Intraoperative epidural analgesia does not reduce time of postoperative analgesic treatment compared to intravenous analgesia.

EDITOR: Thoracic epidural analgesia (TEA) is an effective technique in major abdominal surgery, but in daily clinical routine there is still no consensus on whether it should be used intraoperatively or only postoperatively. One benefit of intraoperative use of TEA should be lower analgesic requirements [1], but the conclusions have been inconsistent [2,3]. This double-blind randomized study was designed to compare two strategies that are often used in clinical practice: combined vs. balanced anaesthesia. We focused on the length of postoperative patientcontrolled epidural analgesia (PCEA), because PCEA is an expensive form of analgesic treatment with costs proportional to duration [4]. Our aim was to determine whether intraoperative TEA could reduce the time of postoperative epidural treatment. Ethics Board approval was obtained, and all patients gave written informed consent. All patients scheduled for major abdominal surgery by laparotomy were screened. Inclusion criteria were age above 18 yr, ASA physical status I-III and knowing the German language. Exclusion criteria were contraindications to epidural analgesia or use of opioid analgesics during the past month. Patients were randomized to either intraoperative combined epidural/general anaesthesia (ICEA) or balanced anaesthesia (control, non-ICEA). Postoperatively both groups received PCEA. All patients were administered midazolam 7.5 or 3.75 mg, according to weight and age, 45 min before transfer. Crystalloids were infused at 10 mL kg over 15 min. Then all patients underwent thoracic epidural catheterization using the midline approach and loss-of-resistance technique. Spinal placement was excluded by aspiration and the injection of a test dose of 2–3 mL bupivacaine 0.5%. Infusion of crystalloids was continued at 10 mL kg h. General anaesthesia was induced in both groups with 3.0–5.0 mg kg thiopental, 1.5–3.0 mg kg fentanyl, 0.1–0.2 mg kg cis-atracurium or 1.0–1.5 mg kg succinylcholine. The ICEA group received a 6–8 mL epidural bolus of sufentanil 1 mg mL and ropivacaine 0.16%, 30 min pre-incision. Anaesthesia and analgesia were maintained with isoflurane in oxygen/air and continuous epidural infusion of sufentanil 1 mg mL and ropivacaine 0.16% at 6 mL h. If necessary, additional epidural boluses of sufentanil/ropivacaine were administered or the rate of the epidural infusion was modified, to maintain a bispectral index (BIS) of 40–50 and clinical signs of sufficient anaesthesia. The control group received a combination of isoflurane in oxygen/air and fentanyl intravenously (i.v.). Shortly before the skin incision, 4–6 mg kg fentanyl was injected. During surgery, fentanyl injection was repeated as necessary to achieve a BIS of 40–50 and clinical signs of sufficient anaesthesia. TEA was started with an 8 mL bolus of 1 mg mL sufentanil in ropivacaine 0.16% at the closure of the abdomen. A continuous epidural infusion of the same sufentanil/ropivacaine solution was started immediately at 6 mL h. Postoperatively, both groups received continuous TEA (sufentanil 1 mg mL and ropivacaine 0.16%), starting with 6 mL h. Additional patient-controlled analgesia via bolus was possible (4 mL bolus, 20 min lockout). The block was tested and documented immediately after the patients awoke. The 24 h sufentanil/ropivacaine requirement, additional analgesic demand and complications of epidural analgesia were documented twice daily thereafter by staff blinded to the patients’ study assignments. Pain was evaluated every 4 h on a 0–100 numeric rating scale (NRS). A protocol algorithm was used for reducing the flow rate of epidural analgesics and for termination of postoperative PCEA. Correspondence to: Erika Schulte, Klinik für Anästhesiologie und operative Intensivmedizin, Charité, Campus Virchow Klinikum, Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany. E-mail: erika. schulte@charite.de; Tel: 149 30 450 551001; Fax: 149 30 450 551909