A patient with pulmonary fibrosis experiences decreased arterial oxygen saturation despite supplemental oxygen. Which mechanism explains why increased inspired oxygen only partially corrects hypoxemia?

💡 Explanation

Alveolar thickening in pulmonary fibrosis impairs gas exchange via diffusion across the membrane; because of this, increased oxygen can only partially compensate for the diffusion limitation. Therefore, thickened alveolar membranes prevent complete oxygen saturation, rather than hemoglobin affinity changes or hyperventilation.

• Why does a thiamine deficiency disrupt cellular energy production more severely than a deficiency in non-cofactor amino acids?
• If a mountain climber rapidly ascends to high altitude without acclimatization, which consequence directly results from decreased oxygen partial pressure in the blood impacting hemoglobin?
• If a hiker ascends to high altitude, experiencing hypothermia despite wearing insulated clothing, which mechanism explains why core body temperature continues to drop despite maximal shivering?
• Why does albuterol, a beta-2 agonist inhaler, relieve asthma symptoms faster than inhaled corticosteroids during an acute asthma attack?
• If a patient has a genetic mutation causing a constitutively active (always on) thyroid stimulating hormone (TSH) receptor in thyroid follicular cells, which consequence follows?
• What causes increased afterload in the left ventricle when a patient has hypertension related to primary hyperaldosteronism?