Effect of Local Anaesthetic Dilution on the Characteristics of Ultrasound Guided Axillary Brachial Plexus Block

NCT ID: NCT03207035

Last Updated: 2021-10-18

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2014-10-15
• Study Completion Date: 2016-03-14

Brief Summary

We propose to compare the effects of local anaesthetic dilution on the characteristics of the ultrasound guided axillary brachial plexus block.

Administration of 40ml lidocaine 1% with epinephrine will shorten the onset time of ultrasound guided axillary brachial plexus block when compared to 20 mL lidocaine 2% with epinephrine for elective upper limb surgical procedures.

Detailed Description

To compare the effects of local anaesthetic 20 mL lidocaine 1% with epinephrine vs 40 mL lidocaine 1% with epinephrine on the onset of sensory and motor block following ultrasound guided axillary brachial plexus block.

Methods:

It is a prospective, randomized, observer blinded study. With institutional ethical approval and having obtained written informed consent from each, 20 patients will be studied.

Randomisation and blinding:

Using a computer generated and sealed envelope technique, 20 patients will be randomly allocated in to one of two groups.

Group 1: patients will receive 20 ml of lidocaine 2% with epinephrine. Group 2: patients will receive 40 ml of lidocaine 1% with epinephrine.

Sample size and statistical analysis:

In the absence of data from previous study using 20 ml of lidocaine with epinephrine for ultrasound guided axillary brachial plexus block. Sample size was calculated based on from our pilot study of 12 patients. We found mean onset of block of 11.25 (SD, 2.3) mins. The minimum sample size required to have an 80% probability of detecting a 30% decrease in onset time (level of significance 0.05) will be 7 patients per group using an unpaired student's t test. Recruited 10 per group

Anaesthetic procedure:

Having established intravenous access, standard anaesthetic monitoring will be applied. Premedication with midazolam will be administered as clinically indicated (to a maximum of 3 mg). The operative arm will be abducted and externally rotated with elbow flexed at 90 degrees. Under strict aseptic condition, ultrasound guided axillary brachial plexus block will be performed. Having identified musculocutaneous, median, radial and ulnar nerves, a 50mm 24-gauge stimuplex short bevel insulated needle will be used with in-plane approach to block each nerve with either 5 (Group 1) or 10 ml (Group 2). All blocks will be performed by operator experienced in the ultrasound peripheral nerve blocks.

Block assessment:

When the block procedure has been completed, a blinded observer will assess the onset of sensory and motor block in the innervation of each nerve every 2.5 mins, until surgical anaesthesia is achieved or 30 mins have elapsed (Table 1). Surgical anaesthesia will be defined as a motor score ≤2, with absent sensation to cold and pinprick. Each nerve distribution will be individually assessed. Onset time will be measured from conclusion of the block (t=0) to attainment of surgical anaesthesia. Block will be deemed failure if surgical anaesthesia has not been achieved at 30 mins in one or more of the four nerve distribution. In case of failure, an additional rescue block or conversion to general anaesthesia will be performed. DATA from these patients will be analysed separately.

Intraoperative period:

All patients will receive 1 g of paracetamol and diclofenac 75 mg iv during surgery. In case of patients discomfort sedation and rescue analgesia in the form of fentanyl 25 micrograms aliquots IV will be administered to a maximum of 100 micrograms.

Postoperative period:

Upon arrival to recovery room, sensory and motor function will be assessed every 15 mins by a blinded observer.15 Assessment will be performed for each nerve separately. Block regression is defined as a return of sensation to cold and pinprick with motor power score ≥3 in any nerve region. Time to first request for postoperative analgesia and total opioid consumption for 24 hrs will be noted. Postoperative analgesia will be prescribed as paracetamol 1 g 6 hourly and diclofenac sodium 75 mg 12 hourly. Oxycodone 5-10 mg orally 4-6 hourly will be administered as rescue analgesia.

Primary Outcome: onset of block.

Secondary Outcomes: Duration of sensory and motor block and block performance data (Imaging time, Needling time, Performance time, No of needle pass, Vascular puncture and parasthesia)

Conditions

Brachial Plexus Blockade

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: OTHER
• Blinding Strategy: SINGLE

Study Groups

20 ml of lidocaine 2% with epinephrine

Patients will receive axillary brachial plexus block with 20 ml of lidocaine 2% with epinephrine.

Group Type: ACTIVE_COMPARATOR

Axillary brachial plexus block

Intervention Type: PROCEDURE

Ultrasound guided axillary brachial plexus block with local anaesthetic lidocaine with epinephrine

40 ml 0f lidocaine 1% with epinephrine

Patients will receive axillary brachial plexus block with 20 ml of lidocaine 1% with epinephrine diluted with 20 ml of nacl 0.9% ( total 40 ml)

Group Type: EXPERIMENTAL

Axillary brachial plexus block

Intervention Type: PROCEDURE

Ultrasound guided axillary brachial plexus block with local anaesthetic lidocaine with epinephrine

Interventions

Axillary brachial plexus block

Ultrasound guided axillary brachial plexus block with local anaesthetic lidocaine with epinephrine

Intervention Type: PROCEDURE

Eligibility Criteria

Inclusion Criteria

• ASA 1-3
• Patients aged >18 years undergoing elective upper limb (forearm or hand) surgical procedures.

Exclusion Criteria

• Contraindications to regional anaesthesia
• Hypersensitivity to amide local anaesthetics.
• Chronic pain
• Language barrier
• Neuromuscular disorders or peripheral neuropathy
• Body mass index > 35
• History of hepatic and renal insufficiency
• Pregnancy
• Cognitive or psychiatric disorder
• Cardiac conduction abnormality.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Cork University Hospital

OTHER

Sponsor Role: lead

Responsible Party

Dr Anil Ranganath

Dr (Fellow in Regional Anaesthesia)

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Anil Ranganath, FCAI

Role: PRINCIPAL_INVESTIGATOR

Cork University Hospital

Other Identifiers

ECM 4 (mm)

Identifier Type: -

Identifier Source: org_study_id