About This Page
This is a clinician-written, evidence-based guide aligned to the MCC Examination Objectives. It is structured by clinical presentation — the way the MCCQE tests and the way patients actually present. Management reflects current Canadian guidelines (CMA, CFPC, CPS). Always cross-reference with institutional protocols and clinical judgment.
The Bottom Line
- Pre-operative assessment is not a battery of routine tests — it is a risk assessment based on urgency, surgical risk, functional capacity, and patient comorbidities
- Postpone elective surgery for ACS, decompensated HF, unstable arrhythmia, severe symptomatic valvular disease, severe respiratory infection/exacerbation, uncontrolled sepsis, or severe metabolic derangement
- Choosing Wisely Canada: avoid routine pre-op labs, ECGs, CXR, echocardiograms, or stress tests for low-risk surgery in asymptomatic low-risk patients
- Medication review is central: anticoagulants/antiplatelets, diabetes medications, ACEi/ARB/diuretics, steroids, opioids, sedatives, herbal supplements, and SGLT2 inhibitors
- Older adults require frailty, delirium, functional, cognitive, falls, nutrition, and goals-of-care assessment, not just cardiac clearance
Approach to the Presentation
The pre-operative assessment asks: is the surgery urgent, what is the procedure risk, what is the patient risk, and what can be modified before surgery? Start with surgical urgency and invasiveness, then evaluate functional capacity, cardiovascular symptoms, respiratory disease, diabetes, renal disease, bleeding/thrombosis risk, anaesthesia history, allergies, pregnancy status, frailty, cognition, substance use, and social supports for recovery. The MCCQE1 frequently tests restraint: routine testing before low-risk surgery in asymptomatic patients causes false positives and delays without improving outcomes. The best answer is often targeted testing and optimization, not “clearance”.
Differential Diagnosis
| diagnosis | likelihood | key features | distinguishing test |
|---|---|---|---|
| Active cardiac condition | must-not-miss | Recent or ongoing chest pain, dynamic symptoms, recent MI, dyspnea, diaphoresis, abnormal ECG | ECG, troponin if symptomatic, cardiology assessment; postpone elective surgery |
| Decompensated heart failure | must-not-miss | Orthopnea, PND, pulmonary oedema, rising weight, elevated JVP, crackles, oedema | Clinical exam, BNP/CXR/ECG, echocardiogram if new or changed |
| Significant arrhythmia | must-not-miss | Syncope, palpitations with instability, rapid AF, high-grade AV block, symptomatic bradycardia | ECG, electrolytes, ambulatory/telemetry assessment depending on urgency |
| Severe valvular disease | must-not-miss | Exertional syncope, angina, dyspnea, harsh systolic murmur, heart failure signs | Echocardiogram when suspected clinically |
| Respiratory instability | must-not-miss | Wheeze, increased sputum, fever, hypoxia, dyspnea, poor exercise tolerance, severe OSA symptoms | Oxygen saturation, CXR if infection suspected, spirometry if it changes management, sleep apnea risk assessment |
| Poorly controlled diabetes or metabolic derangement | common | Hyperglycaemia, hypoglycaemia risk, DKA/HHS symptoms, SGLT2 inhibitor use, CKD | Glucose, HbA1c when control unknown, electrolytes/creatinine if indicated |
| Bleeding or thrombosis risk | common | Warfarin/DOAC/antiplatelet use, VTE history, mechanical valve, liver disease, inherited bleeding disorder | Medication review, INR if warfarin/liver disease, CBC/platelets; perioperative anticoagulation plan |
| Anaemia or malnutrition | common | Fatigue, dyspnea, heavy menses/GI bleeding, low albumin, weight loss, frailty | CBC/ferritin and nutrition assessment if surgery has meaningful blood loss or risk |
| Frailty, cognitive impairment, delirium risk | common | Slow gait, falls, dependence, dementia, polypharmacy, poor nutrition, limited supports | Clinical Frailty Scale, cognition/delirium risk screen, medication review |
| Medication-related perioperative risk | common | Anticoagulants, antiplatelets, insulin/sulfonylureas, SGLT2 inhibitors, steroids, opioids, benzodiazepines, herbal products | Structured medication reconciliation and perioperative plan |
Red Flags & Key History
Symptoms
Chest pain, recent MI, worsening dyspnea, orthopnea, syncope, or unstable palpitations
Fever, productive cough, wheeze, hypoxia, recent respiratory infection or COPD/asthma exacerbation
Bleeding history, anticoagulant/antiplatelet use, VTE history, mechanical valve
Poor functional capacity with higher-risk surgery
Falls, cognitive impairment, delirium history, ADL dependence, poor supports
Previous anaesthetic complication, difficult airway, malignant hyperthermia family history
Low-risk procedure, asymptomatic, good functional capacity
Signs
Raised JVP, crackles, S3, pulmonary oedema
New murmur suggesting severe aortic stenosis or valve disease
Hypoxia, wheeze, fever, active respiratory infection
Severe hypertension with end-organ symptoms or hypotension
