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Iraqi Board Anesthesia study materials
Iraqi Board Anesthesia study resources

Iraqi Board Anesthesia practice questions

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Question 1Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A patient is positioned in the sitting position for a shoulder procedure under general anesthesia. Which change in pulmonary physiology is most expected compared with the supine position?

  1. Increase in functional residual capacity Correct answer.
  2. Decrease in alveolar dead space
  3. Increase in pulmonary blood flow to the apices
  4. Reduction in venous return to the right atrium

Explanation

Sitting upright moves the diaphragm caudally and reduces abdominal compression of the lung bases, so functional residual capacity rises. Venous return to the right heart actually falls in the upright position because of blood pooling in the legs, and dead space tends to increase rather than decrease as apical perfusion declines.

Question 2Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which nerve is at greatest risk of injury during a classical interscalene brachial plexus block because of its superficial course in the neck?

  1. Recurrent laryngeal nerve
  2. Long thoracic nerve
  3. Phrenic nerve
  4. Accessory nerve Correct answer.

Explanation

The spinal accessory nerve runs superficially in the posterior triangle of the neck and can be injured by needle trauma or local anesthetic spread during interscalene block, producing trapezius weakness. The phrenic nerve is also commonly affected but mainly through spread causing hemidiaphragmatic paresis rather than direct needle injury.

Question 3Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A 70 kg adult receives a bolus of a drug with a volume of distribution of 0.5 L/kg. Approximately what loading dose is required to achieve a plasma concentration of 4 mg/L?

  1. 280 mg
  2. 140 mg Correct answer.
  3. 560 mg
  4. 35 mg

Explanation

Volume of distribution equals 0.5 L/kg times 70 kg, giving 35 L. Loading dose equals target concentration times volume of distribution, so 4 mg/L times 35 L equals 140 mg.

Question 4Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which statement best describes the mechanism by which a circle system with a carbon dioxide absorber prevents hypercapnia during low-flow anesthesia?

  1. Diffusion of carbon dioxide across a semipermeable membrane into the ventilator bellows
  2. Chemical binding of carbon dioxide to hemoglobin within the reservoir bag
  3. Dissolution of carbon dioxide into condensed water within the expiratory limb
  4. Absorption of carbon dioxide by calcium hydroxide producing calcium carbonate Correct answer.

Explanation

Soda lime contains calcium hydroxide which reacts with carbon dioxide to form calcium carbonate and water, with the reaction releasing heat. The exhaled gas returning through the absorber therefore has its carbon dioxide removed before rebreathing.

Question 5Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

During one-lung ventilation, which mechanism is the principal cause of hypoxemia in the dependent lung?

  1. Reduction in mixed venous oxygen content
  2. Continuation of perfusion to the non-ventilated lung Correct answer.
  3. Increased dead space ventilation from overdistension
  4. Reflex bronchospasm in the ventilated lung

Explanation

During one-lung ventilation the operative lung remains perfused but is not ventilated, creating a true shunt that lowers arterial oxygen content. Hypoxic pulmonary vasoconstriction reduces but does not abolish this shunt.

Question 6Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which local anesthetic property explains why bupivacaine has a longer duration of action than lidocaine?

  1. Faster hepatic clearance
  2. Higher pKa
  3. Greater lipid solubility and protein binding Correct answer.
  4. Lower molecular weight

Explanation

Bupivacaine is more lipid soluble and more highly protein bound than lidocaine, giving greater potency and longer duration as it remains bound at the nerve and in plasma. The pKa of both agents is similar, so ionization at physiological pH is not the explanation.

Question 7Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A patient with a permanent pacemaker is scheduled for surgery using monopolar electrocautery. Which precaution most directly reduces the risk of pacemaker malfunction?

  1. Using short bursts of coagulation current with the return electrode on a distant limb Correct answer.
  2. Positioning the return electrode on the same side as the generator
  3. Placing the return electrode close to the pacemaker generator
  4. Selecting the cutting mode at maximum power

Explanation

Current density through the pacemaker leads is reduced when the return electrode is placed far from the generator and current is delivered in short bursts. This limits interference and the risk of inappropriate inhibition or reprogramming.

