The Impact of Two Different Intraoperative Analgesia Techniques on Post-operative Outcome After Hepato-pancreato-biliary Surgery

BACKGROUND Inadequate pain control after abdominal procedures might result in increased morbidity, length of stay, and delay in overall recovery. Epidural analgesia is currently an accepted technique in major abdominal surgery [1-4]. Postoperative coagulation disturbances related to liver surgery, even in patients with normal preoperative coagulation undergoing uncomplicated hepatectomy, raises concerns about the safety of postoperative analgesia administered through an epidural catheter. Coagulation changes after liver surgery and the possible increased risk of bleeding complications, including spinal hematoma, have limited the use of epidural analgesia [5-7].

A range of alternative analgesic techniques can be used for major liver or pancreatic resections. A single dose of intrathecal morphine (ITM), administered immediately before surgery, followed by postoperative patient-controlled morphine analgesia (IV PCA), has been demonstrated to provide satisfactory postoperative pain relief which was not inferior to continuous epidural analgesia up to 48 hours after hepatic surgery [8, 9]. Another study in patients undergoing hepato-pancreato-biliary surgery has shown that ITM, compared with thoracic epidural analgesia, is associated with a reduced incidence of postoperative hypotension, intravenous fluid requirements, hospitalization, and incidence of respiratory complications [10]. Alternatively, few reports have demonstrated the advantage of using continuous administration of intravenous (IV) short-acting opioids, such as remifentanil. This regime has been shown to facilitate earlier extubation, to provide excellent intraoperative hemodynamic stability and rapid recovery [11]. Nevertheless, as remifentanil is rapidly metabolized, there is a need at the end of surgery to initiate another post-operative pain strategy to prevent unacceptable pain in the post-operative period. This has been accomplished by the administration of morphine which has been shown to provide an effective postoperative pain control (a bolus followed by IV PCA).

To date, these two analgesic regimens (ITM vs. continuous IV remifentanil) are frequently used in our institution. Nevertheless, there is no data in the literature to show benefit from one regimen over the other. We therefore wish to determine whether there is a difference in analgesic efficacy between the two techniques as optimizing perioperative pain relief in this rapidly expanding surgical field is of utmost importance.

METHODS Study design The study will be conducted as a prospective, randomized, double blinded one. Intra-operatively, anesthesia and surgical management will follow the routines. Intravenous fluid and blood supplements will be administered according to the anesthesiologists' decision. Also, the decision to extubate the patient at the end of surgery will be left to the discretion of the anesthesiologist. Post-operatively, all patients will be transferred to the ICU or to the recovery room for at least 24 hours. Patients may also be transferred first to the recovery room and than to the ICU. These are the routines in our hospital.

Consented patients will be randomly allocated to two groups by a computer-generated list: