An unconscious patient on ventilatory support has ABG results; the nurse should notify the provider if which value is present?

• A. pH of 7.43
• B. SaO2 of 94%
• C. PaO2 of 70 mm Hg
• D. PaCO2 of 35 mm Hg

Answer: (C)

The main idea is recognizing oxygenation status on ABG independent of acid–base balance. In this scenario, the pH is normal and the PaCO2 is normal, which means ventilation and acid–base status are stable. The SaO2 of 94% is near normal, but the arterial oxygen tension tells the full story about how much oxygen is actually dissolved in the blood. A PaO2 of 70 mm Hg is below the normal range (roughly 80–100 mm Hg) and indicates hypoxemia. For an unconscious patient on ventilatory support, this level means the brain may not be getting enough oxygen, so it warrants notifying the provider to adjust oxygen delivery or ventilator settings (e.g., increase FiO2 or adjust PEEP) and re-evaluating the oxygenation targets. The other values do not reflect inadequate oxygenation and are within expected ranges for a stable ventilated patient.