CCRN - Review Neurological Critical Care Questions and Answers 1 — Questions and Answers
Question 1: A patient with a traumatic brain injury has an intracranial pressure (ICP) of 22 mmHg and a mean arterial pressure (MAP) of 70 mmHg. The nurse calculates the cerebral perfusion pressure (CPP) and recognizes the need for which immediate intervention?
- Administering an antihypertensive agent to lower MAP.
- Increasing the head of the bed to 90 degrees.
- Administering a prescribed vasopressor to increase MAP. (Correct answer)
- Performing a deep suctioning of the endotracheal tube.
Correct answer: Administering a prescribed vasopressor to increase MAP.
The cerebral perfusion pressure (CPP) is calculated as MAP - ICP. In this case, CPP is 70 - 22 = 48 mmHg. The goal CPP for TBI patients is typically 60-70 mmHg. A CPP below 50 mmHg can lead to cerebral ischemia. The most direct way to improve a low CPP in this scenario is to increase the MAP using a vasopressor, as the ICP is already elevated. Lowering MAP would worsen cerebral ischemia. Increasing the head of the bed to 90 degrees could decrease MAP and CPP. Deep suctioning can transiently increase ICP.
Question 2: A patient is admitted to the ICU following a ruptured cerebral aneurysm and subsequent subarachnoid hemorrhage (SAH). Which of the following physician's orders should the nurse anticipate to prevent cerebral vasospasm?
- Intravenous mannitol every 6 hours.
- Strict blood pressure control with a target SBP < 120 mmHg.
- Administration of nimodipine 60 mg every 4 hours. (Correct answer)
- Initiation of therapeutic hypothermia.
Correct answer: Administration of nimodipine 60 mg every 4 hours.
Nimodipine, a calcium channel blocker, is the standard of care for preventing cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage. It has been shown to improve neurological outcomes. While mannitol is used to manage ICP and blood pressure control is crucial, nimodipine specifically targets the prevention of vasospasm, a common and dangerous complication that typically occurs 3 to 14 days after the initial hemorrhage.
Question 3: A critical care nurse is performing a neurological assessment on a patient with a large epidural hematoma. The nurse notes the development of a fixed and dilated pupil on the right side, bradycardia, and systolic hypertension. These findings are most indicative of which neurological emergency?
- Central neurogenic hyperventilation.
- Uncal herniation with brainstem compression. (Correct answer)
- Onset of a generalized tonic-clonic seizure.
- Development of cerebral salt wasting.
Correct answer: Uncal herniation with brainstem compression.
The triad of bradycardia, systolic hypertension (with a widening pulse pressure), and an abnormal respiratory pattern (not always present) is known as Cushing's triad, a late sign of severely increased ICP. When combined with a unilateral fixed and dilated pupil (ipsilateral to the lesion), it strongly suggests uncal herniation, where the uncus of the temporal lobe shifts downward, compressing the third cranial nerve (oculomotor) and the brainstem. This is a life-threatening emergency requiring immediate intervention.
Question 4: Which of the following is the first-line pharmacologic intervention for a patient who has been actively seizing for more than five minutes (status epilepticus)?
- Phenytoin (Dilantin) IV infusion.
- Propofol (Diprivan) bolus and infusion.
- Levetiracetam (Keppra) IV piggyback.
- Lorazepam (Ativan) IV push. (Correct answer)
Correct answer: Lorazepam (Ativan) IV push.
For the emergent initial treatment of status epilepticus, a benzodiazepine is the first-line drug class. Lorazepam is a common choice due to its rapid onset and relatively long duration of action compared to other benzodiazepines. While medications like phenytoin, levetiracetam, or propofol are used as second-line or refractory treatments, the immediate priority is to stop the seizure with a fast-acting agent like a benzodiazepine.
Question 5: A nurse is preparing to assist with an apnea test to determine brain death in a patient with a catastrophic brain injury. The nurse confirms that all prerequisites have been met. The test is considered positive, supporting a diagnosis of brain death, if what occurs?
- The patient's heart rate increases by 20% from baseline.
- The patient develops spontaneous respiratory effort.
- The PaCO2 rises to ≥ 60 mmHg without respiratory effort. (Correct answer)
- The SpO2 drops below 85% for more than 30 seconds.
Correct answer: The PaCO2 rises to ≥ 60 mmHg without respiratory effort.
A positive apnea test, which supports the clinical diagnosis of brain death, is defined by the absence of spontaneous respiratory movements despite a significant rise in PaCO2. The standard targets are a PaCO2 of 60 mmHg or higher, or a rise of at least 20 mmHg from a normal baseline PaCO2, in the absence of any breathing effort. The development of respiratory effort would be a negative test, indicating brainstem function. Severe desaturation or hemodynamic instability would lead to the test being aborted.
Question 6: A patient with an acute ischemic stroke is found to be outside the treatment window for thrombolysis. The neurologist has ordered permissive hypertension. The nurse understands the rationale for this order is to:
- Prevent hemorrhagic conversion of the stroke.
- Reduce cerebral edema and lower intracranial pressure.
- Improve blood flow to the ischemic penumbra. (Correct answer)
- Prepare the patient for emergent craniotomy.
Correct answer: Improve blood flow to the ischemic penumbra.
In an acute ischemic stroke, the area surrounding the core infarct, known as the ischemic penumbra, contains brain tissue that is at risk but still viable. Autoregulation is often impaired, making blood flow to this area passively dependent on systemic blood pressure. Allowing a higher blood pressure (permissive hypertension) helps maintain cerebral perfusion to this salvageable penumbral tissue, potentially reducing the final infarct size. Aggressively lowering blood pressure could worsen the ischemia.
CCRN - Review Neurological Critical Care Questions and Answers 1
A patient with a traumatic brain injury has an intracranial pressure (ICP) of 22 mmHg and a mean arterial pressure (MAP) of 70 mmHg.
The nurse calculates the cerebral perfusion pressure (CPP) and recognizes the need for which immediate intervention?