Cerebral Desaturation Monitoring Recommended in Arthroscopic Shoulder Surgery

A new study demonstrates the benefits associated with monitoring absolute cerebral oximetry on patients undergoing arthroscopic shoulder surgery in the "beach chair” position.

Researchers at the NorthShore University Health System (Northshore, Evanston, IL, USA) and the University of Chicago (IL, USA) collected data on 124 patients undergoing elective shoulder arthroscopy, who were then divided into two approximately equal sized groups. One group had surgery performed in the beach chair position (BCP), while the second group had surgery performed in the lateral decubitus position (LDP).

The results of the study showed that cerebral desaturation events occurred frequently in patients in the BCP, whereas no desaturation events were observed in the patients undergoing surgery in the LDP. The study included an intervention protocol for clinicians when a cerebral desaturation event occurred, thereby allowing clinicians to proactively treat the patients and reduce the duration of the event. The study also reported a strong correlation between cerebral desaturation events and a multifold increase in the incidence of postoperative nausea and vomiting.

Desaturation was measured using the Casmed (Branford, CT, USA) Fore-Sight cerebral oximeter, which uses near-infrared spectroscopy technology to provide noninvasive continuous monitoring of regional cerebral tissue oxygen saturation (SctO2), and allows for immediate recognition and treatment of cerebral desaturation events that might otherwise be undetected with conventional intraoperative monitoring. The study was published early online on June 22, 2010, in Anesthesia & Analgesia.

"Although orthopedic patients in the beach chair position are at risk for cerebral hypoperfusion, no previous clinical trials have assessed changes in SctO2 in this patient population,” said lead author Glenn Murphy, M.D., of the department of anesthesiology at Northshore. "Results from this study demonstrate that significant reductions in SctO2 occur in patients in the beach chair position, despite the use of a protocol designed to maintain a systemic mean arterial pressure within 20% of presurgical supine position pressure.”

The beach chair position has been used for shoulder arthroscopic procedures since the early 1980s, and it has gained popularity because it offers a number of technical advantages over the lateral decubitus approach. In the United States, approximately two-thirds of arthroscopic and open shoulder procedures are performed in the beach chair position and, although rare, catastrophic neurologic events such as cerebrovascular events, brain and spinal cord injury, and visual loss have been reported following surgery in this position.

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NorthShore University Health System
University of Chicago