HKCA Final MCQ cheat sheet

Inhalational MAC values in a 40-year-old adult: sevoflurane ~2.0%, isoflurane ~1.15%, desflurane ~6.0%, nitrous oxide ~105%; MAC decreases ~6% per decade after age 40 and falls with hypothermia, pregnancy, sepsis, and opioid or benzodiazepine co-administration.

Rapid sequence induction: pre-oxygenate to end-tidal O2 >90%, apply cricoid force 10-30 N (30 N in adults), give induction agent then suxamethonium 1-1.5 mg/kg IV, and avoid bag-mask ventilation unless desaturation supervenes.

Suxamethonium is contraindicated in hyperkalaemia, burns or denervation beyond 24-72 hours, prolonged immobility, and known pseudocholinesterase deficiency; malignant hyperthermia is treated with dantrolene 2.5 mg/kg IV repeated to a cumulative 10 mg/kg.

Difficult airway algorithm: after failed laryngoscopy, limit attempts to avoid airway trauma, insert a supraglottic device, and proceed to surgical cricothyroidotomy if oxygenation cannot be maintained (cannot intubate, cannot oxygenate).

Spinal anaesthesia block height depends on baricity and patient position; a hyperbaric bupivacaine dose of 2.5-3 mL 0.5% in the sitting position typically blocks to T8-T10, and hypotension is managed with vasopressors and fluids.

Local anaesthetic maximum safe doses: lidocaine 3 mg/kg plain or 7 mg/kg with adrenaline; bupivacaine 2 mg/kg; ropivacaine 3 mg/kg; levobupivacaine 2 mg/kg. Intralipid 20% at 1.5 mL/kg bolus then 0.25 mL/kg/min for systemic toxicity.

Laryngospasm after extubation is managed with 100% oxygen, continuous positive airway pressure, deepening anaesthesia with propofol 0.5-1 mg/kg, and suxamethonium 0.5-1 mg/kg IV if the spasm persists; avoid further airway stimulation.

Postoperative nausea and vomiting prophylaxis uses Apfel risk factors (female sex, non-smoker, history of PONV, postoperative opioids); each factor adds ~20% risk, and ≥2 factors justify multimodal prophylaxis.

Sepsis-3 defines sepsis as suspected infection plus a SOFA score rise of ≥2 points; septic shock is sepsis with vasopressor requirement to maintain MAP ≥65 mmHg and lactate >2 mmol/L despite adequate fluid resuscitation.

ARDS Berlin definition: acute onset within 1 week, bilateral opacities not fully explained by cardiac failure, PEEP ≥5 cmH2O, and PaO2/FiO2 ≤300; severity is mild 200-300, moderate 100-200, severe <100.

Lung-protective ventilation in ARDS: tidal volume 6 mL/kg predicted body weight, plateau pressure ≤30 cmH2O, permissive hypercapnia, and PEEP titration; prone positioning for ≥16 hours/day reduces mortality when PaO2/FiO2 <150.

Surviving Sepsis initial resuscitation: 30 mL/kg crystalloid within the first 3 hours for sepsis-induced hypoperfusion, then target MAP ≥65 mmHg with noradrenaline as the first-line vasopressor.

Acute kidney injury KDIGO staging: stage 1 = creatinine rise ≥26.5 micromol/L in 48 h or 1.5-1.9 times baseline; stage 2 = 2.0-2.9 times; stage 3 = ≥3 times, creatinine ≥354 micromol/L, or initiation of renal replacement therapy.

Hyperkalaemia with ECG changes: give IV calcium gluconate 10 mL 10% for membrane stabilisation, then insulin 10 units with 50 mL 50% dextrose, salbutamol nebulised, and consider dialysis; sodium bicarbonate is reserved for metabolic acidosis.

Delirium in ICU is screened with CAM-ICU; non-pharmacological measures (orientation, sleep hygiene, early mobilisation, minimising sedation) are first line, with antipsychotics only for distressing symptoms and no proven mortality benefit.

Ventilator-associated pneumonia is diagnosed with new infiltrate plus clinical signs after 48 hours of ventilation; use quantitative cultures and start empirical broad-spectrum cover, then de-escalate based on results.

WHO analgesic ladder: step 1 non-opioid (paracetamol, NSAID), step 2 weak opioid (codeine, tramadol), step 3 strong opioid (morphine, oxycodone, fentanyl); co-analgesics such as gabapentinoids and tricyclics are added at any step for neuropathic pain.

Opioid conversion: oral morphine 30 mg ≈ oral oxycodone 20 mg ≈ oral hydromorphone 6 mg ≈ subcutaneous morphine 10 mg; fentanyl transdermal 25 micrograms/h ≈ oral morphine 60-90 mg/day.

Neuropathic pain first line: gabapentin (titrate to 300-1200 mg three times daily), pregabalin, duloxetine, or amitriptyline; opioids are second line and tramadol is the only weak opioid with a recognised neuropathic indication.

NSAIDs are avoided in eGFR <30, active peptic ulcer disease, decompensated heart failure, and third-trimester pregnancy; paracetamol dose is capped at 4 g/day in adults and reduced to 2-3 g/day in hepatic impairment or low body weight.

Nociceptive versus neuropathic pain: nociceptive responds to simple and opioid analgesics, whereas neuropathic pain responds poorly to opioids and requires gabapentinoids, tricyclics, SNRIs, or topical lidocaine/capsaicin.

Postoperative multimodal analgesia combines paracetamol, NSAID or COX-2 inhibitor, regional block, and opioid-sparing agents; a thoracic epidural or erector spinae block is favoured for major abdominal or thoracic surgery.

Opioid-induced hyperalgesia and tolerance are managed by reducing the opioid dose or rotating to a different opioid; opioid-induced constipation is prevented with a stimulant laxative plus osmotic agent.

Palliative pain management: start a strong opioid with a regular long-acting preparation plus a short-acting breakthrough dose of 10-15% of the total daily dose; reassess every 24 hours and use anticipatory prescribing for end-of-life symptoms.