Preoperative Evaluation of Procedural Patients: The When, the Why, and the How

Educational Objectives

The goal of this program is to improve preoperative evaluation of patients undergoing surgery. After hearing and assimilating this program, the clinician will be better able to:

1. Recognize the importance of preoperative evaluation for patients undergoing surgery.
2. Select patients who would benefit most from preoperative evaluation.
3. Choose the preoperative tests most likely to provide clinically relevant information while avoiding unnecessary screenings.
4. Identify patients who are at risk for cardiometabolic syndrome.
5. Hold medications for the appropriate duration before surgical procedures.

Summary

Case example: a 69-yr-old woman scheduled for a segmental mastectomy has diabetes mellitus (DM), is on a new injectable medication with unknown risks, and has hypertension (HTN); the patient quit smoking 15 yr ago and has stage 3 chronic kidney disease, an elevated body mass index (BMI), and a sedentary lifestyle; the patient can climb 2 flights of stairs without stopping and has no cardiopulmonary symptoms; the question is which investigations (if any) should be done before surgery; the approach to preoperative evaluation changes for high-risk procedures (eg, open abdominal aortic aneurysm repair); additionally, a history of falls or cognitive decline affect long-term outcomes beyond the perioperative period

Postoperative mortality (POM): 30-day POM is a growing concern in anesthesia and medicine; recent publications, including the May 2024 American Society of Anesthesiologists (ASA) Monitor, highlight that deaths ≤30 days after a procedure would rank third globally if they were categorized as a distinct cause of death, following cardiovascular disease and cancer; while intraoperative anesthetic-related deaths are rare, many patients succumb ≤1 mo post-surgery because of underlying conditions exacerbated by surgical stress; annually, ≈700,000 Americans die from cardiovascular disease, and 600,000 Americans die from cancer; if considered as a separate entity, 30-day POM claims hundreds of thousands of lives in the United States and ≈4 million worldwide; despite successful surgeries, many patients deteriorate postoperatively; the challenge is to recognize and mitigate these risks; many patients die of known comorbidities or postoperative complications (eg, cardiovascular disease, cancer progression, sepsis, hemorrhage); some patients are not expected to live long and undergo procedures meant to be only palliative; some deaths are unexpected, as surgery-induced stress and inflammation may unmask underlying conditions

Preoperative Evaluation

Timing: evaluating a patient right before surgery is too late because unresolved medical issues may necessitate last-minute delays or cancellations, which are undesirable for all parties involved; if the last medical assessment was >1 yr prior, it is likely outdated; Medicare mandates a history and physical examination ≤30 days of surgery that is updated on the day of the procedure; ideally, preoperative examination should occur with enough time for necessary tests (eg, ≥5 business days prior to surgery at the speaker’s organization); stability of the patient’s condition is a key factor

Purpose: aims to enhance patient outcomes, minimize complications, and reduce 30-day mortality; it also seeks to shorten hospital stays, benefiting both patients and health care systems financially; unnecessary day-of-surgery cancellations and delays are disruptive, with reported rates of ≤25%; while some cases warrant postponement of surgery, reducing preventable delays is the goal; reducing costs and eliminating low-value care is another aspect; low-value care refers to tests and procedures that offer little benefit; for example, a routine preoperative chest radiograph was ordered without a clear indication; no one reviewed the results; 6 mo later, the patient developed respiratory symptoms, leading to repeat imaging that diagnosed lung cancer; upon reviewing the earlier radiograph, the mass was already visible but had gone unnoticed, resulting in a delay in diagnosis and increased legal risk

Effect on POM: a retrospective review by Blitz et al (2016) at New York University compared patients who attended a formal preoperative evaluation clinic with those who did not, focusing on in-hospital POM; the study included ≈14,000 patients in each group and found that in-hospital POM was ≈50% lower in those who underwent a preoperative examination; the study also highlighted a long history of papers demonstrating the benefits of preoperative evaluation clinics, dating back to 1949

Benefits: over the decades, research has shown that preoperative evaluation reduces in-hospital mortality, decreases case cancellations, minimizes unnecessary testing, shortens hospital stays, and occasionally identifies previously undiagnosed medical conditions, thereby decreasing day-of-surgery delays

Controversies: Beckerleg et al (2023) found that 30-day all-cause mortality was slightly higher in patients with preoperative evaluations compared with those without; one possible explanation is that sicker patients were more likely to be referred for preoperative evaluations, and they were inherently at higher risk for postoperative complications; another possibility is that preoperative evaluation sometimes leads to excessive medical interventions, ie, unnecessary medication initiation or invasive cardiac procedures, which carry their own risks

