Which objective data best supports improvement in a patient’s oxygenation?

• A. SpO₂ remained 88% despite therapy
• B. SpO₂ increased from 90% to 92% with RR unchanged
• C. ABG PaO₂ decreased
• D. SpO₂ increased from 88% to 94% on 2 L nasal cannula, RR decreased from 28 to 18, and ABG PaO₂ improved

Answer: (D)

The important idea here is that true improvement in oxygenation shows up in objective measurements of how well oxygen is getting into the blood, not just whether a patient feels or looks better. When oxygenation improves, you expect arterial oxygen tension (PaO2) to rise and peripheral oxygen saturation (SpO2) to increase, often along with a reduction in the work of breathing.

In this scenario, oxygen therapy leads to SpO2 climbing from 88% to 94%, the respiratory rate slowing from 28 to 18 breaths per minute, and the arterial PaO2 improving. That combination demonstrates that more oxygen is entering the blood, the patient is ventilating more effectively with less respiratory effort, and gas exchange is better overall. This is the strongest evidence of actual improvement in oxygenation.

By contrast, a persistent SpO2 of 88% despite therapy indicates ongoing hypoxemia; a modest SpO2 increase with no change in respiratory rate suggests limited clinical improvement; and a decrease in PaO2 shows worsening oxygenation.