The purpose of a preoperative evaluation is to assess whether a patient is medically optimized for the stress of surgery and to identify reversible factors that may increase the perioperative risk for the patient. Important components of the preoperative evaluation are a thorough history and physical examination, identification of patients at greatest risk of a perioperative adverse event, and appropriate diagnostic testing. Preoperative preparation enhances surgical outcomes by improving the patient's functional status, mitigating identified risk factors, and optimizing perioperative medication regimens. This includes optimization of medical treatment, specialty consultation for advanced disease management, patient education on lifestyle modifications, and instruction on day-of-surgery oral intake and medication use. The extent of patient evaluation and preparation varies according to both the proposed surgery and the patient's functional status. Low-risk patients having low-risk surgery seldom need testing or intervention, while patients with a high disease burden having high-risk surgery often require extensive testing, consultation, and possible postponement of surgery. Patients having emergent surgery still require evaluation even though opportunities for management beyond resuscitation are typically limited.
See also “Postoperative management.”
- Confirm the surgical procedure and indication for surgery.
- based on surgery type and urgency.
Evaluate the patient's health and individual risk of perioperative complications. 
- Perform a physical examination. with a complete history and
- Use validated , , e.g., , to improve perioperative risk estimation.
- Order based on combined estimated perioperative risk.
- Consider more focused evaluation and management of high-risk systems (e.g., see “”).
- Make recommendations to the surgical team, for example:
- Proceed with surgery if the patient's comorbidities are optimally treated.
- Optimize treatment of comorbidities if necessary.
- Order advanced testing or specialty consultation if underlying health concerns are unclear or complex.
- Consider delaying surgery if diagnostics and/or treatment are expected to influence perioperative risk.
- Coordinate perioperative preparation steps (e.g., fasting, , ).
Evaluate the procedural risk and the patient's health and functional capacity in order to: decide whether to proceed with surgery without delay, obtain further testing and/or specialist consultation, or consider delaying or canceling the procedure. 
Multidisciplinary team roles
Medical practitioner 
- Determines if the patient is medically optimized for the surgical procedure
- Initiates measures to optimize the patient's health if necessary
- Alerts the perioperative team to special health concerns and abnormal test results
- Anesthesiologist: chooses the appropriate anesthetic technique based on patient health and procedural requirements
Emergency preoperative evaluation 
Patients who need emergency surgery often require simultaneous resuscitation and assessment (e.g., via an ).
- Focus the clinical evaluation on conditions associated with high morbidity.
- Order diagnostic testing that reflects the dual roles of assessment and resuscitation, including:
- Notify members of the perioperative team (e.g., surgery, anesthesiology, ICU) of urgent findings.
Preoperative evaluation of a patient having emergency surgery includes assessing the adequacy of ongoing resuscitation. Continuous reassessment of critical organ function (e.g., tissue perfusion, oxygenation, coagulation) may be necessary.
Type of surgical procedure
|Perioperative mortality by type of surgery |
Urgency of the surgery
- Timing: performed as soon as possible due to threat to life or limb.
- Perioperative mortality: 3.7% at 30 days
- Timing: performed within 24–48 hours due to threat to life or limb
- Perioperative mortality: 2.3% at 30 days
Time-sensitive surgery (e.g., oncologic surgeries)
- Timing: performed within 1–6 weeks to avoid negative outcomes
- Timing: performed within 12 months
- Perioperative mortality: 0.4% at 30 days
Evaluating patient health
- Assess whether current acute and chronic illnesses are being optimally managed.
- Begin treatment of untreated or undertreated medical conditions.
- Identify high-risk patients who may benefit from:
Red flags on the preoperative clinical evaluation
A complete medical history and thorough physical examination are performed in all patients having a preoperative evaluation. Special attention should be paid to red flags for conditions that may increase perioperative risk.
|Preoperative clinical red flags |
Preoperative functional capacity assessment 
Limited functional capacity is associated with an increased risk of perioperative morbidity and mortality. Several techniques are available to estimate functional capacity. 
Subjective patient reporting of exercise capacity 
- Technique: The patient's subjective report of attainable activity is reported in the metabolic equivalents (METs) associated historically with that activity.
- Findings: Exercise capacity of < 4 METs is associated with increased risk of perioperative complication
Duke Activity Status Index (DASI) 
- Description: a validated, self-administered questionnaire that assesses the patient's functional capacity 
- Technique: A 16 item questionnaire completed by the patient results in a score of 0–58
- Findings: A DASI score ≤ 34 predicts an increased risk of major perioperative adverse events.
