Issues of consent in colonoscopy: if a patient says 'stop' should we continue?

Colonoscopy is generally performed under intravenous sedation, which may alter a patient's responses and perception. What should be done if, during the procedure, a patient withdraws the consent previously given? The views of gastroenterologists and patients were ascertained by mailing questionnaires to 100 members of the British Society of Gastroenterology and to 100 patients who had undergone colonoscopy with intravenous sedation. Only 1 of 59 eligible consultants who replied said they would stop the procedure after a single request, but a further 51 would stop if repeatedly asked to do so. Of the remaining 7 who would complete the procedure, 1 nevertheless believed that a sedated patient is capable of making a rational decision. Of the 51 patients who returned a usable questionnaire, 25 thought that the procedure should be stopped immediately following a request, while 26 felt that the doctor should continue. The divergent and sometimes inconsistent views found in this study highlighted the need for further clarification of the issue of informed consent for procedures conducted with the patient under sedation.