Version July 2025
INTRODUCTION —
All patients who undergo surgery must have a preoperative evaluation to assess the patient's medical conditions, perioperative risk, and readiness for the planned procedure. In addition or simultaneously, patients who undergo anesthesia must have a preanesthesia evaluation to create an anesthetic plan. This topic will discuss the components of preoperative evaluation, including risk assessment and assessment for conditions that increase risk.
Preoperative testing is discussed separately. (See "Preoperative testing for noncardiac surgery".)
Preoperative medication management is discussed separately. (See "Perioperative medication management".)
APPROACH TO PREOPERATIVE EVALUATION —
The authors use preoperative evaluation as an opportunity to comprehensively assess and improve a patient’s clinical status. Even for a primary care provider seeing a long-term patient, a preoperative visit affords the opportunity to reassess the patient and identify issues which have not been addressed adequately due to other priorities.
Assessment of the patient's perioperative risk is an important component of the preoperative evaluation. (See 'Risk assessment' below.)
COMPONENTS OF THE PROCESS
Preoperative history and physical examination — Preoperative evaluation (ie, the preoperative history and physical examination) may be performed by surgeons, primary care physicians, specialists, anesthesiologists, and advanced practice providers.
All preoperative evaluations should include the following:
●Identify medical conditions, allergies, and previous complications of anesthesia
●Confirm current medications, including over-the-counter medications and supplements
●Review pertinent existing diagnostic studies and order appropriate testing
●Manage and optimize medical diseases that affect perioperative risk
●Assess perioperative risk to inform shared decisions on alternatives for care and options for anesthesia
●Motivate patients to make positive health behavior changes, including smoking cessation, weight loss if appropriate, and other preventive care
●Provide instructions for preoperative medication management and fasting
●Meet regulatory requirements where applicable
Preanesthesia evaluation — The preanesthesia evaluation must be performed by an anesthesia provider. Preanesthesia evaluations should accomplish the following (see 'Timing and logistics of preoperative evaluation' below):
●Create a plan for anesthesia and postoperative care
●Educate patients and families about anesthesia care
●Determine the appropriate setting for care (eg, hospital, ambulatory setting, or remote location) (see "Office-based anesthesia", section on 'Patient selection')
We agree with the American Society of Anesthesiologists (ASA) Practice Advisory for Preanesthesia Evaluation [1] that the preanesthesia assessment includes, at a minimum, the following:
●Patient interview
●Focused examination of the airway, lungs, and heart
●Review of pertinent medical records
●Indicated preoperative tests
●Consultations with specialists if necessary
TIMING AND LOGISTICS OF PREOPERATIVE EVALUATION
Timing and visit type — The most appropriate clinician to perform the preoperative evaluation and the timing of the assessment depends upon the patient’s general health, their relationship with other care providers, the degree of risk associated with the planned procedure, and the urgency of the procedure. Other patient factors (eg, language barrier, intellectual disability) may also affect the decision on timing, method, and location of the evaluation. Not all patients will benefit from the same approach to preoperative evaluation, and resources need to be matched with expected benefits. In general:
●Patients who are <65 years old who have stable, adequately treated mild medical conditions, and undergoing low-risk procedures can usually have their preoperative evaluation completed by any clinician, including the surgeon, and be seen by the anesthesia clinician on the day of the procedure immediately before anesthesia.
●Intermediate and high-risk patients or patients having high-risk procedures require further evaluation, time for medical interventions, and intensive planning well in advance of the procedure [2]. (See 'Assessment for conditions that increase perioperative risk' below.)
●We perform evaluation in advance for patients >65 years of age unless they are having low risk procedures with monitored anesthesia care.
Much of the literature on the benefits of early preoperative evaluation involves anesthesiology-directed preoperative clinics. As examples, evaluation of high-risk patients in such preoperative clinics may reduce unnecessary testing [3,4], case cancellations, [5] delays on the day of surgery [6], length of stay [7] and mortality [8,9]. Dedicated preoperative clinics have become increasingly common and may be staffed by anesthesiologists, internists, family medicine physicians, and/or advanced practice providers.
The greatest benefits to early preoperative anesthesia consultation appear to be in high-risk patients (eg, those with ischemic heart disease, ASA-PS ≥4, frailty) having intermediate-to high-risk surgeries (eg, vascular surgery) [8].
In addition to potential morbidity and/or mortality benefits, early preoperative evaluation may provide other health benefits beyond surgical outcomes (eg, smoking cessation).
Triage and screening — Many centers have created screening guidelines to triage patients for the timing and method of preoperative evaluation. Examples of patient and procedure triage criteria are provided (table 1).
Screening optimally occurs as soon as a procedure is considered. Screening information can be completed by the patient or family member/guardian in person (paper or electronic version), remotely via electronic health record tools, with web-based programs, or during a telephone interview. Examples of screening forms used by contributors to this topic are provided (table 2 and table 3). At one author’s institution, information in the electronic record combined with the risk of the planned surgery are used to direct the type of preoperative visit (eg, nurse phone call, advanced practice provider tele-visit or an in-person visit) via an algorithm. At the other’s center, patient factors and the type of planned surgery are used to determine the type of provider seeing the patient in the preoperative clinic (advanced practice provider, internist, or anesthesiologist).
RISK ASSESSMENT —
Assessment of the patient's perioperative risk is an important component of the preoperative evaluation. Perioperative risk reflects both the risks associated with the patient's medical conditions and the risk associated with the planned procedure.
●Perioperative assessment of the risks of complications, mortality, likelihood of return to independent living, and the patient’s goals is part of informed consent and may affect shared decisions regarding surgical and nonsurgical options for treatment, anesthesia options, and advanced directives.
●Elevated risk may suggest the need for preoperative intervention, in-hospital or inpatient rather than ambulatory care, and/or enhanced postoperative monitoring and care (eg, intensive care, post-discharge skilled nursing facility).
●Risk assessment informs the plan for anesthesia, including the venue for the procedure, type of anesthesia, intraoperative monitoring, and required resources.
Epidemiology of perioperative complications — Perioperative complications are a major public health issue and a significant cause of avoidable morbidity and mortality [10,11]. Mortality rates vary widely across hospitals and countries [12,13].
●More than 313 million surgeries are performed annually around the world, and up to 7.7 percent of patients will die within 30 days [14,15]. An estimated 15 million surgical procedures are performed annually in the United States [16]. Postoperative mortality within 30 days is the third leading cause of death on a global scale and in the United States [13,17-19].
