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OMSB Anesthesia (OEA) study materials
OMSB Anesthesia (OEA) study resources

OMSB Anesthesia (OEA) practice questions

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Question 1Anesthesia

A 70 kg adult is to receive an intravenous induction dose of propofol at 2 mg/kg. What total dose should be drawn up?

  1. 140 mg Correct answer.
  2. 200 mg
  3. 100 mg
  4. 70 mg

Explanation

Dose calculation multiplies weight by the mg/kg figure: 70 kg × 2 mg/kg = 140 mg. This corresponds to 14 mL of the standard 1% (10 mg/mL) propofol formulation. Always confirm the concentration on the ampoule label before drawing up.

Question 2Anesthesia

Which volatile agent is the most potent trigger of malignant hyperthermia?

  1. Sevoflurane
  2. Desflurane
  3. Halothane Correct answer.
  4. Isoflurane

Explanation

All volatile agents can trigger malignant hyperthermia, but halothane is classically the most potent trigger and is used in susceptibility testing. Sevoflurane, desflurane and isoflurane are also triggers but are regarded as weaker in this respect. The common final pathway is excessive calcium release through a mutated ryanodine receptor.

Question 3Anesthesia

Which depolarizing neuromuscular blocker is associated with hyperkalemia and masseter spasm in susceptible patients?

  1. Atracurium
  2. Rocuronium
  3. Vecuronium
  4. Succinylcholine Correct answer.

Explanation

Succinylcholine is the only depolarizing blocker in routine clinical use and causes potassium efflux from muscle. In patients with upregulation of extrajunctional receptors (burns, denervation, prolonged immobility) this can precipitate dangerous hyperkalemia. Masseter spasm after its administration may herald malignant hyperthermia.

Question 4Anesthesia

What is the recommended first-line drug for anaphylaxis occurring during anesthesia?

  1. Intramuscular adrenaline 0.5 mg Correct answer.
  2. Intravenous chlorphenamine 10 mg
  3. Intravenous hydrocortisone 200 mg
  4. Nebulized salbutamol

Explanation

Intramuscular adrenaline in the anterolateral thigh is the first-line treatment, given as 0.5 mg of the 1:1000 solution in adults and repeated every 5 minutes as needed. It reverses vasodilatation and bronchospasm through alpha- and beta-adrenergic effects. Steroids and antihistamines are adjuncts only and act too slowly to be life-saving.

Question 5Anesthesia

Which preoperative finding most strongly predicts a difficult face-mask ventilation?

  1. Thyromental distance greater than 6.5 cm
  2. Body mass index above 35 kg/m2 Correct answer.
  3. Mallampati class I
  4. Interincisor gap greater than 4 cm

Explanation

Obesity, especially a BMI above 35 kg/m2, is one of the strongest predictors of difficult mask ventilation because of reduced chest wall compliance and pharyngeal soft tissue crowding. Advanced age, edentulous state, snoring and a beard add further risk. The other listed findings are all reassuring airway features.

Question 6Anesthesia

Which local anesthetic has the longest duration of action when used for peripheral nerve blockade?

  1. Prilocaine
  2. Bupivacaine Correct answer.
  3. Chloroprocaine
  4. Lidocaine

Explanation

Bupivacaine is highly protein bound and has the longest duration among the common amide local anesthetics, providing several hours of surgical anesthesia and longer analgesia. Its cardiotoxicity in overdose is a major concern. Lidocaine and prilocaine are intermediate in duration and chloroprocaine is very short acting.

Question 7Anesthesia

Which agent is the specific antidote for benzodiazepine overdose causing respiratory depression?

  1. Naloxone
  2. Flumazenil Correct answer.
  3. Sugammadex
  4. Neostigmine

Explanation

Flumazenil is a competitive benzodiazepine receptor antagonist that reverses sedation and respiratory depression from benzodiazepines. It must be titrated carefully because it can precipitate seizures in chronic benzodiazepine users. Naloxone reverses opioids, not benzodiazepines.

Question 8Anesthesia

During one-lung ventilation, which maneuver best reduces shunt through the non-ventilated lung?

