Postoperative Delayed Neurocognitive Recovery in Elderly Patients Undergoing Spinal Anesthesia: Assessment of Its Prevalence and Correlation With Preoperative Sleep Disorders and Melanin Concentrating Hormone.

Perioperative neurocognitive disorders (PNDs) have gradually become a priority during the perioperative period, including neurocognitive disorder before surgery, delirium and delayed neurocognitive recovery (DNR) within 30 days after surgery, and postoperative neurocognitive disorder up to 12 months after surgery. The incidence of DNR ranges from 9.1% to 45%, which seriously affects the perioperative brain health of older adult patients .

The increasing aging population and the reduced function and compensatory capacity of various systems in elderly patients also significantly increase the risk of cognitive dysfunction .

Sleep disorders are critical risk factors among the various risk factors for DNR after surgery. Meanwhile, aging is an independent risk factor for sleep disorders .

Therefore, it is clinically significant to conduct early cognitive risk prediction, focusing on older adult patients with preoperative sleep disorders. Studies have explored the risk factors for perioperative sleep disorders, while other studies have also explored the risk factors affecting postoperative cognitive outcomes. However, no study has explored the specific risk factors for DNR in patients with preoperative sleep disorders. Considering the relationship between sleep and postoperative cognitive function, especially in older adult patients, it is necessary to link these 2 main risk factors (preoperative sleep disorders and DNR) that impair the perioperative brain health to explore potential biomarkers .

Melanin-concentrating hormone (MCH) is a highly conserved cyclic neuropeptide with 19 amino acids in mammals and has a variety of physiological functions, including orexigenic properties, energy homeostasis, regulation of moods, sleep, wakefulness, and cognitive functions .