Ethiopian Anesthesia University Exit Exam Practice Questions (50 Items)

Q50. A neonate delivered via elective Cesarean section demonstrates poor muscle tone, a heart rate of 80 beats per minute, and irregular, gasping respirations at 1 minute of life. What is the immediate next step in neonatal resuscitation? A) Administer intravenous Epinephrine via the umbilical vein B) Provide positive-pressure ventilation (PPW) with room air or 21-30% O2​ using a T-piece or bag-mask for 30 seconds C) Initiate immediate external chest compressions at a 3:1 ratio D) Slap the baby’s feet forcefully for 2 minutes

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• Correct Answer: B
• Rationale: In neonatal resuscitation, if the newborn remains apneic or has a heart rate <100 bpm after initial drying and stimulation, initiating effective positive-pressure ventilation is the most critical next step.

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Part 6: Pediatric Anesthesia

Q51. What is the primary anatomical difference between the pediatric airway (infant) and the adult airway that affects blade selection for laryngoscopy? A) The infant epiglottis is long, floppy, and U-shaped, and the larynx is positioned more cephalad (C3–C4) B) The infant airway is entirely rigid and straight C) The adult airway has its narrowest portion at the cricoid cartilage D) The tongue of an infant is proportionally smaller than an adult’s

• Correct Answer: A
• Rationale: The infant larynx is higher (C3–C4) and features a long, stiff, omega- or U-shaped epiglottis. A straight Miller blade is typically preferred to lift the epiglottis directly and optimize the view.

Q52. Calculate the estimated endotracheal tube (ETT) internal diameter size for an uncuffed tube suitable for a normally developing 4-year-old child using the standard formula: A) 3.5 mm B) 4.0 mm C) 5.0 mm D) 6.0 mm

• Correct Answer: C
• Rationale: The standard formula for an uncuffed ETT in children over 2 years is: Age/4+4. For a 4-year-old: 4/4+4=1+4=5.0 mm.

Q53. Why are infants and neonates highly vulnerable to rapid arterial oxygen desaturation during periods of apnea or hypoventilation under anesthesia? A) They have a very high functional residual capacity (FRC) B) They have a high oxygen consumption rate (6−8 mL/kg/min) paired with a low functional residual capacity relative to body mass C) Their hemoglobin has a very low affinity for oxygen D) They lack mature pulmonary alveolar cells entirely

• Correct Answer: B
• Rationale: Infants have a metabolic rate and oxygen demand twice that of adults, combined with a limited FRC reservoir, leading to rapid desaturation if ventilation is compromised.

Q54. Which inhalation anesthetic is preferred for smooth, rapid mask induction in pediatric patients due to its sweet taste, lack of pungency, and low incidence of airway irritation? A) Isoflurane B) Desflurane C) Sevoflurane D) Halothane

• Correct Answer: C
• Rationale: Sevoflurane is non-pungent and does not irritate the airway, making it the choice agent for pediatric gas induction, unlike desflurane or isoflurane which can trigger coughing or laryngospasm.

Q55. During a pediatric mask induction, the child suddenly develops severe stridor, followed by a total lack of chest movement and a flat capnography trace. You suspect laryngospasm. What is the first-line management step? A) Emergency surgical cricothyroidotomy B) Apply 100% O2​ with continuous positive airway pressure (CPAP) and perform Larson’s maneuver (jaw thrust with pressure at the laryngospasm notch) C) Give a high-dose infusion of Vecuronium immediately D) Blow cold air onto the child’s face

• Correct Answer: B
• Rationale: Initial management of laryngospasm involves removing airway irritants, applying 100% O2​ with tight-mask CPAP, and performing Larson’s maneuver. If refractory, a low dose of succinylcholine may be required.

Q56. What is the holiday-Segar formula (4-2-1 rule) used to calculate hourly maintenance fluid requirements for a child weighing 25 kg? A) 45 mL/hour B) 65 mL/hour C) 85 mL/hour D) 100 mL/hour

• Correct Answer: B
• Rationale: According to the 4-2-1 rule: 4 mL/kg for the first 10 kg (40 mL) + 2 mL/kg for the next 10 kg (20 mL) + 1 mL/kg for the remaining 5 kg (5 mL) = 40+20+5=65 mL/hour.