●As many as 15 percent of patients will have 30-day postoperative complications [19,20]. The incidence of complications varies across procedures [21] and patient populations. Patients at highest risk are those of advanced age with comorbid diseases having major surgery, who have a hospital mortality rate as high as 12 percent [18]. Low socioeconomic status is associated with higher postoperative mortality, complications, and a lower likelihood of returning home after surgery [22-24]. Frailty, American Society of Anesthesiologists physical status (ASA-PS) class 3-5 and increasing numbers of comorbid conditions predict complications and mortality [18,25].
●Long-term survival is significantly reduced for those patients who have perioperative complications, even if they survive to leave the hospital [10,26].
●The costs associated with complications after surgery are substantial. In one study, mean hospital costs were $19,626 (119 percent) higher for patients with complications ($36,060) compared with those without complications ($16,434) [27]. More than $31.35 billion per year is spent on perioperative complications in the United States alone [20].
Patient risk factors for perioperative morbidity and mortality
ASA physical status — The ASA-PS is a classification system that defines the overall health status of the patient and is used by anesthesiologists, surgeons, and other clinicians involved in perioperative care (table 4). An ASA-PS rating is assigned to every patient who undergoes anesthesia. The ASA-PS was not designed to evaluate patient risks, but it is widely used for this purpose. The ASA-PS only considers patient-level risk factors and not the surgical risk.
ASA-PS designation is subjective, and assignments vary widely among clinicians, especially when determined by non-anesthesiologists [28,29]. Nonetheless, a higher ASA-PS class is associated with complications, increased cost, unexpected hospital admission after ambulatory surgery, postoperative admission to the intensive care unit, hospital length of stay, and mortality (figure 1) [28,30-35].
ASA-PS aligns with Revised Cardiac Risk Index (RCRI) and the Charlson Comorbidity Index as an assessment of disease burden and health of patients [28,36]. The ASA-PS is a component of some more comprehensive tools for assigning perioperative risk. (See 'Risk assessment tools' below.)
Functional capacity — Functional capacity has been shown to predict an increased risk of postoperative cardiopulmonary complications after major noncardiac surgery [37-39]. A metabolic equivalent capacity of less than 4 or a Duke Activity Status Index (DASI) less than 34 are key components of the 2024 ACC/AHA recommendations to consider stress testing before surgery [40]. We use the DASI to assess functional capacity, as it may more reliably predict surgical risk than subjective assessment [41-43]. (See 'Assessing functional capacity' below.)
In general, healthy patients with moderate (or better) functional capacity have a low risk for major postoperative complications [44].
●In a study of 600 consecutive patients undergoing major surgery, poor exercise capacity was defined as the inability to either walk four blocks or climb two flights of stairs [37]. Patients reporting poor exercise capacity had twice as many serious postoperative complications as those who reported good exercise capacity (20 versus 10 percent, respectively). There was also a difference in cardiovascular complications (10 versus 5 percent), but not in total pulmonary complications (9 versus 6 percent).
●The importance of functional capacity was demonstrated in a retrospective study of 847 patients undergoing elective major abdominal surgery [45]. Poor exercise capacity confirmed by cardiopulmonary exercise testing was a stronger predictor of all-cause mortality than any of the conventional cardiac risk factors of the RCRI.
●In an international prospective cohort study of 1400 surgical patients (the METS trial), peak oxygen consumption on cardiopulmonary exercise testing was found to correlate with in-hospital moderate and severe complications [46].
Functional status as a predictor of perioperative cardiac risk is discussed separately. (See "Evaluation of cardiac risk prior to noncardiac surgery", section on 'Assessing functional status or exercise capacity'.)
Biomarkers — Plasma biomarkers (ie, brain natriuretic peptide [BNP], N-terminal pro-BNP [NT-proBNP], troponin) may be used as part of preoperative risk assessment, particularly for major adverse cardiac events [47]. This is discussed in detail separately. (See "Evaluation of cardiac risk prior to noncardiac surgery", section on 'Laboratory testing'.)
Surgical risk — In general, emergency, intraperitoneal, intra-abdominal, intrathoracic, major vascular, and open, longer procedures, and those associated with greater blood loss and intraoperative fluid shifts, are associated with higher perioperative risk [25,29]. Laparoscopic, endovascular, orthopedic, peripheral procedures, and breast surgery usually carry lower risks [29].
However, there are broad variations of surgical risk within these categories. This concept was illustrated by a study that used data from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database to determine the risk of perioperative adverse cardiac events (PACE), defined as cardiac arrest requiring cardiopulmonary resuscitation or acute myocardial infarction, for three million operations that occurred between 2010 and 2015 [29]. There was a continuum of risk across over 1800 operations analyzed, and significant differences in risk among operations within traditionally designated low, intermediate, and high-risk categories. As an example, there was a threefold difference in risk of PACE between laparoscopic total abdominal colectomy and Whipple procedure, both of which are considered high risk according to the RCRI. This risk stratification model requires external validation and may require institution-specific modification for application. Examples of the risk of PACE for selected common operations as determined by this model are shown in a table (table 5).
For several guidelines and perioperative risk assessment tools, surgical risk has been defined according to risk of death or major adverse cardiac events, with high risk arbitrarily defined as having a greater than 5 percent risk of major complications including mortality, intermediate risk as 1 to 5 percent risk, and low risk as less than 1 percent risk [48]. The only well-established very low-risk procedure is cataract extraction [49,50]. (See "Anesthesia for elective eye surgery", section on 'Cataract surgery'.)
Surgical risk for specific postoperative outcomes (eg, cardiac complications versus pulmonary complications) are not equivalent. More accurate assessment of surgical risk is best accomplished by using computer- or web-based calculators of risk such as the ACS NSQIP Surgical Risk Calculator to accurately define the procedural risk and to provide data-supported risk assessment [29]. (See 'Risk assessment tools' below.)
Risk assessment tools — A number of tools have been developed that combine patient and surgical factors to improve the accuracy of prediction of perioperative risk. The choice among these tools may depend on institutional availability. For overall surgical risk assessment, the authors prefer the ACS NSQIP Surgical Risk Calculator described below.
Assessment of overall risk or multiple outcomes
●The ACS NSQIP Surgical Risk Calculator is a free of charge online resource for risk assessment that combines procedure-specific surgical risk with 20 patient factors [51]. The tool calculates risks of 15 separate outcomes, which are displayed in graphic form, with comparison to risk for an average patient. An example of a report generated by the ACS NSQIP calculator is shown in a figure (figure 2). Results can be easily understood by practitioners and patients and may help with shared decision-making, especially regarding specific risks that may be more meaningful to individual patients. For example, older patients are typically less concerned about death than about a degradation of quality of life or an inability to live independently [52]. Use of the results of the NSQIP calculator as part of informed consent is discussed below. (See 'Informed consent and decision making' below.)