Cardiopulmonary exercise testing (CPET) 
- Technique: Laboratory measurement of the patient's maximum during exercise
- Findings: No clear threshold for increased perioperative risk has been established using CPET data.
A patient who cannot achieve and maintain 4 METs is at an increased risk for perioperative complications. Additional evaluation may be warranted. 
A DASI score ≤ 34 consistently predicts an increased risk of major perioperative adverse events. 
Validated risk stratification tools identify which patients may benefit from medical intervention, preoperative diagnostic testing, and/or consultation prior to intermediate or high-risk surgery. The derived scores from these tools also allow quick communication about patient risk between perioperative team members.
The American Society of Anesthesiologists (ASA) classification 
- Description: classification based on subjective reporting of the severity of the patient's comorbid disease
- Clinical application: all perioperative patients
- Key finding: An ASA status ≥ 3 is associated with ≥ 1% perioperative risk of mortality; the patient may be considered at high risk.
American Society of Anesthesiologists physical status classification system (ASA-PS) 
|ASA status||Definition||Thirty-day mortality |
|I|| ||< 0.1%|
|VI|| || |
Revised cardiac risk index (RCRI) 
- Description: a simple calculation using 6 easily obtained factors to predict the risk of major adverse cardiac events (MACE) during hospitalization following noncardiac surgery
- Clinical applications
- Key finding: An RCRI ≥ 2 is associated with > 1% chance of MACE; the patient may be considered at high risk.
|Revised cardiac risk index (RCRI) |
National Surgical Quality Improvement Program (NSQIP) surgical risk calculator 
- Description: web-based patient and surgery-specific risk calculator developed by the American College of Surgeons (ACS)
- Key finding: reports predicted risk for 11 individual perioperative complications, including death and MACE
Myocardial infarction and cardiac arrest (MICA) risk calculator 
- Description: calculator using 5 patient-related inputs (including ASA status) and procedure site
- Key finding: estimated risk of 30-day mortality; greater predictive power than RCRI but requires more time to calculate
- Low-risk patients: Generally, no routine diagnostic testing is required.
- High-risk patients: Consider testing as required for the routine management of chronic conditions.
High- or intermediate-risk surgery
- All patients: See “Preoperative testing for intermediate- or high-risk surgery” for specific indications.
- High-risk patients: Consider additional specialist consultation and advanced testing based on individual factors.
Order diagnostic testing based on the combined risk derived from , , and . Avoid broad, nondirected testing. 
Investigations for intermediate- or high-risk surgery
- Selective testing based on individual indications is preferred. 
- More specialized testing may be indicated depending on the presence and severity of conditions identified during the stratification; see, e.g., “Preoperative cardiac assessment” and “Preoperative pulmonary assessment.” and risk
|Preoperative testing for intermediate- or high-risk surgery |
|Platelet count|| |
|Basic metabolic panel|
|Liver function tests (LFTs)|
|Blood grouping and crossmatching|| |
|Pregnancy test|| |
Management approach for known or suspected CAD 
- If surgery is emergent: Proceed directly to surgery but identify risk factors that affect perioperative management.
- If : Consult cardiology, begin are presentACS management, and discuss surgical timing with the multidisciplinary team.
- For all other patients: Calculate the risk of a major adverse cardiac event.
Advanced testing for CAD 
- : reasonable in patients with an elevated risk of MACE and reduced functional capacity
- Angiography: not routinely recommended in patients with stable CAD (See “ .”) 
- Biomarkers: BNP and NT-proBNP screening are increasingly used to assess perioperative risk and guide the management of patients with known cardiovascular disease. 
In asymptomatic patients, perform advanced cardiac testing only when results will affect the decision to operate or the perioperative management.
Elective surgery after coronary angioplasty 
Discontinuation of P2Y12 receptor blockers (and sometimes aspirin) may be required before surgery. In patients with a cardiac stent, the risks of stent thrombosis must be balanced against the risk of bleeding or delaying surgery.
- Balloon angioplasty (no stent): Delay elective surgery for two weeks.
- Bare metal stent: Delay elective surgery for 30 days.
- Drug-eluting stent: Delay elective surgery for six months postplacement if possible.
Congestive heart failure 
- Obtain an echocardiogram if there are new or progressive symptoms (e.g., worsening dyspnea, chest pain, syncope).
- Consider an echocardiogram in stable patients if it has been > 12 months since the last one.
- Consider measuring BNP or NT-proBNP if cardiac dysfunction is known or suspected.
