Low Dose Dexamethasone in Supraclavicular Blocks

Summary

Brachial plexus nerve blocks provide superior analgesia over opioids while avoiding unwanted side effects. Single shot blocks with local anesthetic alone usually do not last the duration of the acute post-surgical pain period. This has led to the exploration of multiple adjuvants to increase the duration of single shot blocks, the most promising adjuvant being dexamethasone.

Peri-neural administration is an off-label use of dexamethasone. While no adverse events have been reported in human clinical studies, logic would dictate that we minimize the dose needed to produce the desired effect. Most studies thus far have used peri-neural dexamethasone doses ranging from 4-10 mg. However, Albrecht et al. found no difference in block duration comparing 4 mg and 8 mg doses while Liu et al. reported equivalent block duration using doses of 1, 2 and 4 mg.

Recent studies have evaluated whether systemic and peri-neural administrations of dexamethasone are equivalent, which would in turn imply a site of action. Results have been mixed. Four studies concluded peri-neural and intravenous administration are equivalent at prolonging analgesia, though one study had methodological errors, including the administration of intravenous dexamethasone to all patients. All of these studies used dexamethasone doses of 8 to 10 mg. One study where a lower dose (4 mg) was used found that peri-neural administration prolonged block duration whereas intravenous did not.

With that, the rationale of our study is to determine if equivalent block-prolonging analgesia can be achieved using low dose (1 mg) dexamethasone given peri-neural or intravenous. Clinical experience at our centre has been that 1 mg dexamethasone added to 20 mL produces similar block duration to that reported in published studies using higher doses.

Conditions

• Rheumatoid Arthritis
• Osteoarthritis
• Nerve Entrapment
• Ligament Injury

Interventions

DRUG

Control intervention (no dexamethasone)

Patients receive a supraclavicular brachial plexus block with 30 mL of solution containing 0.5% bupivacaine, 1:400,000 epinephrine, 0.1 mL normal saline, and an intravenous solution of 50 mL normal saline.

DRUG

Peri-neural Dexamethasone 1 mg

Patients receive a supraclavicular brachial plexus block with 30 mL of solution containing 0.5% bupivacaine, 1:400,000 epinephrine, 0.1 mL dexamethasone 1% (1 mg dexamethasone), and an intravenous solution of 50 mL normal saline.

DRUG

Intravenous Dexamethasone 1 mg

Patients receive a supraclavicular brachial plexus block with 30 mL of solution containing 0.5% bupivacaine, 1:400,000 epinephrine, 0.1 mL normal saline, and an intravenous solution of 49.9 mL normal saline with 0.1mL dexamethasone 1%

Sponsors & Collaborators

• University of Calgary

  lead OTHER

Principal Investigators

• Nathan JD Brown, BMSc, MD · University of Calgary

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2016-09-30

Primary Completion

2020-02-29

Completion

2021-02-28

Countries

• Canada

Study Locations