Question 8Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which change in arterial blood gas values is expected when a patient is acutely hyperventilated during general anesthesia?

  1. Increased arterial carbon dioxide with decreased pH
  2. Decreased arterial carbon dioxide with increased pH Correct answer.
  3. Increased arterial carbon dioxide with increased pH
  4. Decreased arterial oxygen with unchanged pH

Explanation

Alveolar ventilation removes carbon dioxide faster than it is produced, so arterial carbon dioxide falls and the bicarbonate-to-carbon dioxide ratio rises, producing respiratory alkalosis. Arterial oxygen is generally unaffected or slightly improved.

Question 9Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A patient with severe aortic stenosis is induced with a volatile agent. Which hemodynamic goal is most important to maintain?

  1. Tachycardia with reduced afterload
  2. Low preload with vasodilation
  3. Increased contractility with reduced filling time
  4. Normal to high systemic vascular resistance with sinus rhythm Correct answer.

Explanation

In aortic stenosis the hypertrophied left ventricle depends on adequate preload, sinus rhythm, and afterload to maintain coronary perfusion and cardiac output. Tachycardia shortens diastolic filling time and reduces coronary flow, so it should be avoided.

Question 10Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which receptor mediates the bronchodilator effect of salbutamol during an intraoperative bronchospasm?

  1. Beta-2 adrenergic receptor Correct answer.
  2. Alpha-1 adrenergic receptor
  3. Beta-1 adrenergic receptor
  4. Muscarinic M3 receptor

Explanation

Salbutamol is a selective beta-2 agonist that relaxes bronchial smooth muscle through cyclic AMP-mediated pathways. Beta-2 receptors predominate in airway smooth muscle, so agonism there produces bronchodilation.

Question 11Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A patient receiving a non-depolarizing neuromuscular blocker shows partial recovery on a peripheral nerve stimulator. Which finding indicates residual blockade requiring further reversal?

  1. Sustained tetanus without fade
  2. Absence of post-tetanic potentiation
  3. Train-of-four ratio greater than 0.9
  4. Train-of-four count of two with fade Correct answer.

Explanation

A train-of-four count below four with fade indicates residual non-depolarizing blockade, and a ratio above 0.9 is needed for safe extubation. Fade with tetanic stimulation also reflects blockade at the presynaptic terminal.

Question 12Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which physical principle explains the drop in delivered tidal volume when a compliant breathing circuit and a stiff lung compete for the same gas volume?

  1. Boyle's law
  2. Graham's law
  3. Poiseuille's law
  4. Compliance and the distribution of volume between circuit and lung Correct answer.

Explanation

During inspiration the ventilator volume is shared between the circuit compliance and the patient's respiratory system compliance. A more compliant circuit accepts a larger fraction of the volume, reducing the amount reaching the lung.

Question 13Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which anatomical feature makes the cricothyroid membrane the preferred site for emergency front-of-neck access?

  1. It is located below the cricoid cartilage
  2. It is covered by the thyroid isthmus
  3. It lies superficial with no overlying major vessels or thyroid tissue Correct answer.
  4. It is the widest part of the larynx

Explanation

The cricothyroid membrane lies just beneath the skin between the thyroid and cricoid cartilages, with few overlying vessels, making it accessible for emergency airway access. The thyroid isthmus usually lies lower, over the upper tracheal rings.

Question 14Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A patient with chronic kidney disease receives succinylcholine. Which electrolyte change is most likely to occur after administration?

  1. Hypernatremia
  2. Hypocalcemia
  3. Hypochloremia
  4. Hyperkalemia Correct answer.

Explanation

Succinylcholine depolarizes the motor endplate and causes potassium efflux from muscle. In chronic kidney disease with upregulation of extrajunctional receptors, this can produce dangerous hyperkalemia.

Question 15Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which statement about the uptake of volatile anesthetics is correct?

