Preoperative Assessment and Perioperative Risk Management
This domain tests whether you can grade surgical risk, identify modifiable disease, and decide which investigations actually change management. The Egyptian board favours vignettes with a specific patient and operation, asking whether to cancel, optimise, or proceed.
Risk indices you must know
- ASA physical status predicts mortality but is not operation-specific; it is subjective and rarely justifies cancelling surgery by itself.
- Revised Cardiac Risk Index (Lee) scores six factors: high-risk surgery (intraperitoneal, intrathoracic, vascular), ischaemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, and creatinine above 177 micromol/L. MACE rates are roughly 0.4%, 0.9%, 6.6%, and 11% for 0, 1, 2, and 3 or more factors.
- Functional capacity is graded in METs with 4 METs as the threshold; climbing one flight of stairs briskly is about 4 METs.
- Pulmonary tools: ARISCAT for postoperative pulmonary complications and STOP-BANG for sleep apnoea.
- Frailty assessment and biomarkers such as NT-proBNP refine risk before vascular surgery.
Optimisation and fasting
- Continue beta-blockers and statins; do not start beta-blockers on the morning of surgery.
- Stop smoking at least 4 weeks before elective surgery to reduce pulmonary and wound complications.
- Fasting: 2 h clear fluids, 4 h breast milk, 6 h light meal, 8 h fatty meal.
- Bridging anticoagulation is reserved for high thrombotic risk such as a mechanical mitral valve or recent stroke.
Worked example
A 70-year-old man with insulin-treated diabetes and creatinine 190 micromol/L is booked for elective open colectomy; he climbs stairs slowly and stops twice, about 3 METs. RCRI: high-risk surgery plus insulin-treated diabetes plus creatinine above 177 equals 3 points, MACE about 11%. Because functional capacity is under 4 METs and surgery is high risk, cardiology review with echocardiography and consideration of stress testing is justified; proceeding with invasive monitoring is defensible if surgery is urgent. Reasoning: the index gives the probability, while METs and urgency determine the response.
Traps that cost marks
- Accepting the patient's own MET estimate without probing.
- Ordering stress tests before low-risk surgery where the result would change nothing.
- Withholding antiplatelets in a recently stented coronary artery.
- Forgetting that SGLT2 inhibitors need 3 to 4 days cessation for euglycaemic ketoacidosis risk.