Risk stratification: preoperative evaluation is fundamentally about assessing risk; anesthesia providers are risk-averse, aiming to identify and mitigate risks associated with the patient’s comorbidities and the surgical procedure itself; the evaluation process involves stratifying risk levels based on patient health and surgical complexity; various screening tools and risk calculators help quantify these risks; the ultimate goal is to minimize risk wherever possible, which may involve prehabilitation, comorbidity optimization, and care coordination; preoperative evaluations also present opportunities to promote smoking and alcohol cessation, enhance nutrition, and reduce polypharmacy

Indications: healthy patients undergoing minor procedures generally do not need preoperative clearance or testing; however, a history and physical examination ≤30 days of surgery is required and must be updated on the day of the procedure; laboratory tests should be tailored to surgical and patient-specific needs rather than ordered indiscriminately

Prediction of same-day surgical cancellations: a 2022 study published in Anesthesiology News examined data from hundreds of thousands of surgical patients to identify factors associated with same-day cancellations; the strongest predictor was a history of anxiety; patients with anxiety were ≈3 times more likely to cancel than for any other reason; given the increasing prevalence of anxiety disorders, preoperative evaluations provide an opportunity to address patient concerns, discuss medications, and offer reassurance about the surgical process; anesthesia providers, with their extensive experience in surgical settings, are well-suited to manage preoperative anxiety

Investigations: when considering preoperative testing, the key question is whether a test alters patient management; consider the costs and risks associated with testing; in health care, one test often leads to another, sometimes resulting in invasive and costly procedures that may not be necessary; the “Choosing Wisely” campaign by the ASA reinforces these principles; the ASA advises against ordering baseline laboratory studies in patients without significant systemic disease (ASA I or II) who are undergoing low-risk surgery; the ASA recommends against obtaining baseline cardiac diagnostic testing (eg, transthoracic echocardiography, stress tests) in asymptomatic, stable patients undergoing low to moderate-risk noncardiac surgery; the focus should remain on selecting tests that provide actionable, relevant information rather than conducting broad, unfocused screenings

Artificial intelligence (AI): may shape the future of preoperative risk assessment; emerging studies suggest that machine learning models can analyze vast datasets to identify perioperative risk factors and predict adverse outcomes; as AI technology advances, it is likely to play a larger role in preoperative screening, assisting clinicians with risk stratification and decision-making

Cardiometabolic Syndrome

Overview: often referred to as metabolic syndrome (MS), it is a cluster of metabolic dysfunctions; it includes dyslipidemia, characterized by cholesterol abnormalities that lead to atherogenesis, insulin resistance, which can result in DM, and HTN; a key feature of MS is increased abdominal adipose tissue, particularly intra-abdominal fat, which contributes to a proinflammatory and prothrombotic state; patients with MS face an increased risk of adverse events in daily life and during the perioperative period; traditionally, comorbidities (eg, DM, fatty liver disease, heart failure, coronary artery disease, chronic kidney disease) were viewed as separate conditions; however, MS connects these disorders, illustrating their interrelated nature; the National Cholesterol Education Program Adult Treatment Panel defines MS using the 5 criteria of abdominal obesity measured by waist circumference, low high-density lipoprotein cholesterol, hypertriglyceridemia, elevated fasting glucose, and HTN; a diagnosis of MS requires ≥3 of 5 criteria

Role of BMI: notably, BMI is not included in the MS definition; while BMI alone does not define poor health, excessive intra-abdominal fat, even in individuals with normal weight, increases the risk for MS and its associated conditions; obesity rates in the United States have surged, with some states reporting ≥45% of adults have a BMI >40; while human genetics have remained unchanged, shifts in the food environment have contributed to elevated BMI; although BMI itself does not dictate health outcomes, increased intraabdominal adipose tissue heightens the risk for MS-related comorbidities

Role of MS in heart failure: DM and heart failure are strongly linked, with heart failure (either with reduced or preserved ejection fraction) present in ≤30% of patients with DM; these patients are at increased risk for fluid overload and hospitalization due to heart failure; during the preoperative examination, patients with DM should be considered at risk for heart failure; the presence of adipose tissue around the coronary arteries further contributes to cardiovascular disease and heart failure, highlighting the need for awareness even in asymptomatic individuals

