Ultrasound Guided Nerve Stimulation and Nerve Stimulation Alone for Supraclavicular Brachial Plexus Block – A Randomized Comparative Study

Abstract

Background: The safety of regional anaesthesia become more pronounced by the use of ultrasound andnerve stimulator. Supraclavicular nerve blocks known as ‘spinal of the arm’ are the most attractiveupper extremity blocks to perform in our practice. In this study less experienced hands try to found thebest approach for upper extremity block.

Objective: To comparethe success rate when Ultrasound addedwith Peripheral nerve stimulator insupraclavicular brachial plexus block.

Methods: After IRB approval and written consents from patients, total 66 patients divided into twogroups,Group USNS had supraclavicular block guided by both ultrasound and Nerve stimulator. Onthe other hand Group BNS had this block by only Nerve stimulator. All the equipments kept ready andmaintaining sterility a mixture of 0.5% Bupivacaine and 2% plain Lignocaine were prepared. The amountinjected according to the body weight without crossing the toxic dose (2mg/Kg 0.5% Bupivacaine, 5mg/Kg 2% Lignocaine). Total volumes were 25-30ml for every patient.The sensory block was assessed byobservers who unaware of the technique for every 2 minutes till the onset of block and every 10 minutesthereafter for 30 minutes. Any failure in establishing the block was converted to GA. The sensorydermatomes were assessed by alcohol swab. The motor blocks were evaluated by the same observer ineach jointfor every 2 minutes till onset than 10, 20 & at the end of 30 minutes.Successful block wasconsidered if no supplementation or conversion to general anaesthesia required.

Results: In all demographic variables and ASA Class, there was no differences in between the USNSgroup and BNS group.In group USNS block execution time was significantly higher(P<0.05). The timerequired for both sensory and motor block was statistically significantly less in Group USNS comparedto Group BNS (P value < 0.05). Regarding quality of motor block, at wrist joint statistical significancepresent between two groups ( p value < 0.05 ). The duration of analgesia is significantly lower in GroupBNS than Group USNS (P value is 0.012).In Group USNS, only one (3.03%) patient neededsupplementation. But in Group BNS 7 (21.21%) patients needed supplementation. According to thedefinition, these cases were regarded as failed case. The success rate is significantly higher in GroupUSNS (P value is 0.024).

Conclusion: Combined use of ultrasound and peripheral nerve stimulator increases success rate thanperipheral nerve stimulator alone in supraclavicular brachial plexus block. This combined method alsoreduces block execution time, early onset of both sensory and motor block, improve quality of sensory andmotor block and less incidence of complications.

JBSA 2018; 31(2): 54-61