Application Of Ultrasound-guided Erector Spinae Plane Block Combined With Dexmedetomidine In Modified Radical Mastectomy For Breast Cancer

Objective: One of the most common malignancies in women worldwide is breast cancer,postoperative analgesia effect is one of the factors affecting patients’ rapid recovery.Erector spinae plane block（ESPB）can reduce pain after modified radical mastectomy for breast cancer,but the duration of nerve block analgesia is limited if local anesthetic agents are used alone.This study investigated whether Dexmedetomidine（Dex）combined with local anesthetic injection could prolong the analgesic time and reduce the amount of opioids when ESPB was used in modified radical mastectomy for breast cancer under ultrasound guidance compared with local anesthetic injection alone.It provided a clinical basis for better relief of postoperative pain in breast cancer patients.Methods: In this double-blind,randomized study,75 female patients undergoing modified radical mastectomy for breast cancer under selective general anesthesia were selected,,and 60 cases were finally completed.They were randomly divided into 2groups: 0.33% ropivacaine for ultrasound（US）-guided ESPB group（R group,n=30）,1ug/kg dexmedetomidine plus 0.33% ropivacaine for US-guided ESPB group（DR group,n=30）.US-guided ESPB at the T3 vertebral level was performed preoperatively in all patients.The mean arterial blood pressure（MAP）and heart rate（HR）of all patients were recorded in the baseline level when entering the operating room（T0）,immediately after anesthesia induction（T1）,immediately after incision（T2）,immediately after axillary lymph node dissection（T3）,end of the surgery（T4）.The indicators were 1-,6-,12-,24-,and 48-h visual analog scale（VAS）pain scores after surgery in the resting state and at 90-degree shoulder abduction.Intraoperative sufentanil and remifentanil,postoperative nausea and dosage of flurbiprofen within 48 hours,post-anesthesia care unit（PACU）and length of stay of all patients were recorded.In addition,the incidence of postoperative bradycardia,hypotension,postoperative nausea and vomiting（PONV）of all patients were recorded.Results: 60 patients completed the study.The VAS pain score was lower in group DR than ingroup R at any time in the resting state,except at 1 h after surgery.The VAS pain score was lower in group DR than group R at 12 and 24 h in an active state after surgery（P < 0.05 for each time interval）.The heart rate of group DR was lower than that of group R after anesthesia induction（T1）,pericarpectomy（T2）,and axillary dissection（T3）and at the end of surgery（T4）.The intraoperative dosages of remifentanil and sufentanil in group DR were lower than that in group R.The lengths of PACU stay were longer in group DR than in group R.The postoperative dosage of flurbiprofen in group DR was lower than that in group R（P = 0.038）.No significant difference was found in PONV and hospital stay between the two groups.No sinus bradycardia or hypotension after surgery occurred in the two groups.Conclusions: Dexmedetomidine as an adjunctive to ESPB can prolong postoperative analgesia time,reduce pain degree during activity and reduce the amount of opioids compared with ropivacaine alone.