HYPOXEMIA/O2 AND SHUNT/DEADSPACE

A patient with acute pulmonary embolism presents with tachypnea and mild hypoxemia. Despite high minute ventilation, PaCO2 remains near normal. What explains this finding?

• Increased alveolar compliance

• Increased deadspace ventilation

• Decreased anatomic shunt

A COPD patient is given 100% oxygen in the ER and later develops CO2 retention and confusion. What mechanism explains this?

• Increased diffusion capacity

• Depression of hypoxic drive

• Decreased alveolar deadspace

During oxygen challenge testing, a patient’s PaO2 fails to rise despite FiO2 of 0.60. What condition does this suggest?

• Low V/Q mismatch

• Refractory hypoxemia

• Hypoventilation syndrome

A patient on mechanical ventilation develops overdistention of alveoli with large tidal volumes. What complication is most likely?

• Absorption atelectasis

• Increased alveolar deadspace

• Retinopathy of prematurity

A premature infant receives uncontrolled high-concentration oxygen. Which complication is most concerning?

• Pulmonary embolism

• Retinopathy of prematurity

• Pulmonary hypertension

A 60-year-old woman with left lower lobe pneumonia remains hypoxemic despite oxygen therapy. Which mechanism explains her condition?

• Shunt-producing pathology

• Increased anatomic deadspace

• Hyperoxic acute lung injury

A patient with pulmonary hypertension demonstrates decreased end-tidal CO2. What does this indicate?

• Increased perfusion

• Increased deadspace ventilation

• Low V/Q mismatch

A patient with COPD presents with oxygen saturation of 87%. Oxygen therapy is initiated at 2 L/min via nasal cannula. Why is this appropriate?

• It avoids worsening CO2 retention

• It ensures FiO2 > 80%

• It prevents absorption atelectasis

In pulmonary embolism, ventilation-perfusion mismatch leads to which gas abnormality?

• Respiratory acidosis

• Respiratory alkalosis with hypoxemia

• Hypercapnic hypoventilation

A patient with ARDS develops worsening hypoxemia unresponsive to high FiO2. What is the likely explanation?

• Increased deadspace ventilation

• Shunt physiology

• Hypoxic ventilatory drive suppression