Older adults represent a growing patient population with unique care needs. As perioperative physicians, our goal is to optimize our patients’ physical, psychological, social, and cognitive health. In a holistic model of care, all the above domains are interconnected, and accordingly our care should be highly integrated across all the domains with specific interventions targeted to areas of risk. High-yield targets for preoperative evaluation include functional status and mobility, nutrition, cognitive screening, and communication and shared decision-making (asamonitor.pub/3nQFLGv). As an example, a high percentage of older adults have probable cognitive impairment when screened preoperatively. These patients are at risk for perioperative neurocognitive disorders, which often impacts physical and psychological health – and, ultimately, outcomes.
The aging process is associated with physiological changes that increase perioperative risk, including a decline in respiratory mechanics, impaired temperature regulation, decreased heart rate variability, and reductions in esophageal muscle tone, renal function, and hematopoietic reserves (Anesthesiol Clin 2019;37:423-36). Thus, perioperative management of the older patient may be complex due to narrower therapeutic windows and the potential for competing clinical goals. In contrast to the physiologic aging process, frailty is a multidimensional syndrome marked by deficits across physiologic, psychologic, cognitive, and social domains. Frailty embodies a state of diminished reserve and increased vulnerability to stressors in the perioperative period that predisposes the patient to postoperative complications and higher resource utilization requirements (Anaesthesiol 2021;34:373-80). A comprehensive approach to the preoperative evaluation of older adults will facilitate the identification of patients at increased perioperative risk such that interventions designed to optimize the patient’s preoperative state are provided.
Functional capacity, mobility, and cardiopulmonary risk assessment
The degree of age-related anatomic and physiologic changes to the respiratory and cardiovascular systems varies widely among older individuals; thus, preoperative functional status assessment is an integral component of preoperative evaluation (Anesthesiol Clin 2019;37:423-36). Results of the 2018 METS trial suggest that assessment of functional capacity via a standardized questionnaire is superior to subjective assessment of METs (metabolic equivalents) for prediction of postoperative mortality and myocardial infarction (Lancet 2018;391:2631-40). The Duke Activity Status Index (DASI) consists of 12 questions, on a scale from 0 to 58.2, with a score >34 associated with reduced odds of 30-day death or myocardial injury (Lancet 2018;391:2631-40). A low DASI score may reflect limitations in cardiopulmonary fitness, poor musculoskeletal strength, self-imposed physical limitations due to pain or psychological state, or frailty syndrome. The American College of Cardiology/American Heart Association guideline on the perioperative cardiovascular evaluation of patients undergoing noncardiac surgery provides a stepwise approach for determining whether additional cardiac testing is warranted. The guideline recommends using a risk prediction tool such as the American College of Surgeons NSQIP Surgical Risk Calculator to estimate the risk of major adverse cardiac events (MACE) and assess functional capacity in patients at elevated risk (J Am Coll Cardiol 2014;64:e77-137). Patients with poor functional capacity should undergo additional cardiac stress testing only if the results will improve perioperative care or decision-making (J Am Coll Cardiol 2014;64:e77-137). Preoperative echocardiography is warranted in cases of newfound or worsening dyspnea. While aging is associated with an increased prevalence of EKG abnormalities, the prognostic significance of these changes is not clear (J Am Coll Cardiol 2014;64:e77-137). By contrast, the incorporation of a cardiac biomarker into risk assessment does appear to improve risk stratification. Levels of NT-proB-type natriuretic peptide (NT-proBNP) ≥300 ng/L are associated with increased cardiac risk (Can J Cardiol 2017;33:17-32; Ann Intern Med 2020;172:843). NT-proBNP is a low-cost, effective method to evaluate patients as compared to cardiac imaging and stress testing. Furthermore, levels of NT-proBNP >300 ng/L are also associated with poorer prognosis and survival in patients with pulmonary hypertension (Chest 2019;156:323-37).
The preoperative evaluation of a patient’s pulmonary status and functional reserve is essential for mitigating postoperative pulmonary complications. The ARISCAT score is the most commonly used risk prediction tool (Anesthesiology 2010;113:1338-50). The ARISCAT risk index incorporates seven risk factors (including age) to stratify patients into low, intermediate, and high-risk groups. Obstructive sleep apnea (OSA) acts as a risk multiplier for perioperative complications, including respiratory depression, major adverse cardiac events, and prolonged hospitalization (World J Surg 2020;44:2609-13). The combination of high prevalence in older adults and strong association with adverse perioperative events has catalyzed the emergence of perioperative protocols to screen, diagnose, and mitigate risk in patients with OSA. The STOP-BANG score is an eight-question, cost-effective, and quick screening tool. A score of ≥5 classifies patients as intermediate-high risk (Ann Thorac Surg 2018;106:966-72). In patients with a formal diagnosis of OSA, emphasizing perioperative adherence to a positive airway pressure device is an opportunity to improve both perioperative and long-term health outcomes.
Mobility and gait speed assessments are other important components of a comprehensive geriatric assessment and are included in several frailty screening tools. Tests frequently used in the preoperative setting include the six-minute walk test, a timed up and go test, and chair sit to stand test. Patients with a slow gait speed or decreased balance may benefit from a preoperative exercise regimen (Anaesthesiol 2021;34:373-80).