  1. A higher blood-gas solubility coefficient slows the rise in alveolar concentration Correct answer.
  2. Increasing alveolar ventilation slows induction with a soluble agent
  3. Increasing cardiac output raises the alveolar concentration rapidly
  4. A lower oil-gas solubility coefficient predicts greater potency

Explanation

A more soluble agent is taken up extensively by blood, so alveolar partial pressure rises slowly and induction is slower. Low cardiac output and high ventilation accelerate the alveolar rise.

Question 16Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which structure must be identified to avoid intravascular injection during a supraclavicular brachial plexus block?

  1. Vertebral artery
  2. External carotid artery
  3. Subclavian artery Correct answer.
  4. Internal jugular vein

Explanation

The subclavian artery lies close to the brachial plexus in the supraclavicular fossa, so needle placement near the plexus risks arterial puncture. Aspiration and ultrasound guidance help avoid intravascular injection.

Question 17Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which best explains why a patient with a full stomach is at increased risk of aspiration during induction of anesthesia?

  1. Reduced lower esophageal sphincter tone and loss of airway reflexes Correct answer.
  2. Increased gastric emptying rate
  3. Increased gastric pH
  4. Reduced intragastric pressure

Explanation

Anesthetic agents reduce lower esophageal sphincter tone and abolish protective airway reflexes, allowing gastric contents to regurgitate and enter the airway. Gastric volume and acidity also influence the severity of aspiration injury.

Question 18Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A patient's oxygen cylinder contains gas at 13,700 kPa. Using Boyle's law, what volume would 2 L of this gas occupy at 100 kPa, assuming constant temperature?

  1. 548 L
  2. 68 L
  3. 274 L Correct answer.
  4. 137 L

Explanation

Boyle's law states that pressure times volume is constant at constant temperature, so 13,700 kPa times 2 L equals 27,400 kPa·L. Dividing by 100 kPa gives 274 L.

Question 19Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which mechanism explains the analgesic effect of opioids when administered into the epidural space?

  1. Inhibition of prostaglandin synthesis in the spinal cord
  2. Activation of mu receptors in the substantia gelatinosa of the dorsal horn Correct answer.
  3. Direct blockade of motor neurons in the ventral horn
  4. Blockade of sodium channels in the dorsal root ganglia

Explanation

Epidural opioids diffuse into the cerebrospinal fluid and bind mu receptors in the substantia gelatinosa, reducing transmission of nociceptive input. This presynaptic and postsynaptic action produces analgesia without motor blockade.

Question 20Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which factor most increases the risk of gastric aspiration during rapid sequence induction in an obstetric patient?

  1. Reduced oxygen consumption in pregnancy
  2. Reduced functional residual capacity and increased intra-abdominal pressure Correct answer.
  3. Delayed gastric emptying due to increased gastric pH
  4. Increased functional residual capacity from progesterone

Explanation

Pregnancy reduces functional residual capacity and raises intra-abdominal pressure, shortening the safe apnea time and increasing regurgitation risk. Progesterone also delays gastric emptying, further increasing aspiration risk.

Question 21Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which nerve block is most appropriate for providing anesthesia for a forearm laceration repair on the lateral aspect of the forearm?

  1. Posterior tibial nerve block
  2. Ulnar nerve block at the elbow
  3. Musculocutaneous nerve block at the elbow Correct answer.
  4. Median nerve block at the wrist

Explanation

The musculocutaneous nerve supplies sensation to the lateral forearm through the lateral cutaneous nerve of the forearm, making a block at the elbow appropriate. The ulnar and median nerves supply medial and palmar areas respectively.

Question 22Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which statement about the pharmacokinetics of propofol is correct?

  1. It undergoes extensive renal excretion unchanged
  2. It is highly water soluble at physiological pH
  3. It has a large volume of distribution and rapid redistribution Correct answer.
  4. It has a long elimination half-life limiting its use as an infusion

Explanation

Propofol is highly lipid soluble, has a large volume of distribution, and is rapidly redistributed from the brain to other tissues, giving quick recovery after a bolus. It is cleared mainly by hepatic metabolism and is formulated as an emulsion because of poor water solubility.

Question 23Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which change in the oxygen-hemoglobin dissociation curve occurs with hypothermia?