The ACS NSQIP calculator is based on data from hospitals participating in NSQIP and has not been widely validated externally. In addition, accuracy of risk estimates may be uneven across outcome measures, and the calculator may be less useful for some categories of procedures than others [53-56]. An advantage of this tool is that it is regularly updated using machine learning. A disadvantage is that it can only be accessed through the proprietary portal maintained by the ACS.
●A simple risk score has been developed for predicting 30-day mortality after noncardiac surgery using data from the ACS NSQIP database [57]. Three elements, ASA PS status, surgery risk, and whether the procedure is performed on an emergency basis, are scored and assigned points. The scoring system and associated mortality are shown in a table (table 6).
●A newly described automated machine learning model using only data in the electronic health record identified patients at high risk of perioperative adverse outcomes [58]. In one multi-institution study the model outperformed the ACS NSQIP calculator.
Assessment of specific outcomes
●Risk calculators specifically for cardiovascular complications include the Myocardial Infarction or Cardiac Arrest (MICA) calculator (available online), and the RCRI (table 7). These tools and their use in evaluating preoperative cardiac risk are discussed separately. (See "Evaluation of cardiac risk prior to noncardiac surgery", section on 'Using risk assessment tools'.)
●The Society of Neuroscience in Anesthesiology and Critical Care published consensus guidelines for risk assessment and reduction for perioperative stroke in noncardiac and non-neurologic surgery [59]. (See "Perioperative stroke following noncardiac, noncarotid, and nonneurologic surgery", section on 'Risk prediction tools'.)
●Risk calculators have been developed to estimate the risk of postoperative respiratory failure or pneumonia. Some have used the ACS NSQIP data to create these [60,61]. (See "Evaluation of perioperative pulmonary risk", section on 'Estimating postoperative pulmonary risk'.)
CLINICAL EVALUATION
Medical history and review of systems — Clinicians who care for patients having anesthesia need to have ready access to the patient’s medical information. The importance of complete information was demonstrated in a single institution review of over 90,000 electronic records of patients who had inpatient surgery [62]. Lack of documentation of existing comorbidities (eg, chronic pain, diabetes, congestive heart failure) in the anesthesia preoperative evaluation was associated with increased mortality and length of hospital stay.
●Medical and surgical history – The history should include the history of the present illness and the planned procedure, past and current medical conditions, past surgical history, and past experiences and problems with anesthesia or surgery in the patient or family members.
The patient should be asked about personal or family history of abnormal bleeding, which is particularly important for procedures with a high risk of bleeding or severe harm should bleeding occur (eg, neurosurgery, tonsillectomy, cardiac surgery). (See "Preoperative assessment of bleeding risk" and 'Hematologic disorders' below.)
Personal or family history of thromboembolism is also important as it may impact the perioperative management of antithrombotic therapy and the selection of venous thromboembolism prophylaxis.
The patient’s allergies and medications should be confirmed, including over-the-counter, complementary, herbal, and alternative medications and they should be asked about tobacco, alcohol, and substance use, all of which may have implications for anesthesia and perioperative care. (See "Perioperative medication management".)
The history should probe for the following issues related to anesthesia:
•Difficulty with airway management, severe postoperative nausea and vomiting, or a personal or family history of malignant hyperthermia or pseudocholinesterase deficiency.
Conditions associated with difficulty with airway management appear in a table (table 8).
•Excessive sore throat after anesthesia, dental injury related to anesthesia, or 'requiring a small breathing tube' with previous anesthetics, which may indicate difficulty with airway management.
If any of these issues are reported, records from previous anesthetics should be reviewed when possible and may assist with planning for airway management.
●Review of systems – A review of organ systems may uncover symptoms that establish previously undiagnosed conditions. A review of records, including notes from primary care clinicians or specialists, and test results can reveal issues the patient may not recall.
Assessing functional capacity — All patients should be asked about their functional or exercise capacity as part of the preoperative evaluation. Functional capacity reflects the integrated responses of the pulmonary, cardiovascular, circulatory, neuromuscular, and hematologic systems and muscle metabolism. Exercise capacity is an important determinant of overall perioperative risk; patients with good exercise tolerance generally have low risk. (See 'Functional capacity' above.)
The assessment of functional status or exercise capacity can range from a self-reported ability to engage in activities of daily living, to six-minute walk tests [63-65], to objective testing of oxygen uptake with cardiopulmonary exercise testing (CPET) [45,66].
For assessment of functional status we use the Duke Activity Status Index (DASI), a questionnaire that includes 12 measures of functional capacity (table 9). The DASI provides a more granular assessment of functional status than the commonly used subjective assessment, whereby patients are asked to name the most strenuous activity they do regularly, or have done most recently, and whether such activity causes chest pain, dyspnea, or claudication. More formal assessment of functional capacity with the DASI may more reliably predict surgical risk [41-43]. Preoperative assessment of functional status is discussed separately. (See "Evaluation of cardiac risk prior to noncardiac surgery", section on 'Assessing functional status or exercise capacity' and "Evaluation of perioperative pulmonary risk", section on 'Exercise testing'.)
Physical examination — The preoperative physical examination should be comprehensive, including evaluation of major organ systems and should be based on symptoms, history, and comorbidities. The examination performed by an anesthesia clinician prior to anesthesia is typically more limited, and per the American Society of Anesthesiologists (ASA) guidelines, focused on the airway, heart, and lungs.
Anesthesia directed physical examination — At a minimum, the preanesthetic examination includes measurement of vital signs (blood pressure [BP], heart rate, ventilatory rate, and oxygen saturation); height and weight with body mass index calculation; auscultation of the heart and lungs (especially for irregular rhythms, murmurs, rales, or wheezing); basic neurologic examinations; and an airway assessment (table 10). (See "Airway management for general anesthesia in adults", section on 'Airway assessment' and "Management of the anatomically difficult airway for general anesthesia in adults", section on 'Recognition of the anatomically difficult airway'.)
●Blood pressure – The need to routinely measure BP in preoperative clinics has been questioned. Guidelines in the United Kingdom suggest that preoperative clinics do not need to measure BPs in patients being seen for elective procedures if they have documented BPs <160/100 mmHg in the referral letter from primary care [67]. The consensus among guidelines suggests that elective surgery in a hypertensive patient does not need to be delayed if diastolic BP is <110 mmHg and systolic BP is <180 mmHg [67]. (See 'Cardiovascular disease' below.)
