Early Detection of Supraclavicular Brachial Plexus Block Failure Using Infrared Thermography and Perfusion Index

Assiut University

Status: Not yet enrolling

Conditions: Brachial Plexus Blocks; Regional Anaesthsia

Treatments: Device: Ultrasound; Device: Infrared Thermography Camera; Device: Pulse Oximeter; Procedure: Ultrasound-Guided Supraclavicular Block; Drug: Bupivacaine Hydrochloride 0.5 % Injectable Solution

Study type: Interventional

Funder types: Other

Identifiers

NCT07092891

Brachial Plexus Block Failure

Details and patient eligibility

About

Successful peripheral nerve blockade is fundamental to modern regional anesthesia, particularly for upper limb surgeries. Ensuring the efficacy of a nerve block early in the perioperative period is critical, as delayed recognition of block failure may lead to intraoperative pain, the need for additional sedation or general anesthesia, and overall poorer patient outcomes. Conventional methods for assessing block success, such as sensory testing with pinprick or cold stimuli and motor assessment using strength scales, require patient cooperation and often take 15-30 minutes to yield definitive results. These delays are especially limiting in fast-paced surgical environments or when early decisions regarding anesthesia management are necessary.

Emerging non-invasive monitoring technologies offer promising alternatives for the early, objective assessment of block efficacy. Infrared Thermography (IRT) measures skin surface temperature, which increases due to sympathetic nerve blockade-induced vasodilation.

Full description

Successful peripheral nerve blockade is fundamental to modern regional anesthesia, particularly for upper limb surgeries. Ensuring the efficacy of a nerve block early in the perioperative period is critical, as delayed recognition of block failure may lead to intraoperative pain, the need for additional sedation or general anesthesia, and overall poorer patient outcomes. Conventional methods for assessing block success, such as sensory testing with pinprick or cold stimuli and motor assessment using strength scales, require patient cooperation and often take 15-30 minutes to yield definitive results. These delays are especially limiting in fast-paced surgical environments or when early decisions regarding anesthesia management are necessary.

Emerging non-invasive monitoring technologies offer promising alternatives for early, objective assessment of block efficacy. Infrared Thermography (IRT) measures skin surface temperature, which increases with sympathetic nerve blockade-induced vasodilation. Perfusion Index (PI), derived from pulse oximetry, reflects peripheral perfusion and also rises as vascular tone decreases following a successful nerve block. Both IRT and PI provide quantifiable, real-time physiological markers of sympathetic and circulatory changes that precede full sensory or motor blockade. Although several studies support their individual utility, there is limited evidence on their combined predictive value or their integration into routine clinical practice. Further investigation is needed to validate their role in enhancing the accuracy and timeliness of block assessment.

Enrollment: 80 estimated patients

Sex: All

Ages: 18 to 70 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Adults aged 18-70 years
• ASA Physical Status I-III

Exclusion criteria

• General

  • Coagulopathy
  • Allergy to local anesthetics

• Special

  • Neurological deficits in the affected limb
  • Peripheral vascular disease or Raynaud's phenomenon
  • Infections or skin lesions at the site of injection
  • Use of a tourniquet

Trial design

Primary purpose: Diagnostic

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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80 participants in 1 patient group

Supraclavicular Brachial Plexus Block with Thermographic and Perfusion Monitoring

Experimental group

Description:

Participants will receive an ultrasound-guided supraclavicular brachial plexus block using 30 mL of 0.5% bupivacaine for upper limb surgery. Infrared thermography and perfusion index measurements will be recorded at baseline, and at 5, 10, and 15 minutes post-block to detect early physiological changes. Clinical assessment of sensory and motor block will be performed at 20 minutes post-injection using standardized testing. The goal is to evaluate the predictive accuracy of these non-invasive measures in detecting block success or failure.

Treatment:

Drug: Bupivacaine Hydrochloride 0.5 % Injectable Solution

Procedure: Ultrasound-Guided Supraclavicular Block

Device: Pulse Oximeter

Device: Infrared Thermography Camera

Device: Ultrasound