  1. No change in affinity but reduced oxygen content
  2. Shift to the right with decreased hemoglobin affinity
  3. Shift to the left with increased hemoglobin affinity Correct answer.
  4. Shift to the right with increased 2,3-DPG

Explanation

Hypothermia reduces metabolic activity and increases hemoglobin affinity for oxygen, shifting the curve to the left. This means oxygen is released less readily to tissues, which is relevant during cardiopulmonary bypass and deep hypothermia.

Question 24Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

Which monitor directly measures the fraction of inspired oxygen delivered to the patient?

  1. Capnograph
  2. Pulse oximeter
  3. Mass spectrometer measuring nitrogen
  4. Paramagnetic oxygen analyzer Correct answer.

Explanation

A paramagnetic oxygen analyzer measures the oxygen concentration in the inspired gas because oxygen is paramagnetic. Pulse oximetry estimates arterial saturation, while capnography measures exhaled carbon dioxide.

Question 25Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A patient develops a sudden rise in peak airway pressure with a normal plateau pressure during laparoscopy. Which cause is most likely?

  1. Kinked endotracheal tube Correct answer.
  2. Bronchospasm
  3. Tension pneumothorax
  4. Reduced lung compliance from pneumoperitoneum

Explanation

A high peak pressure with a normal plateau indicates increased resistance in the airway or circuit rather than a compliance problem. A kinked tube, secretions, or bronchospasm raise the peak but not the plateau, whereas compliance problems raise both.

Question 26Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

During a supraclavicular brachial plexus block, which anatomical structure must be identified to avoid intravascular injection?

  1. Subclavian vein
  2. Internal jugular vein
  3. Axillary artery
  4. Subclavian artery Correct answer.

Explanation

The subclavian artery runs in close proximity to the brachial plexus in the supraclavicular fossa, and inadvertent puncture can occur during needle advancement. Identifying the artery with ultrasound or Doppler reduces the risk of intravascular injection of local anesthetic.

Question 27Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A patient with severe aortic stenosis is induced with a volatile agent. Which hemodynamic goal is most important to maintain during induction?

  1. Maintain systemic vascular resistance and preload. Correct answer.
  2. Target a mean arterial pressure of 50–60 mmHg.
  3. Reduce afterload to improve forward flow.
  4. Increase heart rate to 100–110 beats per minute.

Explanation

In severe aortic stenosis, the fixed outflow obstruction makes the left ventricle highly dependent on adequate preload and systemic vascular resistance to maintain coronary perfusion and cardiac output. Tachycardia and afterload reduction can precipitate ischemia and hypotension.

Question 28Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

During one-lung ventilation, which mechanism is the principal cause of hypoxaemia in the first minutes after the pleural cavity is opened?

  1. Diffusion of oxygen across the pleura is impaired by surgical retraction
  2. Blood continues to perfuse the non-ventilated lung, creating true shunt Correct answer.
  3. Bronchial blood flow to the ventilated lung increases and dilutes alveolar gas
  4. Ventilation of the dependent lung becomes excessive and washes out carbon dioxide

Explanation

When the operative lung is no longer ventilated but still perfused, blood returning to the left atrium has not been oxygenated, which is true shunt; this is the dominant early cause of desaturation. Hypoxic pulmonary vasoconstriction then gradually reduces perfusion to that lung and limits the shunt over the following minutes. Shunt is poorly corrected by raising inspired oxygen, which is why one-lung ventilation is managed with other measures.

Question 29Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A 60 kg patient is receiving an infusion of a drug with a volume of distribution of 1.5 L/kg and a clearance of 6 L/h. Approximately what loading dose is required to achieve a target plasma concentration of 2 mg/L?

  1. 12 mg
  2. 60 mg
  3. 180 mg Correct answer.
  4. 360 mg

Explanation

Loading dose equals target concentration multiplied by volume of distribution, and the volume here is 60 kg × 1.5 L/kg = 90 L. Multiplying 90 L by 2 mg/L gives 180 mg. Clearance determines the maintenance infusion rate, not the loading dose, so it is not used in this calculation.