  1. Applying continuous positive airway pressure to the non-dependent lung Correct answer.
  2. Applying positive end-expiratory pressure to the dependent lung
  3. Increasing the inspired oxygen fraction to 1.0
  4. Increasing tidal volume to 12 mL/kg

Explanation

Applying a small amount of continuous positive airway pressure to the non-dependent, non-ventilated lung reduces the shunt by maintaining some oxygenation and limiting hypoxic pulmonary vasoconstriction reversal. It must be balanced against surgical exposure. PEEP to the dependent lung improves ventilation-perfusion matching but does not directly address shunt through the collapsed lung.

Question 9Anesthesia

What is the most sensitive early sign of malignant hyperthermia under general anesthesia?

  1. Hypothermia
  2. Bradycardia
  3. Rising end-tidal carbon dioxide despite adequate ventilation Correct answer.
  4. Peak airway pressure falling

Explanation

An unexplained, progressive rise in end-tidal carbon dioxide that persists despite increased minute ventilation is the earliest and most sensitive sign of malignant hyperthermia. Masseter spasm, tachycardia and hyperthermia follow. Treatment is immediate cessation of triggering agents and dantrolene administration.

Question 10Anesthesia

A patient with severe aortic stenosis is undergoing induction of anesthesia. Which hemodynamic change is most likely to cause myocardial ischemia?

  1. Tachycardia with reduced diastolic filling time Correct answer.
  2. Mild hypovolemia compensated by vasoconstriction
  3. Increased systemic vascular resistance
  4. Bradycardia with prolonged diastolic time

Explanation

In aortic stenosis the hypertrophied left ventricle depends on adequate diastolic time for coronary perfusion and needs a high filling pressure. Tachycardia shortens diastole, reduces coronary filling and increases oxygen demand, precipitating ischemia. Maintaining sinus rhythm, afterload and preload is the goal of induction.

Question 11Anesthesia

Which formula is used to calculate the maximum allowable dose of a local anesthetic containing adrenaline?

  1. Body surface area multiplied by the mg/kg limit
  2. Lean body mass divided by the mg/kg limit
  3. Weight in lb multiplied by the mg/kg limit
  4. Weight in kg multiplied by the mg/kg limit Correct answer.

Explanation

Maximum dose limits are expressed in mg/kg, so the calculation uses the patient's weight in kilograms multiplied by the appropriate limit. For lidocaine with adrenaline the limit is typically 7 mg/kg, and for bupivacaine around 2 mg/kg. Using pounds or body surface area would give an incorrect total.

Question 12Anesthesia

Which statement about succinylcholine is correct?

  1. It undergoes Hofmann elimination
  2. It is metabolized by the liver
  3. It is excreted unchanged by the kidney
  4. It is hydrolyzed by plasma pseudocholinesterase Correct answer.

Explanation

Succinylcholine is rapidly broken down by plasma butyrylcholinesterase (pseudocholinesterase) into succinylmonocholine and choline. Genetic deficiency of this enzyme, or acquired reduction, prolongs paralysis. Hofmann elimination applies to atracurium and cisatracurium, not to succinylcholine.

Question 13Anesthesia

A patient becomes hypotensive and tachycardic immediately after placement of a spinal anesthetic for cesarean delivery. What is the most appropriate initial treatment?

  1. Immediate delivery of the fetus
  2. Rapid infusion of 5% dextrose
  3. Intravenous epinephrine 1 mg
  4. Intravenous phenylephrine or ephedrine with left uterine displacement Correct answer.

Explanation

Spinal-induced hypotension results from sympathetic blockade and is treated with a vasopressor plus left uterine displacement to relieve aortocaval compression. Phenylephrine is preferred when heart rate is adequate, while ephedrine is useful if bradycardia accompanies hypotension. Fluid loading and oxygen are adjuncts.

Question 14Anesthesia

Which change in pulmonary function is expected in a morbidly obese patient in the supine position?

  1. Reduced functional residual capacity with airway closure during tidal breathing Correct answer.
  2. Decreased closing capacity relative to functional residual capacity
  3. Increased functional residual capacity
  4. Increased chest wall compliance

Explanation

Obesity reduces functional residual capacity through abdominal pressure on the diaphragm and reduced chest wall compliance, so closing capacity may exceed functional residual capacity and airways close during tidal breathing. This promotes atelectasis and rapid desaturation during apnea. Preoxygenation and ramped positioning mitigate the risk.

