Evaluation of Supraclavicular Brachial Plexus Blocks at Various Volumes: Impact on Optic Nerve Sheath Diameter

Summary

This study aimed to evaluate the anesthesia adequacy, side effects, and complication rates, as well as the postoperative pain relief effectiveness of supraclavicular brachial plexus blocks administered at different volumes under ultrasound guidance. Additionally, the investigators utilized ultrasound to measure optic nerve sheath diameters and investigated their relationship with intracranial pressure across varying block volumes.

Conditions

• Upper Limb Injury
• Intracranial Pressure Increase

Interventions

PROCEDURE

Supraclavicular brachial plexus block

A supraclavicular brachial plexus block will be performed under ultrasound guidance. The patient will be taken to the preoperative block room, positioned supine with the bed elevated at a 30° angle, and the head turned away from the arm being blocked. To avoid intraneural injection, the block will use both ultrasound and a nerve stimulator (Plexygon, Vygon-Italy) with a 22G 50 mm 20° stimulating needle (Echoplex, Braun-France). A low-frequency ultrasound probe will be placed above the clavicle to visualize the subclavian artery and vein. Using an in-plane approach, the needle will be inserted laterally to medially from the mid-clavicular point through the skin and subcutaneous tissue. Under ultrasound guidance, the needle will be advanced towards the anatomical corner where the brachial plexus and subclavian artery are adjacent (corner pocket), and a local anesthetic agent will be injected to perform the block.

DEVICE

Measurement of Optic Nerve Sheath Diameter (ONSD) Using B-Mode Ultrasound

Before the block, both eyes will be measured for optic nerve sheath diameter (ONSD) using B-mode ultrasound (USG) with a GE LOGIQ E device. The patient will be supine with the bed elevated at a 30° angle, eyes closed, and a protective barrier applied. Both globes will be filled with water-soluble ultrasound gel, and imaging will be done with a 7.5 MHz linear probe at a 7 cm depth. For transverse ONSD measurement, the probe will be placed transversely in the coronal plane, with the marker notch pointing right. When the optic nerve entry into the globe is clear, transverse ONSD will be measured 3 mm below. For sagittal measurement, the probe will be placed sagittally in the coronal plane, with the marker notch pointing towards the body. Sagittal ONSD will be measured 3 mm below the entry point. Both internal and external diameters of the optic nerve sheath will be measured in transverse and sagittal planes, and the transverse diameter of the globe will also be measured.

DEVICE

Assessment of Peripheral Nerve Block Success Using Perfusion Index Measurement

Investigator plan to measure the Perfusion Index (PI) as an objective method for determining the success of peripheral nerve blocks, different from traditional tests. PI is an indicator of peripheral perfusion that can be continuously measured non-invasively with a pulse oximeter. PI represents the ratio of pulsatile blood flow to non-pulsatile blood flow in peripheral tissue. The Mindray uMEC 12 device will be used for this measurement.

DEVICE

End-Tidal Carbon Dioxide (EtCO2) Measurement

End-tidal carbon dioxide (EtCO2) measurement: The Medtronic Capnostream 35 device will be used for EtCO2 measurements. All patients will receive oxygen support at a rate of 1-2 L/min. If peripheral oxygen saturation falls below 95%, oxygen support will be increased to 3-6 L/min via nasal cannula.

Sponsors & Collaborators

• Pamukkale University

  lead OTHER

Principal Investigators

• Rıza Hakan Erbay · Pamukkale University

Study Design

Allocation

RANDOMIZED

Purpose

SCREENING

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

50 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2024-05-20

Primary Completion

2024-08-03

Completion

2025-04-10

Countries

• Turkey (Türkiye)

Study Locations