Patients often have anxiety-related elevated BPs during the preoperative visit even without a history of hypertension. In this setting, the BP should be repeated, medical records reviewed, or the patient asked about typical BP readings; if necessary, the patient can be asked to measure the BP at home and report the results. Risk associated with hypertension and preoperative management are discussed separately. (See 'Cardiovascular disease' below and "Perioperative management of hypertension", section on 'Perioperative risks associated with hypertension'.)
●Dentition – Patients should be assessed for loose, capped, damaged, missing, and artificial teeth, which are at increased risk for damage during airway management. Abnormalities should be documented and confirmed with the patient.
●Regional anesthesia site – If regional anesthesia (ie, neuraxial anesthesia/analgesia, peripheral nerve block) is planned or possible, the regional anesthesia site should be examined to assess for potential difficulty or infection, and any preexisting neuropathy or weakness should be documented.
ASSESSMENT FOR CONDITIONS THAT INCREASE PERIOPERATIVE RISK —
Patients with known or suspected medical conditions that are associated with increased perioperative risk may require more extensive preoperative evaluation and/or testing. Some of the conditions listed here will prompt intervention, though many will not. However, awareness of these conditions is important to assess surgical risk and anticipate complications, which may dictate postoperative care and monitoring.
Older age — Older adults, typically those 65 years and above, have a higher risk for perioperative complications than younger patients, primarily as a result of comorbidities. Older adults have increased mortality after surgery, particularly in those with frailty, dementia, or who undergo non-elective surgery [68]. Frailty is associated with up to five times greater risk of complications, mortality, non-home discharge, and development of a new disability. [69,70].
Advanced age is an independent risk factor for postoperative pulmonary complications. This is discussed separately. (See "Evaluation of perioperative pulmonary risk".)
A number of commonly employed and validated indices consider age as a minor component of preoperative cardiac risk. (See "Evaluation of cardiac risk prior to noncardiac surgery".)
Assessment for aging related conditions that increase risk — A checklist for preoperative assessment of older patients is shown in a table (table 11). Older adults should be assessed for the following:
●Frailty – All patients older than 65 years of age having major surgery should be screened for frailty. We screen older adults with the FRAIL scale or the Clinical Frailty Scale (figure 3). (See "Frailty", section on 'Rapid screening tools'.)
Frailty is a stronger predictor of morbidity and mortality than age. Frail patients are at increased risk even for relatively minor, ambulatory procedures [71]. Heterogeneous literature has suggested multimodal prehabilitation may benefit frail patients. At a minimum, frailty assessment should be incorporated into the overall risk discussion with patients since it may impact their decisions regarding surgery. (See "Anesthesia for the older adult", section on 'Assessment for frailty'.)
●Cognitive dysfunction – Impaired cognition and dementia are common and are often unrecognized in older adults [72]. These conditions are associated with postoperative delirium and cognitive decline. We use a basic cognitive screening tool such as the Mini-Cog (freely available on line) to screen patients preoperatively. We screen all patients 65 years and older and selectively evaluate younger patients who are impaired or have significant risk factors.
Preoperative evaluation and interventions to reduce risk related to cognitive dysfunction are not clearly identified at this time. However, preexisting cognitive impairment is a significant risk factor for perioperative neurocognitive disorders. As with frailty, identification of cognitive dysfunction serves an important purpose in risk-benefit discussions.
Perioperative neurocognitive dysfunction, including cognitive disorders and delirium, and anesthetic management of patients with cognitive dysfunction are discussed separately. (See "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies".)
●History of falls – One study found that 100 percent of patients who had fallen three or more times in the six months before major surgery had a perioperative complication [73].
●Dependency in activities of daily living – Patients who are dependent or partially dependent on others to assist with bathing, feeding, and dressing have higher risks of perioperative adverse events [44]. Nursing home residents are at particularly high risk of death and further functional decline even with minor surgeries [74]. The inability to independently perform activities of daily living is a factor in several risk prediction tools (eg, the American College of Surgeons National Surgical Quality Improvement Program [ACS NSQIP] surgical risk calculator).
Cardiovascular disease
●Hypertension – Hypertension is associated with an increased risk of perioperative cardiovascular complications, but it is not clear that preoperative normalization of blood pressure (BP) reduces perioperative risk. There is little evidence for an association between perioperative complications and preoperative BP <180 mmHg systolic or 110 mmHg diastolic [40,75]. (See "Perioperative management of hypertension", section on 'Perioperative risks associated with hypertension' and "Anesthesia for patients with hypertension".)
The optimal BP level that should be achieved in anticipation of elective surgery is unclear. For most patients, we agree with the Joint Guidelines from the Association of Anaesthetists of Great Britain and Ireland and the British Hypertension Society on the preoperative measurement and management of hypertension, which state that primary care practices should aim to control BPs to <160/100 before referral for elective surgery, and surgery should not be delayed if BPs are <180 mmHg systolic and 110 mmHg diastolic in the preoperative clinic or on the day of surgery [40,67]. The 2024 American College of Cardiology/American Heart Association (AHA/ACC) guideline on cardiac evaluation for noncardiac surgery recommends that BP measurements on the day of surgery should not impact decision-making, and that elevated BP >180/110 mmHg only impacts outcomes in patients with revised cardiac risk index (RCRI) risk factors [40]. The decision to delay surgery for BP optimization or institute new antihypertensive treatment must be individualized, based on patient factors and the urgency of surgery [76]. Regardless of BP on the day of surgery, if patients have taken their BP medications, are asymptomatic, and there is evidence that the patient's BPs before the day of surgery are usually <160/100, then proceeding with planned anesthesia is acceptable.
Most antihypertensive agents can be continued up to and including the day of surgery, with the possible exception of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs). ACE inhibitors and ARBs may increase the incidence of hypotension during anesthesia. One author of this topic routinely continues these drugs, particularly for patients with heart failure.
Whether to continue or stop ACE inhibitors or ARBs preoperatively is discussed in detail separately.(See "Perioperative medication management", section on 'ACE inhibitors and angiotensin II receptor blockers'.)
●Heart failure – Patients with heart failure (HF) have a significantly higher risk of postoperative death than patients with coronary artery disease without HF. Whenever possible, surgery should be delayed in patients with decompensated HF. HF is an important risk factor in the risk stratification models for preoperative assessment. (See 'Risk assessment tools' above.)
Decisions on whether and when to proceed with surgery, preoperative assessment, and preoperative medical managementshould reflect the urgency of the surgery, the stability of the patient's HF, and the possible therapeutic alternatives. Strategies for preoperative assessment, decision making regarding the timing of surgery, and perioperative management of patients with HF are discussed separately, and are shown in algorithms (algorithm 1 and algorithm 2). (See "Perioperative management of heart failure in patients undergoing noncardiac surgery".)
