When to let the fellow do the procedure.

Background And Aims: In complex endoscopies, the initial attempt is often associated with the highest success and subsequent attempts to achieve the same outcome have a higher failure rate. An attending physician needs to decide how the ultimate success may become compromised by letting a fellow start the procedure. A decision analysis is aimed to shed light on this issue.

Methods: A formula is derived to calculate the point in time when to switch the instrument between an attending and fellow physician. This time point is determined by the ratio of benefit to the patient over benefit to the fellow, the difference in probability of achieving success by an attending versus a fellow, and the decline in probability of success during consecutive procedural attempts.

Results: The attending should undertake the first attempts at doing the procedure, if the fellow is inexperienced and the difference in success rate between attending and fellow is still large, if the procedure is risky, and if the benefit of a successful outcome outweighs the benefit of a teaching experience to the fellow. Vice versa, fellows should take the lead, if they have become well trained and the difference in their procedural success rate compared with the attendings' has grown relatively small. The fellow should also be trusted to lead in all instances where the risk to the patient is small.

Conclusions: Such rules can serve as general guidance when to pass the endoscope to a fellow physician. Medical decision analysis is helpful to enlighten complex situations during training of fellows.