Well-performed studies on sedation versus general anaesthesia using a randomized controlled trial design with observer blinding will contribute to improve the decision-making for the optimal comfort measures in minimally invasive procedures. At our knowledge such a randomized controlled trial has not been reported before. The investigators hypothesize that deep sedation without tracheal intubation will achieve similar success rates for ERCP as general anaesthesia and will have similar rates of harmful postoperative effects.