AS3.1-6 | Preoperative Evaluation and Medication — Graded Quiz

Correct. Elective surgery within 6 weeks of an acute MI carries substantially elevated reinfarction risk (historically >30%). Current guidelines recommend deferring elective surgery for at least 60–90 days post-MI. Uncontrolled hypertension (>160/100) also warrants optimisation before elective procedures.

Elective surgery contraindications: MI within 60 days, uncontrolled BP >160/100 at rest. Optimisation window = time to reduce modifiable risk. Echocardiogram result alone does not override the post-MI waiting period.

Post-MI waiting period for elective surgery: minimum 60–90 days (some guidelines 6 months for major surgery). Resting BP >160/100 is an additional indication to postpone and optimise. These two factors together make immediate surgery inappropriate.

Correct. Malignant hyperthermia (MH) is autosomal dominant. The described death (hyperthermia + rigidity intraoperatively) is pathognomonic. MH is triggered by volatile anaesthetics (halothane, isoflurane, sevoflurane) and suxamethonium — all must be avoided; TIVA (total intravenous anaesthesia) with non-depolarising NMBs is mandated.

MH triggers: volatile agents + suxamethonium. Management: dantrolene. Family history of anaesthetic death with hyperthermia/rigidity = take MH precautions (TIVA, non-depolarising NMB, have dantrolene ready).

The family history of intraoperative hyperthermia + rigidity = malignant hyperthermia until proven otherwise. MH is autosomal dominant; first-degree relative history mandates avoidance of all triggering agents. This is one of the most important family history questions in the pre-anaesthetic assessment.

Correct. Difficult airway prediction is multifactorial. Multiple concurrent predictors (Mallampati III, thyromental distance <6.5 cm, limited extension, reduced mouth opening) increase the probability of difficulty. No single test is sufficient; combined assessment is mandatory.

Difficult airway = LEMON: Look (external), Evaluate 3-3-2, Mallampati, Obstruction, Neck mobility. No single test is sufficient. Multiple predictors = plan for difficult intubation with alternatives (video-laryngoscopy, fibreoptic, surgical airway standby).

Thyromental distance <6 cm (not ≥6) is a predictor of difficulty. Mallampati class III, thyromental distance 5.5 cm (borderline), limited neck extension, and reduced mouth opening together constitute multiple predictors — each alone has modest sensitivity, but concurrence substantially raises difficulty risk.

Correct. Moderate aortic stenosis requires up-to-date echocardiographic assessment (severity may have progressed) and cardiology input before major surgery. Warfarin mandates INR measurement and a perioperative anticoagulation plan (bridging vs hold). ECG for baseline rhythm, FBC for anaemia (common, poorly tolerated in AS), and renal function.

Investigations are problem-driven. Documented disease still needs up-to-date status: aortic stenosis worsens over time. INR is mandatory for every patient on warfarin. Always ask: 'Is this still current?'

Investigations must address every active clinical problem. Aortic stenosis: echocardiogram (is it still moderate or has it progressed?); warfarin: INR + bridging plan; atrial fibrillation: ECG for rate and rhythm; major joint replacement: FBC for baseline haemoglobin.

Correct. A complete fitness statement documents: (1) risk classification (ASA III), (2) the anaesthetic plan (GA with invasive monitoring), (3) specialist optimisation (cardiologist reviewed), and (4) informed consent. All four elements are present.

Complete preoperative fitness documentation = ASA class + specific anaesthetic plan + specialist clearance where indicated + informed consent. 'Fit for surgery' without a plan is insufficient documentation.

Fitness documentation requires four elements: risk classification, anaesthetic plan, specialist input where needed, and informed consent. Intraoperative drug doses are in the anaesthetic record, not the preoperative fitness statement.

Correct. HbA1c >9% and fasting glucose >12 mmol/L indicate poor glycaemic control. Elective surgery should be postponed until HbA1c is <8.5% and perioperative glucose is <10 mmol/L, as poor control increases surgical site infection, delayed healing, and perioperative hyperglycaemia risk.

