Randomized Comparison of Two Application Procedures: Programmed Intermittent Epidural Bolus in Patient-controlled Epidural Analgesia (PCEA) Versus Continous PCEA in Abdominal Oncological Surgery

Usually, patient controlled epidural analgesia (PCEA) is performed with a constant background infusion and patient-controlled bolus applications. An alternative approach is to give boluses at a regular rate for basic medication, instead of the continuous background infusion, maintaining the same amount of medication delivered per hour, (Programmed Intermittent Epidural Bolus injection; PIEB). In both cases, the patient has the option to trigger additional boluses. PIEB has been applied successfully in pain relief for lumbar epidural anesthesia in obstetrics, with better quality of analgesia and less total volume of local anesthetic required. It is assumed that the higher pressure in the epidural space with bolus injection results in a better and more uniform spread of the local anesthetic. In this study the PIEB-mode will be applied in major gynecological and abdominal surgery. In order to address the possibility that the different types of surgery result in different degrees of postoperative pain, the patients are stratified in three groups and randomized within these groups (Wertheim, Whipple, major colon surgery).