A Comparison Between Ultrasound Guidance Versus Nerve Stimulator Assisted Ultrasound Guidance On The Efficacy Of Supraclavicular Brachial Plexus Block For Upper Limb Surgeries

Abstract

Introduction: In conventional techniques of performance of brachial plexus bock the search for target nerves remains “blind”; leading to prolonged time for nerve localization. Blind techniques cause patient discomfort, increased incidence of complications and require multiple needle attempts. Ultrasound (USG) imaging ensures accurate needle positioning and monitors the distribution of local anesthetic in real time. Thus, improving the quality of block and increasing chances of successful nerve block. In patients with distorted anatomy, obesity and in inexperienced hands USG can be difficult to perform leading incomplete blocks or failure. Nerve stimulation can be used to assist ultrasound guidance to achieve more efficient nerve localization. Objective: Our study aims to compare USG guided and nerve simulator assisted USG guidance for supraclavicular brachial plexus block in patients undergoing upper limb surgeries for 1. Time for the onset and duration of sensory and motor blockade. 2. Time taken for performance of block. Method: After obtaining approval of the Ethical committee and written informed consent, 70 ASA I-II patients aged between 18-60 years posted for elective upper limb surgeries under supraclavicular brachial plexus block were included in the study. Patients were randomly divided into two groups of 35 each by computer generated table. • Group A –Supraclavicular brachial plexus block under ultrasound guidance. • Group B – Supraclavicular brachial plexus block under nerve stimulation assisted ultrasound guidance. Student’s ‘t’ test was used to compare quantitative variables in both groups. P<0.05 was considered statistically significant. Result: In our study the mean time taken for performance of block was 10.22±2.11 minutes in group A and 5.87 ±1.07 minutes in group B. The onset of sensory block 9.28±1.86 minutes in group A and 6.79±1.04 minutes in group B. The mean time of onset of motor block was 17.69±1.45 minutes in group A and 14.56±2.53 minutes in group B. The results were statistically significant with a p<0.001. The mean time for duration of sensory block was 297.29±47.79 minutes in group A and was 396±37.57 minutes in group B. The mean time for duration of motor block was 225.94±42.72 minutes in group A and 245.60±42.82 minutes in group B. These results were not statistically significant. The haemodynamic changes between the two groups were both comparable and were statistically and clinically not significant. Conclusion: In conclusion, the use of nerve stimulation along with ultrasound guidance significantly reduces the time taken for the performance of the block, the onset of sensory and motor block compared to ultrasound guidance alone in patients undergoing supraclavicular brachial plexus block.