Preoperative Evaluation

Procedure- and system-related (largely non-modifiable)

• Emergency/urgent surgery: the single strongest driver of morbidity — no time for optimization, and the ACC/AHA perioperative guideline for noncardiac surgery explicitly states testing must not delay a time-sensitive operation
• High-risk surgery type: open aortic/major vascular, intraperitoneal, and intrathoracic procedures generate the largest fluid shifts, catecholamine surge, and myocardial oxygen demand; cataract and superficial procedures are low risk regardless of comorbidity
• Prolonged operative time and general anesthesia (vs regional/neuraxial): longer exposure to atelectasis, hypothermia, and immobility

Cardiovascular (mechanism: demand ischemia and pump failure)

• Non-modifiable: prior MI, ischemic heart disease, heart failure, cerebrovascular disease, and insulin-treated diabetes — the RCRI variables; severe aortic stenosis and decompensated HF are active cardiac conditions that defer elective surgery
• Modifiable: uncontrolled hypertension, untreated anemia (reduces oxygen delivery into a demand-ischemia state), and electrolyte derangement

Pulmonary (mechanism: reduced FRC, impaired clearance, aspiration)

• Non-modifiable: advanced age, COPD, pulmonary hypertension, ASA class ≥3
• Modifiable: active smoking (cessation several weeks before surgery, not days, reduces pulmonary complications), untreated OSA (STOP-BANG positive), poor dentition/upper respiratory infection, deconditioning

Metabolic, hepatic, and nutritional

• Modifiable: hyperglycemia and elevated HbA1c (impaired neutrophil function → surgical site infection), hypoalbuminemia/malnutrition, obesity, heavy alcohol use, exogenous steroid exposure sufficient to suppress the HPA axis
• Non-modifiable: cirrhosis (MELD/Child-Pugh predict mortality), CKD, frailty

Hematologic and pharmacogenetic

• Antithrombotics: warfarin, DOACs, and P2Y12 inhibitors — bleeding vs thrombosis is the balance the CHEST perioperative antithrombotic guideline addresses
• Inherited: RYR1 mutation (malignant hyperthermia, autosomal dominant), pseudocholinesterase deficiency, von Willebrand disease, sickle cell disease

• Neuroendocrine activation: Surgery triggers catecholamine and cortisol release, increasing heart rate, blood pressure, and myocardial oxygen demand; this places patients with coronary artery disease at high risk for perioperative myocardial infarction (PMI)
• Inflammatory cascade: Surgical trauma activates tissue damage responses, complement activation, and cytokine release, contributing to postoperative complications including thromboembolism, infection, and organ dysfunction
• Hemodynamic stress: Blood loss, anesthesia, and positioning changes cause dramatic shifts in preload, afterload, and oxygen delivery; patients with cardiac or pulmonary disease cannot compensate adequately
• Coagulation abnormalities: Surgery activates tissue factor and platelets while simultaneously consuming clotting factors and fibrinogen, increasing thrombotic and hemorrhagic risk
• Metabolic derangement: Anesthesia impairs temperature regulation, glucose metabolism, and fluid homeostasis; elderly and diabetic patients are particularly vulnerable
• Pulmonary complications: Atelectasis, reduced mucociliary clearance, and aspiration risk increase due to anesthesia and immobility, especially in patients with underlying COPD or sleep apnea

• Cardiac symptoms: Chest pain, dyspnea on exertion, orthopnea, palpitations, syncope, or edema suggesting unstable angina, decompensated heart failure, or arrhythmias—these require investigation before elective surgery
• Pulmonary symptoms: Cough, dyspnea, wheezing, or exercise limitation suggesting COPD, asthma, or sleep apnea; patients with baseline hypoxemia or hypercarbia face higher risk
• Metabolic/endocrine signs: Poorly controlled diabetes (elevated glucose, HbA1c >8%), thyroid dysfunction (tremor, heat intolerance, weight changes), or adrenal insufficiency history indicating need for perioperative steroid dosing
• Bleeding history: Spontaneous bleeding, easy bruising, prolonged bleeding after dental work, or family history of coagulopathy—essential to identify before surgery to prevent catastrophic hemorrhage
• Medication history: Anticoagulants (warfarin, DOACs), antiplatelet agents, beta-blockers, ACE inhibitors, or herbal supplements requiring perioperative management
• Anesthesia history: Prior adverse reactions (malignant hyperthermia, anaphylaxis, difficult airway), postoperative nausea/vomiting, or prolonged recovery suggesting genetic or metabolic concerns
• Functional status: Inability to climb stairs or walk >1 block suggests poor functional capacity (≤4 metabolic equivalents [METs]) and higher cardiac risk