Q57. Infants rely almost entirely on alterations in their heart rate to maintain cardiac output under stress or deep anesthesia. This dependency occurs because: A) Their stroke volume is relatively fixed due to a non-compliant, immature left ventricle B) They have an excessively high baseline systemic vascular resistance C) Their baroreceptor reflexes are non-functional D) Their heart cannot respond to circulating epinephrine

• Correct Answer: A
• Rationale: Infant myocardium contains fewer contractile elements, making the ventricle less compliant and rendering stroke volume relatively fixed. Cardiac output is therefore highly dependent on heart rate.

Q58. A 6-month-old infant is scheduled for an elective pyloromyotomy. Preoperatively, the infant demonstrates persistent vomiting. Which metabolic and electrolyte abnormality is expected and must be corrected prior to anesthesia? A) Hypochloremic, hypokalemic metabolic alkalosis B) Hyperchloremic metabolic acidosis C) Hyperkalemic respiratory acidosis D) High anion gap metabolic acidosis

• Correct Answer: A
• Rationale: Loss of gastric hydrochloric acid and potassium from persistent vomiting results in hypochloremic, hypokalemic metabolic alkalosis, which requires correction with intravenous fluid resuscitation before surgery.

Q59. Which regional anesthesia technique can be easily performed at the conclusion of general anesthesia to provide excellent postoperative analgesia for a child undergoing a circumcision or inguinal hernia repair? A) Thoracic epidural block B) Caudal epidural block C) Interscalene block D) Stellate ganglion block

• Correct Answer: B
• Rationale: Caudal anesthesia is a widely used regional technique in pediatrics. Accessing the epidural space through the sacral hiatus provides effective postoperative analgesia for infra-umbilical procedures.

Q60. What is the maximum allowable fasting limit for clear fluids (e.g., water, clear juices) in a pediatric patient before an elective surgical procedure? A) 1 hour B) 2 hours C) 4 hours D) 6 hours

• Correct Answer: B
• Rationale: Current guidelines allow clear liquids up to 2 hours before induction in both pediatric and adult patients to ensure hydration while minimizing gastric volume.

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Part 7: Advanced Subspecialties (Cardiothoracic & Neuroanesthesia)

Q61. A patient is scheduled for an urgent craniotomy to excise a large supratentorial brain tumor. Which of the following strategies is effective for reducing elevated intracranial pressure (ICP) intraoperatively? A) Inducing respiratory acidosis by hypoventilating the patient B) Administering intravenous Mannitol (0.25−1 g/kg) and establishing mild hyperventilation (PaCO2​ 30–35 mmHg) C) Placing the patient in a steep Trendelenburg position D) Administering high-dose Ketamine as the primary maintenance agent

• Correct Answer: B
• Rationale: Mannitol reduces brain tissue volume through osmotic diuresis. Mild hyperventilation lowers PaCO2​, causing cerebral vasoconstriction and reducing cerebral blood volume and ICP.

Q62. During a posterior fossa craniotomy performed in the sitting position, the patient develops sudden hypotension, a precipitous drop in end-tidal CO2​, and a new “mill-wheel” murmur is heard via precordial stethoscope. What is the likely diagnosis? A) Acute myocardial infarction B) Venous air embolism (VAE) C) Anaphylactic shock from antibiotics D) Tension pneumothorax

• Correct Answer: B
• Rationale: The sitting position creates negative pressure in open dural veins, risking venous air embolism. Entrained air blocks pulmonary blood flow, causing a drop in EtCO2​, hypotension, and a classic mill-wheel murmur.

Q63. Which intravenous anesthetic agent is strictly avoided or used with caution in neuroanesthesia when an accurate intraoperative somatosensory evoked potential (SSEP) monitoring sequence is required? A) Propofol B) Volatile inhalation anesthetics at high concentrations (>1 MAC) C) Fentanyl D) Remifentanil

• Correct Answer: B
• Rationale: Volatile anesthetics cause a dose-dependent reduction in amplitude and increase in latency of evoked potentials. High concentrations can interfere with intraoperative neuromonitoring.

Q64. During an elective coronary artery bypass graft (CABG) surgery using cardiopulmonary bypass (CPB), what target activated clotting time (ACT) value must be achieved before initiating bypass flow? A) >150 seconds B) >250 seconds C) >400 seconds D) Exactly 100 seconds

• Correct Answer: C
• Rationale: Cardiopulmonary bypass requires systemic anticoagulation to prevent clotting in the circuit. High-dose heparin is administered to achieve an ACT >400 seconds before bypass begins.