Question 30Basic sciences applied to anesthesia: anatomy, physiology, pharmacology, physics and equipment

A circle breathing system is used with a fresh gas flow below the patient's minute ventilation. Which consequence follows from this arrangement?

  1. Rebreathing of carbon dioxide occurs because the absorber is bypassed
  2. The delivered volatile concentration always exceeds the vaporiser setting
  3. The inspired oxygen fraction falls to zero as nitrogen accumulates
  4. Inspired volatile agent concentration rises more slowly than with a high fresh gas flow Correct answer.

Explanation

At low fresh gas flow most of the gas breathed is recirculated, so the circuit and the patient's lungs must be filled with agent before the inspired concentration approaches the dialled value, making equilibration slower. Carbon dioxide is still removed by the soda lime absorber, and oxygen is supplied by the fresh gas and monitored continuously. The final inspired concentration approaches but does not exceed the vaporiser setting.

Question 31Preoperative assessment, risk stratification and optimization

A 58-year-old man scheduled for elective open cholecystectomy has a preoperative platelet count of 62 × 10⁹/L. He has no bleeding history, no bruising, and normal renal and liver function tests. Which is the most appropriate next step before proceeding?

  1. Repeat the count and review the blood film to exclude pseudothrombocytopenia Correct answer.
  2. Give one adult dose of platelet concentrate immediately before induction
  3. Cancel surgery permanently and refer for bone marrow biopsy
  4. Proceed with surgery because counts above 50 × 10⁹/L are always adequate

Explanation

An unexpected isolated thrombocytopenia in an asymptomatic patient is most often spurious, caused by platelet clumping in EDTA anticoagulant. Confirming with a repeat sample in citrate or heparin and inspecting the film prevents unnecessary cancellation, transfusion, or invasive investigation. A genuine count of 62 × 10⁹/L would still permit most elective surgery without prophylactic platelets.

Question 32Preoperative assessment, risk stratification and optimization

Which preoperative finding best predicts difficult face-mask ventilation in an adult?

  1. A body mass index of 26 kg/m² with full dentition
  2. Presence of a beard together with edentulous state and obesity Correct answer.
  3. A history of treated obstructive sleep apnoea on CPAP
  4. Mallampati class II with a normal thyromental distance

Explanation

The strongest predictors of difficult mask ventilation are age over 55 years, raised body mass index, edentulousness, a beard, and a history of snoring or obstructive sleep apnoea, with the combination of several factors being most predictive. Beard plus edentulism plus obesity combines three independent risk factors. Single mild features such as a Mallampati II airway or mild obesity carry little weight alone.

Question 33Preoperative assessment, risk stratification and optimization

A patient with severe aortic stenosis is being assessed before elective hip replacement. Which feature indicates the highest perioperative risk?

  1. Aortic valve area of 0.8 cm² with exertional syncope Correct answer.
  2. Left ventricular ejection fraction of 55% with mild LV hypertrophy
  3. A systolic murmur radiating to the carotids without symptoms
  4. Peak aortic jet velocity of 3.2 m/s with no symptoms

Explanation

Severe aortic stenosis is defined by a valve area below about 1.0 cm², a mean gradient of 40 mmHg or more, or a peak velocity of 4 m/s or more. The presence of symptoms such as exertional syncope, angina, or dyspnoea marks a much higher risk of perioperative cardiac events and warrants cardiology review, possible valve intervention, or deferral of elective surgery.

Question 34Preoperative assessment, risk stratification and optimization

Which tool is specifically designed to estimate 30-day postoperative pulmonary complication risk in adults undergoing non-cardiac surgery?

  1. CHA₂DS₂-VASc score
  2. ARISCAT score Correct answer.
  3. Revised Cardiac Risk Index
  4. Caprini score

Explanation

The ARISCAT score was derived and validated to predict postoperative pulmonary complications such as pneumonia and respiratory failure after non-cardiac surgery, using variables including age, oxygen saturation, respiratory infection, incision site, and duration. The Revised Cardiac Risk Index addresses cardiac events, CHA₂DS₂-VASc addresses thromboembolism in atrial fibrillation, and Caprini addresses venous thromboembolism.

