Reduced opioid utilization and post-operative pain in Asian vs. Caucasian populations after video-assisted thoracoscopic surgery lobectomy with liposomal bupivacaine-based intercostal nerve blockade

Background: Regional analgesia, such as intercostal nerve blockade (INB), is a viable modality for postoperative pain control in thoracic surgery patients. Asian patients have historically been underrepresented in studies of pain responses and pain medication requirements based on race. In this study, we examined the postoperative opioid medications used by Asian and Caucasian patients undergoing video-assisted thoracoscopic surgery (VATS) lobectomy who received different bupivacaine-based INB. Methods: We retrospectively reviewed patients undergoing VATS lobectomy who received standard bupivacaine (SB), liposomal bupivacaine (LB), or liposomal bupivacaine mixed with standard bupivacaine (MIX). Length of stay (LOS), postoperative pain scores, postoperative opioid use (in intravenous morphine equivalents) were evaluated. The Chi-square test was used to compare categorical variables; Student's t-test for normally distributed variables; and the Wilcoxon rank-sum test for non-normally distributed variables. Multivariable linear regression was used to assess opioid use in Asians compared to Caucasians. Results: Of the 239 patients in the cohort, 212 received LB or MIX and 27 received SB. In the LB/MIX group, 48 (22.6%) were Asian and 164 (77.4%) were Caucasian. In the SB group, 7 (25.9%) were Asian and 20 (74.1%) were Caucasian. There were no differences in height, weight, and body mass index (BMI) between the SB and LB/MIX groups, but there was a significant difference in weight and BMI between Asian and Caucasian patients. The median LOS was comparable between the SB and LB/MIX groups. The average 24-hour postoperative pain score in the LB/MIX group was 2.5, and 2.0 and 2.7 in the Asian and Caucasian subgroups, respectively (P<0.01). The median opioid use in the LB/MIX group was 27.2 mg, and 16.9 and 31.1 mg in the Asian and Caucasian subgroups, respectively (P<0.01). On multivariable linear regression analysis adjusting for sex, age, BMI, and bupivacaine type, we found Asians used 25.5 mg less opioids compared to Caucasians (P<0.01). Conclusions: INB with LB or liposomal-standard bupivacaine mix resulted in statistically significant decreased postoperative pain scores and opioid use in Asians compared to Caucasians. There was no difference in LOS between the LB/MIX and SB groups.