Q65. What pharmacological agent is administered at the conclusion of a cardiopulmonary bypass procedure to reverse the anticoagulant effects of systemic Heparin? A) Vitamin K B) Protamine Sulfate C) Aminocaproic acid D) Tranexamic acid

• Correct Answer: B
• Rationale: Protamine sulfate is a positively charged protein that binds ionically to negatively charged heparin molecules, forming a stable, inactive complex to reverse anticoagulation.

Q66. A patient scheduled for a left pneumonectomy requires isolated lung ventilation to optimize surgical exposure. Which device is preferred to achieve one-lung ventilation? A) A standard single-lumen endotracheal tube advanced into the right bronchus B) A double-lumen endotracheal tube (DLT) or an endobronchial blocker C) A laryngeal mask airway flexible type D) A laryngeal tube suction device

• Correct Answer: B
• Rationale: Double-lumen tubes allow for anatomical and functional separation of the lungs, permitting selective ventilation or collapse of either lung during thoracic surgery.

Q67. During one-lung ventilation for thoracic surgery, the patient’s oxygen saturation drops to 84%. What is the most appropriate initial troubleshooting step? A) Abandon the surgery and close the chest immediately B) Insufflate low-flow oxygen (CPAP) to the non-ventilated operative lung, or apply recruitment maneuvers and PEEP to the dependent ventilated lung C) Disconnect the ventilator entirely for 5 minutes D) Increase the volatile anesthetic concentration to 3 MAC

• Correct Answer: B
• Rationale: Hypoxemia during one-lung ventilation stems from a right-to-left transpulmonary shunt through the non-ventilated lung. Applying CPAP to the operative lung or optimizing PEEP to the dependent lung helps improve ventilation-perfusion matching.

Q68. Autoregulation of cerebral blood flow (CBF) remains effective within which average mean arterial pressure (MAP) range in a normotensive adult? A) 30–100 mmHg B) 50–150 mmHg C) 90–180 mmHg D) 40–80 mmHg

• Correct Answer: B
• Rationale: In normotensive individuals, cerebral blood flow is autoregulated to remain constant across a mean arterial pressure range of approximately 50 to 150 mmHg.

Q69. A patient with a history of severe carotid artery stenosis is undergoing a carotid endarterectomy. What is the primary anesthetic goal regarding hemodynamic management during the cross-clamping phase? A) Maintain blood pressure slightly above the patient’s baseline (mild hypertension) to promote collateral cerebral perfusion B) Induce deep hypotension to reduce surgical bleeding C) Keep the heart rate above 120 beats per minute D) Induce severe hypoventilation

• Correct Answer: A
• Rationale: During carotid cross-clamping, perfusion to the ipsilateral hemisphere relies on collateral flow via the Circle of Willis. Maintaining a normal to slightly elevated blood pressure helps preserve cerebral perfusion.

Q70. Which of the following physiological changes is a direct consequence of a rapid intravenous injection of Succinylcholine that can complicate neurosurgical cases? A) A significant drop in intracranial pressure B) A transient increase in intracranial pressure (ICP), intraocular pressure, and intragastric pressure C) Complete blockage of histamine release D) Marked generalized skeletal muscle atrophy

• Correct Answer: B
• Rationale: Succinylcholine-induced fasciculations can cause transient increases in intracranial, intraocular, and intragastric pressures, requiring careful consideration in patients with intracranial pathology.

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Part 8: Emergency Anesthesia & Trauma Management

Q71. A 22-year-old trauma patient arrives in the emergency department in hemorrhagic shock following a motor vehicle accident. He is unresponsive and requires immediate intubation. What is the fluid resuscitation strategy of choice? A) Large volumes of 5% Dextrose in water B) Balanced crystalloids and immediate activation of a massive transfusion protocol (MTP) with a 1:1:1 ratio of packed red cells, fresh frozen plasma, and platelets C) Hydroxyethyl starch solutions until blood arrives D) Restricting all fluid intake to prevent lung edema

• Correct Answer: B
• Rationale: Hemorrhagic shock management focuses on damage control resuscitation, utilizing a balanced 1:1:1 ratio of PRBCs, FFP, and platelets to replace volume and mitigate trauma-induced coagulopathy.

