To evaluate the effectiveness of mechanical ventilation with mild hyperventilation for head injury, the nurse should monitor

• A. Assess patient breath sounds.
• B. Check arterial blood gases (ABGs).
• C. Monitor oxygen saturation.
• D. Monitor intracranial pressure (ICP).

Answer: (D)

When head injury is managed with mild hyperventilation, the goal is to reduce cerebral blood volume and lower intracranial pressure by decreasing PaCO2. The best way to evaluate whether this approach is working is to monitor intracranial pressure itself, because ICP directly reflects the intracranial environment and shows whether pressures are trending toward the target range. Arterial blood gases can confirm the CO2 level being achieved, and oxygen saturation verifies adequate oxygenation, but they don’t measure the intracranial response. Breathing quality and oxygenation are still important, but ICP provides the direct readout of effectiveness for this strategy. Remember that excessive hyperventilation can risk cerebral ischemia, so use ICP trends alongside neurologic status to guide care.