Study on MEV90 of 0.5% ropivacaine for US-guided caudal epidural block in anorectal surgery

Abstract

BackgroundChoosing the appropriate concentration and volume of anesthetics is critical for a successful nerve block. The current study aimed to determine the minimum effective volume (MEV) of 0.5% ropivacaine for US-guided CEB in 90% of patients (MEV90) undergoing anorectal surgery. The aims were to reduce the occurrence of complications associated with a sacral blockade in anorectal surgery, broaden the indications for surgical procedures and treatment, and improve patient satisfaction. This study presents the groundwork for the development of individualized anesthetic programs. We believe that the study would serve as a reference for the use of caudal epidural block (CEB) in lower abdominal surgery for intraoperative and postoperative analgesia.MethodsThis study used a biased coin design (BCD) up-and-down method (UDM). We divided the participants into two groups based on gender, and each group independently performed the biased coin design up-and-down method. We used 0.5% ropivacaine for the first patient in each group; however, the volume was 10 ml for men and 8 ml for women. Therefore, the dose of anesthetics given to each patient was determined by the response of the previous patient. If the block of the previous patient failed, the volume was increased by 2 ml in the following patient. Otherwise, the next subject had an 11% chance of receiving a volume of 2 ml less or an 89% chance of receiving no volume change. We defined a successful block as painless surgery with anal sphincter relaxation 15 min after the drug injection. Enrollment was completed after 45 successful caudal blocks for each group.ResultsCaudal epidural block was successfully performed on 50 men and 49 women. The MEV90 of ropivacaine for CEB was calculated to be 12.88 ml (95% CI: 10.8–14 ml) for men and 10.73 ml (95% CI: 9.67–12 ml) for women. Men had a MEV99 of 13.88 ml (95% CI: 12.97–14 ml), and women had a MEV99 of 11.87 ml (95% CI: 11.72–12 ml).ConclusionWith operability and general applicability, it is possible to increase the success rate of CEB for anorectal surgery to 99% as well as decrease the incidence of anesthesia-related complications. CEB can meet the needs of patients for rapid postoperative rehabilitation, improve patient satisfaction, and lay a solid foundation for postoperative analgesia.

Ultrasound-Guided Brachial Plexus Block by Costoclavicular Space Approach: A Narrative Review

“…Ropivacaine, known for its unique sensorimotor separation effect at low concentrations [ 41 ], has gained popularity among surgeons, especially orthopedic surgeons, and patients [ 42 , 43 ]. The concentration of ropivacaine is often determined based on its pharmacological properties, with intraoperative concentrations ranging from 0.5% to 0.75% [ 41 ].…”

“…Continuous brachial plexus block is frequently employed for postoperative pain management and upper-limb rehabilitation exercises [ 37 , 58 , 59 ]. Due to the long block time, it can significantly reduce postoperative rebound pain [ 57 ] and promote recovery of postoperative function, thus improving patient satisfaction [ 43 ]. Traditional approaches include interscalene, supraclavicular, and infraclavicular techniques [ 60 ].…”

The impact of combined administration of ropivacaine and dexamethasone on postoperative analgesia in perianal surgery with pudendal nerve block under ultrasound guidance: a prospective randomized controlled study

“…Previous studies have reported that the incidence of postoperative urinary retention caused by perianal pain ranges from 3% to 50% ( Kunitake and Poylin, 2016 ). Some acute severe pain after surgery can also affect the wound healing, extend the length of hospital stay, reduce the patients’ satisfaction ( Zhang et al, 2022 ; Ni et al, 2023 ). Moreover, various data suggest that effective management of acute pain can reduce the risk of pain development ( Sinatra, 2010 ; Gerbershagen et al, 2013 ).…”