A nurse is preparing a client for transfer to the ICU for placement of a pulmonary artery catheter. The nurse should explain to the client that this catheter is used to monitor which of the following conditions?

Choice A: Drainage of clear fluid from the ears is not an expected finding for a client who has an epidural hematoma, but rather a sign of a basilar skull fracture, which is a different type of head injury. The clear fluid is cerebrospinal fluid (CSF), which leaks from the brain through the fractured skull.

Choice B: Alternating periods of alertness and unconsciousness is an expected finding for a client who has an epidural hematoma, because it indicates a rapid increase in intracranial pressure (ICP) due to bleeding between the dura mater and the skull. The client may have a brief loss of consciousness at the time of injury, followed by a lucid interval, and then a rapid deterioration of mental status.

Choice C: Narrowing pulse pressure is not an expected finding for a client who has an epidural hematoma, but rather a sign of increased ICP due to any cause. Pulse pressure is the difference between systolic and diastolic blood pressure. As ICP rises, it compresses the brainstem and causes bradycardia and hypertension, resulting in a decreased pulse pressure.

Choice D: Extensive bruising in the mastoid area is not an expected finding for a client who has an epidural hematoma, but rather a sign of a basilar skull fracture, which is a different type of head injury. The bruising is also known as Batle's sign, and it occurs due to blood pooling behind the ear.

Choice A Reason: This is incorrect because preparing for mechanical ventilation is not the priority nursing intervention, as it is an invasive and potentially harmful procedure that should be reserved for clients who have severe respiratory failure and cannot maintain adequate oxygenation with noninvasive methods.

Choice B Reason: This is correct because administering oxygen via face mask is the priority nursing intervention, as it is a noninvasive and effective way to improve oxygenation and reduce hypoxemia in a client who has low PaO2 and SaO2. Oxygen therapy can also decrease the workload of the heart and lungs and prevent further complications.

Choice C Reason: This is incorrect because preparing to administer a sedative is not the priority nursing intervention, as it may worsen the client's respiratory status and mask the signs and symptoms of hypoxemia. Sedatives should be used with caution and only after oxygenation has been optimized.

Choice D Reason: This is incorrect because assessing for indications of pulmonary embolism is not the priority nursing intervention, as it is a diagnostic rather than a therapeutic action. Pulmonary embolism is a possible cause of the client's condition, but it does not address the immediate problem of hypoxemia.