Which condition is an indication for oxygen therapy?

• A. Hypoxia
• B. Hyperglycemia
• C. Hypokalemia
• D. Hyponatremia

Answer: (A)

Oxygen therapy is indicated when tissues are not getting enough oxygen, i.e., when there is hypoxia. Hypoxia means insufficient oxygen delivery to the body's tissues, which can lead to organ dysfunction if not corrected. Clinically this is often identified as hypoxemia: a PaO2 around 60 mm Hg or an SpO2 of 90% or less on room air. In many patients with chronic lung disease, targets may be adjusted (for example, an SpO2 in the 88–92% range) to avoid CO2 trapping, but the reason to start therapy remains the presence of inadequate oxygenation. So the best answer is hypoxia because it directly reflects the need to raise arterial oxygen content to meet tissue demands.

Hyperglycemia, hypokalemia, and hyponatremia are metabolic or electrolyte disturbances. They do not indicate the need for supplemental oxygen; they require targeted electrolyte or metabolic management, fluid status assessment, and other specific interventions rather than oxygen therapy.