Effect of Anaesthesiologists’ Experience on Preferred Technique and Volume of Local Anaesthetic Administered for Brachial Plexus Nerve Block: A Retrospective Observational Analysis

Abstract

Introduction: Faculty and Residents are trained in peripheral nerve blocks guided by blind technique, Peripheral Neuro Stimulator (PNS) or Ultrasound (USG) guided technique. But due to unavailability of USG machine in all institutes and requiring special training, techniques used for peripheral nerve blocks vary from institute to institute. Aim: To analyse the effect of anaesthesiologists’ experience on preferred technique and Local Anaesthetic (LA) volume used for brachial plexus nerve block retrospectively. Materials and Methods: In this retrospective observational study, 129 adults American Society of Anesthesiologists (ASA) grade I and II patients requiring brachial plexus nerve block for upper limb orthopaedic surgical anaesthesia for both elective and emergency surgery were divided into three groups for each year depending on technique for nerve block used. Group A: Received USG guided (Micromaxx Sonosite Inc, USA) brachial plexus nerve block. Group B: Received peripheral nerve stimulator (Inmed) guided brachial plexus nerve block. Group C: Received brachial plexus nerve block by traditional anatomical landmark based paraesthesia elicitation blind technique. Patients with inadequate surgical analgesia were given general anaesthesia and were categorised as failure rate. Year wise demographic data, type of technique used for giving brachial plexus nerve block, volume of drug used, failure rate, complications observed were collected and analysed by Student’s t-test and Chi-square test. Results: USG guided technique was the most prefered technique in both years (57.6%, n=38 in year 2018 and 49.2%, n=31 in year 2019). In remaining nearly half of the patients PNS and blind technique was used (PNS 24.2%, n=16 in year 2018 and 20.6%, n=13 in year 2019; blind technique 18.2%, n=12 in year 2018 and 30.2%, n=19 in year 2019). Significantly, less volume of LA drug (mL) was used in group A in year 2019 (16.43±6.07) than in year 2018 (22.34±4.75) (p<0.001). Failure rate in group A in year 2019 (3.2%) was significantly less than in year 2018 (5.2%), but the difference was insignificant in all three groups. In group A, no complications were observed in year 2019 while one incidence of hemidiaphragm paralysis was observed in year 2018, while in group B and C, complications were observed in both years. Conclusion: USG guided nerve block was the most preferred technique for nerve block in the study institute. In 24 months observation period, with increasing experience with USG there was significant increase in success rate and decrease in the volume of LA administered and complications.