Study objectiveTo determine if continuous bilateral erector spinae plane (ESP) blocks would improve the postoperative analgesia in the first 48 h after laparoscopic donor hepatectomy, compared to intrathecal morphine (ITM). DesignProspective, randomized controlled trial. SettingA single tertiary care center from October 2019 and September 2020. PatientsA total of 60 donors scheduled to undergo elective laparoscopic right hepatectomy. InterventionsSixty donors were randomized to receive either bilateral continuous T8 ESP blocks with a programmed intermittent bolus regimen of 10 mL 0.2% ropivacaine every 3 h for 48 h (n = 30) or 400 μg ITM (n = 30), in addition to IV fentanyl PCA and multimodal analgesia. MeasurementsThe primary outcome was cumulative opioid consumption over the first 48 h, expressed as IV morphine equivalents. Secondary outcomes included pain scores, Quality of Recovery-15 scores, ambulation within 24 h, time to first flatus, and opioid-related adverse drug events over 72 h. Main resultsFifty-nine donors were analyzed. Cumulative 48-h opioid consumption was similar between the ITM and ESP groups (29.8 ± 18.2 vs. 35.1 ± 21.9 mg, mean difference (ESP-ITM) (95% CI), 5.3 (−11.5 to 22) mg; p > 0.99). Resting pain scores at 48 and 72 h postoperatively were significantly lower in the ESP group (0 [0–2] vs. 3 [1.5–3], and 0 [0–2] vs. 3 [1–3] respectively, both p<0.001) (Goldaracena and Barbas, 2019; Ko et al., 2009; Choi et al., 2007 [1–3]) respectively, both p < 0.001). The ESP group had significantly lower incidences of postoperative nausea, vomiting, and pruritus at all timepoints. There were no differences in recovery outcomes. ConclusionsContinuous ESP blocks did not reduce cumulative 48-h opioid consumption compared to 400 μg ITM after laparoscopic donor hepatectomy, but it was associated with a significantly reduced risk of postoperative nausea, vomiting and pruritus. Clinical trial number and registry URLClinical Trial Registry of Korea; https://cris.nih.go.kr/cris/index.jsp and identifier: KCT0004313; date of registration: October 15, 2019; principal investigator's name: Justin Sangwook Ko.