Minimum Effective Volume (MEV90) of Local Anesthetic Required for Ultrasound-Guided Interscalene Block for Supraclavicular Nerve Block: A Dose-Finding Study
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 发起方
- 入组人数
- 55
- 试验地点
- 1
- 主要终点
- Minimum Effective Volume (MEV90) for Supraclavicular Nerve Block via Interscalene Approach
研究概览
简要总结
This study aims to determine the minimum effective volume (MEV90) of local anesthetic required to achieve sensory block of the supraclavicular nerves when performing a single-shot ultrasound-guided interscalene brachial plexus block (ISB). These nerves provide sensation to the skin over the clavicle and shoulder and are often involved in surgeries such as shoulder arthroscopy and clavicle repair.
详细描述
This prospective dose-finding study seeks to determine the minimum effective volume (MEV90) of local anesthetic required to achieve sensory block of the supraclavicular nerves following a single-shot ultrasound-guided interscalene brachial plexus block (ISB). These nerves, branches of the superficial cervical plexus, provide cutaneous innervation over the clavicle and shoulder and may contribute to postoperative pain after shoulder and clavicular surgery. Establishing MEV90 is clinically relevant to optimize analgesia while minimizing the risk of local anesthetic systemic toxicity.
The study employs a biased coin up-and-down sequential design, commonly used in regional anesthesia dose-finding trials. The initial volume is 12 mL of bupivacaine 0.5% with epinephrine (5 µg/mL), with subsequent volumes adjusted in 2 mL increments based on the prior patient's response. The maximum permitted volume is 30 mL.
All blocks are performed under ultrasound guidance by experienced anesthesiologists (≥60 ISBs), following standard safety protocols.
This intervention does not introduce additional risk beyond routine care, as ISB is the gold standard for shoulder surgery analgesia. Results will inform whether a single interscalene injection provides adequate coverage of supraclavicular nerves or if a separate cervical plexus block is necessary for procedures involving both plexuses, such as clavicle surgery. Findings may refine volume recommendations, improve analgesic strategies, and reduce unnecessary drug exposure.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Supportive Care
- 盲法
- None
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
- •ASA physical status I to III
- •Body Mass Index (BMI) between 18 and 35 kg/m²
- •Weight ≥ 50 kg
- •Scheduled for shoulder arthroscopy requiring an interscalene brachial plexus block for analgesia
- •Able to provide informed consent
排除标准
- •Inability to provide informed consent
- •Coagulopathy (platelet count ≤100,000; INR ≥1.4)
- •Significant pulmonary disease (restrictive or obstructive)
- •Renal insufficiency (creatinine ≥1.2 mg/dL)
- •Hepatic insufficiency (transaminases ≥100 U/L)
- •Allergy to local anesthetics
- •Pregnancy
- •Pre-existing neuropathy
- •Previous surgery in ipsilateral cervical or supraclavicular region
- •Contralateral hemidiaphragmatic paralysis or vocal cord paralysis
研究组 & 干预措施
Minimum Effective Volume 90 (MEV90)
Participants in this arm will receive a single-shot ultrasound-guided interscalene brachial plexus block as part of standard perioperative analgesia for shoulder arthroscopy. The intervention consists of injecting bupivacaine 0.5% with epinephrine (5 µg/mL) between the anterior and middle scalene muscles at the level of the C5-C6 nerve roots, using an in-plane technique under real-time ultrasound guidance.
干预措施: Ultrasound-Guided Interscalene Block with Bupivacaine (Drug)
结局指标
主要结局
Minimum Effective Volume (MEV90) for Supraclavicular Nerve Block via Interscalene Approach
时间窗: 30 minutes after completion of the block
The primary outcome is the calculation of the minimum effective volume of local anesthetic (MEV90) required to achieve complete sensory block of the supraclavicular nerves following a single-shot ultrasound-guided interscalene brachial plexus block. Success is defined as absence of cold and touch sensation at the midpoint of the clavicle, assessed using an ice test.
次要结局
- Sensorimotor Block Score for Interscalene Block(Every 5 minutes up to 30 minutes after block completion.)
- Onset Time of Sensorimotor Block(Up to 30 minutes after block completion.)
- Sensory Block at Shoulder Arthroscopy Portals(30 minutes after block completion.)
- Sensory Block of Auricular, Occipital, and Transverse Cervical Nerves(30 minutes after block completion.)
- Pain Score During Block Procedure(Immediately after block completion.)
- Block Performance Times(During block procedure.)
- Incidence of Block-Related Adverse Events(From block completion until end of surgery.)
研究者
Germán Armando Aguilera Ceballos
Principal Investigator
Hospital del Trabajador de Santiago