Neuro HESI Pt. Review: Mrs. Thorne

14. "Triple H" therapy is commonly used to treat cerebral vasospasm, with the aim of preventing stroke. You know that "triple H" therapy involves use of:

- Hypertension "Triple H" therapy is designed to increase cerebral perfusion pressure (CPP) by raising mean arterial pressure (MAP) through plasma volume expansion and dilution. It includes induced hypertension. "Triple H" therapy is not used with an untreated cerebral aneurysm, since it could cause rupture. - Hypervolemia "Triple H" therapy is designed to increase cerebral perfusion pressure (CPP) by raising mean arterial pressure (MAP) through plasma volume expansion and dilution. It includes induced hypervolemia. "Triple H" therapy would not be safe with an untreated cerebral aneurysm, since it could cause rupture. - Hemodilution "Triple H" therapy is designed to increase cerebral perfusion pressure (CPP) by raising mean arterial pressure (MAP) through plasma volume expansion and dilution. It includes induced hemodilution.

13. Mrs. Thorne has many needs. You take time to work on her plan of care. Which of the following are relevant for Mrs. Thorne?

- Self-care deficit syndrome - Deficient knowledge - Risk for impaired skin integrity - Risk for injury - Decreased Intracranial Adaptive Capacity Correct

Cerebral vasospasm typically begins within_______days after an initial subarachnoid bleed.

3-5

11. At the time Mrs. Thorne's initial ICP reading of 20 mm Hg was obtained, her BP was 150/90. Her CPP at that time was:

90 mm Hg Using intracranial pressure (ICP) and arterial blood pressure, cerebral perfusion pressure (CPP) can be calculated. First, the mean arterial blood pressure (MAP) is calculated (diastolic pressure + 1/3 of the pulse pressure). With a BP of 150/90, Mrs. Thorne's MAP was 110 mm Hg (90 + 1/3 of 60). Next, CPP is calculated: CPP = MAP - ICP = 110 - 20 = 90 mm Hg. This normal CPP indicates adequate pressure for normal cerebral blood flow. A CPP of 70-95 mm Hg is required for normal cerebral blood flow and adequate perfusion of brain cells.

Intracranial pressure (ICP) monitoring allows for calculation of cerebral perfusion pressure (CPP).

As intracranial pressure (ICP) increases and approaches blood pressure, cerebral perfusion pressure (CPP) decreases, and cerebral blood flow decreases. A CPP of 70-95 mm Hg is required for normal cerebral blood flow and adequate perfusion of brain cells.

After extensive discussion with the neurologist, Mrs. Thorne decides to have surgical clipping. She feels she would constantly worry about the aneurysm reopening if she had coiling done instead.

Astute assessment and prompt intervention are critical with Mrs. Thorne, as she awaits surgery. The incidence of morbidity and mortality associated with subarachnoid hemorrhage (SAH) is high. Early complications are predictable and care and therapy are aimed at prevention of these complications.

Preventing increases in ICP

Coughing increases intrathoracic pressure and intracranial pressure (ICP) and should be discouraged in patient with an elevated ICP. Sneezing and blowing the nose also increase intrathoracic and intracranial pressure (ICP) and should be avoided. If nausea and vomiting are present, these should be controlled, to prevent elevations in ICP from vomiting. Valsalva's maneuver should also be avoided. Valsalva's maneuver increases intrathoracic pressure and decreases venous return to the heart. It also increases ICP.

6. You know that the Glasgow Coma Scale (GCS) is used to grade level of consciousness based on assessment of:

Eye-opening ability, motor responses, verbal responses

10. Intracranial pressure (ICP) monitoring is initiated with Mrs. Thorne. She has an intraventricular catheter and ICP monitor in place. An initial ICP reading of 20 mm Hg is obtained. An ICP reading of 20 mm Hg is:

High Normal intracranial pressure (ICP) is under 10 mm Hg. An ICP of 20 mm Hg is high. Generally an ICP above 20 mm Hg is treated.

5. Mrs. Thorne requires frequent neurological assessment for signs of increased intracranial pressure (ICP). In assessing Mrs. Thorne for indications of increased ICP, which of the following assessments is most important?

Level of consciousness The most sensitive assessment parameter in patients with increased intracranial pressure (ICP) is level of consciousness. Level of consciousness decreases as intracranial pressure (ICP) increases. The Glasgow Coma Scale (GCS) is one source of data regarding level of consciousness. Use of the Glasgow Coma Scale (GCS) allows for standardized neurological assessment and reporting of arousal and awareness. Serial assessments allow for identification of subtle changes over time.

