(801) Adjunctive Quadratus Lumborum Block to Reduce Opioid Use after Cesarean Delivery

Peripheral nerve blockade in addition to neuraxial morphine (NM) and enhanced recovery protocols may improve analgesia following cesarean delivery (CD). We assessed if adjunctive quadratus lumborum (QL) block will reduce the oral morphine equivalent (OME) consumption for the first 24 and 48 hours after CD.


Study Design:

Retrospective cohort comprising patients enrolled in a single tertiary center RCT of reduced NM dose (50mcg NM+QL block vs 150mcg NM+QL block) aimed at minimizing OME use and NM adverse effects after scheduled CD; and a historical cohort who received 150mcg of NM without a QL block. Patients in the RCT were excluded for preeclampsia, insulin-treated diabetes, placental abnormalities or history of opioid use disorder. Intervention groups were 50mcg NM+QL, 150mcg NM+QL, and 150mcg NM without QL block. Comparison groups were 150mcg NM+QL vs. 150mcg NM without QL and 50mcg NM+QL vs. 150mcg NM without QL. Primary outcomes were total OME on postoperative days 1 and 2 and opioid use 24hr prior to discharge. Secondary outcomes included total OME, opioid adverse effects, and pain scores. Linear regression and log-binomial models were used to calculate risk differences and 95% confidence intervals between groups.

Results:

Of 243 patients were included, 43 were in the 50mcg NM+QL arm, 42 in the 150mcg NM+QL arm, and 158 in the 150mcg NM without QL arm. Patients in the 150mcg NM without QL arm delivered earlier and had higher rates of preeclampsia, pregestational diabetes and ASA class. There were no significant differences in the primary outcomes between all comparison groups. QL block was associated with lower parenteral opioid use and lower pain scores in the first 6 hours after surgery for patients receiving 150mg NM. There were no other significant differences in secondary outcomes.

Conclusion:

Routine QL block in addition to multimodal pain management and NM did not significantly reduce total OMEs after scheduled CD however, it reduces parenteral opioid use and improve pain control in the immediate post cesarean period. Larger studies may be needed to confirm.