Complications include:
- Ipsilateral phrenic nerve block resulting in diaphragmatic paresis occurs in 100% of patients undergoing interscalene blockade, even with dilute solutions of local anesthetics, and is associated with a 25% reduction in pulmonary function. Involvement of the vagus, recurrent laryngeal, and cervical sympathetic nerves is rarely significant, but a patient experiencing symptoms related to these side effects may require reassurance. [More…]