Question 15Anesthesia

Which monitoring parameter best reflects the adequacy of neuromuscular reversal after neostigmine administration?

  1. Post-tetanic count of zero
  2. Train-of-four ratio of at least 0.9 Correct answer.
  3. Single twitch height equal to baseline
  4. Double-burst stimulation showing two equal responses

Explanation

A train-of-four ratio of 0.9 or greater at the adductor pollicis indicates adequate recovery of neuromuscular function and is the accepted threshold for safe extubation. A double-burst with two equal responses is reassuring but less quantitative. Post-tetanic count is used to assess deep blockade, not recovery.

Question 16Anesthesia

Which arterial blood gas finding is most consistent with acute respiratory alkalosis?

  1. pH 7.28, PaCO2 60 mmHg
  2. pH 7.50, PaCO2 28 mmHg Correct answer.
  3. pH 7.44, HCO3 32 mmol/L
  4. pH 7.30, HCO3 15 mmol/L

Explanation

A raised pH with a low PaCO2 indicates respiratory alkalosis caused by hyperventilation. The carbon dioxide is being blown off faster than it is produced. Metabolic compensation would take days and would lower bicarbonate.

Question 17Anesthesia

Which intravenous induction agent is most appropriate for a hemodynamically unstable trauma patient requiring rapid airway control when avoiding suppression of adrenal steroid synthesis is a specific priority?

  1. Thiopentone 5 mg/kg
  2. Propofol 2 mg/kg
  3. Ketamine 1-2 mg/kg Correct answer.
  4. Etomidate 0.3 mg/kg

Explanation

Ketamine is the best listed choice when hemodynamic stability and avoidance of adrenal suppression are priorities. Etomidate is also an accepted agent for unstable patients, but it suppresses adrenal steroid synthesis. Ketamine dosing must be individualized and reduced in profound shock; propofol and thiopentone can cause substantial cardiovascular depression.

Question 18Anesthesia

A patient with myasthenia gravis is sensitive to non-depolarizing muscle relaxants. Which perioperative consideration is most important?

  1. Reduced dose requirement for non-depolarizing blockers Correct answer.
  2. Avoidance of all volatile anesthetics
  3. Routine use of high-dose neostigmine at induction
  4. Increased dose requirement for succinylcholine is always expected

Explanation

Myasthenia gravis reduces the number of functional acetylcholine receptors at the neuromuscular junction, so patients are highly sensitive to non-depolarizing blockers and require reduced doses. Response to succinylcholine is variable and often resistance is seen, but it is not universally increased. Neuromuscular monitoring is essential.

Question 19Anesthesia

Which finding suggests a misplaced endotracheal tube in the right main bronchus?

  1. High-pitched inspiratory stridor
  2. Rising end-tidal carbon dioxide with a normal waveform
  3. Absent breath sounds over the left chest with reduced left-sided chest excursion Correct answer.
  4. Bilateral equal breath sounds with a normal capnogram

Explanation

Right main bronchus intubation leaves the left lung unventilated, producing absent or reduced breath sounds and diminished excursion on the left. The capnogram may be normal because gas exchange continues in the right lung. Withdrawal of the tube under direct vision corrects the position.

Question 20Anesthesia

Which agent is preferred for sedation of a patient with severe reactive airways disease undergoing bronchoscopy?

  1. Dexmedetomidine
  2. Morphine
  3. Propofol Correct answer.
  4. Ketamine

Explanation

Propofol produces bronchodilatation and reliably blunts airway reflexes, making it useful in reactive airway disease. It also allows rapid titration and smooth recovery. Ketamine increases airway secretions and can provoke bronchospasm, and morphine causes histamine release.

Question 21Anesthesia

What is the most appropriate initial dose of dantrolene for an adult in malignant hyperthermia crisis?

  1. 10 mg/kg intravenously as a single dose
  2. 1 mg/kg intravenously repeated as needed
  3. 2.5 mg/kg intravenously repeated until symptoms resolve Correct answer.
  4. 0.1 mg/kg intravenously every hour

Explanation

The initial dantrolene dose is 2.5 mg/kg intravenously, repeated until the end-tidal carbon dioxide and heart rate normalize, often requiring 10 mg/kg or more in total. Each vial contains 20 mg and must be reconstituted rapidly. Hyperkalemia, acidosis and arrhythmias are managed concurrently.

