CCRN Acute Respiratory Failure 2

Question 1

A patient has a PaO2 of 55 mmHg on room air with a normal PaCO2. This finding is most consistent with which type of respiratory failure?

Accepted Answer

Type I (hypoxemic) respiratory failure

Answer

Type I respiratory failure is defined by hypoxemia (PaO2 < 60 mmHg) with a normal or low PaCO2.

Question 2

Which arterial blood gas finding defines Type II respiratory failure?

Accepted Answer

PaCO2 > 45 mmHg with hypoxemia

Answer

Type II (hypercapnic) failure is defined by alveolar hypoventilation with PaCO2 > 45 mmHg.

Question 3

A widened alveolar-arterial (A-a) oxygen gradient with hypoxemia suggests which mechanism?

Accepted Answer

Ventilation-perfusion mismatch or shunt

Answer

A widened A-a gradient indicates a gas-exchange problem such as V/Q mismatch, shunt, or diffusion impairment.

Question 4

Which condition causes hypoxemia that does NOT correct with 100% supplemental oxygen?

Accepted Answer

Intrapulmonary shunt

Answer

True shunt allows blood to bypass ventilated alveoli, so it responds poorly to increased FiO2.

Question 5

A patient with a COPD exacerbation has pH 7.28, PaCO2 68, HCO3 30. This represents:

Accepted Answer

Acute-on-chronic respiratory acidosis

Answer

The elevated HCO3 shows chronic retention, while the low pH with high CO2 indicates an acute worsening.

CCRN Review Practice Test