New medications for DM: glucagon-like peptide-1 (GLP-1) receptor agonists, dipeptidyl peptidase 4 (DPP4) inhibitors, and sodium-glucose cotransporter 2 (SGLT2) inhibitors have gained prominence in perioperative and general health care settings; these medications, particularly GLP-1 receptor agonists, are now routinely considered in both perioperative and preoperative settings; GLP-1 receptor agonists mimic the effects of incretins, which are metabolic hormones that lower blood glucose levels; incretins, eg, GLP-1 and glucose-dependent insulinotropic polypeptide (GIP), are secreted by L cells in the gut in response to food intake; they slow nutrient absorption, delay gastric emptying, and signal satiety to the brain; DPP4 inhibitors work by preventing the breakdown of incretins, thereby prolonging their glucose-lowering effects

GLP-1 receptor agonists: the development of synthetic, long-acting GLP-1 receptor agonists has shown several benefits; these medications, including semaglutide, liraglutide, and dulaglutide, promote weight loss by reducing appetite and delaying gastric emptying; they also improve renal and cardiovascular outcomes; recently, tirzepatide, a combination GLP-1 and GIP receptor agonist, has entered the market; these medications have distinct trade names depending on whether they are prescribed for DM or weight loss

Adverse effects of GLP-1 receptor agonists: despite their advantages, common gastrointestinal side effects include nausea, reflux, constipation, and diarrhea, which may persist even after dose adjustments; rare complications, including pancreatitis, angioedema, and anaphylaxis, have also been reported; in animal studies, GLP-1 receptor agonists have been linked to thyroid cancer, although this risk does not appear to be present in humans; additionally, discontinuing these medications often leads to weight regain and increased blood glucose levels; a 2024 pharmacy study found that >67% of patients stopped GLP-1 therapy ≤1 yr, citing cost, supply issues, side effects, lack of continued weight loss, or unwillingness to continue with weekly self-injections

Implications of GLP-1 receptor agonists: case reports have highlighted unexpected regurgitation and aspiration risks; instances of retained gastric contents in patients who were appropriately “nothing by mouth” raise concerns, particularly for anesthesiologists; in response, the ASA issued guidance (Ushakumari et al [202]) recommending patients hold weekly GLP-1 injections for >7 days before surgery; however, implementing these recommendations requires coordinated patient communication and DM management planning; a multisociety guideline by Kindel et al (2024) provided updated recommendations; they suggested that patients without gastroesophageal reflux disease or regurgitation risk factors could continue their medication as usual; alternatively, a 24-hr liquid diet before surgery may mitigate risks; the guideline acknowledges limited evidence to support an optimal perioperative approach; in clinical practice, many institutions continue to advise patients to stop injectable GLP-1 medications ≥7 days before surgery and hold oral GLP-1 medications for 24 hr

DPP4 inhibitors: these gliptins, eg, saxagliptin and sitagliptin, work by inhibiting the enzyme that breaks down GLP-1; these drugs function similarly to sulfonylureas but in a milder manner; they do not cause significant weight loss or a dramatic drop in hemoglobin A_1C but help manage DM effectively; they are particularly useful for older patients or those who are less aware of hypoglycemia because they do not drastically lower blood glucose levels

SGLT2 inhibitors: (eg, empagliflozin, dapagliflozin) inhibit the SGLT2 receptor in the proximal convoluted tubule, preventing glucose reabsorption; this leads to glucose being excreted in urine and results in lower blood sugar levels; while these drugs do not lower hemoglobin A_1C as effectively as GLP-1 receptor agonists, they are still effective for managing DM; additionally, they offer significant benefits for heart failure and kidney disease, resulting in a Food and Drug Administration-approved class 1 recommendation for all types of heart failure; in the perioperative setting, these drugs are commonly encountered because of their use in patients with multiple comorbidities; one critical concern with SGLT2 inhibitors is their association with euglycemic metabolic acidosis, prompting the American Heart Association (AHA) to recommend holding them for 3 days before major surgery; for minor outpatient procedures, the speaker’s practice is to hold them only on the day of surgery, despite the AHA recommendation to hold for 3 days; in emergency surgery cases, it is crucial to inform the surgical team if a patient has been taking these medications because they could be at risk for euglycemic metabolic acidosis