Pre-surgical glycaemic targets: HbA1c <8.5%, fasting glucose <10 mmol/L. Poorly controlled diabetes is a modifiable risk factor — postponing elective surgery to optimise control reduces SSI and perioperative complications.

Poor glycaemic control (HbA1c >9%, fasting glucose >12 mmol/L) is an indication to postpone elective surgery. Targets before elective surgery: HbA1c <8.5–9%, morning glucose <10 mmol/L. Type 2 diabetes significantly impairs wound healing and immune function.

Correct. For patients with coronary stents or recent ACS on antiplatelet therapy, abrupt withdrawal risks acute stent thrombosis. The perioperative antiplatelet decision requires a multidisciplinary risk-benefit discussion (cardiologist + surgeon + anaesthesiologist). In low-to-moderate bleeding risk surgery, aspirin is often continued.

Antiplatelet perioperative decision = multidisciplinary. In IHD with stents: aspirin withdrawal risk (stent thrombosis) > surgical bleeding risk for most procedures. Continue aspirin unless high bleeding risk surgery (intracranial, posterior eye); involve cardiologist.

Perioperative antiplatelet management in coronary disease is not a unilateral surgical or anaesthetic decision — it requires cardiology input. Aspirin withdrawal within 7 days raises the risk of stent thrombosis and acute MI. Clopidogrel has a longer withdrawal effect and is NOT an appropriate substitute.

Correct. Chronic alcohol use causes enzyme induction, increasing drug metabolism and requiring higher doses of many anaesthetic agents. It also increases PONV risk. Recent smoking cessation (<8 weeks) transiently increases secretions — longer cessation reduces airway reactivity. Both are directly relevant to anaesthetic planning.

Social history for anaesthesia: alcohol (drug tolerance, PONV, withdrawal), smoking (airway reactivity, secretions — quit >8 weeks for full benefit), recreational drugs (sympathomimetics, opioid tolerance). These directly modify anaesthetic drug selection and doses.

Social history — specifically alcohol and smoking — directly affects anaesthetic drug dosing and airway management. Chronic alcohol: enzyme induction (higher propofol/opioid requirement), withdrawal risk if abrupt cessation, PONV. Recent ex-smoking: sputum increase for first few weeks before airway reactivity normalises.

Correct. ASA 2-4-6-8 rule: clear fluids 2 h, breast milk 4 h, formula/non-human milk/light solid meal 6 h, fatty or fried foods/meat 8 h. Blanket 'nil by mouth from midnight' causes unnecessary dehydration and patient discomfort.

ASA fasting rule mnemonic '2-4-6-8': clear water/juice = 2 h; breast milk = 4 h; light meal/formula = 6 h; heavy meal = 8 h. Applies to all elective adults and children without gastroparesis or full-stomach risk factors.

ASA preoperative fasting guidelines: clear fluids = 2 h, breast milk = 4 h, light meal/formula = 6 h, fatty/fried/meat meal = 8 h. 'Nil by mouth from midnight' is outdated and not evidence-based. For elective morning surgery, clear fluids until 2 h before is safe.

Correct. For high aspiration risk patients (obesity, GORD), aspiration prophylaxis combines: an H2 blocker (ranitidine) to reduce gastric acid secretion — given the night before AND 2 hours preoperatively — and sodium citrate (a non-particulate antacid) to neutralise existing gastric acid immediately before induction.

Aspiration prophylaxis: ranitidine H2 blocker (reduce acid production) + sodium citrate (neutralise residual acid, given immediately before). Also consider prokinetics (metoclopramide). RSI is a technique, not a medication; both are complementary.

Ondansetron/dexamethasone address PONV, not aspiration. Opioids increase gastric transit time, worsening aspiration risk. RSI alone reduces but does not eliminate aspiration risk. Active aspiration prophylaxis = H2 blocker (raises gastric pH) + sodium citrate (neutralises acid) for high-risk patients.