Cerebral Perfusion in the Beach Chair Position
The beach chair position is frequently used during shoulder and upper extremity surgeries. In this position, the patient’s torso is elevated approximately 30 to 70 degrees, and the head is positioned above the heart.1 Not only does this posture improve access to the site of surgery, but it also aids in drainage from the vein at the surgical site, potentially limiting intraoperative bleeding. However, it introduces a phenomenon known as a hydrostatic gradient, in which blood pressure differs between two points (in this case, between the heart and the brain). Cerebral perfusion—the flow of oxygenated blood to brain tissue—can thus be reduced in the beach chair position. To prevent complications, active monitoring is necessary.
Cerebral perfusion pressure (CPP) is defined as the mean arterial pressure at brain level minus intracranial or central venous pressure.2 Normally, the brain maintains constant blood flow despite changes in blood pressure. However, when patients undergo anesthesia and are placed in the beach chair position, the combined effects of head elevation, vasodilation, and anesthetic-induced cardiovascular depression can lower CPP, potentially resulting in inadequate cerebral perfusion and ensuing symptoms like dizziness and vision changes, as well as more severe consequences like stroke or permanent brain damage.
There have been reports of adverse neurologic outcomes linked to the beach chair position, though these incidents are rare. A 2005 case series described four instances of catastrophic ischemic injuries, including stroke and spinal cord infarction, following shoulder surgery performed in the beach chair position under general anesthesia.3 Other studies have shown that increased body mass index has a statistically significant association with oxygen desaturation in the brain.4 Such desaturations are usually temporary, but their cumulative effects may contribute to postoperative complications. Notably, a patient can have multiple such events in the course of a single operation.
To monitor cerebral perfusion in the beach chair position, some experts suggest monitoring cerebral oxygen saturation using near-infrared spectroscopy (NIRS) and mean arterial pressures.5 Others report using phenylephrine in addition to monitoring to maintain a certain blood pressure level.6 One challenge in this area is that practices for managing cerebral perfusion in this context can vary widely. For instance, more than 500 anesthesiologists and surgeons from the United Kingdom were surveyed, and together they reported using a wide range of chair angles and cerebrovascular monitoring practices and whether they rely on local guidelines.7
Cognitive outcomes in the days following surgery are at stake. A 2023 study from researchers in Germany examined postoperative cognitive dysfunction (POCD) in older adults undergoing orthopedic surgery in the beach chair versus supine (lying on one’s back) positions. POCD at one week occurred in 21% of patients in the beach chair group compared to 10% in the supine group.8
However, some research, including a recent study of 863 patients who underwent arthroscopic shoulder surgery,9 shows that the beach chair position does not affect cognitive function, as compared to pre-surgery levels. Nonetheless, further research is needed to better understand the interaction between the beach chair position, cerebral perfusion, and possible complications.
References
1. Mannava, S. et al. Basic Shoulder Arthroscopy: Beach Chair Patient Positioning. Arthroscopy Techniques 5, e731–e735 (2016), DOI: 10.1016/j.eats.2016.02.038
2. Mount, C. A. & Das, J. M. Cerebral Perfusion Pressure. in StatPearls (StatPearls Publishing, Treasure Island (FL), 2025).
3. Pohl, A. & Cullen, D. J. Cerebral ischemia during shoulder surgery in the upright position: a case series. J Clin Anesth 17, 463–469 (2005), DOI: 10.1016/j.jclinane.2004.09.012
4. Salazar, D. et al. Cerebral desaturation events during shoulder arthroscopy in the beach chair position: patient risk factors and neurocognitive effects. J Shoulder Elbow Surg 22, 1228–1235 (2013), DOI: 10.1016/j.jse.2012.12.036
5. Ko, S.-H. et al. Cerebral oxygenation monitoring of patients during arthroscopic shoulder surgery in the sitting position. Korean J Anesthesiol 63, 297–301 (2012), DOI: 10.4097/kjae.2012.63.4.297
6. Mori, Y. et al. Cerebral oxygenation in the beach chair position before and during general anesthesia in patients with and without cardiovascular risk factors. J Clin Anesth 27, 457–462 (2015), DOI: 10.1016/j.jclinane.2015.06.007
7. Ensor, D. et al. Should the beach chair position have national guidelines to reduce the risk of cerebrovascular complications? Results from a National Survey of Surgeons and Anaesthetists. Shoulder Elbow 17, 459–465 (2024), DOI: 10.1177/17585732241269147
8. Groene, P. et al. Postoperative cognitive dysfunction after beach chair positioning compared to supine position in orthopaedic surgery in the elderly. Arch Orthop Trauma Surg 144, 575–581 (2024), DOI: 10.1007/s00402-023-05109-0
9. Takayama, K., Ichimura, A. & Ito, H. Arthroscopic shoulder surgery in the beach chair position under single interscalene block does not affect patients’ cognitive function. JSES International https://doi.org/10.1016/j.jseint.2025.09.007 (2025) DOI:10.1016/j.jseint.2025.09.007.