Anesthesia, Conduction, Nerve Block, Regional Blood Flow, Sympathectomy
Conditions
Brief summary
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.
Interventions
OTHERMonitoring
Sponsors
University of Western Ontario, Canada
London Health Sciences Centre
St. Joseph's Health Care London
London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's
Study design
Observational model
CASE_CONTROL
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes in regional blood flow and perfusion characteristics in the upper arm arteries from baseline to 20 minutes after unilateral axillary block. | 30 minutes | Physiologic parameter |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes in the caliber of the arteries of the arm between arms from baseline to 20 minutes after unilateral axillary block. | 30 minutes | Physiologic parameter |
| Changes in skin temperature between hands from baseline to 20 minutes after unilateral axillary block. | 30 minutes | Physiologic parameter |
| Sensory loss in radial, ulnar, and median nerve distribution between hands from baseline to 20 minutes after unilateral axillary block. | 30 minutes | Physical examination |
| Motor weakness in radial, ulnar, and median nerve distributions between hands from baseline to 20 minutes after unilateral axillary block | 30 Minutes | Physical examination |
Outcome results
None listed