• History and physical examination (foundational): Focus on cardiac risk factors (prior MI, angina, arrhythmia, heart failure), pulmonary disease, diabetes, renal disease, liver disease, and previous anesthesia complications; assess functional capacity using METs (1 MET = resting energy expenditure; surgery <4 METs = low risk, ≥4 METs = higher risk requiring cardiac workup for moderate-to-high risk patients)
• Revised Cardiac Risk Index (RCRI): Simplified scoring system assigning points for age >65, ASA class ≥3, high-risk surgery type, history of ischemic heart disease, heart failure, cerebrovascular disease, and insulin-dependent diabetes; identifies intermediate- and high-risk patients who may benefit from preoperative cardiac testing (stress test, ECG, troponin)
• 12-lead ECG: Recommended for all men >40 and women >50 undergoing moderate-to-high risk surgery, or with cardiac symptoms/risk factors; also for baseline if on cardiac medications; look for ischemic changes, arrhythmias, or left ventricular hypertrophy
• Troponin and B-type natriuretic peptide (BNP): Increasingly used to identify high-risk patients; elevated preoperative troponin predicts perioperative MI; BNP correlates with heart failure severity and perioperative risk
• Transthoracic echocardiography: Indicated for dyspnea of unclear etiology, known or suspected heart failure, or murmurs suggestive of hemodynamically significant valvular disease; quantifies ejection fraction and wall motion
• Stress testing (exercise or pharmacologic): Recommended for intermediate-risk patients (RCRI score 1-2) with poor functional capacity (<4 METs) undergoing high-risk surgery; normal result reduces perioperative cardiac event risk; positive result requires further evaluation (angiography) or alternative risk reduction strategy
• Coronary angiography: Reserved for acute coronary syndrome or high-risk stress test results; timing is critical—elective surgery should be delayed after angiography/stent placement per guidelines (minimum 5 days for bare-metal stent, 365 days for drug-eluting stent without dual antiplatelet coverage)
• Pulmonary function tests (PFTs): Obtain for dyspneic patients or those with significant respiratory history undergoing thoracic/major abdominal surgery; FEV₁ <50% predicted or DLCO <50% indicates high risk
• Chest radiography: Obtain only if new cardiopulmonary symptoms, significant cardiac/pulmonary disease, or acute illness; routine CXR in asymptomatic patients is low-yield
• Coagulation studies (PT, PTT, platelet count): Obtain if bleeding history, anticoagulant use, liver disease, or malnutrition; obtain baseline for patients on anticoagulation therapy; routine screening in asymptomatic patients without risk factors is not cost-effective
• Complete blood count (CBC): Baseline hemoglobin/hematocrit important for major surgery with expected blood loss; preoperative anemia (Hgb <7-10 g/dL depending on cardiac reserve) may require transfusion or delay
• Basic metabolic panel (BMP): Assess electrolytes, renal function (Cr, BUN), and glucose; critical in elderly, diabetic, or renally impaired patients; hypokalemia increases arrhythmia risk
• Liver function tests (LFTs): Obtain for known liver disease; assess synthetic function (PT, albumin) as marker of reserve
• Glucose and HbA1c: Preoperative glucose >180 mg/dL increases infection and cardiac event risk; HbA1c estimates long-term glycemic control and perioperative risk
• Pregnancy test: Mandatory for all women of childbearing age before elective surgery (teratogenic period first trimester)
• Sleep apnea screening: STOP-BANG questionnaire identifies high-risk patients; obstructive sleep apnea increases perioperative airway complications and hypoxemia
• ASA Physical Status Classification: Standardized system (I-VI) correlating with perioperative risk; useful for prognostication

• Beta-blockers for cardiac patients: Continue perioperatively in patients on chronic beta-blocker therapy; reduce perioperative MI risk in high-risk patients; target heart rate 50-60 bpm; avoid abrupt discontinuation (rebound tachycardia); atenolol, metoprolol, or carvedilol are typical agents; start 2-4 weeks before surgery if not already on them
• ACE inhibitors and angiotensin receptor blockers (ARBs): Controversial perioperative management; withhold morning of surgery to prevent intraoper

