ULTRASONOGRAPHIC EVALUATION OF DIAPHRAGMATIC PARALYSIS FOLLOWING SUPRACLAVICULAR BRACHIAL PLEXUS BLOCK BY DIFFERENT VOLUMES OF 0.5% BUPIVACAINE

Background: Ultrasound guidedsupraclavicular brachial plexus block is widely used technique in anaesthesiafor upper limb surgeries. However it can block phrenic nerve to cause diaphragmatic palsy. It is difficult to avoid even with ultrasound-guided supraclavicular brachial plexus block.

Objectives: Our primary objective was to assess the incidence of hemidiaphragmatic paralysis following ultrasound-guided supraclavicular brachial plexus block using different volumes of 0.5% bupivacaine.

Methods: Sixty patients with American Society of Anesthesiologists (ASA) physical status I and II were randomized to receive 20ml (group A) and 30 ml (group B) of 0.5% bupivacaine in a double blinded fashion. Ultrasound guided supraclavicular brachial plexus block was performed. Diaphragmatic excursion was studied using a curvilinear 3.5 MHz transducer before and 20 min after giving the block.

Results: The incidence of partial diaphragmatic paralysis in the group A and group B were 33% and 40% respectively. None of the patient in group A had complete paralysis whereas only 2(6.6%) patients had complete paralysis in group B.

Conclusion: Risk of phrenic nerve block was involved even in ultrasound guided supraclavicular brachial plexus block. Hemidiaphragmatic paralysis is volume dependent, and the overall incidence is higher at greater volumes. Hence, caution is required in patients with pre-existing cardiorespiratory dysfunction.