Q72. A trauma patient with multiple rib fractures develops progressive dyspnea, hypotension, jugular venous distention, and absent breath sounds on the right side. What is the immediate treatment? A) Order an emergency chest CT scan B) Perform immediate needle decompression in the second intercostal space at the midclavicular line or fifth intercostal space at the anterior axillary line, followed by chest tube insertion C) Intubate and initiate high-pressure mechanical ventilation D) Administer high doses of loop diuretics

• Correct Answer: B
• Rationale: The signs indicate a life-threatening tension pneumothorax. Immediate needle decompression is required to relieve intrathoracic pressure before confirming with imaging.

Q73. When performing a rapid sequence induction (RSI) on a trauma patient with an unverified fasting status and an open globe eye injury, which neuromuscular blocker is preferred over Succinylcholine to avoid increasing intraocular pressure? A) High-dose Rocuronium (1.2 mg/kg) B) Pancuronium C) Atracurium D) Mivacurium

• Correct Answer: A
• Rationale: Succinylcholine can elevate intraocular pressure, risking extrusion of intraocular contents in an open globe injury. High-dose rocuronium provides rapid intubating conditions within 60 seconds without affecting intraocular pressure.

Q74. A patient is admitted with severe full-thickness thermal burns covering 40% of her total body surface area that occurred 48 hours ago. Which anesthetic agent is strictly contraindicated due to the risk of hyperkalemic cardiac arrest? A) Propofol B) Succinylcholine C) Ketamine D) Etomidate

• Correct Answer: B
• Rationale: Beyond 24 hours post-burn, upregulation of immature acetylcholine receptors across skeletal muscle can cause a massive release of intracellular potassium if succinylcholine is administered, risking cardiac arrest.

Q75. What is the primary purpose of applying manual in-line stabilization (MILS) during the airway management of an unconscious blunt trauma victim? A) To make laryngoscopy technically easier for the operator B) To minimize movement of the cervical spine and prevent secondary spinal cord injury during intubation attempts C) To prevent the tongue from occluding the hypopharynx D) To reduce the force needed for cricoid pressure

• Correct Answer: B
• Rationale: MILS involves an assistant holding the patient’s head and neck in a neutral position to reduce cervical movement during laryngoscopy, protecting against cord injury without applying traction.

Q76. A 45-year-old male with a history of chronic alcohol abuse requires emergency surgery for a perforated peptic ulcer. What alteration in anesthetic drug requirements is typically observed in an acutely intoxicated patient? A) Intoxicated patients require double the standard dose of all agents B) Acute alcohol consumption acts synergistically with CNS depressants, reducing the required dose of induction agents and volatile anesthetics C) They are completely resistant to local anesthetics D) They exhibit a massive increase in MAC values

• Correct Answer: B
• Rationale: Acute alcohol consumption potentiates GABAergic pathways, acting synergistically with anesthetics to decrease induction dose requirements and volatile MAC values. Chronic, sober alcoholics, conversely, often require higher doses due to enzyme induction.

Q77. What is the classic clinical triad that defines a life-threatening cardiac tamponade resulting from penetrating chest trauma (Beck’s Triad)? A) Hypertension, bradycardia, and irregular respirations B) Hypotension, jugular venous distention, and muffled heart sounds C) Tachycardia, wheezing, and skin rash D) Fever, localized chest pain, and hemoptysis

• Correct Answer: B
• Rationale: Beck’s triad includes hypotension (from reduced stroke volume), jugular venous distention (from impaired diastolic filling), and muffled heart sounds (due to fluid accumulation in the pericardial sac).

Q78. During emergency trauma surgery, hypothermia, coagulopathy, and severe metabolic acidosis are collectively referred to as: A) The Cushing reflex triad B) The lethal triad of trauma C) Virchow’s triad of thrombosis D) Samter’s triad

• Correct Answer: B
• Rationale: The “lethal triad” in trauma involves hypothermia, metabolic acidosis, and coagulopathy. These factors worsen each other, significantly increasing mortality unless corrected during resuscitation.