Cardiovascular — mostly emergencies

• Perioperative MI / myocardial injury after noncardiac surgery (MINS): supply–demand mismatch under catecholamine surge; peaks in the first 48 hours and is frequently silent or masked by analgesia, so the signal is a troponin rise on surveillance, hypotension, new arrhythmia, or unexplained tachycardia rather than chest pain. Emergency. Remember a new LBBB is not a stand-alone STEMI criterion — apply Sgarbossa criteria
• Stent thrombosis: premature interruption of dual antiplatelet therapy plus the prothrombotic surgical state; presents as abrupt ST-elevation MI or cardiac arrest. Emergency
• New atrial fibrillation, decompensated HF, perioperative stroke: driven by volume shifts, pain, and hypotension
• Beta-blocker started immediately before surgery: POISE showed fewer MIs but more hypotension, stroke, and death — a treatment complication examiners love

Pulmonary

• Atelectasis → pneumonia → respiratory failure: reduced FRC and impaired mucociliary clearance; low-grade fever POD 1–2, hypoxemia, new infiltrate
• Aspiration pneumonitis (Mendelson syndrome): NPO violation or full stomach; abrupt hypoxemia with dependent infiltrates. Emergency
• Opioid-related respiratory depression in undiagnosed OSA

Anesthetic

• Malignant hyperthermia: *RYR1*-mediated calcium release with volatile agents or succinylcholine; earliest sign is a rising end-tidal CO₂ with masseter rigidity, then hyperthermia, rigidity, rhabdomyolysis. Emergency — dantrolene immediately (MHAUS protocol)
• Prolonged paralysis with pseudocholinesterase deficiency; anaphylaxis (neuromuscular blockers, latex) — epinephrine 0.3 mg IM (0.3–0.5 mg) is the answer

Metabolic/endocrine

• Adrenal crisis in chronic steroid users: refractory hypotension unresponsive to fluids/pressors. Emergency
• Euglycemic DKA from SGLT2 inhibitors continued too close to surgery; DKA/HHS or hypoglycemia from mismanaged insulin
• AKI: hypotension compounded by continued ACEI/ARB or NSAIDs

Hematologic

• Hemorrhage from heparin bridging — BRIDGE showed bridging in atrial fibrillation increased major bleeding without reducing thromboembolism, and CHEST guidance now reserves bridging for the highest-risk patients
• VTE/PE: Virchow triad; unexplained tachycardia and hypoxemia POD 3–7. Emergency
• Postoperative delirium and surgical site infection in frail, hyperglycemic patients

• Emergency surgery trumps workup: if the operation is emergent, proceed — the ACC/AHA perioperative guideline directs risk stratification and surveillance to occur perioperatively, not before. The distractor answer is "obtain stress test."
• Order a test only if the result changes management: in a patient with ≥4 METs of functional capacity (climb a flight of stairs, walk up a hill), proceed to surgery without further cardiac testing regardless of RCRI. Routine preoperative CBC, coagulation studies, and CXR in an asymptomatic healthy patient for low-risk surgery are Choosing Wisely negatives.
• ASA fasting rule (2-4-6-8): per the ASA preoperative fasting guideline — 2 h clear liquids, 4 h breast milk, 6 h infant formula/nonhuman milk/light meal, 8 h fried or fatty foods and meat. Clear liquids up to 2 hours is the fact stems hinge on.
• Malignant hyperthermia: a family history of "death or fever under anesthesia" plus succinylcholine or a volatile agent; the first sign is a rising end-tidal CO₂, not fever. Best next step is stop the trigger and give dantrolene. Nitrous oxide, propofol, and regional anesthesia are safe.
• Steroid-dependent patients: continue the home glucocorticoid and give stress-dose coverage for major surgery; refractory intraoperative hypotension unresponsive to pressors = adrenal crisis until proven otherwise.
• Diabetes medications: hold SGLT2 inhibitors several days preoperatively (ADA Standards of Care) to avoid euglycemic DKA, hold metformin and other orals the morning of surgery, and reduce — do not omit — basal insulin.
• Anticoagulation: warfarin is stopped several days out with INR checked; DOACs are held based on renal function and bleeding risk, and bridging is not routine (BRIDGE, CHEST guideline). Never bridge a DOAC.
• Continue, don't stop: beta blockers (rebound ischemia), statins (plaque stabilization), and aspirin in a recent-stent patient. Do not initiate a beta blocker on the day of surgery (POISE).