●Undiagnosed murmurs – Systolic murmurs may be the most common incidental finding during a cardiac physical examination. The differential diagnoses include aortic stenosis or sclerosis, mitral or tricuspid regurgitation, hypertrophic cardiomyopathy and hyperdynamic states secondary to anemia, infection, fever, thyrotoxicosis, and pregnancy. Patients with undiagnosed murmurs require a careful history. Any electrocardiogram (ECG) abnormalities, symptoms of dyspnea, chest pain, syncope or near-syncope, or suspicion of valvular disease in individuals >50 years of age warrant an echocardiogram. (See "Preoperative testing for noncardiac surgery", section on 'Cardiac testing'.)
Diastolic murmurs are always pathologic and warrant further evaluation. Mitral stenosis (MS) and aortic insufficiency are the most common causes with the former posing a significant perioperative risk if more than mild. (See "Rheumatic mitral stenosis: Overview of management", section on 'Management of noncardiac surgery'.)
●Valvular heart disease – Stenotic cardiac valvular diseases (ie, aortic stenosis [AS] and MS) are associated with an increased risk of perioperative complications. Risks of anesthesia and surgery can be minimized by an accurate diagnosis of type and severity of disease, planning the appropriate anesthetic, instituting a higher level of monitoring (such as an arterial line, transesophageal echocardiography [TEE], or pulmonary artery catheter), changing venue for the procedure (for example, not an ambulatory surgical center), and postoperative intensive care [40]. Patients with known moderate or severe valvular disease should undergo preoperative echocardiography if there has been no echocardiogram within one year, or if there has been a significant change in physical examination or clinical status since the last evaluation [77].
•AS is a common valvular lesion that increases in frequency with age and is associated with coronary artery disease. The preoperative evaluation and risk assessment for patients with AS, and indications for intervention, are discussed separately. (See "Noncardiac surgery in adults with aortic stenosis".)
•Severe asymptomatic and untreated symptomatic MS are associated with high perioperative risk. Preoperative evaluation and indications for intervention are discussed separately. (See "Rheumatic mitral stenosis: Overview of management", section on 'Management of noncardiac surgery'.)
•Regurgitant valvular lesions (ie, aortic regurgitation [AR] or mitral regurgitation [MR]) are typically better tolerated perioperatively than stenotic lesions. Preoperative risk assessment and evaluation are discussed separately. (See "Noncardiac surgery in patients with mitral or aortic regurgitation".)
•Patients with mechanical heart valves are usually maintained on anticoagulants. (See "Overview of the management of patients with prosthetic heart valves".)
For most procedures, other than cataract surgery, these drugs are stopped preoperatively based on the half-life of the drug to allow normalization of coagulation parameters. Perioperative management of anticoagulants is discussed separately. (See "Perioperative management of patients receiving anticoagulants".)
●Arrhythmias – The perioperative risk associated with some arrhythmias (eg, supraventricular tachycardia, asymptomatic ventricular arrhythmias) is unclear [78]. However, some arrhythmias, including symptomatic bradycardia, symptomatic ventricular arrhythmias, Mobitz II, and third-degree heart block all increase perioperative risk [78], and may be associated with underlying cardiac disease [79]. Patients with Mobitz II and complete heart block need to have all except emergency surgery delayed for further evaluation and likely pacemaker insertion. (See "The preoperative ECG: Evaluation and implications for management in adults".)
Clinically stable patients with atrial fibrillation (AF) are at elevated risk of perioperative complications but generally do not require special evaluation or a change in medical management unless there is a rapid ventricular rate. However, they may require modification of anticoagulation. (See "Perioperative management of patients receiving anticoagulants", section on 'Atrial fibrillation'.)
If AF is newly identified on a preoperative ECG or by physical examination, nonemergency surgery is usually delayed for evaluation. If necessary, an urgent cardiology consultation can be requested with a multidisciplinary discussion of the risks and benefits of proceeding with surgery. It may be reasonable to proceed with minor procedures, such as cataract surgery or colonoscopy, especially under monitored anesthesia care in patients with newly discovered preoperative AF as long as the patient has a controlled rate (ie, less than 100 beats per minute) and adequate BP. These patients require expedited referral for evaluation and management of their AF. (See "Atrial fibrillation in patients undergoing noncardiac surgery", section on 'Patients with newly discovered atrial fibrillation' and "Atrial fibrillation: Overview and management of new-onset atrial fibrillation".)
●Coronary artery disease – Coronary artery disease (CAD) is a risk factor for perioperative myocardial ischemia and infarction and death. CAD varies from a mild, stable disease with little impact on perioperative outcome, to severe disease that accounts for serious complications during anesthesia or in the postoperative period. A goal for preoperative evaluation is to identify a small subset of patients who have unstable or severe CAD that will pose a significant risk with the planned surgical procedure. Even patients with significant CAD have a low risk when having low-risk surgeries [78,80].
Preoperative cardiac risk assessment, including evaluation for CAD, and management of cardiac risk, are discussed separately. (See "Evaluation of cardiac risk prior to noncardiac surgery" and "Management of cardiac risk for noncardiac surgery".)
Preoperative coronary revascularization (ie, coronary artery bypass grafting and/or percutaneous coronary intervention) is discussed separately. (See "Management of cardiac risk for noncardiac surgery", section on 'Revascularization before surgery'.)
●Cardiac implantable electronic devices – Patients with pacemakers and implantable cardioverter defibrillators (ICDs) are often older adults, and may have HF, ischemic or valvular disease, cardiomyopathies, or potentially lethal arrhythmias that increase perioperative risk. Pacemakers and ICDs can be affected by intraoperative electrical interference; a systematic approach to the perioperative evaluation and management of these devices is required and is discussed separately. (See "Perioperative management of patients with a pacemaker or implantable cardioverter-defibrillator".)
Cerebrovascular disease — Individuals with cerebrovascular disease are at increased risk of cardiovascular and cerebrovascular events in the perioperative period [78,81]. The presence of cerebrovascular disease is often a marker for coexisting cardiovascular disease [82], and a stroke or transient ischemic attack (TIA) is a risk factor equivalent to known chronic coronary syndrome, also referred to as stable ischemic heart disease, in the RCRI. (See 'Risk assessment tools' above.)
The timing of surgery should be considered and elective surgery should be deferred in patients with recent stroke [83,84]. The timing of surgery for patients with a history of stroke, the risk of perioperative stroke, and management of asymptomatic carotid bruits are discussed separately. (See "Perioperative stroke following noncardiac, noncarotid, and nonneurologic surgery", section on 'Patient risk factors'.)
