Comparative evaluation of two approaches of infraclavicular brachial plexus block for below elbow orthopaedic surgeries under dual guidance of USG and PNS- A randomised single blinded clinical study

AIM

To compare retroclavicular and classical approaches to infraclavicular brachial plexus block for providing anaesthesia for forearm surgeries under dual guidance of ultrasound and peripheral nerve stimulator.

 OBJECTIVES

Primary objective:

To compare the procedure time between both the groups

Secondary objectives:

Needle visibility

Number of needle passes

Success rate

Onset and duration of sensory and motor block

Complications if any

                                                          METHODLOGY

Ethical consideration- The principles of Helsinki declaration will be followed throughout the study. This study will be conducted after getting approval from local Ethical Committee of GMERS Medical College and Hospital, Gotri, Vadodara. It will be registered under clinical trial registry of India. Written and informed consent will be taken from all participants. Data collected will be kept confidential.

Study design- Randomised controlled, single blinded study

Study setting- Tertiary care teaching hospital (GMERS medical college and hospital, Gotri, Vadodara)

Study duration- approximately 1 year

Study population- Total 80 patients with below elbow trauma undergoing orthopaedic surgeries of forearm, wrist and hand under regional anaesthesia.

Inclusion criteria:

Age:  18-60 years

BMI : < 25 kg/m2

American society of Anaesthesia grading : I and II

Exclusion criteria:

Patient refusal

Allergy to LA

Local site infection

Anatomical distortion of clavicle

Polytrauma

Pre-existing neurological deficit

Pre-existing systemic illness like uncontrolled hypertension or ischemic heart disease, severe pulmonary disease, renal or hepatic dysfunction, sepsis

Surgeries requiring tourniquet

Coagulopathy

Patients with hearing disability, dementia, psychiatric illness or mentally challenged or having a language barrier, who cannot express scoring system used in the study

STUDY PROCEDURE

Randomization and allocation :

Patients will be randomly assigned to either CIB (C) or RCB (R) group in 1:1 ratio using predetermined computer generated randomisation table. To ensure concealment, sequentially numbered, opaque and sealed envelopes will be used. Only the research assistant will have access to the envelopes. A research assistant, resident or Anaesthesiology department staff member will be responsible for assessing participant eligibility and recruitment. Intervention

Patients will be randomized in two groups:

Group C (n=40): Classical approach of ICB

Group R (n=40): Retroclavicular approach of ICB

After a detailed Pre-Anaesthetic examination and taking patient in a pre-operative room, an 18 or 20 gauge intravenous catheter will be secured in upper limb contralateral to surgical upper limb and intravenous pre-medication (0.03 mg/kg midazolam) will be administered to all patients. Supplemental oxygen (by nasal cannula at 4L/min) and standard ASA monitors will be applied throughout the procedure.

All blocks will be performed under aseptic and antiseptic precautions and after local anaesthesia infiltration of skin (2 or 3 ml of inj. Lignocaine 1%). Inj. Levobupivacaine 0.5%- 15 ml (2 mg/kg) and inj. Lignocaine 0.2%- 15ml (5 mg/kg) will be given to all patients.

USG+ PNS guided Classical approach

With the patient in the proper position with arm abducted to 90 degrees and the elbow flexed, the skin will be disinfected. After identifying coracoid process, high-frequency linear transducer is positioned just medial to the coracoid process and inferior to the clavicle in the parasagittal plane, scanning medially and laterally to identify the axillary artery. Once the artery has been identified, an attempt will be made to identify the hyperechoic cords of the brachial plexus and their corresponding positions relative to the artery.The needle then will be inserted in-plane from the cephalad end of the probe, with the insertion point just inferior to the clavicle. The needle, aimed toward the posterior aspect of the axillary artery and passes through the pectoralis major and minor muscles. Nerve stimulation with long (80-100mm) PNS needle will be used concurrently (0.5–0.8 mA, 0.1 m sec), the first motor response is often from the lateral cord (either elbow flexion or finger flexion). As the needle is advanced further beneath the artery, a posterior cord motor response may appear (finger and wrist extension). After careful aspiration, 1–2 mL of local anaesthetic will be injected to confirm proper needle placement and spread. The total drug volume should spread cephalad and caudal to cover the lateral and medial cords, respectively.

USG + PNS guided Retroclavicular approach

The technique will be performed with the patient supine and the arm adducted. A high-frequency linear ultrasound transducer will be placed inferiorly to the clavicle just medially to the coracoid process in the parasagittal plane such that the axillary vessels and cords of the brachial plexus are viewed in cross-section. In this short axis view, the lateral cord appears in the anterocranial position, posterior cord in the posterocranial position, and median cord in the posterocaudal position. A needle insertion point is chosen in the supraclavicular fossa, between the clavicle and trapezius, so that the needle will pass behind the clavicle and enter the ultrasound image nearly parallel to the transducer (or perpendicular to the beam) and tip of the needle is directed near 5 or 6 o’clock position of axillary artery. A long (80-100mm) needle of PNS will be required given the distance from the supraclavicular fossa to the axillary artery.

In this technique, the US probe is initially angled towards the clavicle to identify the needle approaching from behind the clavicle.  After confirming with motor response as described in classical approach with PNS, 0.5% Levobupivacaine 15ml and 0.2% lignocaine 15ml will be given after negative aspiration.

OUTCOME MEASURES-

Primary outcome:

Comparison of performance time (time interval from the contact of the ultrasound probe with the patient to appreciate axillary artery to removal of the block needle) of Classical and Retroclavicular approaches.

Secondary outcome:

Needle visibility

Needle passes

To compare success rates ( patients requiring additional analgesia)

To compare onset of sensory and motor block in both groups

Complications