theoretically prolong sedation and recovery. Up to date, no study has addressed a head-to-head comparison of both regimens administered by non-anesthesiologists and titrated to moderate sedation. This study aims to evaluate the impact on propofol sedation of premedication with a fixed dose of midazolam (2 mg)2 minutes before propofol administration targeted to moderate sedation, in terms of depth of sedation, recovery times, safety and satisfaction. The onset of sedative action of midazolam has been reported to be 1-2.5 minutes and the peak effect of midazolam occurs 8-12 minutes. Taking into account that colonoscopy usually lasts a minimum of 15-20 minutes, our hypothesis is that synergy between propofol and midazolam may increase the depth of sedation through the initial phases of the procedure, diminishing propofol requirements, but not prolonging significantly recovery times.