Anesthesia for Shoulder Surgery

Surgery on the Upper Extremity

Procedures on the upper extremities include those for disorders of the shoulder (eg, subacro-mial impingement or rotator cuff tears), traumatic fractures, nerve entrapment syndromes (eg, car-pal tunnel syndrome), and joint arthroplasties (eg, rheumatoid arthritis).

SHOULDER SURGERY

Shoulder operations may be open or arthroscopic. These procedures are performed either in a sitting (“beach chair”) or, less commonly, the lateral decu-bitus position. The beach chair position may be associated with decreases in cerebral perfusion as measured by tissue oximetry; cases of blindness, stroke, and even brain death have been described, emphasizing the need to accurately measure blood pressure at the level of the brain. When using non-invasive blood pressure monitoring, the cuff should be applied on the upper arm because systolic blood pressure readings from the calf can be 40 mm Hg higher than brachial readings on the same patient. If a surgeon requests controlled hypotension, an arte-rial catheter for invasive blood pressure monitoring is recommended, and the transducer should be positioned at least at the level of the heart or, prefer-ably,

the brainstem (external meatus of the ear).The interscalene brachial plexus block using ultrasound or electrical stimulation is ideallysuited for shoulder procedures. The supraclavicular approach also can be used. Even when general anes-thesia is employed, an interscalene block can supple-ment anesthesia and provide effective postoperative analgesia. Intense muscle relaxation is usually required for major shoulder surgery during general anesthesia, particularly when not combined with a brachial plexus block.

Preoperative insertion of an indwelling peri-neural catheter with subsequent infusion of a dilute local anesthetic infusion solution allows postoperative analgesia for 48–72 h with most fixed-reservoir disposable pumps following arthroscopic or open shoulder operations . Alternatively, surgeons may insert asubacromial catheter to provide continuous infu-sion of local anesthetic for postoperative analgesia. Direct placement of intraarticular catheters into the glenohumeral joint with infusion of bupivacaine has been associated with postarthroscopic gleno-humeral chondrolysis in retrospective human and prospective animal studies and is not currently rec-ommended. Multimodal analgesia, including sys-temic NSAIDs (if no contraindications) and local anesthetic infusions in the perioperative period, can help reduce postoperative opioid requirements.