A 28-year-old client is receiving mechanical ventilation in the intensive care unit following a severe traumatic brain injury. An external ventricular drain is in place, and the monitor displays a sustained intracranial pressure (ICP) of 24 mm Hg. The nurse evaluates the client's morning arterial blood gas (ABG) results, which reveal a pH of 7.29, PaCO2 of 54 mm Hg, PaO2 of 92 mm Hg, and HCO3- of 25 mEq/L (25 mmol/L). Which of the following interventions is the highest priority for the nurse to implement to reduce the risk of further neurological damage?
- Request a prescription to increase the mechanical ventilator respiratory rate.Answer
- BAdminister an intravenous infusion of sodium bicarbonate to resolve the metabolic acidosis.
- CPlace the client in a supine position without head elevation to maximize cerebral arterial perfusion.
- DRequest that the unlicensed assistive personnel closely monitor the client for subtle changes in pupillary reaction.
Answer
Request a prescription to increase the mechanical ventilator respiratory rate.
The correct answer addresses the root cause of the worsening physiological state. The client has an elevated intracranial pressure (24 mm Hg) and respiratory acidosis (PaCO2 54 mm Hg). Carbon dioxide is a potent vasodilator of cerebral blood vessels. When vessels dilate, more blood enters the rigid cranial vault, causing intracranial pressure to spike and risking fatal brain herniation. By increasing the mechanical ventilator's respiratory rate, the client will blow off the excess carbon dioxide. As PaCO2 normalizes, the cerebral blood vessels will constrict, reducing cerebral blood volume and safely lowering the intracranial pressure.
Step-by-Step Solution
Key Concept
Hypercapnia (elevated PaCO2) causes cerebral vasodilation, which significantly increases intracranial pressure. Managing ventilation to maintain normocapnia is a critical risk reduction strategy in traumatic brain injury.