The Efficacy of Personalized Local Anesthetic Dosing Based on Ultrasound-Measured Nerve Cross-Sectional Area in Brachial Plexus Block: a Non-Inferiority Randomized Controlled Trial.

Northern Jiangsu People's Hospital

Status: Not yet enrolling

Conditions: Upper Limb Surgery

Treatments: Drug: Weight-based dosing of Ropivacaine; Drug: CSA-based dosing of Ropivacaine; Drug: Experience-based dosing of Ropivacaine

Study type: Interventional

Funder types: Other

Identifiers

NCT07353047

2025ky401

Details and patient eligibility

About

This is a prospective, randomized, assessor-blinded, three-arm, non-inferiority clinical trial. The study aims to compare the effectiveness and safety of an individualized dosing strategy for local anesthetic in brachial plexus blocks against two standard methods. The experimental intervention uses ultrasound to measure the cross-sectional area (CSA) of the brachial plexus nerves to calculate a patient-specific dose of 0.5% ropivacaine. This is compared to a standard weight-based dosing regimen (2.5 mg/kg) and dosing based on the anesthesiologist's clinical experience. A total of 350 adult patients scheduled for elective unilateral upper limb surgery will be randomly assigned to one of the three groups. The primary outcome is the success rate of the nerve block 30 minutes after administration. Secondary outcomes include assessments of diaphragmatic function, postoperative pain scores, the incidence of complications (such as nerve involvement or systemic toxicity), and patient satisfaction. The hypothesis is that the CSA-based dosing method will be non-inferior to the conventional methods in achieving successful anesthesia while potentially optimizing drug dosage.

Enrollment: 300 estimated patients

Sex: All

Ages: 18 to 80 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

Age 18-80 years old, proposed for elective unilateral upper extremity surgery; ASA grade I-III; Planned to undergo ultrasound-guided interscalene sulcus brachial plexus block; Normal preoperative respiratory function; No history of neck surgery; No use of drugs that affect nerve conduction or opioids within 30 days prior to surgery

Exclusion criteria

Local infection, coagulation dysfunction, neuropathy; Allergy to ropivacaine or amide local anesthetics; Severe hepatic and renal insufficiency; Pregnancy or lactation; Expected dosing required to exceed the maximum safe single safe dose of ropivacaine; Inability to cooperate with ultrasound measurements or nerve block operators.

Trial design

Primary purpose: Other

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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300 participants in 3 patient groups

CSA-based Dosing Group

Experimental group

Description:

The cross-sectional area (CSA) of the brachial plexus nerves at the interscalene groove is measured using ultrasound in the short-axis view. The dose of 0.5% ropivacaine is calculated individually using the formula: Volume (mL) = CSA (mm²) × Conversion Coefficient (mL/mm²). The conversion coefficient is derived from a pilot dose-finding study conducted prior to the main trial. The total dose for any participant will not exceed the maximum recommended safe dose of ropivacaine (≤225 mg). The nerve block is performed under ultrasound guidance by an experienced anesthesiologist.

Treatment:

Drug: CSA-based dosing of Ropivacaine

Experience-based Dosing Group

Other group

Description:

The dose of 0.5% ropivacaine is determined solely by the clinical judgment and experience of the attending anesthesiologist, reflecting common real-world practice.The nerve block is performed under ultrasound guidance by an experienced anesthesiologist.

Treatment:

Drug: Experience-based dosing of Ropivacaine

Weight-based Dosing Group

Other group

Description:

The dose of 0.5% ropivacaine is calculated based on the participant's body weight using a standard formula: Dose (mg) = 2.5 mg/kg. The corresponding volume is then administered. The nerve block is performed under ultrasound guidance by an experienced anesthesiologist.

Treatment:

Drug: Weight-based dosing of Ropivacaine