Question 22Anesthesia

Which mechanism explains the prolonged paralysis seen after a large dose of rocuronium in a patient with renal failure?

  1. Rapid hepatic metabolism to active metabolites
  2. Accumulation of the active parent drug due to reduced renal clearance Correct answer.
  3. Increased plasma cholinesterase activity
  4. Enhanced sensitivity of the motor end plate to acetylcholine

Explanation

Rocuronium is primarily cleared by the liver and bile, but a substantial fraction is eliminated unchanged by the kidney, so renal failure prolongs its effect after large or repeated doses. Sugammadex can reliably reverse even deep blockade. Vecuronium is more dependent on renal clearance of active metabolites.

Question 23Anesthesia

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

  1. Placing the return electrode so the current path avoids the pacemaker and leads Correct answer.
  2. Using a higher electrocautery power setting
  3. Setting the pacemaker to asynchronous mode in all patients
  4. Positioning the return electrode on the ipsilateral limb as the pacemaker

Explanation

The return electrode should be positioned so that the current path runs longitudinally through the body and away from the generator and leads, minimizing the risk of sensing interference or lead heating. Bipolar cautery is preferred where feasible. Asynchronous mode is reserved for pacemaker-dependent patients after cardiology consultation.

Question 24Anesthesia

Which statement about the pharmacokinetics of propofol is correct?

  1. It is primarily eliminated unchanged by the kidneys
  2. It undergoes extensive hepatic and extrahepatic conjugation to inactive metabolites Correct answer.
  3. It is highly protein bound and has a very long elimination half-life
  4. It is metabolized mainly by plasma esterases

Explanation

Propofol is rapidly cleared through hepatic conjugation, with some extrahepatic metabolism, to inactive glucuronide and sulfate metabolites. Its short duration results from rapid redistribution and high clearance rather than from plasma esterase hydrolysis. This underlies its suitability for continuous infusion.

Question 25Anesthesia

A patient with chronic obstructive pulmonary disease has an arterial PaCO2 of 55 mmHg at baseline. Which ventilation strategy is most appropriate during general anesthesia?

  1. Apply high extrinsic PEEP without measuring intrinsic PEEP
  2. Hyperventilate to a PaCO2 of 30 mmHg to improve oxygenation
  3. Use large tidal volumes of 12 mL/kg to overcome airway resistance
  4. Target a PaCO2 near the patient's baseline to avoid acidosis and auto-PEEP Correct answer.

Explanation

Patients with chronic hypercapnia have compensatory metabolic alkalosis, and rapid correction of PaCO2 toward normal can cause post-hypercapnic alkalosis and apnea. Ventilation should approximate the baseline PaCO2 with prolonged expiratory time to limit air trapping. Large tidal volumes and high PEEP worsen dynamic hyperinflation.

Question 26Anesthesia

A 70 kg adult is receiving a lidocaine infusion for postoperative analgesia. Which plasma concentration is the threshold above which systemic local anesthetic toxicity typically begins?

  1. 5 mcg/mL Correct answer.
  2. 25 mcg/mL
  3. 15 mcg/mL
  4. 1 mcg/mL

Explanation

Systemic toxicity from lidocaine usually appears when plasma levels exceed about 5 mcg/mL, where perioral numbness, tinnitus, and agitation begin. Levels approaching 10 mcg/mL are associated with seizures and cardiovascular collapse.

Question 27Anesthesia

Which nerve block is most appropriate for analgesia after open inguinal hernia repair?

  1. Interscalene brachial plexus block
  2. Adductor canal block
  3. Femoral nerve block
  4. Ilioinguinal and iliohypogastric nerve block Correct answer.

Explanation

The ilioinguinal and iliohypogastric nerves supply the skin and musculature of the inguinal region, making their blockade the targeted choice for hernia repair analgesia. The other blocks listed anesthetize the shoulder, anterior thigh, or medial knee.

Question 28Anesthesia

Which preoperative finding best predicts difficulty with face-mask ventilation rather than with laryngoscopy?