Slow gait, sarcopenia, poor grip, dependence, malnutrition
Approach to Investigation
First-line
Risk stratification: surgery risk + functional capacity + comorbiditiesDetermine urgency, invasiveness, expected blood loss/fluid shifts, functional capacity, cardiac/respiratory symptoms, frailty, and recovery supports
Medication reconciliationAnticoagulants/antiplatelets, diabetes medications including SGLT2 inhibitors, steroids, antihypertensives, opioids/sedatives, supplements, allergies
Targeted CBC, creatinine/electrolytes, glucose/HbA1c, INROnly when indicated by patient condition, procedure risk, expected blood loss, anticoagulation, renal disease, diabetes, or symptoms
Pregnancy test where relevantWhen pregnancy status could affect anaesthesia, imaging, or surgery timing
Second-line
ECGIndicated for symptoms, known cardiovascular disease, significant risk factors with intermediate/high-risk surgery, or arrhythmia concern — not routine in low-risk asymptomatic patients
CXROnly for new/worsening cardiopulmonary symptoms or suspected acute disease; not routine pre-op screening
EchocardiogramIf unexplained dyspnea, suspected significant valvular disease, or decompensated/new HF
Stress testingOnly if results would change management and patient has poor/unknown functional capacity plus elevated surgical/cardiac risk
Specialist
Anesthesia/pre-admission clinicComplex comorbidity, difficult airway, high-risk surgery, prior anaesthetic complication, frailty, or uncertain perioperative plan
Cardiology/internal medicineActive cardiac condition, decompensated HF, severe valve disease, unstable arrhythmia, or complex anticoagulation/cardiac risk decision
GeriatricsFrailty, cognitive impairment, delirium risk, polypharmacy, or complex discharge planning
Management Principles
Choosing Wisely Canada Drop the Pre-Op Toolkit + Anesthesiology Recommendations1
Decide whether to proceed
- Proceed without routine testing for asymptomatic low-risk patients undergoing low-risk surgery
- Delay elective surgery for active cardiac disease, decompensated HF, severe respiratory infection/exacerbation, uncontrolled sepsis, or severe metabolic abnormality
- Urgent/emergency surgery: optimize in parallel rather than delaying life-saving operation
2
Optimize comorbidities
- Cardiac: stabilize ACS/HF/arrhythmia; continue most beta-blockers if already prescribed; avoid starting high-dose beta-blockers immediately pre-op
- Respiratory: optimize inhalers, treat exacerbation/infection, smoking cessation support, OSA precautions
- Diabetes: perioperative glucose plan; hold SGLT2 inhibitors before surgery according to local protocol because of euglycaemic DKA risk
- Anaemia: investigate and treat iron deficiency when time allows, especially before major surgery
3
Medication planning
- Anticoagulants/antiplatelets: balance bleeding versus thrombosis and coordinate with surgeon/anesthesia/cardiology when high-risk
- Steroids: assess adrenal suppression and need for perioperative stress dosing
- Opioids/sedatives: anticipate tolerance, respiratory depression, delirium, constipation, and postoperative pain planning
- Document allergies and previous anaesthetic complications clearly
4
Frailty and discharge planning
- Assess cognition, delirium risk, falls, nutrition, mobility, caregiver support, and goals of care
- Plan postoperative supports: home care, rehab, medication simplification, pain plan, and follow-up
Complications & Pitfalls
- “Routine clearance” misconception: Pre-op assessment should identify modifiable risk, not provide a blanket guarantee of safety.
- Low-value testing: Routine CXR/ECG/labs in asymptomatic low-risk surgery can delay care and create false positives.
- Missing frailty: Frailty predicts postoperative complications beyond traditional cardiac risk tools.
- Medication omissions: Anticoagulants, SGLT2 inhibitors, steroids, and sedatives are frequent perioperative traps.
- Delaying emergency surgery unnecessarily: In life-threatening surgical disease, resuscitate and optimize while proceeding.
MCCQE1 Exam Tips
- 1Choosing Wisely Canada: do not order routine pre-op tests for low-risk surgery in asymptomatic low-risk patients
- 2Active cardiac conditions that delay elective surgery: ACS, decompensated HF, unstable arrhythmia, severe symptomatic valve disease
- 3Good functional capacity and low-risk surgery usually means proceed without stress testing
- 4Pre-op assessment in older adults includes frailty, cognition, delirium risk, falls, nutrition, and discharge supports
- 5Do not call it medical clearance in exam reasoning; frame as risk assessment and optimization
- 6SGLT2 inhibitors are a perioperative trap because of euglycaemic DKA risk
- 7CanMEDS collaborator role: coordinate with surgeon, anesthesia, primary care, cardiology, pharmacy, and home supports
practicetest your knowledge on pre-operative assessmentApply what you've learnt with MCCQE1-style questions from the iatroX Q-Bank — general & constitutional and beyond.
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