A randomised controlled trial in patients undergoing arthroscopic shoulder surgery comparing interscalene block with either 10 ml or 20 ml levobupivacaine 0.25

• Published in: Anaesthesia Vol. 77; no. 10; pp. 1106 - 1112
• Main Authors: Oliver‐Fornies, P., Gomez Gomez, R., Ortega Lahuerta, J. P., Carbonel Bueno, I., Gonzalo Pellicer, I., Ripalda Marin, J., Orellana Melgar, C. E., Fajardo Perez, M.
• Format: Journal Article
• Language: English
• Published: 01-10-2022
• Subjects: arthroscopic shoulder surgery; diaphragmatic paralysis; interscalene brachial plexus block; postoperative pain; ultrasound
• ISSN: 0003-2409; 1365-2044
• DOI: 10.1111/anae.15822

Summary
The interscalene brachial plexus block is recommended for analgesia after shoulder surgery but it may cause hemidiaphragmatic dysfunction. We tested whether ipsilateral hemidiaphragmatic contraction was better after a smaller dose of local anaesthetic without impairing analgesic effect. We randomly allocated 48 adults to 10 ml or 20 ml levobupivacaine 0.25% before arthroscopic shoulder surgery. The primary outcome was hemidiaphragmatic paralysis, defined as inspiratory thickness < 1.2 times expiratory thickness, measured by ultrasound 4 h after block. Hemidiaphragmatic paralysis was recorded for 6/24 vs. 23/24 supine participants after 10 ml vs. 20 ml levobupivacaine 0.25%, respectively, and for 4/24 vs. 23/24 sitting participants, respectively, p < 0.001 for both. Pain scores after 10 ml injectate were not worse than after 20 ml injectate. Median (IQR [range]) morphine doses in the first 24 postoperative hours after 10 ml and 20 ml levobupivacaine 0.25% were 2 (0–6 [0–23]) mg vs. 1 (0–2 [0–11]) mg, respectively, p = 0.12. No participant had a complication after 10 ml interscalene levobupivacaine, whereas seven had complications after 20 ml levobupivacaine, p = 0.009. Hemidiaphragmatic function was better after 10 ml vs. 20 ml interscalene levobupivacaine 0.25% without impairing analgesia for 24 postoperative hours.