  1. Mallampati class IV
  2. Reduced interincisor opening
  3. Edentulous mouth with a beard Correct answer.
  4. Thyromental distance of 5 cm

Explanation

The MOANS mnemonic identifies mask-ventilation difficulty through factors such as Mask seal problems, Obstruction, Age over 55, No teeth, and Snoring or Stiff lungs; an edentulous bearded face impairs the mask seal. The other listed findings are classic predictors of difficult laryngoscopy.

Question 29Anesthesia

In a patient breathing spontaneously through a circle system, which factor most increases the risk of rebreathing carbon dioxide?

  1. High fresh gas flow
  2. Use of a heated humidifier
  3. Low respiratory rate
  4. Exhausted soda lime absorbent Correct answer.

Explanation

Rebreathing occurs when the carbon dioxide absorbent is exhausted and can no longer remove CO2 from the exhaled gas. High fresh gas flow and low respiratory rate do not cause rebreathing, and humidifiers do not affect absorbent capacity.

Question 30Anesthesia

A patient with a history of postoperative nausea and vomiting undergoing laparoscopic cholecystectomy is at high risk on the Apfel score. Which prophylactic combination is most appropriate?

  1. Droperidol plus a second butyrophenone
  2. Metoclopramide alone
  3. Ondansetron plus dexamethasone Correct answer.
  4. Ondansetron plus a second serotonin antagonist

Explanation

Multimodal prophylaxis combines agents from different classes, such as a 5-HT3 antagonist with dexamethasone, to target separate emetic pathways. Combining two drugs of the same class adds toxicity without additional benefit, and single-agent prophylaxis is inadequate in high-risk patients.

Question 31Anesthesia

Which finding on routine preoperative testing most strongly suggests the need to delay elective surgery for further cardiac evaluation?

  1. Sinus bradycardia of 55 beats per minute
  2. Frequent premature ventricular complexes on ECG
  3. New left bundle branch block with syncope Correct answer.
  4. First-degree atrioventricular block

Explanation

New left bundle branch block accompanied by syncope raises concern for high-grade conduction disease and warrants cardiology assessment, possibly pacing, before elective surgery. The other findings are common and generally do not require postponement.

Question 32Anesthesia

A patient with severe sepsis requires emergency laparotomy. Which vasopressor is recommended as the first-line agent to maintain mean arterial pressure?

  1. Norepinephrine Correct answer.
  2. Dopamine
  3. Vasopressin
  4. Phenylephrine

Explanation

Current sepsis guidelines recommend norepinephrine as the initial vasopressor because it provides vasoconstriction with modest beta-mediated inotropy. Phenylephrine and vasopressin are generally second-line or adjunctive agents, and dopamine carries a higher arrhythmia risk.

Question 33Anesthesia

A patient with severe preeclampsia is receiving a magnesium sulfate infusion. Which sign is the earliest clinical indicator of magnesium toxicity?

  1. Respiratory depression
  2. Loss of deep tendon reflexes Correct answer.
  3. Cardiac arrest
  4. Oliguria

Explanation

Magnesium toxicity progresses predictably: reflexes are lost first, followed by respiratory depression, then cardiac arrest. Monitoring patellar reflexes therefore allows detection before life-threatening events occur.

Question 34Anesthesia

Which analgesic technique provides the most reliable pain control for a patient undergoing open thoracotomy?

  1. Thoracic epidural analgesia Correct answer.
  2. Intravenous patient-controlled morphine
  3. Oral oxycodone scheduled every six hours
  4. Intercostal nerve blocks with bupivacaine

Explanation

Thoracic epidural analgesia with a local anesthetic-opioid mixture gives superior segmental analgesia, improves respiratory mechanics, and is the reference standard after thoracotomy. Systemic opioids and single-shot intercostal blocks provide inferior and shorter-lasting relief.

Question 35Anesthesia

A patient is undergoing craniotomy for a supratentorial tumor. Which ventilation strategy best supports cerebral perfusion while limiting brain relaxation?

  1. Permit hypercapnia to a PaCO2 of 55 mmHg
  2. Hyperventilate to a PaCO2 of 25 mmHg throughout
  3. Maintain normocapnia with adequate depth of anesthesia Correct answer.
  4. Apply positive end-expiratory pressure of 15 cmH2O

Explanation

Normocapnia preserves cerebral blood flow and avoids the ischemia risk of prolonged hypocapnia, while adequate anesthesia prevents cerebral metabolic and flow increases. Hypercapnia raises intracranial pressure and high PEEP can impair cerebral venous drainage.

