Efficacy of dexmedetomidine as an adjunct to ropivacaine in bilateral dual-transversus abdominis plane blocks in patients with ovarian cancer who underwent cytoreductive surgery

OBJECTIVE: We sought to evaluate the postoperative control of pain and recovery in patients with ovarian cancer who underwent cytoreductive surgery by adding dexmedetomidine to ropivacaine in bilateral dual-transversus abdominis plane (Bd-TAP) blocks. METHODS: We enrolled 90 patients with an American Society of Anesthesiologists physical status I to III undergoing open abdominal cytoreductive surgery in this study. Patients were randomized and assigned into three groups (TAP-R, TAP-DR, or CON) of 30 participants each. All of the patients received standardized general anesthesia, and postoperative Bd-TAP blocks were performed. The TAP-R, TAP-DR, and CON groups received Bd-TAP blocks with 0.3% ropivacaine, 0.3% ropivacaine and 0.5 μg/kg of dexmedetomidine, and 0.9% normal saline, respectively. All of the patients received patient-controlled analgesia (PCA) (formula, 100 μg of sufentanil and 16 mg of ondansetron diluted with normal saline to 100 mL). Flurbiprofen axetil was used as a rescue drug if the visual analog scale (VAS) score was more than four points. The first request time for PCA bolus; the VAS scores at 0, 6, 12, 24, and 48 h after operation; and the cumulative sufentanil consumption within 24 and 48 h, respectively, were compared. Pulmonary function was evaluated preoperatively and at 24 h after the operation. The use of the rescue drug was recorded. Postoperative functional recovery, including time to stand, time to walk, time to return of bowel function, time to readiness for discharge, and postoperative complications, were recorded. RESULTS: Median values of the first request time for PCA of the TAP-R group was significantly prolonged compared to that of the CON group (median [interquartile range], 7.3 [6.5–8.0] hours vs. 3.0 [2.3–3.5] hours) (P < .001), while the TAP-DR group has the longest request time among the three groups (median [interquartile range], 13.5 [12.4–14.5] hours) (P < .001). The VAS scores at rest and upon coughing of the TAP-R group in the first 12 h were significantly lower than those of the CON group (P < 0.05), but showed no significant difference compared to those of the TAP-DR group. The VAS scores at rest and upon coughing were lower in the TAP-DR group at each time point compared to those of the CON group (P < .05). The cumulative sufentanil consumption in the TAP-DR group was significantly lower at 48 h (P = .04) after surgery than in the CON group, while there was no significant difference compared to that in the TAP-R group (P > .05). Less rescue analgesic was required by patients in the TAP-DR group than in the CON group (P < .05). Postoperative mean measured forced expiratory volume in 1 s (FEV(1)) and FEV(1)/forced vital capacity values in the TAP-DR group were significantly higher than those of the CON group (P = .009), while there was no significant difference compared to those of the TAP-R group (P = .10). There was no significantly difference in postoperative functional recovery between TAP-DR and CON group (P > 0.05). CONCLUSION: TAP blocks can provide effective pain relief up to 12 h postoperatively without a significant improvement in postoperative pulmonary function. The addition of dexmedetomidine to ropivacaine for Bd-TAP block prolonged the first bolus time of PCA when compared to that in the TAP-R group and decreased sufentanil consumption and the need of rescue analgesia relative to in the CON group at 48 h postoperative. The procedure provided better postoperative analgesia and improved postoperative pulmonary function relative to the CON group. Our results indicate that dexmedetomidine as an adjuvant of Bd-TAP can provide effective pain relief up to 48 h.