The following blood gas results were obtained: The patient's results are compatible with which of the following?

• A. fever
• B. uremia
• C. emphysema
• D. dehydration

Answer: (C)

Interpreting arterial blood gas results often hinges on distinguishing respiratory from metabolic disturbances and whether the pattern is acute or chronic. In emphysema, a chronic lung condition, hypoventilation leads to CO2 buildup (hypercapnia) and reduced oxygen levels. Over time the kidneys compensate by increasing bicarbonate (HCO3−), which helps restore the pH toward normal. So the ABG picture you’d expect in emphysema is elevated PaCO2 with a raised HCO3− and a pH that is near normal or only mildly acidotic, often with a low PaO2 as gas exchange worsens.

That combination fits chronic respiratory acidosis with metabolic compensation, as seen in COPD/emphysema. Fever would more likely cause tachypnea and a respiratory alkalosis (low PaCO2, high pH). Uremia produces a metabolic acidosis (low HCO3−, low pH) rather than a primary respiratory pattern. Dehydration can vary but doesn’t specifically create the COPD-like pattern of CO2 retention with compensatory bicarbonate rise.

So the results point to emphysema because they reflect chronic CO2 retention with renal compensation, characteristic of this condition.