One Hundred Percent Incidence of Hemidiaphragmatic Paresis Associated with Interscalene Brachial Plexus Anesthesia as Diagnosed by Ultrasonography

Ropivacaine for ultrasound-guided interscalene block: 5 mL provides similar analgesia but less phrenic nerve paralysis than 10 mL

“…Previous investigations have indicated a 100% incidence of ipsilateral hemidiaphragmatic paralysis after interscalene block. 20,21 Thus, the ability to reduce the incidence of hemidiaphragmatic paralysis by using a small volume of local anesthetic for interscalene block is important.…”

Anatomical study of phrenic nerve using ultrasound

“…Precise mapping of the course of this nerve in the cervical region, the only portion readily accessible by ultrasonography, might have useful clinical implications, such as percutaneous interventions, or facilitating the injection of anaesthetics when a selective nerve block is considered [3][4][5]. On the other hand, one must avoid anaesthetising this nerve when performing other therapeutical cervical or supraclavicular brachial plexus blocks [6][7][8].…”

Ultrasound-guided interscalene block for postthoracotomy ipsilateral shoulder pain

“…Concerns with this approach are the incidence of phrenic nerve paresis with associated diaphragmatic dysfunction and respiratory depression [7,8]. An adequately placed interscalene block is believed to be associated with a 100% incidence of phrenic nerve paresis [8], which could result in a 25% reduction in vital capacity.…”