Obstructive sleep apnea (OSA): is a widespread but underdiagnosed condition affecting ≈1 billion people worldwide; diagnosis is made through polysomnography, in which apnea is defined as a ≥90% reduction in airflow for ≥10 sec, while hypopnea is defined as a >30% reduction; mild sleep apnea is characterized by 5 to 14 episodes/hr, whereas severe cases involve >30 episodes/hr; OSA is associated with body weight, aging, medications, neuromuscular diseases, and facial anatomy, contributing to HTN, pulmonary HTN, coronary disease, stroke, atrial fibrillation, type 2 DM, traffic accidents related to daytime hypersomnolence, and increased all-cause mortality; OSA also poses significant perioperative risks, including difficulty with intubation, prolonged ventilation, aspiration, and extended hospital stays; screening tools, eg, the STOP-BANG questionnaire, help identify high-risk patients preoperatively; a high STOP-BANG score strongly indicates a moderate to severe risk for OSA, emphasizing the importance of preoperative screening for improved surgical outcomes

Readings

Aronson S, Murray S, Martin G, et al. Roadmap for transforming preoperative assessment to preoperative optimization. Anesth Analg. 2020;130(4):811-19. doi:10.1213/ANE.0000000000004571; Beckerleg W, Kobewka D, Wijeysundera DN, et al. Association of preoperative medical consultation with reduction in adverse postoperative outcomes and use of processes of care among residents of Ontario, Canada. JAMA Intern Med. 2023;183(5):470-78. doi:10.1001/jamainternmed.2023.0325; Blitz JD, Kendale SM, Jain SK, et al. Preoperative evaluation clinic visit is associated with decreased risk of in-hospital postoperative mortality. Anesthesiology. 2016;125(2):280-94. doi:10.1097/ALN.0000000000001193; Centers for Medicare & Medicaid Services (CMS), DHHS. Medicare and Medicaid programs; hospital conditions of participation: requirements for history and physical examinations; authentication of verbal orders; securing medications; and postanesthesia evaluations. Final rule. Fed Regist. 2006;71(227):68671-95; Chang JL, Goldberg AN, Alt JA, et al. International consensus statement on obstructive sleep apnea. Int Forum Allergy Rhinol. 2023;13(7):1061-482. doi:10.1002/alr.23079; Chow E, Clement S, Garg R. Euglycemic diabetic ketoacidosis in the era of SGLT-2 inhibitors. BMJ Open Diabetes Res Care. 2023;11(5):e003666. doi:10.1136/bmjdrc-2023-003666; Fahed G, Aoun L, Bou Zerdan M, et al. Metabolic syndrome: updates on pathophysiology and management in 2021. Int J Mol Sci. 2022;23(2):786. doi:10.3390/ijms23020786; Filipovic MG, Schwenter A, Luedi MM, et al. Modern preoperative evaluation in ambulatory surgery - who, where and how?. Curr Opin Anaesthesiol. 2022;35(6):661-66. doi:10.1097/ACO.0000000000001192; Forzano I, Varzideh F, Avvisato R, et al. Tirzepatide: a systematic update. Int J Mol Sci. 2022;23(23):14631. doi:10.3390/ijms232314631; Kindel TL, Wang AY, Wadhwa A, et al. Multisociety clinical practice guidance for the safe use of glucagon-like peptide-1 receptor agonists in the perioperative period. Clin Gastroenterol Hepatol. Published online October 29, 2024. doi:10.1016/j.cgh.2024.10.003; Modha K, Whinney C. Preoperative evaluation for noncardiac surgery. Ann Intern Med. 2022;175(11):ITC161-ITC176. doi:10.7326/AITC202211150; Tulloch I, Rubin JS. Assessment and management of preoperative anxiety. J Voice. 2019;33(5):691-96. doi:10.1016/j.jvoice.2018.02.008; Ushakumari DS, Sladen RN. ASA Consensus-based guidance on preoperative management of patients on glucagon-like peptide-1 receptor agonists. Anesthesiology. 2024;140(2):346-48. doi:10.1097/ALN.0000000000004776; Zhang HT, Tan N, Gao Y, et al. Prediction of postoperative mortality in older surgical patients by clinical frailty scale: a systematic review and meta-analysis. Geriatr Nurs. 2024;59:581-89. doi:10.1016/j.gerinurse.2024.08.013.

Disclosures

For this program, members of the faculty and the planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Trentman was recorded exclusively for Audio Digest. Audio Digest thanks Dr. Trentman for his cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 2.00 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 2.00 CE contact hours.

Lecture ID:

AN671601

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.