- Consider delaying intermediate- or high-risk surgery if there is newly diagnosed heart failure to allow improvement in ventricular function.
- Presence of a CIED)  (
Valvular disease: Obtain an echocardiogram if symptoms are progressive or it has been > 12 months since the last echocardiogram. 
- Severe aortic stenosis: Consider aortic valve replacement (open or TAVI) prior to noncardiac surgery.
- Severe mitral stenosis: Consider percutaneous mitral commissurotomy if the patient is symptomatic or pulmonary artery pressure is > 50 mm Hg.
- Aortic or mitral regurgitation: Treatment is generally not required prior to surgery.
- Pulmonary hypertension: Consult a pulmonary hypertension specialist for possible optimization prior to intermediate- or high-risk surgery. 
- Acute respiratory tract infection 
Chronic pulmonary disease 
- Stable pulmonary disease and adequate oxygenation: Further testing is typically not necessary.
- Unstable pulmonary disease, impaired oxygenation or ventilation: Consider delaying surgery to allow for further assessment and treatment.
- Obstructive sleep apnea (OSA) 
- Advanced pulmonary testing 
Evaluation and management of other systems
- Preoperative nutrition screening is recommended for all patients undergoing major surgery.
- Consult a dietitian for formal dietary assessment if any of the following are present:
- Provide (preferably ) to at-risk patients prior to surgery to optimize their nutritional status.
Malnutrition is associated with a higher risk of postoperative mortality and morbidity, e.g., infectious complications and ICU admission. Arrange formal dietary assessment for all patients with risk factors or signs of malnutrition on screening. 
Hepatic disorders 
- Acute hepatitis: Delay elective surgery until there is documented improvement in LFTs.
- Chronic liver disease: Calculate the MELD score or Child class for the liver disease.
Hematologic disorders 
Venous thromboembolism (VTE)
- Assess all patients for . 
- Recommend appropriate thrombosis. based on bleeding risk and risk of
- Bleeding disorders: Optimize in consultation with the managing hematologist.
- Anemia 
- Sickle cell anemia: Optimize in consultation with the managing hematologist. 
Chronic glucocorticoid use
- Document the dosage and duration of glucocorticoid administration.
- Consider optimizing if indicated. 
- Stroke: Consider delay if surgery is planned < 9 months after CVA. 
Cognitive impairment 
- Cognitive impairment is a risk factor for postoperative delirium and is associated with increased perioperative morbidity and mortality. 
- Screen older adults at risk for dementia with a standardized tool, e.g., Mini-Cog. 
- Recommend consultation or perioperative comanagement with internal medicine or geriatrics specialists for .
Preoperative preparation measures
Instruct all patients on recommended perioperative medication changes, oral intake on the day of surgery, and lifestyle modifications that may reduce perioperative risk.
Preoperative lifestyle modifications
- Smoking cessation: Patients should be encouraged to stop smoking, ideally 4–8 weeks or longer before surgery. 
- Alcohol use: Chronic alcohol use is associated with numerous perioperative complications. 
- Exercise: Preoperative exercise programs (often called prehabilitation) may improve some surgical outcomes. 
- Fasting guidelines for elective surgery 
- Protracted NPO status or preoperative hypovolemia: Correct any volume deficit and replace any ongoing fluid loss with .
Perioperative antibiotic prophylaxis 
- Purpose: reduce the incidence of postoperative
- Timing: ideally 30–60 minutes prior to skin incision
- Antibiotics of choice
Preoperative medication management
|Perioperative medication management |
|Cardiac || |
|ACEIs or ARBs|| |
|Hematologic||Antiplatelet agents |
|Anticoagulants || |
|Endocrine || |
|Estrogens, progestins, and androgens|| |
|Thyroid hormones|| |
MAOIs other than
|MAOIs || |
|Others ||Conventional DMARDs|| |
|Herbal medications || |
Special patient groups
Preoperative management in pregnant individuals 
- Approximately 2% of pregnant patients require nonobstetric surgery, primarily for appendicitis, cholecystitis, or adnexal disease. 
- If time-sensitive surgery cannot be delayed until after delivery, surgery in the second trimester is optimal.
- Consultation with an obstetrician is required.
- Obtain a CBC and type and screen.
Preoperative management in patients with opioid use disorder (OUD) 
- Preoperative evaluation of patients with known OUD is necessary to prevent undertreatment of perioperative pain and avoid the risk of OUD relapse.
- Pain management specialists should be consulted when feasible.
- See “Preoperative medication management” for the perioperative management of opioid substitution therapy.