Neurologic disease — A number of neurologic diseases increase perioperative risk or require specific perioperative evaluation and management. These issues are discussed separately. (See "Perioperative care of the surgical patient with neurologic disease".)
Pulmonary disease — Postoperative pulmonary complications contribute significantly to overall perioperative morbidity and mortality. In one large United States hospital database study of patients who underwent bowel surgery, postoperative pulmonary complications were associated with greater morbidity than postoperative cardiac complications [85]. Estimation of pulmonary risk is a standard element of all preoperative medical evaluations. Preoperative evaluation of pulmonary risk, including pulmonary function testing, the risks associated with pulmonary hypertension, and strategies to prevent pulmonary complications, are discussed separately. (See "Evaluation of perioperative pulmonary risk" and "Strategies to reduce postoperative pulmonary complications in adults" and "Anesthesia for patients with chronic obstructive pulmonary disease", section on 'Preanesthesia consultation'.)
Specialized testing, including cardiopulmonary exercise test and the six-minute walk test, are discussed separately. (See "Evaluation of perioperative pulmonary risk", section on 'Exercise testing' and "Overview of pulmonary function testing in adults", section on 'Six-minute walk test'.)
Obstructive sleep apnea — Patients with obstructive sleep apnea (OSA) are at increased risk of perioperative complications, including respiratory and cardiovascular complications, difficulty with airway management, and postoperative delirium. The STOP-Bang questionnaire (table 12) has been validated and used widely for preoperative screening for OSA, with scores of 3 or greater associated with increased risk of moderate to severe OSA and postoperative complications. The authors use an alternative scoring model that includes any two STOP criteria and either body mass index (BMI) >35 kg/m2 or male sex; this model is even more predictive of OSA and does not require measurement of neck circumference [86]. Surgical risk and preoperative evaluation and management of patients with OSA are discussed separately. (See "Surgical risk and the preoperative evaluation and management of adults with obstructive sleep apnea".)
Kidney disease — Chronic kidney disease (CKD) is associated with cardiovascular disease and increases the risk of postoperative morbidity and mortality [87,88]. CKD is a factor in several risk scores, including the RCRI and the Myocardial Infarction or Cardiac Arrest (MICA) cardiac risk calculator. (See "Overview of the management of chronic kidney disease in adults", section on 'Association with cardiovascular disease, end-stage kidney disease, and mortality' and "Evaluation of cardiac risk prior to noncardiac surgery", section on 'Using risk assessment tools'.)
The strongest predictor of postoperative kidney dysfunction is preoperative kidney disease [89]. We measure creatinine preoperatively if CKD is known or suspected, the patient is >65 years of age planning intermediate to high-risk surgery, or if the use of intravenous contrast dye is planned. Serum electrolytes should also be measured in patients with CKD.
Patients with end-stage kidney disease on dialysis have a high incidence of other comorbidities and are at increased risk of perioperative complications. Preanesthesia evaluation of patients on dialysis is discussed separately. (See "Medical management of the dialysis patient undergoing surgery".)
Liver disease — Severe liver disease increases perioperative risk, especially with major surgery. Metabolic dysfunction-associated steatotic liver disease (MASLD), previously called nonalcoholic fatty liver disease (NAFLD), affects 25 percent of the global population, is often asymptomatic, and can lead to advanced liver fibrosis [90]. (See "Clinical features and diagnosis of metabolic dysfunction-associated steatotic liver disease (nonalcoholic fatty liver disease) in adults", section on 'Clinical features'.)
One author of this topic screens patients with risk factors for MASLD (eg, obesity, dyslipidemia, type 2 diabetes) with the liver fibrosis-4 (FIB-4) tool as part of preoperative evaluation. An elevated score on a FIB-4 screening tool which considers age, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and platelet count is associated with higher postoperative mortality [91,92].
Preoperative evaluation, including preoperative laboratory evaluation, and assessment of perioperative risk in patients with liver disease, are discussed separately. (See "Anesthesia for the patient with liver disease", section on 'Preoperative evaluation for patients with known liver disease' and "Assessing surgical risk in patients with liver disease", section on 'Screening for liver disease before surgery'.)
Endocrine disease
●Diabetes – Diabetes mellitus is associated with increased risk of perioperative infection, postoperative cardiovascular morbidity and mortality, and comorbidities that may affect perioperative management. Preoperative assessment and perioperative management of blood glucose in patients with diabetes mellitus are discussed separately. (See "Anesthesia for patients with diabetes mellitus and/or hyperglycemia", section on 'Level of blood glucose control' and "Perioperative management of blood glucose in adults with diabetes mellitus" and "Overview of general medical care in nonpregnant adults with diabetes mellitus".)
Poorly controlled diabetes is associated with increased surgical site infections. Optimal blood glucose targets have not been determined, but for some procedures (eg, joint replacement or major spine surgeries) some surgeons have established absolute A1C cutoffs for performing elective surgery (eg, <7.5 to 8 percent) [93]. (See "Susceptibility to infections in persons with diabetes mellitus", section on 'Risk of infection'.)
●Thyroid disease – Significant hyper- or hypothyroidism may increase perioperative risk [94]. Preoperative evaluation and anesthetic management for patients with thyroid disease are discussed separately. (See "Nonthyroid surgery in the patient with thyroid disease" and "Anesthesia for patients with thyroid disease and for patients who undergo thyroid or parathyroid surgery".)
●Adrenal disorders – Patients with Cushing’s disease and adrenal insufficiency require management to lower perioperative risk. (See "Overview of the treatment of Cushing syndrome" and "Treatment of adrenal insufficiency in adults", section on 'Surgery'.)
Patients with pheochromocytoma are at high risk of hemodynamic instability and arrhythmias during surgery. Preoperative evaluation and preparation of these patients are discussed separately. (See "Anesthesia for the adult with pheochromocytoma" and "Anesthesia for the adult with pheochromocytoma", section on 'Preoperative evaluation'.)
Patients who have been taking glucocorticoid medication are at risk for adrenal insufficiency in the perioperative period. Perioperative management of these patients is discussed separately. (See "The management of the surgical patient taking glucocorticoids".)
●Pituitary abnormalities – Pituitary abnormalities can cause hormonal hyposecretion or hypersecretion that may increase perioperative risk. As examples, both acromegaly and Cushing’s syndrome increase the risk of difficulty with airway management [95] and are associated with cardiovascular disease and OSA. (See "Epidemiology and clinical manifestations of Cushing syndrome", section on 'Cardiovascular' and "Causes and clinical manifestations of acromegaly", section on 'Cardiovascular disease' and "Causes and clinical manifestations of acromegaly", section on 'Sleep apnea'.)
