LAUSR

In the United States alone, over 50 million general anesthetics for surgery are administered every year (Hall et al., 2017). Reduced cognition post-operatively, referred to here as post-operative cognitive dysfunction (POCD), is decreased neurocognitive function after anesthesia and surgery, as compared to preoperative neurocognitive function. It is commonly measured objectively by a battery of neuropsychological tests (Moller et al., 1998). The nomenclature has since evolved under the term of perioperative neurocognitive disorders, which encompass pre-operative impairment, post-operative delirium (POD), as well as cognitive dysfunction within the first 30 days of surgery, known as delayed neurocognitive recovery, and from days 31 to 12 months known as postoperative neurocognitive disorder (Evered et al., 2018; Evered and Goldstein, 2021). While not as emphasized of a risk to patients as the risk of major bleeding, for example, in current practice, the risk of developing POCD is not negligible. For example, in patients undergoing coronary artery bypass surgery on cardiopulmonary bypass, 53% have evidence of POCD at time of discharge, and 24% still have evidence of POCD 6 months later (Newman et al., 2001). When looking at non-cardiac surgery, a remarkable percentage of patients have evidence of POCD at discharge. An early study published in 1999 looked patients over the age of 60 undergoing a variety of orthopedic, urologic, vascular, and abdominal surgeries. Three months after discharge, approximately 10% of patients had evidence of POCD (Moller et al., 1998). A second study confirmed these findings using young, middle, and elderly age groups, with the young and middle-aged groups having a higher number of intra-abdominal and thoracic surgeries, and a lower number of orthopedic surgeries compared to the elderly group (Monk et al., 2008). More importantly, POCD is associated with poor clinical outcomes. There is a correlation between POCD and mortality (Monk et al., 2008), decreased participation in the labor market (Steinmetz et al., 2009), and time to discharge is longer (Silbert et al., 2006). Given these findings, and with an aging population, research into identifying contributing factors to this neurocognitive dysfunction can have huge impacts on our ability to predict its development, and improve how physicians, patients, and families can prepare, prevent, or lessen the risk and severity of its occurrence.