A nurse is admitting a patient with a subarachnoid hemorrhage and expects to administer which of the following medications to decrease intracranial pressure (ICP)?

Choice A rationale

Hyperoxia, or high oxygen levels, can cause unfavorable outcomes for a client who has a traumatic brain injury and is being mechanically ventilated. Too much oxygen can lead to oxygen toxicity and cause damage to the lungs and other organs, including the brain.
Choice B rationale
A platelet count of 250,000/mm^3 is within the normal range and would not typically cause unfavorable outcomes for a client who has a traumatic brain injury and is being mechanically ventilated.
Choice C rationale
A hemoglobin level of 16 g/dL is within the normal range and would not typically cause unfavorable outcomes for a client who has a traumatic brain injury and is being mechanically ventilated.
Choice D rationale
A Glasgow Coma Scale score of 16 is not possible as the maximum score is 15. A higher score indicates a less severe injury, so it would not typically cause unfavorable outcomes for a client who has a traumatic brain injury and is being mechanically ventilated.

Choice A rationale
Regulation of the amount of carbon dioxide exhaled can affect cerebral blood flow, but it does not directly maintain cerebral perfusion pressure constant.
Choice B rationale
Catecholamines circulating throughout the body can affect blood pressure and heart rate, but they do not directly maintain cerebral perfusion pressure constant.

Choice C rationale
How much blood is pumped from the heart, also known as cardiac output, can affect cerebral perfusion pressure. However, it does not directly maintain cerebral perfusion pressure constant.
Choice D rationale
Regulation of constriction and dilation of blood vessels in the brain, also known as cerebral autoregulation, is a key mechanism that maintains cerebral perfusion pressure constant. When pressure autoregulation is impaired, cerebral blood flow becomes dependent on cerebral perfusion pressure.