Screening and optimization of nutritional deficiencies
Suboptimal nutritional status is an independent risk factor for postoperative mortality, morbidity, and prolonged length of stay, yet the majority of patients at risk for malnutrition remain unidentified and without preoperative intervention (Anesth Analg 2018;126:1883-95; JPEN J Parenter Enteral Nutr 2020;44:1185-96). The Preoperative Nutrition Score (PONS) is a modified version of the malnutrition universal screening tool. Patients aged >65 years are at increased risk of malnutrition when one or more of the following risk factors are present: body mass index (BMI) <20 kg/m2, recent weight loss, decreased oral intake of 50%, and a preoperative albumin level <3.0 g/dL. A PONS score >1 has been associated with an increased risk of postoperative complications (JPEN J Parenter Enteral Nutr 2020;44:1185-96).
Anemia due to a deficiency of iron, folate, or B12 is common in older adults. Even mild anemia (hemoglobin >10g/dL) is associated with increased perioperative morbidity and mortality, and the presence of severe anemia (Hgb <6 g/dl) carries a perioperative mortality rate of 33% (Lancet 1996;348:1055-60). Anemia also multiplies perioperative risk associated with advanced age and comorbidities, including cardiac disease, chronic obstructive pulmonary disease, and diabetes (Lancet 2011;378:1396-407). Thus, preoperative anemia should be addressed before surgery. Iron may be replaced either orally or intravenously depending on patient preference, degree of anemia, and proximity to surgery (Anesth Analg 2020;130:1364-80).
Cognitive screening and assessment of psychological state
Routine preoperative cognitive screening should be incorporated into any comprehensive geriatric preoperative evaluation. Approximately 10%-20% of preoperative cognitive screens performed upon older adults will reveal abnormal results – a finding associated with an increased risk of postoperative delirium and prolonged length of hospitalization (Br J Anaesth 2021;126:230-7; Anesthesiology 2020;133:1184-91).
A test commonly used in preoperative clinics is the Mini-Cog, due to its predictive ability with regard to postoperative complications, its brevity, and its feasibility for use in a busy clinical setting. Derived from the Montreal Cognitive Assessment (MoCA), it is a non-diagnostic screening tool involving a three-word recall and clock-drawing test. Scores less than 3 suggest an increased risk for the development of postoperative delirium (Anesth Analg 2019;129:1283-90). For patients who undergo virtual preoperative evaluation, the Telephone Interview for Cognitive Status (“TICS”), the Short Blessed Test (“SBT”), and Alzheimer’s Disease-8 (“AD8”) have been demonstrated to be feasible for use in a preoperative evaluation clinic and may be preferred for this setting (Anaesthesiol 2021;34:373-80; Br J Anaesth 2021;126:230-7).
Anxiety and depression can be common findings in patients facing a new diagnosis and upcoming surgery. Unrecognized and untreated anxiety and depression can be barriers to successful adherence to a prehabilitation program and can increase postoperative pain, length of hospitalization, and prolonged opioid use. Assessing the patient’s psychological state is therefore another important element of the preoperative evaluation. The Patient Health Questionnaire-9 (“PHQ-9”) for depression is a widely used clinical test to screen for depression in older adults (JMIR Form Res 2022;6:e31209). The Generalized Anxiety Disorder (“GAD-7”) scale specifically screens for anxiety (JMIR Form Res 2022;6:e31209). The Hospital Anxiety and Depression Score (“HADS”) screens for both anxiety and depression; sensitivity and specificity were maximized at a cutoff value of 8 or higher (BMJ 2021;373:n972).
While several conceptual frameworks exist, frailty is often defined by the presence of increased vulnerability to perioperative stress across multiple health domains such as physical, nutritional, and mental fitness. The screening tool selected for inclusion in the preoperative evaluation depends upon whether the deficit accumulation or energy depletion framework is used and the aim of the intended intervention. Screening tools in common use in preoperative clinics include the Clinical Frailty Scale and the FRAIL Scale (Anaesthesiol 2021;34:373-80). The Clinical Frailty Scale has been demonstrated to have both the greatest predictive accuracy and feasibility (Anesthesiology 2020;133:78-95).
Enhancing communication and shared decision-making
The primary goal of a comprehensive preoperative evaluation is to provide our older adult patients with high-quality care that results in the achievement of optimal perioperative outcomes and aligns with their individual health goals. The patient’s preferences and understanding of their clinical situation are vital. Yet, a deficit in preoperative decision-making and/or communication exists in more than one-third of patients (Patient Educ Couns 2014;94:328-33). Deficits in communication or health literacy impact informed consent, advanced care planning, and engagement with a preoperative optimization regimen. We must capitalize upon the preoperative period to identify areas of opportunity to optimize the patient’s preoperative status and to effectively communicate our findings and recommendations to the patient and their family.
Older adults represent a clinically heterogeneous population with perioperative care needs that span across domains of physical, cognitive, psychological, and social status. A comprehensive screening process should result in our ability to triage and implement interventions based upon individual patient risk profiles. Brain health should not be thought of as a silo but rather one component of a holistic model of care. A comprehensive assessment of the above domains with patient-specific, multimodal interventions aimed at improving perioperative outcomes for this growing patient population is warranted. The paradigm of preoperative evaluation is evolving, and it is a best practice to incorporate these advancements into patient care.
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