Screening Older Patients for Cognitive Risk Before Surgery 

Disclaimer: This article is intended solely for informational and educational purposes only. It does not constitute medical advice.

Older adults undergoing surgery may have cognitive impairment or risk factors that are not apparent during a routine preoperative history and physical examination. Identifying these risks is important because baseline cognition can influence how patients tolerate the physiologic and environmental stresses of surgery and hospitalization. In one cohort of older adults undergoing major elective operations, 44% had impaired cognition on preoperative Mini-Cog testing. Among patients scheduled for elective hip or knee replacement who had no diagnosis of dementia, 24% screened positive for probable cognitive impairment. Cognitive screening of older patients before surgery can reveal clinically relevant concerns, allowing clinicians to better prepare and manage patients at risk of postoperative cognitive dysfunction (1). 

The principal concern with impairments in cognition is the association between impaired baseline cognition and adverse postoperative outcomes. Robinson et al. reported that older patients with impaired preoperative cognition experienced more postoperative complications and longer hospital stays and were more likely to require institutional care after discharge (1). Similarly, Culley et al. found that patients with probable cognitive impairment before elective orthopedic surgery had greater odds of delirium, longer hospitalization, and discharge somewhere other than home (2). Thus, cognition provides information about postoperative risk that is not encompassed by evaluation of organ-system disease alone. 

Preoperative cognitive screening should be brief enough to fit into routine clinical assessment while still identifying patients who may require closer evaluation. The Mini-Cog is a short screening test for cognitive impairment that assesses memory through three-word recall and executive and visuospatial function through a clock-drawing task. It can be administered in only a few minutes and does not require an extensive neuropsychological evaluation, making it practical for preoperative use (3). When a broader assessment is appropriate, the Montreal Cognitive Assessment (MoCA) evaluates several cognitive domains, including memory, attention, language, executive function, and visuospatial ability. Among instruments evaluated for detecting mild cognitive impairment in older adults, the MoCA has demonstrated relatively high sensitivity and specificity (4). 

The purpose of screening must also be distinguished from diagnosis. An abnormal Mini-Cog or MoCA result does not establish dementia, and cognitive impairment alone is not a reason to deny an otherwise appropriate operation. Instead, the result can identify a patient who warrants closer evaluation or additional perioperative support. It also provides a baseline against which postoperative mental-status changes can be compared. Without documentation of preoperative cognition, distinguishing a new postoperative disorder from preexisting impairment may be difficult (4). 

Screening becomes most useful when the result changes care. Identified impairment can prompt review of medications that contribute to delirium, involvement of family or caregivers in perioperative discussions, and assessment of whether the patient will need additional assistance after discharge. It can also inform delirium-prevention measures, including orientation, early mobility, adequate hydration, sleep preservation, pain management, and ready access to hearing aids and eyeglasses. Cognitive findings should be interpreted alongside functional status, frailty, comorbid disease, and surgical complexity rather than considered in isolation. Used this way, preoperative cognitive screening supplies information that can improve risk discussions, establish a meaningful baseline, and help the surgical team plan for the needs of older patients throughout recovery. 

References 

1. Robinson TN, Wu DS, Pointer LF, Dunn CL, Moss M. Preoperative cognitive dysfunction is related to adverse postoperative outcomes in the elderly. J Am Coll Surg. 2012;215(1):12-18. doi:10.1016/j.jamcollsurg.2012.02.007 

2. Culley DJ, Flaherty D, Fahey MC, et al. Poor Performance on a Preoperative Cognitive Screening Test Predicts Postoperative Complications in Older Orthopedic Surgical Patients. Anesthesiology. 2017;127(5):765-774. doi:10.1097/ALN.0000000000001859

3. Long LS, Shapiro WA, Leung JM. A brief review of practical preoperative cognitive screening tools. Can J Anaesth. 2012;59(8):798-804. doi:10.1007/s12630-012-9737-1 

4. Pas MT, Olde Rikkert M, Bouwman A, Kessels R, Buise M. Screening for Mild Cognitive Impairment in the Preoperative Setting: A Narrative Review. Healthcare (Basel). 2022;10(6):1112. Published 2022 Jun 15. doi:10.3390/healthcare10061112