Question 36Anesthesia

Which agent is most appropriate for rapid-sequence induction in a patient with hyperkalemia and a crush injury?

  1. Cisatracurium
  2. Rocuronium Correct answer.
  3. Vecuronium
  4. Succinylcholine

Explanation

Succinylcholine is contraindicated in crush injury and hyperkalemia because it can trigger dangerous potassium efflux. Rocuronium at 1.2 mg/kg provides rapid intubating conditions and is the appropriate alternative.

Question 37Anesthesia

A patient with a known difficult airway is planned for elective surgery. Which strategy is most appropriate for airway management?

  1. Intubation after mask ventilation with high-dose propofol
  2. Rapid-sequence induction with cricoid pressure
  3. Awake fiberoptic intubation with topical anesthesia Correct answer.
  4. Deep inhalational induction with a supraglottic airway

Explanation

In a predicted difficult airway, awake fiberoptic intubation preserves spontaneous ventilation and allows the airway to be secured before induction. Techniques that abolish spontaneous breathing risk a cannot-intubate cannot-ventilate scenario.

Question 38Anesthesia

Which change in cardiac output occurs immediately after a sudden increase in afterload in a failing ventricle?

  1. Cardiac output rises because preload increases
  2. Cardiac output is unchanged because heart rate compensates fully
  3. Cardiac output rises because contractility increases
  4. Cardiac output falls because stroke volume decreases Correct answer.

Explanation

In a failing ventricle, an afterload increase reduces stroke volume because the ventricle cannot generate the extra pressure needed to eject the same volume. Compensation through heart rate and preload is limited and does not fully restore output.

Question 39Anesthesia

A patient with chronic kidney disease on hemodialysis is scheduled for surgery the day after a session. Which electrolyte abnormality is most likely to persist despite dialysis?

  1. Hyperphosphatemia Correct answer.
  2. Hyperkalemia
  3. Volume overload
  4. Metabolic acidosis

Explanation

Dialysis effectively lowers potassium, corrects acidosis, and removes fluid, but phosphate clearance is limited and hyperphosphatemia often persists. This reflects the large phosphate burden and its slow removal kinetics.

Question 40Anesthesia

Which mechanism best explains the reduced minimum alveolar concentration of volatile anesthetics in elderly patients?

  1. Increased cardiac output
  2. Decreased body fat content
  3. Reduced alveolar ventilation
  4. Increased sensitivity of the central nervous system to anesthetics Correct answer.

Explanation

MAC declines with age primarily because the aging central nervous system becomes more sensitive to anesthetic effects. Pharmacokinetic changes such as altered ventilation or cardiac output do not explain the reduced anesthetic requirement.

Question 41Anesthesia

Which maneuver is most appropriate for managing a suspected venous air embolism during a sitting-position neurosurgical procedure?

  1. Administer intravenous fluid boluses without position change
  2. Increase the inspired oxygen concentration alone
  3. Place the patient in the left lateral head-down position and aspirate the central line Correct answer.
  4. Place the patient in the reverse Trendelenburg position

Explanation

A venous air embolism is managed by positioning the patient left lateral and head-down to trap air in the right ventricular apex away from the outflow tract, and by aspirating air from a right atrial catheter. This reduces the risk of an air lock obstructing pulmonary outflow.

Question 42Anesthesia

Which finding most suggests that a patient has developed postoperative residual curarization in the recovery room?

  1. Tongue depressor test demonstrating an inability to maintain a bite Correct answer.
  2. Sustained tetanus on train-of-four stimulation
  3. Normal grip strength
  4. Ability to lift the head for five seconds

Explanation

Inability to maintain a bite on a tongue depressor reflects residual weakness of the upper airway and jaw muscles, a clinical sign of residual blockade. Normal grip strength, sustained head lift, and sustained tetanus each indicate adequate recovery.

Question 43Anesthesia

In a patient receiving total intravenous anesthesia with propofol and remifentanil, which monitoring is essential to detect inadequate depth of anesthesia?