Q79. An emergency patient presents with a severe head injury and a Glasgow Coma Scale (GCS) score of 7. What is the immediate airway management directive? A) Apply a non-rebreather oxygen mask and monitor in the ward B) Perform endotracheal intubation to secure the airway and protect against aspiration C) Schedule an elective tracheostomy for the following week D) Give high-dose sedatives without securing the airway

• Correct Answer: B
• Rationale: A GCS score of 8 or less indicates an inability to protect the airway or sustain adequate ventilation, establishing a definitive indication for endotracheal intubation.

Q80. Which inductive agent is often selected for trauma patients presenting with severe hypovolemic shock due to its ability to stimulate the sympathetic nervous system and preserve blood pressure? A) Propofol B) Thiopental C) Ketamine D) Midazolam

• Correct Answer: C
• Rationale: Ketamine stimulates the sympathetic nervous system, causing catecholamine release that helps support heart rate and blood pressure, making it useful in hypovolemic trauma cases if endogenous catecholamines are not fully exhausted.

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Part 9: Critical Care Medicine & PACU

Q82. A 62-year-old female in the Intensive Care Unit develops severe acute respiratory distress syndrome (ARDS) secondary to urosepsis. Which mechanical ventilation strategy is proven to reduce mortality in ARDS? A) High tidal volume ventilation (12 mL/kg) to recruit alveoli B) Low tidal volume ventilation (6 mL/kg of predicted body weight) combined with optimal positive end-expiratory pressure (PEEP) C) Keeping peak inspiratory pressures above 50 cm H2​O D) Maintaining zero PEEP to prevent barotrauma

• Correct Answer: B
• Rationale: Lung-protective ventilation using low tidal volumes (6 mL/kg) and limiting plateau pressures to <30 cm H2​O reduces ventilator-induced lung injury and mortality in ARDS.

Q82. A patient in the Post-Anesthesia Care Unit (PACU) is unarousable 2 hours after the conclusion of surgery. He received high doses of Midazolam intraoperatively. Which agent should be considered to reverse suspected benzodiazepine-induced sedation? A) Naloxone B) Flumazenil C) Neostigmine D) Physostigmine

• Correct Answer: B
• Rationale: Flumazenil is a competitive antagonist at the benzodiazepine binding site of the GABAA​ receptor, used to reverse residual benzodiazepine-induced sedation.

Q83. Which form of shock is characterized by a high cardiac output, a low systemic vascular resistance (SVR), and warm, flushed extremities? A) Cardiogenic shock B) Hypovolemic shock C) Septic (distributive) shock D) Obstructive shock

• Correct Answer: C
• Rationale: Septic shock features widespread vasodilation from inflammatory mediators, leading to decreased SVR and a compensatory increase in cardiac output, presenting as “warm shock.”

Q84. A patient on mechanical ventilation in the ICU demonstrates a sudden drop in airway pressure and a complete loss of the exhaled tidal volume alarm. What is the most probable cause? A) Endotracheal tube obstruction by a mucous plug B) Disconnection of the ventilator circuit or a deflated endotracheal tube cuff C) Acute severe bronchospasm D) Development of a tension pneumothorax

• Correct Answer: B
• Rationale: A sudden drop in airway pressure and low exhaled volume suggest a circuit leak or disconnection, whereas obstructions or pneumothoraxes typically cause an increase in peak airway pressures.

Q85. What are the key clinical criteria required to safely discharge a patient from the Post-Anesthesia Care Unit (PACU) to a general hospital ward using the standard Aldrete Scoring System? A) The patient must achieve a score of at least 9 or 10, demonstrating adequate oxygenation, ventilation, circulation, consciousness, and motor activity B) The patient must be able to walk 100 meters without assistance C) The patient’s pain score must be exactly zero D) The patient must remain in the PACU for a mandatory minimum of 24 hours

• Correct Answer: A
• Rationale: The Aldrete score evaluates five areas: activity, respiration, circulation, consciousness, and oxygen saturation. A score of ≥9 is typically required for safe discharge to a ward.

Q86. A patient with severe septic shock remains hypotensive despite adequate fluid resuscitation with 3 liters of balanced crystalloids. What is the first-line vasopressor of choice recommended by the Surviving Sepsis Campaign? A) Epinephrine B) Phenylephrine C) Norepinephrine D) Isoproterenol

• Correct Answer: C
• Rationale: Norepinephrine is the first-line vasopressor for septic shock. Its alpha-1 agonist effects increase SVR, while its mild beta-1 activity supports cardiac output with a lower risk of dysrhythmias compared to dopamine.

Q87. While monitoring a patient in the PACU, you observe a pattern of rapid, deep breathing alternating with periods of total apnea. This breathing pattern is known as: A) Kussmaul respirations B) Cheyne-Stokes respirations C) Biot’s breathing D) Apneustic hyperventilation

• Correct Answer: B
• Rationale: Cheyne-Stokes respiration involves a gradual crescendo-decrescendo pattern of tidal volume interspersed with periods of apnea, often seen in severe congestive heart failure or central nervous system injuries.

Q88. Which of the following parameters provides the best objective indication that a critically ill patient is ready to be successfully weaned from mechanical ventilation? A) A Rapid Shallow Breathing Index (RSBI) less than 105 breaths/min/L B) A fraction of inspired oxygen (FiO2​) requirement of 80% C) Active severe metabolic acidosis with a pH of 7.20 D) Absence of any spontaneous respiratory effort

• Correct Answer: A
• Rationale: The RSBI (Respiratory rate/Tidal volume in liters) is a reliable predictor of weaning success. A value <105 indicates the patient can sustain spontaneous ventilation without rapid, shallow breathing.

Q89. A postoperative patient in the PACU develops acute oliguria (urine output <0.5 mL/kg/hour for 3 hours). What is the initial diagnostic approach to differentiate pre-renal dehydration from post-renal obstruction? A) Administer high doses of intravenous fluids blindly without checking the patient B) Perform a bedside bladder ultrasound and check the patency of the indwelling urinary catheter C) Schedule an emergency renal biopsy D) Start a continuous renal replacement therapy (CRRT) machine immediately

• Correct Answer: B
• Rationale: Postoperative oliguria can result from mechanical catheter obstruction or urinary retention. Checking catheter patency and performing a bladder scan help rule out correctable post-renal causes before pursuing fluid challenges or diuretics.

Q90. According to the international guidelines for Cardiopulmonary Resuscitation (CPR), what is the correct compression depth and rate recommended for high-quality chest compressions in an adult cardiac arrest victim? A) Depth: 1 inch; Rate: 60 compressions/minute B) Depth: 2 to 2.4 inches (5 to 6 cm); Rate: 100 to 120 compressions/minute C) Depth: 4 inches; Rate: 150 compressions/minute D) Depth: As deep as possible; Rate: 80 compressions/minute

• Correct Answer: B
• Rationale: High-quality CPR guidelines recommend a compression rate of 100–120 beats per minute and a depth of 2 to 2.4 inches (5–6 cm) for adults, allowing full chest recoil between compressions.

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Part 10: Physics, Equipment & Special Techniques

Q91. What physical principle explains how a pulse oximeter differentiates between oxygenated hemoglobin (O2​Hb) and deoxygenated hemoglobin (HHb) using two distinct wavelengths of light? A) The Doppler effect B) The Beer-Lambert law utilizing red light (660 nm) and infrared light (940 nm) C) The Fick principle of gas diffusion D) The Venturi effect through narrow orifices

• Correct Answer: B
• Rationale: Pulse oximetry relies on the Beer-Lambert law, which links light absorption to substance properties. O2​Hb absorbs more infrared light (940 nm), while deoxygenated hemoglobin absorbs more red light (660 nm).

Q92. An anesthesia department is located in an area at a high altitude above sea level. How does a significant reduction in ambient atmospheric pressure affect the output of a traditional variable-bypass volatile vaporizer? A) The delivered partial pressure of the anesthetic gas remains mostly constant, requiring little to no dial adjustment B) The vaporizer delivers a lethal overdose at any setting C) No vapor can be generated due to the low pressure D) The splitting ratio triples the liquid output volume

• Correct Answer: A
• Rationale: Although lower atmospheric pressure increases the volume concentration (vol%) of volatile gas leaving the vaporizer, the absolute partial pressure delivered to the alveoli remains stable, meaning clinical effects are largely unchanged at high altitude.

Q93. Which type of medical gas cylinder is color-coded light blue internationally and exists as a liquid-vapor equilibrium state when completely full at room temperature? A) Oxygen (O2​) B) Carbon Dioxide (CO2​) C) Nitrous Oxide (N2​O) D) Helium (He)

• Correct Answer: C
• Rationale: Nitrous oxide cylinders are color-coded blue and contain liquid under pressure. The cylinder pressure gauge reads a constant ≈745 psi at room temperature until all liquid has vaporized, meaning pressure does not reflect volume until the tank is nearly empty.

Q94. While using a standard Mapleson F (Jackson-Rees modification of Ayre’s T-piece) breathing circuit for a pediatric case, what operational parameter is critical to prevent rebreathing of carbon dioxide? A) The fresh gas flow rate must be set high, typically 2 to 3 times the patient’s minute ventilation B) The APL valve must be closed completely during spontaneous breathing C) A large soda lime canister must be integrated into the circuit lane D) The fresh gas flow must be turned off during expiration

• Correct Answer: A
• Rationale: Mapleson A through F circuits lack unidirectional valves or CO2​ absorbents. Preventing rebreathing relies entirely on adequate fresh gas flow to flush exhaled gases from the circuit before the next inspiration.

Q95. What safety system utilizes specific, non-interchangeable threaded connections to connect high-pressure gas cylinders directly to the yokes of an anesthesia machine? A) Diameter Index Safety System (DISS) B) Pin Index Safety System (PISS) C) Quick-connect color couplers D) Central line pressure relief valve

• Correct Answer: B
• Rationale: The Pin Index Safety System uses unique pin-and-hole configurations for each gas cylinder type to prevent accidental connection of an incorrect gas (e.g., nitrous oxide) to an oxygen yoke.

Q96. During an electrosurgical procedure, a patient sustains a thermal burn at the site of the grounding pad (return electrode). What is the likely cause of this complication? A) The grounding pad was too large for the patient B) The grounding pad had poor skin contact, concentrating the electrical current over a small surface area C) The surgeon used a bipolar instrument instead of a monopolar one D) The electrocautery machine was set to a low voltage mode

• Correct Answer: B
• Rationale: Monopolor electrosurgery requires a large-surface return electrode to disperse current safely. If contact is poor, current concentrates over a small area, generating heat that can cause tissue burns.

Q97. Which of the following clean-room practices is most effective for preventing cross-contamination and health-care associated infections when using multi-dose medication vials under anesthesia? A) Wiping the rubber stopper with a clean dry finger B) Using a sterile needle and sterile syringe for every entry into the vial C) Storing open vials at room temperature uncovered for weeks D) Re-using the same needle across different patients if the drug is identical

• Correct Answer: B
• Rationale: Proper multi-dose vial management requires strict aseptic technique, using a new sterile needle and syringe for every entry to prevent contamination.

Q98. What physical law dictates that the flow rate of an intravenous fluid through a peripheral cannula is directly proportional to the fourth power of the cannula’s internal radius, highlighting the advantage of large-bore catheters for rapid resuscitation? A) Poiseuille’s Law B) Charles’s Law C) Henry’s Law D) Dalton’s Law

• Correct Answer: A
• Rationale: Poiseuille’s law states that fluid flow through a tube is directly proportional to the fourth power of its radius. Doubling the internal radius increases the flow rate sixteenfold, making short, wide cannulas optimal for rapid volume replacement.

Q99. What is the technical function of the line isolation monitor (LIM) installed in modern operating room electrical systems? A) It automatically cuts off power to all life-support machines if an overload occurs B) It monitors the integrity of the ungrounded power system, sounding an alarm if a single fault occurs to warn that the system is no longer isolated from ground C) It measures the total water consumption of the facility D) It regulates the temperature of the anesthesia machine vaporizers

• Correct Answer: B
• Rationale: Operating rooms use isolated power systems to prevent microshocks. The line isolation monitor checks for ground faults and alarms if isolation is compromised, indicating a second fault could pose a shock hazard.

Q100. A patient requires an urgent diagnostic procedure under Monitored Anesthesia Care (MAC) or deep sedation. Which clinical finding indicates the sedation depth has progressed into the zone of “General Anesthesia”? A) The patient responds purposefully to verbal commands B) The patient maintains spontaneous ventilation and a patent airway independently C) The patient is unarousable even by painful physical stimuli and requires airway interventions or mechanical support D) The patient exhibits mild slurring of speech but squeezes your hand

• Correct Answer: C
• Rationale: Deep sedation allows patients to respond to painful stimuli and maintain airway reflexes. A progression to general anesthesia is defined by a lack of response to painful stimuli, loss of independent airway patency, and potential cardiovascular depression.