Continuous basal infusion versus programmed intermittent bolus for quadratus lumborum block after laparoscopic colorectal surgery: a randomized-controlled, double-blind study.

BACKGROUND: Quadratus lumborum block (QLB) has recently attracted attention as a part of multimodal analgesia after abdominal surgery. It has been shown that programmed intermittent boluses of local anesthetic can produce better analgesia and wider sensory blockade compared with continuous basal infusion with some peripheral nerve blocks. The present study was conducted to see if this theory holds true for QLB in patients undergoing laparoscopic colorectal surgery. METHODS: Fifty patients undergoing laparoscopic colorectal surgery were divided into 2 groups to receive continuous basal infusion (group C) or programmed intermittent boluses (group PIB) of local anesthetic. After surgery, patients received the posterior approach to QLB and a catheter was introduced bilaterally. Patients in group C received a continuous infusion of 0.15% levobupivacaine at 3 ml/h, and those in group PIB received a bolus of 12 ml every 4 h. All patients received intravenous patient-controlled analgesia using fentanyl. Measurements were taken for cumulative fentanyl consumption, pain scores, cutaneous sensory blockade, analgesic requirements, and adverse events for 46 h. RESULTS: The primary outcome of cumulative fentanyl consumption at 22 h showed no significant difference between the groups [group C: 11.9 (11.2-15.5) µg/kg (median (interquartile range)) and group PIB: 12.3 (11.6-15.3), p = 0.473]. Pain scores, demands for rescue analgesics, and spread of cutaneous sensory blockade were similar for the two groups. CONCLUSION: Programmed intermittent boluses of local anesthetic for continuous QLB did not produce better analgesia or wider sensory blockade compared with continuous basal infusion in patients undergoing laparoscopic colorectal surgery.