Question 35Preoperative assessment, risk stratification and optimization

A 70-year-old woman on warfarin for a mechanical mitral valve is listed for urgent incision and drainage of a large abscess. Her INR is 4.2. Which management plan is most appropriate?

  1. Give vitamin K and fresh frozen plasma, then proceed once the INR is below 1.5
  2. Delay surgery for five days while simply omitting warfarin
  3. Proceed immediately without reversal because the procedure is superficial
  4. Withhold warfarin, give prothrombin complex concentrate with vitamin K, and proceed after correction Correct answer.

Explanation

Patients with mechanical mitral valves are at high thrombotic risk, so reversal should be targeted and rapid rather than achieved by simply stopping warfarin for days. Prothrombin complex concentrate with intravenous vitamin K corrects the INR within minutes and is preferred over fresh frozen plasma for urgent reversal. Bridging or resumption planning with cardiology is also required.

Question 36Preoperative assessment, risk stratification and optimization

Which preoperative laboratory test is routinely indicated before elective surgery in an otherwise healthy 30-year-old asymptomatic patient undergoing low-risk surgery?

  1. Chest radiograph
  2. No routine test is indicated Correct answer.
  3. Coagulation profile
  4. Serum electrolytes and creatinine

Explanation

Guidelines recommend against routine preoperative testing in healthy asymptomatic patients having low-risk surgery, because abnormal results rarely alter management and can generate unnecessary delay and cost. Testing should be driven by history, comorbidity, and the specific procedure. Ordering electrolytes, coagulation, or imaging by habit is not supported.

Question 37Preoperative assessment, risk stratification and optimization

A 45-year-old man with a BMI of 42 kg/m² and type 2 diabetes is scheduled for laparoscopic sleeve gastrectomy. Which preoperative measure most improves pulmonary outcomes?

  1. Routine preoperative tracheostomy
  2. Two weeks of preoperative inspiratory muscle training and smoking cessation where applicable Correct answer.
  3. Preoperative broad-spectrum antibiotics for one week
  4. Prophylactic postoperative ventilation for 48 hours

Explanation

In obese patients undergoing bariatric surgery, preoperative inspiratory muscle training and smoking cessation improve respiratory mechanics and reduce postoperative pulmonary complications. Enhanced recovery pathways, early mobilisation, and appropriate thromboprophylaxis complement these measures. Tracheostomy, prolonged ventilation, and prolonged antibiotics are not justified prophylactically.

Question 38Preoperative assessment, risk stratification and optimization

Which statement about the American Society of Anesthesiologists Physical Status classification is correct?

  1. It is a validated numerical predictor of 30-day mortality
  2. It describes the patient's overall health status and is assigned by the anaesthetist Correct answer.
  3. It must be assigned by the operating surgeon before induction
  4. It incorporates the invasiveness of the planned surgical procedure

Explanation

The ASA Physical Status is a subjective descriptor of a patient's systemic health, assigned by the anaesthetist, and is not a quantitative risk calculator. It does not include surgical invasiveness, which is assessed separately when estimating perioperative risk. It correlates broadly with outcome but is not a validated numerical mortality predictor.

Question 39Preoperative assessment, risk stratification and optimization

A patient with Child-Pugh class C cirrhosis is assessed for elective hernia repair. Which conclusion is most appropriate?

  1. Only the platelet count needs correction before proceeding
  2. The risk of perioperative mortality is low enough to proceed after correction of ascites alone
  3. Elective surgery should generally be deferred because perioperative mortality is very high Correct answer.
  4. Regional anaesthesia eliminates the excess mortality risk

Explanation

Child-Pugh class C cirrhosis carries a perioperative mortality that may exceed 50% for major abdominal surgery, and even minor procedures carry substantial risk. Elective surgery is generally deferred or reconsidered in favour of medical management or transplantation assessment. Correcting a single variable such as ascites or platelets does not normalise the underlying risk.

Question 40Preoperative assessment, risk stratification and optimization

Which preoperative finding is most consistent with undiagnosed phaeochromocytoma in a patient scheduled for elective surgery?

