Assessment of the C8 Dermatomal Block with Photoplethysmographic Amplitude After Interscalene Brachial Plexus Block

With the head rotated contralateral to interscalene brachial plexus block (ISBPB), the compactly arranged brachial plexus is visualized lateral to the pulsating subclavian artery under ultrasound guidance. The linear ultrasound transducer is moved cephalad until the C5-to-C8 nerve roots are visualized between the anterior and middle scalene muscles. A block needle is introduced from lateral to medial direction. A nerve root is blocked by placing at least 5 ml of 0.75% ropivacaine around it. The most caudal cervical nerve root (C6 nerve root) is blocked first, and the most cephalad one (C5 nerve root) is blocked last. Then, 3 ml of 0.75% ropivacaine is placed between the scalene and sternocleidomastoid muscles to block the supraclavicular nerves. An equivalent volume of a standard study drug is planned to be used (A total of 25 ml of 0.75% ropivacaine).

With the head rotated contralateral to interscalene brachial plexus block (ISBPB), the compactly arranged brachial plexus is visualized lateral to the pulsating subclavian artery under ultrasound guidance. The linear ultrasound transducer is moved cephalad until the C5-to-C8 nerve roots are visualized between the anterior and middle scalene muscles. A block needle is introduced from lateral to medial direction. A nerve root is blocked by placing at least 5 ml of 0.75% ropivacaine around it. The most caudal cervical nerve root (C8 nerve root) is blocked first, and the most cephalad one (C5 nerve root) is blocked last. Then, 3 ml of 0.75% ropivacaine is placed between the scalene and sternocleidomastoid muscles to block the supraclavicular nerves. An equivalent volume of a standard study drug is planned to be used (A total of 25 ml of 0.75% ropivacaine).