Does Perineural Clonidine Prolong Duration of a Nerve Block?

Zealand University Hospital

Status and phase: Completed; Phase 2

Conditions: Healthy

Treatments: Drug: Ropivacaine 20ml 5mg/ml+ Clonidine 150ug; Drug: Ropivacaine 20ml 5mg/ml+ Placebo

Study type: Interventional

Funder types: Other

Identifiers

NCT02444559

SM1-JH-14

2014-005640-18 (EudraCT Number)

Details and patient eligibility

About

The aim of this trial is to investigate if clonidine prolongs the duration of an adductor canal block. By using healthy volunteers the investigators can perform a bilateral adductor canal block and thereby control for a systemic effect to clarify if the effect is actually peripheral or systemic. The investigators hypothesis is that clonidine/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 clonidine to the local anaesthetic ropivacaine in peripheral nerve blocks.

The prolonging effect of using clonidine as adjuncts 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 clonidine will be investigated using the adductor canal block. This is a nerve block that besides being efficient as pain treatment after knee surgery, is primarily sensory, and therefore augments mobilization after total knee arthroplasty.

Method:

On the trial day the volunteers will receive bilateral adductor canal blocks. In one thigh they will receive the local anaesthetic ropivacaine 20ml 5mg/ml and placebo (saline) and in the other thigh ropivacaine 20ml 5mg/ml and Clonidine 150μg. The allocation is blinded to volunteer and investigator.

The duration of the nerve block will be measured by five different tests: Temperature test, Pinprick, Pain during tonic heat stimulation, Warmth detection threshold and pain detection threshold. All tests are validated within pain research.

Enrollment: 21 patients

Sex: Male

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• American Society of Anesthesiologists class 1
• Body Mass Index 18-30

Exclusion criteria

• Allergy to study medication
• Earlier trauma or surgery to lower limb
• Diabetes Mellitus
• Alcohol or drug abuse
• Daily intake of opioids or steroids last 4 weeks
• Daily intake of any analgesics last 48 hours Heart block Sick sinus node.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Quadruple Blind

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21 participants in 2 patient groups, including a placebo group

Ropivacaine+Clonidine

Experimental group

Description:

Adductor Canal Block Ropivacaine 20ml 5mg/ml+ Clonidine 150ug

Treatment:

Drug: Ropivacaine 20ml 5mg/ml+ Clonidine 150ug

Ropivacaine+Placebo

Placebo Comparator group

Description:

Adductor Canal Block Ropivacaine 20ml 5mg/ml+ saline

Treatment:

Drug: Ropivacaine 20ml 5mg/ml+ Placebo