Oxygen Delivery Systems and Ventilation MCQs

Anaesthesia · 13 free questions with answers & explanations.

1. A Venturi mask is used to deliver a precise FiO2 to a COPD patient who is hypoxaemic but hypercapnic. The Venturi mask delivers accurate FiO2 because it operates on the principle of:
2. During positive pressure mechanical ventilation, PEEP (positive end-expiratory pressure) is added. The primary physiological benefit of PEEP in ARDS management is:
3. Pressure-controlled ventilation (PCV) has which key advantage over volume-controlled ventilation (VCV) in a patient with acute lung injury?
4. During one-lung ventilation (OLV) for left pneumonectomy, hypoxaemia occurs. Which mechanism primarily contributes to hypoxaemia during OLV?
5. Pressure-controlled ventilation (PCV) differs from volume-controlled ventilation (VCV) in that PCV delivers a fixed pressure with which resulting gas flow pattern?
6. In a patient with ARDS being ventilated with lung-protective strategy, which combination best reflects ARDSnet ventilation targets?
7. During one-lung ventilation (OLV) for thoracic surgery, hypoxaemia occurs primarily due to which physiological mechanism?
8. High-flow nasal cannula (HFNC) oxygen therapy generates a small but clinically significant positive nasopharyngeal pressure. At a flow rate of 60 L/min, approximately what positive end-expiratory pressure equivalent does it generate in adults?
9. In a ventilated patient, peak airway pressure is 38 cmH2O and plateau pressure is 22 cmH2O. The resistance-derived pressure (Raw) is therefore 16 cmH2O. This elevated peak minus plateau pressure difference most likely indicates:
10. High-flow nasal oxygen (HFNO) therapy is increasingly used as a pre-oxygenation technique before intubation. It maintains apnoeic oxygenation during the intubation attempt primarily because:
11. Venturi mask delivers a fixed FiO2 regardless of patient respiratory rate or tidal volume. The mechanism ensuring constant FiO2 is:
12. During one-lung ventilation (OLV) for a left pneumonectomy, hypoxaemia develops (SpO2 88%). CPAP 5 cmH2O is applied to the non-dependent (operative) lung. What is the mechanism by which this improves oxygenation while still allowing surgical access?
13. High-flow nasal oxygen (HFNO) at 60 L/min with FiO2 1.0 is used for pre-oxygenation before RSI in an obese patient. Compared to standard facemask pre-oxygenation, the primary advantage of HFNO during the apnoeic phase of RSI is: