FANZCA Core Knowledge and Fundamentals 3 — Questions and Answers
Question 1: During one-lung ventilation (OLV), hypoxic pulmonary vasoconstriction (HPV) is inhibited by which of the following?
- PEEP applied to the ventilated lung
- Volatile anaesthetic agents (Correct answer)
- Hypercapnia
- Acidosis
Correct answer: Volatile anaesthetic agents
Volatile anaesthetic agents directly inhibit HPV in a dose-dependent manner, increasing shunt fraction and worsening hypoxaemia during one-lung ventilation.
Question 2: The Haldane effect describes:
- CO2 transport as bicarbonate in erythrocytes
- Increased CO2 carrying capacity of deoxygenated haemoglobin (Correct answer)
- The shift of the oxygen-haemoglobin dissociation curve with pH changes
- Decreased O2 affinity at high altitude
Correct answer: Increased CO2 carrying capacity of deoxygenated haemoglobin
The Haldane effect describes how deoxygenated haemoglobin carries more CO2 than oxygenated haemoglobin, facilitating CO2 uptake in tissues and release in the lungs.
Question 3: A patient with severe COPD is breathing spontaneously. Their hypoxic drive to breathe is supplemented by which receptor type?
- Central chemoreceptors in the medulla
- Peripheral chemoreceptors in the carotid bodies (Correct answer)
- Pulmonary stretch receptors
- Aortic arch baroreceptors
Correct answer: Peripheral chemoreceptors in the carotid bodies
Peripheral chemoreceptors in the carotid bodies (and aortic arch) respond to low PaO2, and in some severe COPD patients who are chronically hypercapnic, this hypoxic drive becomes proportionally more important.
Question 4: Functional residual capacity (FRC) is the lung volume at which:
- Maximum forced expiration ends
- Elastic recoil of the lung equals outward chest wall recoil (Correct answer)
- Tidal breathing begins after a maximal inspiration
- Residual volume plus expiratory reserve volume is achieved
Correct answer: Elastic recoil of the lung equals outward chest wall recoil
FRC is the resting end-expiratory lung volume where the inward elastic recoil of the lung exactly balances the outward recoil of the chest wall, requiring no active muscle work.
Question 5: Which equation correctly expresses alveolar ventilation (VA)?
- VA = tidal volume × respiratory rate
- VA = (tidal volume − dead space) × respiratory rate (Correct answer)
- VA = minute ventilation − FRC
- VA = FVC / FEV1 × respiratory rate
Correct answer: VA = (tidal volume − dead space) × respiratory rate
Alveolar ventilation accounts for physiological dead space, so only the portion of tidal volume reaching alveoli (tidal volume minus dead space) contributes to gas exchange, multiplied by respiratory rate.
Question 6: In a patient under general anaesthesia in the supine position, which lung zone predominates due to the effect of anaesthesia on pulmonary blood flow and ventilation?
- West Zone 1 (dead space predominates)
- West Zone 2 (intermittent flow)
- West Zone 3 (continuous flow, ventilation-perfusion mismatch) (Correct answer)
- West Zone 4 (reduced flow due to high interstitial pressure)
Correct answer: West Zone 3 (continuous flow, ventilation-perfusion mismatch)
Under anaesthesia, atelectasis in dependent lung zones shifts perfusion to better-ventilated non-dependent zones, and overall V/Q mismatch increases, with Zone 3 conditions predominating in most regions.
Question 7: Hypercapnia during general anaesthesia most reliably causes which haemodynamic effect?
- Decreased heart rate via vagal stimulation
- Increased sympathetic activity and cardiac output (Correct answer)
- Decreased systemic vascular resistance
- Reduced myocardial contractility
Correct answer: Increased sympathetic activity and cardiac output
Hypercapnia stimulates the sympathetic nervous system, releasing catecholamines that increase heart rate, contractility, and cardiac output, often masking any direct myocardial depressant effects of CO2.
FANZCA Core Knowledge and Fundamentals 3
During one-lung ventilation (OLV), hypoxic pulmonary vasoconstriction (HPV) is inhibited by which of the following?