Comparison of ultrasound-guided and electrical nerve stimulation techniques for interscalene brachial plexus block in patients undergoing clavicle surgeries: A randomized clinical study

Introduction: Interscalene brachial plexus block is one of the commonly performed techniques for upper limb regional anaesthesia which can be performed by paraesthesia, nerve stimulator, or ultrasound guided technique. The present study compares ultrasound and electrical nerve stimulator guided techniques in terms of their efficacy and safety when used for administering interscalene brachial plexus blocks. Materials and Method: 60 patients belonging to ASA physical status I or II, aged between 18 to 65 years, undergoing elective clavicle surgeries were randomized into two groups of 30 each. They received an interscalene brachial plexus block with 25ml of 0.75% ropivacaine + 1.5ml (75mcg) of fentanyl, with either nerve stimulator (group N) or ultrasound guidance (group U). The time taken to complete the block, onset of sensory and motor block and the number of inadvertent vascular punctures were noted. Post block haemodynamic parameters and adverse events were also noted. The observations were statistically analyzed using the student's t test and chi square test. P value of less than 0.05 was considered statistically significant. Results: The procedural time in group U (5.93+1.11min) was significantly shorter when compared to that in group N (10.46+2.81min) (p=0.0001). The onset of sensory and motor blocks was similar in both the groups with a P value of 0.91 and 0.89 respectively. Accidental aspiration of blood was seen in 1 patient in Group N (3.33%) but not in Group U. The haemodynamic parameters were in the normal range and there were no adverse events in either group. Conclusion: Though the block onset times are similar with both ultrasound guidance and nerve stimulator, the use of ultrasound is advocated as it has a better utility (shorter procedural time) and safety profile.