  1. Pulse oximetry
  2. Processed EEG monitoring such as the bispectral index Correct answer.
  3. Noninvasive blood pressure
  4. Capnography

Explanation

Because propofol-based TIVA lacks the end-tidal agent concentration that guides inhalational anesthesia, processed EEG monitoring such as BIS helps titrate depth and reduce awareness risk. The other monitors assess oxygenation, ventilation, and hemodynamics rather than depth of hypnosis.

Question 44Anesthesia

Which statement correctly describes the effect of positive end-expiratory pressure on cardiac output in a hypovolemic patient?

  1. Cardiac output is unaffected because PEEP acts only on the lungs
  2. Cardiac output rises because left ventricular afterload is reduced
  3. Cardiac output rises because preload is increased
  4. Cardiac output falls because venous return and right ventricular filling are reduced Correct answer.

Explanation

In hypovolemia, applied PEEP raises intrathoracic pressure and reduces venous return, lowering right ventricular filling and cardiac output. The afterload-reducing benefit seen in a well-filled left ventricle is outweighed by the preload deficit.

Question 45Anesthesia

A patient with a suspected malignant hyperthermia susceptibility is scheduled for elective surgery. Which anesthetic plan is most appropriate?

  1. Isoflurane with cisatracurium
  2. Total intravenous anesthesia with propofol and remifentanil Correct answer.
  3. Desflurane with rocuronium
  4. Sevoflurane with succinylcholine for intubation

Explanation

A trigger-free anesthetic avoids all volatile agents and succinylcholine, and TIVA with propofol and remifentanil is the standard approach. Non-depolarizing relaxants such as rocuronium or cisatracurium are safe, but volatile agents are not.

Question 46Anesthesia

Which statement about the placental transfer of local anesthetics used for epidural analgesia in labor is correct?

  1. Less protein-bound agents cross the placenta less readily
  2. Placental transfer is independent of maternal plasma concentration
  3. Ionized drug crosses the placenta more readily than nonionized drug
  4. More highly protein-bound agents cross the placenta less readily Correct answer.

Explanation

Placental transfer depends on the free (unbound) fraction, so highly protein-bound agents such as bupivacaine cross less and cause less fetal exposure. Only nonionized, lipid-soluble drug crosses readily, and transfer clearly depends on maternal concentration.

Question 47Anesthesia

Which measure most effectively prevents aspiration pneumonitis in a patient with a full stomach undergoing emergency surgery?

  1. Awake oral airway placement
  2. Deep inhalational induction with a laryngeal mask
  3. Rapid-sequence induction with cricoid pressure and endotracheal intubation Correct answer.
  4. Delayed induction until gastric emptying is confirmed

Explanation

Rapid-sequence induction with cricoid pressure and a cuffed endotracheal tube protects the airway by minimizing the interval between loss of consciousness and tracheal sealing. Supraglottic devices do not protect against aspiration.

Question 48Anesthesia

Which finding on arterial blood gas analysis indicates a compensatory response to chronic metabolic acidosis?

  1. Decreased anion gap
  2. Decreased PaCO2 Correct answer.
  3. Increased PaCO2
  4. Increased bicarbonate

Explanation

Chronic metabolic acidosis is compensated by alveolar hyperventilation, which lowers PaCO2. Increased bicarbonate would suggest a metabolic alkalosis rather than compensation, and the anion gap reflects the cause rather than the compensation.

Question 49Anesthesia

Which statement about the pharmacodynamics of dexmedetomidine is correct?

  1. It causes profound respiratory depression at sedative doses
  2. It acts primarily as a GABA-A receptor agonist
  3. It reliably produces deep hypnosis suitable for general anesthesia
  4. It provides sedation with analgesia and minimal respiratory depression Correct answer.

Explanation

Dexmedetomidine is a selective alpha-2 agonist producing sedation and analgesia with little respiratory depression, which makes it useful for awake procedures and ICU sedation. It is not a GABA agonist and cannot reliably produce general anesthesia alone.

Question 50Anesthesia

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

  1. Avoid any intraoperative cardiac monitoring
  2. Place the return pad over the pacemaker generator
  3. Increase the pacemaker output to maximum before surgery
  4. Use bipolar electrocautery and place the return pad away from the generator Correct answer.

Explanation

Bipolar electrocautery and a return pad positioned so the current path avoids the generator reduce electromagnetic interference and the risk of inhibition or reprogramming. Placing the pad over the generator concentrates current through the device.