  1. Painless jaundice and weight loss
  2. Persistent bradycardia with hypotension
  3. Episodic headache, sweating, and palpitations with labile hypertension Correct answer.
  4. Bilateral leg oedema with raised jugular venous pressure

Explanation

The classic triad of episodic headache, diaphoresis, and palpitations with paroxysmal or sustained hypertension suggests phaeochromocytoma. Undiagnosed disease risks a catastrophic hypertensive crisis during induction and surgery, so biochemical testing with plasma free metanephrines and alpha-blockade before surgery are essential.

Question 41Preoperative assessment, risk stratification and optimization

Which measure most reliably reduces the risk of pulmonary aspiration during induction in a patient with symptomatic gastro-oesophageal reflux and a full stomach?

  1. Awake fibreoptic intubation under light sedation
  2. Rapid sequence induction with cricoid pressure and prompt intubation Correct answer.
  3. Insertion of a nasogastric tube and immediate intravenous induction
  4. Deep inhalational induction with spontaneous ventilation

Explanation

When aspiration risk is significant, rapid sequence induction with preoxygenation, a rapid-acting neuromuscular blocker, and prompt tracheal intubation minimises the interval without a protected airway. Cricoid pressure is traditionally applied, though evidence for it is debated. Awake techniques and deep inhalational induction may be considered in specific airway scenarios but are not the default for full-stomach aspiration risk.

Question 42Preoperative assessment, risk stratification and optimization

A patient with a permanent pacemaker is scheduled for surgery using monopolar electrocautery. Which precaution is most important?

  1. Switch the pacemaker to asynchronous mode in all patients regardless of device type
  2. Use short bursts of diathermy with the lowest effective energy and arrange perioperative pacing backup Correct answer.
  3. Place the diathermy return pad so current passes through the pacemaker generator
  4. Avoid all intraoperative ECG and pulse oximetry monitoring

Explanation

Monopolar diathermy can inhibit pacing or cause inappropriate pacing through electromagnetic interference, so short bursts at the lowest effective energy and a plan for backup pacing or magnet application are important. The return pad should be positioned so the current path does not cross the generator or leads. Device interrogation and cardiology input guide reprogramming.

Question 43Preoperative assessment, risk stratification and optimization

Which preoperative factor most strongly increases the risk of postoperative nausea and vomiting in a non-smoking woman undergoing laparoscopic surgery?

  1. Age over 70 years
  2. A history of migraine and previous postoperative nausea and vomiting Correct answer.
  3. Absence of opioid use
  4. Male sex

Explanation

The main Apfel risk factors are female sex, non-smoking status, a history of postoperative nausea and vomiting or motion sickness, and planned postoperative opioid use. A history of migraine and previous postoperative nausea and vomiting adds substantial risk in a patient who already has two factors. Male sex and older age are protective or neutral.

Question 44Preoperative assessment, risk stratification and optimization

A 68-year-old man with chronic kidney disease stage 4 and a creatinine of 320 µmol/L is scheduled for elective surgery. Which preoperative consideration is most important for drug dosing?

  1. Use standard doses of renally cleared drugs because creatinine overestimates renal function
  2. Withhold all opioid analgesia postoperatively
  3. Adjust doses of renally excreted drugs and avoid nephrotoxic agents Correct answer.
  4. Give a fluid load of 20 mL/kg regardless of cardiac status

Explanation

In advanced chronic kidney disease, drugs cleared by the kidney accumulate and require dose or interval adjustment, and nephrotoxic agents such as NSAIDs should be avoided. Creatinine overestimates rather than underestimates renal function in this setting because of reduced muscle mass. Fluid loading must be individualised, and opioids are used with appropriate selection and monitoring.

Question 45Preoperative assessment, risk stratification and optimization

Which preoperative assessment finding should prompt postponement of elective surgery for further evaluation?

