Continuous epidural infusion (CEI) is the standard application setting for epidural infusion. A new mode, the programmed intermittent epidural bolus (PIEB) technique, showed reduced local anesthetic (LA) consumption and improved analgesia in obstetric analgesia. Goal of this trial was to evaluate the effects of PIEB versus CEI [combined with patient-controlled bolus (PCEA)] on LA consumption and pain scorings in major abdominal cancer surgery.

This is the first randomized triple-blinded trial (patient blind, researcher blind, blinded statistician) to investigate the effects of PIEB versus continuous epidural infusion (CEI) for postoperative analgesia in combination with PCEA option after major open abdominal and gynaecological (i.e., pancreatic, colonic, ovarian, and cervical) cancer surgery on LA consumption (primary endpoint) and postoperative pain management including opioid consumption and potential side effects (secondary endpoints).

Following ethical approval, patients scheduled for major abdominal cancer surgery under general anesthesia in combination with epidural analgesia were randomized to receive either a PIEB mode of 6 mL/h or a CEI mode set at 6 mL/h of ropivacaine 0.2%, both combined with a PCEA mode set at a 4 mL bolus. LA consumptions and pain scorings were documented until the second postoperative evening.

Postoperative Analgesia

Eighty-four datasets were analyzed (CEI: n = 40, PIEB: n = 44). Regarding the primary endpoint, cumulative LA PCEA bolus volumes until day 2 differed significantly between the groups [PIEB 10 mL (2–28 mL) versus CEI, 28 mL (12–64 mL), median (25th–75th percentiles), p = 0.002]. Overall, LA consumption volumes were significantly lower in the PIEB group versus in the CEI group [PIEB: 329 mL (291–341 mL) vs. CEI: 350 mL (327–381 mL), p = 0.003]. Pain scores were comparable at each time point.

This trial demonstrates reduced needs for PCEA bolus in the PIEB group. There were no clinically relevant benefits regarding morphine consumption, pain scorings, or other secondary outcome parameters.

The research did not perform an economic analysis of the different types of epidural infusion. PIEB modes are restricted to specific types of commercially available electronic pumps, which potentially might result in higher costs in comparison with other pump systems.
Moreover, the programmed intermittent bolus application is applied by the pumps with a higher pressure than in continuous infusion technique, resulting in higher energy consumption as compared with the constant infusion. In this triple-blinded randomized trial, local anesthetic consumption was significantly lower in patients with a PIEB versus a standard CEI.

However, overall pain scores were comparable, as were side effects and patient satisfaction scorings. From a clinical perspective, the overall reduction of local anesthetic consumption was mild comparing the PIEB mode with the CEI mode. Hence, the use of PIEB mode in thoracic epidural analgesia after major abdominal surgery should be further evaluated with regard to optimized programmed bolus volumes and time intervals and outcome before widespread implementation in the clinical setting.