Perineural Dexmedetomidine for Ulnar Nerve Block.

Zealand University Hospital

Status and phase: Unknown; Phase 2

Conditions: Healthy

Treatments: Drug: Ropivacaine 5mg/ml; Drug: Ropivacaine 7.5mg/ml; Drug: Dexmedetomidine perineurally; Drug: Isotonic saline; Drug: Dexmedetomidine systemically

Study type: Interventional

Funder types: Other

Identifiers

NCT03222323

2016-004883-20 (EudraCT Number)

REG-158-2016

Details and patient eligibility

About

The aim of this trial is to investigate if dexmedetomidine prolongs the duration of an ulnar nerve block. By using healthy volunteers the investigators can perform bilateral ulnar nerve blocks and thereby control for a systemic effect to clarify if the effect is actually peripheral or systemic. The investigators hypothesis is that dexmedetomidine as an adjunct to a local anaesthetic prolongs the duration of a peripheral nerve block by a peripheral mechanism.

Full description

Background:

Efficient pain management promoting mobilization and convalescence is essential in an ideal perioperative course. Regional nerve blocks are a central element in postoperative regimes for many patients and it is therefore important that these nerve blocks are both long lasting and efficient. This trial will investigate whether it is possible to optimize the postoperative pain management when adding dexmedetomidine to the local anaesthetic ropivacaine in peripheral nerve blocks.

The prolonging effect of using dexmedetomidine as adjunct in peripheral nerve blocks have been investigated in several studies. However, it remains uncertain whether the effect is mediated by a systemic-, a peripheral- or a combined systemic/peripheral mechanism. In this trial the adjuvating effect of dexmedetomidine will be investigated using an ulnar nerve block.

Method:

The participants will attend two trial days.

On one trial day the volunteers will receive bilateral ulnar nerve blocks. In one arm they will receive the local anaesthetic ropivacaine 4ml 5mg/ml and placebo (saline) and in the other arm ropivacaine 4ml 5mg/ml and dexmedetomidine 100μg. The dexmedetomidine administered perineurally is absorbed and redistributed and will influence the two nerve blocks equally systemically. On the other trial day the participants will receive ropivacaine 4ml 5mg/ml and placebo (saline) and in the other arm ropivacaine 4ml 7.5mg/ml and placebo (saline). The allocation is blinded to volunteer and investigator.

In this setup we therefore have a perineural- and a systemic dexmedetomidine group and also a placebo group , and a group testing if higher doses of local anesthetics will prolong the duration of a nerve block.

The duration of the nerve block will be measured by 3 different tests: pinprick, temperature test (alcohol) and Pain during tonic heat stimulation. All tests are validated within pain research.

Enrollment: 22 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Participants must understand the protocol fully and sign the written in-formed consent.
• ASA 1-2
• BMI > 18 to < 30
• For fertile women: safe contraceptives for the last month and a nega-tive urin HCG.

Exclusion criteria

• Participants unable to cooperate in the trial.
• Participants unable to speak or read Danish
• Allergy to study medication.
• Alcohol consumption >21 units for men and >14 for women per week
• Daily intake of prescription painkillers within the last 4 weeks.
• Over the counter painkillers during the last 48 hours.
• Neuromuscular defects or wounds on the arms or hands preventing test performance.
• Diabetes Mellitus
• 2. degree heart block
• Sick sinus node.
• For fertile women a positive urine HCG

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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22 participants in 4 patient groups, including a placebo group

Perineural dexmedetomidine

Experimental group

Description:

Ulnar nerve block 4ml ropivacaine 5mg/ml + 1ml 100ug/ml dexmedetomidine perineurally

Treatment:

Drug: Dexmedetomidine perineurally

Drug: Ropivacaine 5mg/ml

Systemic dexmedetomidine

Active Comparator group

Description:

Ulnar nerve block 4ml ropivacaine 5mg/ml + 1ml isotonic saline (placebo) perineurally + 100ug dexmedetomidine systemically (absorbed and redistributed from the opposite ulnar nerve block)

Treatment:

Drug: Isotonic saline

Drug: Dexmedetomidine systemically

Drug: Ropivacaine 5mg/ml

Placebo

Placebo Comparator group

Description:

Ulnar nerve block 4ml ropivacaine 5mg/ml + 1ml isotonic saline (placebo) perineurally

Treatment:

Drug: Isotonic saline

Drug: Ropivacaine 5mg/ml

High dose Ropivacaine

Active Comparator group

Description:

Ulnar nerve block 4ml ropivacaine 7.5mg/ml + 1ml isotonic saline (placebo) perineurally

Treatment:

Drug: Isotonic saline

Drug: Ropivacaine 7.5mg/ml