It's a prospective monocentric randomized controlled clinical trial in 2 parallel groups in double blind.~the study concerns patients undergoing arthroscopic shoulder surgery with ISB. The study seeks to show that interscalene injection of a small volume (<8ml) of ropivacaine at a low concentration (0.1%) reduces the frequency of hemi-diaphragmatic paresis compared to low volume injection at the standard concentration (0.5%) in patients undergoing arthroscopic shoulder surgery with ISB.~Randomization in one of the two arms:~Experimental group: <8ml ropivacaine 0.1%.~Control group: <8mL of ropivacaine 0.5%.~Evaluation of diaphragmatic stroke by ultrasound and ventilatory function by spirometry and snip test before performing the ISB, then after installation of the ISB.~Performing the surgical procedure under general anesthesia assessment of postoperative analgesia and patient satisfaction during the following 48 hours.
The study seeks to show that interscalene injection of a small volume (<8ml) of ropivacaine at a low concentration (0.1%) reduces the frequency of hemi-diaphragmatic paresis compared to low volume injection at the standard concentration (0.5%) in patients undergoing arthroscopic shoulder surgery with ISB.