  1. A haemoglobin of 13.5 g/dL in a man
  2. New-onset atrial fibrillation with a ventricular rate of 150 beats per minute Correct answer.
  3. A resting heart rate of 88 beats per minute in a healthy adult
  4. A blood pressure of 138/86 mmHg in a treated hypertensive patient

Explanation

New-onset rapid atrial fibrillation is an uncontrolled arrhythmia that may indicate thyrotoxicosis, sepsis, or structural heart disease and can compromise cardiac output during anaesthesia. It warrants rate control, evaluation of cause, and consideration of anticoagulation before elective surgery. The other findings are within acceptable ranges.

Question 46Preoperative assessment, risk stratification and optimization

A patient with myasthenia gravis is being optimised before thymectomy. Which preoperative factor most increases the risk of postoperative respiratory failure?

  1. Treatment with pyridostigmine
  2. A history of thymoma
  3. Seropositivity for acetylcholine receptor antibodies
  4. Bulbar symptoms with a vital capacity below 2 L Correct answer.

Explanation

Bulbar weakness and reduced vital capacity reflect significant respiratory muscle involvement and predict postoperative ventilation and airway complications after thymectomy. Antibody status and a history of thymoma define the disease but do not by themselves quantify respiratory reserve. Pyridostigmine is standard therapy and is not a risk marker.

Question 47Preoperative assessment, risk stratification and optimization

Which statement about informed consent for anaesthesia is correct?

  1. Consent is unnecessary for emergency surgery under any circumstances
  2. The anaesthetist should discuss material risks, including those the patient would consider significant Correct answer.
  3. Written consent is legally required for every regional block in all jurisdictions
  4. Consent obtained by the surgeon for the operation also covers the anaesthetic

Explanation

Consent for anaesthesia is a separate discussion in which the anaesthetist explains the planned technique, material risks, and alternatives, judged by what a reasonable patient would want to know. Surgical consent does not automatically cover anaesthetic interventions. Emergency situations and jurisdictional documentation requirements vary, but the principle of patient-centred disclosure applies.

Question 48Preoperative assessment, risk stratification and optimization

A 60-year-old smoker with an ankle fracture is scheduled for open reduction. Which preoperative measure most effectively reduces pulmonary complications?

  1. Smoking cessation started four weeks before surgery with physiotherapy and incentive spirometry teaching Correct answer.
  2. Routine postoperative ventilation
  3. Preoperative bronchodilator therapy in a patient without airflow obstruction
  4. A course of prophylactic oral steroids for one week

Explanation

Smoking cessation several weeks before surgery, combined with physiotherapy and preoperative instruction in incentive spirometry, reduces postoperative pulmonary complications. Steroids, routine ventilation, and bronchodilators in patients without obstructive disease are not indicated prophylactically.

Question 49Preoperative assessment, risk stratification and optimization

Which preoperative finding in a patient with sickle cell disease most strongly predicts perioperative complications?

  1. Haemoglobin genotype confirmation
  2. A history of recurrent vaso-occlusive crises requiring hospitalisation Correct answer.
  3. A family history of the disease
  4. Mild baseline anaemia

Explanation

A history of frequent vaso-occlusive crises indicates more active disease and predicts higher perioperative complication rates. Preoperative optimisation includes hydration, temperature control, oxygenation, and consideration of transfusion to a target haemoglobin, with avoidance of dehydration and hypothermia. Genotype and baseline anaemia alone do not grade severity as well.

Question 50Preoperative assessment, risk stratification and optimization

A patient on long-term high-dose prednisolone for rheumatoid arthritis is scheduled for major surgery. Which preoperative strategy is most appropriate regarding adrenal suppression?

  1. Withhold all steroids because immunosuppression increases infection risk
  2. Continue the usual dose and give additional perioperative hydrocortisone according to the magnitude of surgery Correct answer.
  3. Give a single intramuscular dose of dexamethasone on the morning of surgery only
  4. Stop steroids five days before surgery to allow adrenal recovery

Explanation

Patients on long-term systemic corticosteroids may have suppression of the hypothalamic-pituitary-adrenal axis and require perioperative supplementation, with the dose scaled to the surgical stress. The usual maintenance dose is continued and additional hydrocortisone is given for major procedures. Abrupt withdrawal risks an adrenal crisis.