Regional Changes in Upper Limb Perfusion Following Brachial Plexus Block: A Pilot Study (RAFFAB)

Ultrasound-guided regional anesthesia is increasingly being used in the modern surgical environment to provide specific intraoperative anesthesia and postoperative analgesia. Infiltration of local anesthesics around peripheral nerves firs blocks sympathetic, then sensory, then motor nerve function. Sympathectomy-induced vasodilation following brachial plexus block results in increased skin temperature and arterial flow within minutes.

Although it has not been shown to reliably increase diameter or cross-sectional area of distal arteries, brachial plexus block does change the pattern and quantity of blood flow to the hand. Given that the magnitude of change of flow cannot be attributed to vessel radius, the investigators suspect that the more laminar fluid dynamics are due to vascular tone.

The investigators study aims to quantify alterations in physiology and peripheral vasodilator response. The investigators anticipate that axially block will significantly improve regional blood flow.

Study Overview

• Status: Completed
• Conditions: Nerve Block; Regional Blood Flow; Anesthesia, Conduction; Sympathectomy
• Intervention / Treatment: Other: Monitoring

• Study Type: Observational
• Enrollment (Actual): 18

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Individuals coming for elective upper extremity surgery who would already be having a brachial plexus block for their anesthesia.

Description

Inclusion Criteria:

• ASA physical status I, II, III
• BMI less than or equal to 39
• Presenting for elective upper limb surgery
• Does not meet any exclusion criteria

Exclusion Criteria:

• Age over 80
• ASA physical status IV or V
• BMI greater or equal to 40
• Language barrier precluding ability to give informed consent
• History of coagulopathy
• INR < 1.4
• Platelet count < 100
• Allergy to local anesthetics
• Known peripheral vascular disease of the upper limbs
• Amputation of one or both upper limbs, not including digits
• Peripheral neurological disease
• Does not consent to participate in study

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patients	Other: Monitoring

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in regional blood flow and perfusion characteristics in the upper arm arteries from baseline to 20 minutes after unilateral axillary block.	Physiologic parameter	30 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in the caliber of the arteries of the arm between arms from baseline to 20 minutes after unilateral axillary block.	Physiologic parameter	30 minutes
Changes in skin temperature between hands from baseline to 20 minutes after unilateral axillary block.	Physiologic parameter	30 minutes
Sensory loss in radial, ulnar, and median nerve distribution between hands from baseline to 20 minutes after unilateral axillary block.	Physical examination	30 minutes
Motor weakness in radial, ulnar, and median nerve distributions between hands from baseline to 20 minutes after unilateral axillary block	Physical examination	30 Minutes

Collaborators and Investigators

• Sponsor: Lawson Health Research Institute
• Collaborators: University of Western Ontario, Canada; London Health Sciences Centre; St. Joseph's Health Care London

Study record dates

Study Major Dates

• Study Start: November 1, 2015
• Primary Completion (Actual): January 1, 2016
• Study Completion (Actual): March 1, 2016

Study Registration Dates

• First Submitted: October 22, 2015
• First Submitted That Met QC Criteria: October 26, 2015
• First Posted (Estimate): October 28, 2015

Study Record Updates

• Last Update Posted (Actual): March 30, 2017
• Last Update Submitted That Met QC Criteria: March 29, 2017
• Last Verified: October 1, 2015

More Information

Terms related to this study

• Other Study ID Numbers: 106285