How long is a piece of string? Issues inherent to the use of aggregate data include a variety of confounders. Using total dose administered will be misleading, particularly when comparing midazolam (usually administered as a once-off or intermittent bolus, and usually by the endoscopist - either a surgeon or gastroenterologist) with propofol (commonly administered as an infusion and in my country invariably by an anesthesiologist, so duration of procedure and personnel would have to be taken into account), I do a lot of sedations for endoscopy, but mostly for ERCP. When I am asked to sedate for colonoscopy, it is usually because the surgeon or gatroenterologist has had to abandon a previous procedure on the patient because of unwanted movement or pain/distress, or because the endoscopist is concerned that the patient might die during the procedure due to preexisting comorbidity. So operator and patient dependent factors would have to be incorporated in the original studies and corrections made for covariance, Even then, simply dividing average dose over average time would be a problem because both are likely to be skewed distributions. Added to which, while iv infusion of propofol (usually using target controlled infusion pumps these days) will generally result in a dose that matches duration, a single up-front dose of midazolam won't, and even a controlled infusion might result in a relative overdose for unexpectedly brief procedures.

Christopher C Rout Thank you for your answer. So typically no sedation for colonoscopy unless warranted by patient circumstances? Or does the surgeon or gastroenterology still use sedation, but given by nurse or surgeon/gastroenterologist, not monitored by anesthesiologist? A project in the future, I had a thought of stratifying data by non-anesthesiologist sedation vs. anesthesiologists sedation between proprofol vs. midazolam and looking at adverse cardiorespiratory events in surgical procedure e.g. ERCP. Do you think safety of propofol sedation by surgeon or nurse parallels safety of propofol sedation by anesthesiologists?

the use of propofol in these procedures is not usual

Jordan, commonly the endoscopist will use a stat dose of iv midazolam before the colonoscopy. Yelson's comment is correct. As to the safety of propofol in the hands of anyone but an anaesthetist/anesthesiologist, it is not a good idea. Remember Michael Jackson??

Christopher C Rout thank you for your time responding to my inquiries. oh yes, I remember MJ.