<p>Effects of Ropivacaine Concentration on Analgesia After Ultrasound-Guided Serratus Anterior Plane Block: A Randomized Double-Blind Trial</p>

Abstract

Serratus anterior plane (SAP) block is effective for analgesia after breast surgery. Whether a higher local anesthetic concentration prolongs sensory block duration and improves postoperative analgesia remains unclear. The aim of this study was to compare the analgesic effects of SAP block with different concentrations of ropivacaine. Patients and Methods: Sixty patients scheduled for breast surgery were enrolled in this randomized double-blind trial. SAP block was induced with 20 mL of 0.375%, 0.5%, or 0.75% ropivacaine in Group R0.375, Group R0.5, and Group R0.75, respectively. The primary endpoint was the area under the curve (AUC) of numerical rating scale (NRS) pain intensity scores at rest over time. The secondary endpoints were AUC of NRS pain intensity scores on movement over time, active sensory block duration, tramadol consumption, and the elapsed time between completion of surgery and the first administration of rescue analgesia. Results: The AUC of NRS pain intensity scores at rest of Group R0.375 was significantly higher than that of Groups R0.5 and R0.75 (P=0.025, and P=0.001). The AUC of NRS pain intensity scores on movement of Group R0.375 was also significantly higher than that of Groups R0.5 and R0.75 (both P<0.001). At higher ropivacaine concentrations, the duration of SAP sensory block increased (P<0.001). Tramadol consumption and the elapsed time between completion of surgery and the first administration of rescue analgesia were similar in the three groups (P>0.05). Conclusion: A comparison of 0.5% and 0.75% ropivacaine showed no significant difference in postoperative analgesia, but both were superior to 0.375% ropivacaine, although higher ropivacaine concentration lengthened the duration of SAP block. Therefore, SAP block with 0.5% ropivacaine is recommended for postoperative analgesia in breast surgery.

A narrative review of ultrasound-guided serratus anterior plane block

“…According to studies and case reports, the commonly used local anesthetics for clinical SAPB are ropivacaine and bupivacaine. Huang et al (5) used a randomized doubleblinded experiment to compare the analgesic time and the effect of different concentrations (0.375%, 0.5%, and 0.75%) of ropivacaine in breast surgeries. The results showed that the higher the ropivacaine concentration, the longer the sensory block time.…”

Practical Review of Abdominal and Breast Regional Analgesia for Plastic Surgeons: Evidence and Techniques

“… 62 – 64 Two other RCTs assessed the efficacy of varying volumes and concentrations of the local anesthetic used in the SAP block. 65 , 66 They found that increasing the volume of the local anesthetic increases dermatomal anesthesia coverage; however, it does not increase the duration of block or the overall post-operative pain. On the other hand, increasing the concentration of bupivacaine from 0.375% to 0.5% led to significantly lowered pain and longer duration of anesthesia.…”

<p>The Safety and Efficacy of Ultrasound-Guided Serratus Anterior Plane Block (SAPB) Combined with Dexmedetomidine for Patients Undergoing Video-Assisted Thoracic Surgery (VATS): A Randomized Controlled Trial</p>

“…29 Huang et al showed that SAPB with 0.5% ropivacaine was beneficial for postoperative analgesia during the first 24 h after breast surgery. 30 Kunigo et al reported that the number of affected dermatomes (assessed by both cold and pinprick test) was significantly greater for patients receiving 40 mL of 0.375% ropivacaine than for patients receiving 20 mL; however, the time to the first dose of rescue analgesia was similar between the two groups. 31 Because of this finding and for safety reasons, we injected 20 mL of 0.5% ropivacaine combined with different doses of DEX in the superficial plane before surgery.…”