Determination of the Median Effective Volume (ED50) of Bupivacaine for Serratus Posterior Superior Intercostal Plane Block in Patients Undergoing Video-Assisted Thoracoscopic Surgery Using the Dixon Up-and-Down Method
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 27
- 试验地点
- 2
- 主要终点
- Median Effective Volume (EV50) of 0.25% Bupivacaine for Successful SPSIP Block
研究概览
简要总结
This study determined the median effective volume (EV50) of bupivacaine required for the serratus posterior superior intercostal plane (SPSIP) block in patients undergoing video-assisted thoracoscopic surgery (VATS). The SPSIP block is an ultrasound-guided regional anesthesia technique used to provide postoperative pain relief after thoracic surgery. All patients received bupivacaine at a final concentration of 0.25%, prepared by diluting the commercially available 0.5% preparation 1:1 with 0.9% sodium chloride. Using a sequential up-and-down dose-adjustment method, the volume of local anesthetic was increased or decreased according to the block outcome of the preceding patient. The main outcome of the study was the volume that provided an effective block in 50% of patients. EV50 is not a recommended clinical dose; the results are intended to inform future studies targeting higher effective percentiles.
详细描述
This prospective interventional dose-finding study was designed to determine the median effective volume (EV50) of 0.25% bupivacaine for ultrasound-guided serratus posterior superior intercostal plane (SPSIP) block in patients undergoing video-assisted thoracoscopic surgery (VATS). The local anesthetic solution was prepared by diluting 0.5% bupivacaine (Buvacin 0.5%, Polifarma, Türkiye) 1:1 with 0.9% sodium chloride, yielding a final concentration of 0.25%; the 0.5% descriptor refers to the commercial preparation, not to the administered concentration. The concentration specified in the ethics committee-approved protocol is 0.25%.
The up-and-down sequential allocation method described by Dixon and Massey was used. The initial volume of bupivacaine was administered to the first patient, and subsequent volumes were adjusted in 2 mL increments according to the response of the preceding patient. If the block was successful, the volume for the next patient was decreased by 2 mL. In case of block failure, the volume was increased by 2 mL. Volumes were constrained to a range of 15 to 40 mL, and one patient was enrolled per day.
Block success was defined as the presence of sensory loss to cold in at least two consecutive dermatomes between T3 and T6, assessed 20-30 minutes after block performance, combined with a cumulative fentanyl requirement of less than 2 µg/kg within the first 60 minutes after induction of general anesthesia. Failure was defined as absence of adequate sensory blockade or the need for fentanyl ≥2 µg/kg.
The up-and-down sequence was continued until nine reversal points were obtained. The EV50 was calculated as the mean of the midpoint doses of all independent success-failure pairs. Secondary outcomes included postoperative pain scores and opioid consumption. This study aimed to provide clinically relevant data to optimize the volume of local anesthetic for SPSIP block while maintaining effective analgesia and minimizing potential adverse effects.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Sequential
- 主要目的
- Treatment
- 盲法
- None
盲法说明
The anesthesiologist performing the block was aware of the administered volume. Sensory block assessment, intraoperative assessment of analgesic adequacy, and postoperative data collection were performed by separate anesthesiologists blinded to the administered volume and to the block outcome.
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Age 18 years or older
- •Scheduled for elective video-assisted thoracoscopic surgery (VATS)
- •American Society of Anesthesiologists (ASA) physical status I-III
- •Planned to receive ultrasound-guided serratus posterior superior intercostal plane block for postoperative analgesia
- •Ability to provide written informed consent
排除标准
- •Refusal to participate in the study
- •Known allergy or contraindication to local anesthetics
- •Infection at the block injection site
- •Coagulation disorders or anticoagulant therapy contraindicating regional anesthesia
- •Severe respiratory insufficiency
- •Chronic opioid use or chronic pain syndrome
- •Pregnancy
- •Inability to cooperate or communicate postoperative pain scores
研究组 & 干预措施
Serratus Posterior Superior Intercostal Plane Block (SPSIPB)
Participants received an ultrasound-guided serratus posterior superior intercostal plane block (SPSIPB) with 0.25% bupivacaine before video-assisted thoracoscopic surgery (VATS). The solution was prepared by diluting commercially available 0.5% bupivacaine (Buvacin 0.5%, Polifarma, Türkiye) 1:1 with 0.9% sodium chloride, giving a final administered concentration of 0.25%, as specified in the ethics committee-approved protocol. The injected volume was determined using the Dixon up-and-down sequential allocation method, starting from an initial volume of 30 mL and adjusted by 2 mL increments or decrements based on block success or failure in the preceding patient, within a permitted range of 15 to 40 mL. Sensory block was assessed by an outcome assessor blinded to the administered volume, and intraoperative analgesic adequacy was assessed by an anesthesiologist blinded to the administered volume and to the block outcome, according to predefined criteria.
干预措施: Ultrasound-Guided Serratus Posterior Superior Intercostal Plane Block (Other)
结局指标
主要结局
Median Effective Volume (EV50) of 0.25% Bupivacaine for Successful SPSIP Block
时间窗: Within the first 30 minutes after block performance
The median effective volume (EV50) of 0.25% bupivacaine required for a successful ultrasound-guided serratus posterior superior intercostal plane block, determined using the Dixon up-and-down sequential allocation method. Bupivacaine 0.25% was prepared by diluting the commercial 0.5% preparation 1:1 with 0.9% sodium chloride; the concentration specified in the ethics committee-approved protocol is 0.25%. Block success was defined by a composite criterion: sensory loss to cold in at least two consecutive dermatomes between T3 and T6, combined with a cumulative fentanyl requirement of less than 2 µg/kg (including the 1 µg/kg induction dose) within the first 60 minutes after induction of general anesthesia. Failure was defined as absence of adequate sensory blockade or a cumulative fentanyl requirement of 2 µg/kg or more.
Median Effective Volume (ED50) of 0.5% Bupivacaine for Successful SPSIP Block
时间窗: Within the first 30 minutes after block performance
The median effective volume (ED50) of 0.5% bupivacaine required to achieve successful postoperative analgesia following ultrasound-guided serratus posterior superior intercostal plane block, determined using the Dixon up-and-down sequential allocation method.
次要结局
- Postoperative Pain Scores (NRS)(Up to 24 hours postoperatively)
- Postoperative Morphine Consumption via Patient-Controlled Analgesia (PCA)(First 24 hours after surgery)
- Postoperative Adverse Effects(Up to 24 hours postoperatively)
- Quality of Recovery Score (QoR-15)(24 hours after surgery)
- Postoperative Pulmonary Function Parameters(Preoperative baseline and 24 hours after surgery)
研究者
Mursel Ekinci
prof.
Bursa City Hospital