Use of saline solution to reverse interscalene block-induced phrenic nerve palsy: a case report.

Brachial plexus block at the interscalene level is a regional anesthetic technique widely used to provide analgesia in shoulder and upper extremity surgery; However, it is associated with a high incidence of phrenic nerve block with diaphragmatic paralysis which has clinical implications in patients with underlying respiratory disease, showing respiratory difficulty symptoms. As consequence, it has been contraindicated in certain population groups. Once diaphragmatic paralysis and respiratory symptoms are established, management is supportive and expectant.