Hematologic disorders
●Anemia – Anemia is present in 5 to 7 percent of elective surgical patients, depending on associated comorbidities and age [96]. Preoperative anemia, even when mild, is associated with increased 30-day mortality after major noncardiac surgery [97-99], and also increases the need for perioperative transfusions. This is discussed separately. (See "Perioperative blood management: Strategies to minimize transfusions", section on 'Treatment of anemia and iron deficiency' and "Indications and hemoglobin thresholds for RBC transfusion in adults", section on 'Impact of anemia on morbidity and mortality'.)
When hemoglobin testing is indicated, it should be done early enough to allow time for diagnosis and treatment of the causes of anemia or hemostatic abnormalities. Elective surgery is best delayed to allow time to identify and potentially correct abnormalities (algorithm 3). (See "Treatment of iron deficiency anemia in adults", section on 'Perioperative' and "Perioperative blood management: Strategies to minimize transfusions", section on 'Preoperative strategies' and "Preoperative testing for noncardiac surgery".)
Patients with sickle cell disease are at risk of perioperative complications, some of which may be ameliorated by modifications in management. Perioperative management of these patients, including preoperative transfusion and control of acute pain, are discussed separately. (See "Management of adults with sickle cell disease or thalassemia during cardiac surgery", section on 'Sickle cell disease' and "Acute vaso-occlusive pain management in sickle cell disease", section on 'Overview of acute pain management'.)
Perioperative concerns for patients with thalassemia, including anemia, skeletal abnormalities, and possible cardiac or hepatic complications, are discussed separately. (See "Management of adults with sickle cell disease or thalassemia during cardiac surgery", section on 'Thalassemia'.)
●Bleeding risk – A careful personal and family history of bleeding is the foundation for determining the risk of harmful bleeding with procedures [100]. The components of preoperative determination of bleeding risk are discussed separately. (See "Preoperative assessment of bleeding risk".)
●Venous thromboembolism (VTE) risk – VTE is a common postoperative complication, and pulmonary embolism is one of the most common preventable causes of in-hospital deaths following surgery. The risk of postoperative VTE should be assessed prior to surgery. Patients at elevated risk of perioperative VTE include those with a history of previous VTE (particularly recent VTE), cancer, obesity, inactivity, and having major lower extremity surgery. Risk assessment and strategies for prevention are discussed separately. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients" and "Prevention of venous thromboembolism in adults undergoing hip fracture repair or hip or knee replacement" and "Overview of the causes of venous thrombosis in adults".)
Patients who are anticoagulated for AF, prosthetic heart valves, and/or recent or previous thromboembolic events may require interruption of anticoagulation or perioperative bridging strategies. Perioperative management of these patients is discussed separately. (See "Perioperative management of patients receiving anticoagulants".)
Malnutrition — Malnutrition is a strong predictor of perioperative mortality and morbidity, longer length of stay postoperatively, higher readmission rates, and increased costs of care [101]. It is estimated that 50 percent or more of older adult patients having major surgery are undernourished [102]. We screen patients for malnutrition and either send those who screen positive for evaluation in a nutrition clinic or prescribe nutritional supplementation for several weeks before surgery. Screening for malnutrition is discussed separately. (See "Geriatric nutrition: Nutritional issues in older adults", section on 'Screening for nutritional status'.)
Patients screened as nutritionally at risk before major surgery may benefit from preoperative oral nutritional supplements with a minimum of 18 g protein two to three times per day for 7 to 14 days [103].
Obesity — With the exception of thromboembolism, obesity itself is not consistently associated with an increased risk of major adverse outcomes and is not a factor in most commonly used preoperative risk screening tools other than STOP-BANG [104-112].
However, obesity is associated with difficulty with airway management, positioning-related peripheral nerve injuries, wound infection, and with a number of comorbidities that increase perioperative risk, including OSA, heart disease, hypertension, and diabetes mellitus. (See "Preanesthesia medical evaluation of the patient with obesity", section on 'Preoperative evaluation'.)
Smoking — Exposure to tobacco, directly or through second-hand smoke, increases the risk of postoperative pulmonary complications, wound complications, infections, neurologic complications, and intensive care unit (ICU) admission. Those who smoke should be encouraged to quit preoperatively; preoperative clinics play an important role in discussing the benefits of smoking cessation and offering patients both pharmacologic and non-pharmacologic interventions.
The perioperative risks of smoking and the benefits and optimal duration of preoperative smoking cessation are discussed separately.
●(See "Evaluation of perioperative pulmonary risk", section on 'Smoking'.)
●(See "Smoking or vaping: Perioperative management", section on 'Perioperative risks of smoking'.)
Alcohol misuse — Patients who misuse alcohol on a regular basis have an increased risk for postoperative complications [113]. We screen all adults for alcohol use disorder with the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) questionnaire (table 13). In two studies of male United States veterans who had major surgery and who completed the AUDIT-C questionnaire in the year prior to surgery, increasing AUDIT-C scores were associated with increasing risk of postoperative complications [114] and longer length of stay, more ICU days, and increased unplanned reoperation [115]. A similar study in male veterans who underwent joint arthroplasty found similar results [116].
While the benefit of directed alcohol cessation programs before surgery is not well-established in the literature, there is little apparent risk to such a strategy. The optimal period of cessation is unknown, however at least four weeks of abstinence are required to reverse selected physiologic abnormalities [113]. Most trials of alcohol cessation interventions have been conducted in the nonoperative setting; a small trial in patients undergoing colorectal surgery found reduced postoperative complications in patients randomly assigned to alcohol cessation for one month prior to surgery [117].
PREOPERATIVE TESTING —
Preoperative testing should be performed selectively, based on the patient's medical status, the planned procedure, and the likelihood that test results will change management or help with risk assessment (table 14 and table 15). For most of the conditions discussed above, there are no data to support routine preoperative testing or screening for the stage or stability of the disease, particularly if the patient is asymptomatic or their disease is well controlled. There are good data to suggest that preoperative tests increase costs and delay surgeries with no clear improvement in outcomes. Thus, preoperative tests are best used only when a patient has new or unstable symptoms, and when the necessary tests can be obtained without delaying necessary (eg, for urgent or emergency surgery). Tests may also be useful in higher-risk patients to aid shared decision making around the benefits of surgery but are not likely to improve outcomes. Preoperative testing is discussed separately. (See "Preoperative testing for noncardiac surgery".)
POSTOPERATIVE PLANNING —
When postoperative intensive care is indicated, arrangements for it are often initiated during the preoperative evaluation session.
