Background: Ipsilateral diaphragmatic paralysis, caused by the
retrograde diffusion of the local anesthetic (LA) inside the neural
sheath, occurs after supraclavicular blocks, like interscalene
blocks. Therefore, we have tried using ultrasonography (US) to
evaluate diaphragmatic paralysis after varying volumes of
supraclavicular brachial plexus blocks (SCB) Aim: to use an
ultrasound to compare the diaphragmatic paralysis incidence with
varying amounts of LA volumes used in supraclavicular brachial
plexus block. Methods: In a randomized controlled clinical study,
sixty patients with American Society of Anesthesiologists (ASA)
Physical Status I, II&III were randomly assigned to take LA of 25
ml of 0.25% bupivacaine or 30 ml of 0.25% bupivacaine. An inplane supraclavicular block was conducted under ultrasound
guidance. Before and at 30, 45, and 60 minutes after administering
the block, diaphragmatic thickness was measured using a linear
transducer set to 10 MHz, and diaphragmatic excursion was
measured using a curvilinear 3.5 MHz transducer. Results: While
the diaphragmatic thickness fraction was negligible about the
volume, there was a decrease in diaphragmatic excursion in the
group that received 30 mL of diaphragmatic excursion reduction.
The T-test was used to analyze the pre- and post-block data. In
group 2, which received a larger volume, there was less than a 0.05
chance that diaphragmatic excursion would diminish. indicating
statistical significance. Conclusion: findings imply that even in
cases of supraclavicular brachial plexus block, there is a higher
chance of unintentional phrenic nerve blocking. The incidence is
higher at higher volumes, and the ensuing hemidiaphragmatic
paralysis is volume dependent.