The plan for postoperative care is discussed in the UpToDate topics on anesthesia for specific surgical procedures and for patients with specific comorbidities.
Breastfeeding patients — All women with children younger than two years of age should be asked whether they are breastfeeding. Breastfeeding patients who will be separated from the infant for more than a few hours should be encouraged to express and store breast milk preoperatively for feeding the infant. There is no need to discard expressed breast milk after anesthesia. There is no evidence of adverse effects from drugs used perioperatively on the breastfed infant because the drugs are transferred to breast milk in only very small amounts. However, there are limited or no data on the transfer of some anesthetic drugs to breast milk. Further guidance and general principles of perioperative care in breastfeeding patients are shown in a table (table 16). For information on specific medications, consult the LactMed database.
INFORMED CONSENT AND DECISION MAKING —
Preoperative evaluation results in a risk assessment that should be part of shared decision-making regarding the planned procedure and anesthetic care.
●Shared decision making – In our experience, most patients want to be made aware of findings from their preoperative evaluation, be informed of risks, and be involved in decisions about their care. The risks of surgery, the likelihood of the patient returning to baseline functional status, and advance directives should be reviewed with all patients and are particularly important for older patients. The results of risk assessment tools can be used as part of shared decision making and informed consent. In a single-center study that evaluated sharing the results of the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) calculator with patients, patient perceptions of the experience were favorable; 93 percent of patients said the results improved their understanding of their risks and 81 percent stated that they would want to know the details of risk before consenting to surgery [118]. Overall, patients tended to overestimate their risks of surgery, though high-risk patients tended to underestimate their risks. Knowledge of personal risk decreased preoperative anxiety in 70 percent of patients and had no effect on anxiety in 20 percent. The majority of patients were willing to undergo prehabilitation if it would reduce their risks of complications.
●Consent for anesthesia – Informed consent must be obtained for anesthetic care and is based on the principle of patient autonomy (ie, the patient's right to be involved in decisions that affect them). In our experience, discussing options for upcoming anesthesia can lower anxiety and improve patient satisfaction. Important components of patient preparation for shared decisions regarding their anticipated anesthesia appear in a table (table 17) [119,120]. Patients should be informed of the more common risks and, when appropriate, of complications that rarely occur after certain procedures but would have a major impact (eg, postoperative visual loss associated with prone positioning for spine surgery). Complex discussions ideally occur before the day of surgery, with adequate time to address all questions.
The Association of Anaesthetists of Great Britain and Ireland has created guidelines for consent for anesthesia [121], whereas the American Society of Anesthesiologists (ASA) has not.
●Do not resuscitate and advanced directives – Patients with do not resuscitate (DNR) orders should not be denied anesthesia and procedural care simply because of their DNR status [122]. Whenever possible, the anesthesia clinician should involve the patient, family members, and surrogates, as appropriate, in a detailed discussion of the patient's values and preferences with respect to resuscitation. Some aspects of anesthesia care necessarily involve procedures that in other circumstances would be considered resuscitation (eg, endotracheal intubation). The patient's acceptance of specific procedures and levels of resuscitation (eg, pharmacologic reversal of hypotension related to anesthetic medication) should be determined and documented. The plan for postoperative reinstatement of any existing directives should be determined and documented.
Informed consent for medical procedures is discussed in detail separately. (See "Informed procedural consent".)
SOCIETY GUIDELINE LINKS —
Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Preoperative medical evaluation and risk assessment".)
SUMMARY AND RECOMMENDATIONS
●Timing of preoperative evaluation – Healthy patients having low-risk procedures can be evaluated on the day of the procedure immediately before anesthesia. High-risk patients (those who have conditions that increase perioperative risk) or those planning high-risk procedures may require testing, time for medical interventions, and intensive planning, and may therefore benefit from assessment well in advance of the procedure, depending on the timing and intent of the procedure. (See 'Timing and logistics of preoperative evaluation' above.)
●Components of evaluation – Preoperative evaluation should include clinical evaluation, risk assessment, and assessment for and optimization of medical diseases that affect perioperative risk. Preanesthesia evaluation should also include an anesthesia directed physical examination, patient education and in some cases, informed consent for anesthesia, and creation of a plan for anesthesia and postoperative care. (See 'Components of the process' above.)
●Medical history and review of systems – Patients should be assessed with a medical history and complete review of systems to assess for conditions that increase perioperative risk. The history should include prior problems with anesthesia or surgery in the patient or family members. (See 'Medical history and review of systems' above.)
●Physical examination – A comprehensive physical examination should be performed as part of preoperative evaluation. The anesthesia-directed examination typically focuses on the heart, lungs, and airway. (See 'Physical examination' above.)
●Assessment for conditions that increase perioperative risk – Patients with known or suspected medical conditions that are associated with increased perioperative risk may require more extensive preoperative evaluation and/or testing (table 1 and table 15). For example, older patients, patients with frailty, and those with significant cardiopulmonary or pulmonary disease are at increased risk if undergoing intermediate or high-risk surgery. These and other conditions associated with increased risk are discussed above. (See 'Assessment for conditions that increase perioperative risk' above.)
●Risk assessment – Assessment of the patient's risks of anesthesia and the planned procedure informs the plan for anesthesia, may suggest the need for preoperative intervention and perioperative care, and may affect shared decisions regarding surgical and alternative options for treatment. (See 'Risk assessment' above.)
•Patients are assigned an American Society of Anesthesiologists Physical Status (ASA-PS) class in anticipation of anesthesia (figure 1). Patient factors, including comorbidities and functional status, affect the patient's predicted risk. (See 'Patient risk factors for perioperative morbidity and mortality' above.)
•Surgical procedures are classified as high, intermediate, or low risk of mortality or major adverse events (table 5). Cataract surgery is considered a very low-risk procedure. (See 'Surgical risk' above.)
•Risk assessment tools that include patient and surgical risk factors may be used to predict perioperative risks of cardiac and pulmonary adverse events and perioperative mortality (figure 2). (See 'Risk assessment tools' above.)
●Preoperative testing – Preoperative testing should be performed selectively, when needed to estimate risk, or to address new or unstable symptoms or signs (table 15 and table 14). (See "Preoperative testing for noncardiac surgery".)
●Informed consent and decision-making – The risks of surgery and anesthesia, the likelihood of the patient returning to baseline functional status, and advance directives should be reviewed with all patients, to allow shared decision-making about options for care (table 17). (See 'Informed consent and decision making' above.)
For patients with do not resuscitate (DNR) orders, the patient's acceptance of specific procedures and levels of resuscitation should be determined and documented, including the procedures necessary for anesthesia that would be considered resuscitation in other circumstances.