CPP is calculated by subtracting ICP from the mean arterial pressure (MAP).

Mean arterial blood pressure (MAP) is calculated by adding together the diastolic pressure and 1/3 of the pulse pressure.

You phone the neurologist responsible for Mrs. Thorne's care and notify him of the current IV infusion. He asks that the IV fluid be changed to 0.9% sodium chloride (normal saline) at a rate of 75 mL per hour. The IV rate is slow to avoid cerebral edema, but adequate enough to allow cerebral perfusion. Because this order is a phone order, you write the order down, read it back to the physician, and have him confirm the order. This "read back" procedure is designed to prevent medication errors and keep patients safe.

Mrs. Thorne has cerebral angiography. An aneurysm of the right internal carotid artery is identified. The aneurysm is not currently bleeding. The neurologist evaluates Mrs. Thorne's overall condition and grades the severity of her subarachnoid hemorrhage (SAH) using the Hunt-Hess Scale. The Hunt-Hess Scale is commonly used to classify and guide management of patients with subarachnoid hemorrhage (SAH). Using the Hunt-Hess Grading Scale, higher grades reflect more severe presenting neurological symptoms, higher risk, and less chance for a favorable outcome.

8. You dim the lights around Mrs. Thorne and examine her eyes, comparing pupil size bilaterally. Pupil size is similar at 4 mm. This finding is:

Normal A pupil size of 4 mm is usually normal. Pupil size larger than 5 mm may be abnormal (dilated). Pupil size smaller than 3 mm may be abnormal (constricted). Pupils should be of equal size. When pupil size is unequal, it should be reported to the physician immediately.

Rationale 1.

Subarachnoid hemorrhage (SAH) secondary to a cerebral aneurysm is a result of arterial bleeding into the subarachnoid space, a result of aneurysm rupture. A cerebral aneurysm is an abnormal outpouching of a blood vessel, usually an artery, due to weakness of the vessel wall. Saccular (berry) cerebral aneurysms occur in arteries at the base of the brain, especially at the bifurcations of the major arteries, often on the Circle of Willis. Most cerebral aneurysms are a result of degenerative vessel wall injury related to hemodynamic stresses. Some genetic diseases are associated with cerebral aneurysms. There may also be a familial tendency to develop cerebral aneurysms. Aneurysms are not common in veins. Venous bleeding, therefore, does not occur.

The neurologist discusses two options for treating the aneurysm: endovascular therapy (aneurysm coiling) and surgical clipping. Endovascular coiling is a minimally invasive procedure that is performed by an interventional neuroradiologist, usually with the patient under general anesthesia. The procedure involves passing a catheter from the femoral artery to the aneurysm. Through the catheter, platinum coils or other materials that promote thrombosis are placed within the aneurysm. This thrombosis reduces risk for bleeding.

Surgical clipping of a cerebral aneurysm involves scalp incision and craniotomy. The aneurysm is located and a metal clip is placed at the neck of the aneurysm. This procedure immediately eliminates risk of bleeding. Because surgical repair involves deep anesthesia and invasive brain surgery, risk of morbidity is greater with this treatment option. Damage to important brain structures can cause permanent disability or even death. Endovascular coiling is considered to be safer but less durable that surgical clipping. Over time, coils can compact and cause the aneurysm to reopen and bleed, although recoiling can be done.

Meningeal layers of the brain are connective tissue membranes that protect the brain. The meningeal layers of the brain include the dura mater, the arachnoid mater, and the pia mater.

The dura mater is a thick fibrous membrane that lies directly beneath the skull. Above the dura is a major artery, the middle meningeal artery. Beneath the dura is the subdural space, which includes a large number of small veins.

Using the Hunt-Hess Grading Scale, Grade 1, 2, and 3 patients are often good candidates for treatment. These patients present with less neurological deficit and the best chances for recovery. The neurologist classifies Mrs. Thorne as a Hunt-Hess Grade 3 patient. Except for her current problem, Mrs. Thorne is healthy. Her clinical condition is currently stable.

The neurologist speaks with Mrs. Thorne and her husband about treatment options. He explains that although Mrs. Thorne's aneurysm is not currently bleeding, treatment is needed since the aneurysm could bleed again. Rebleeding (rerupture) of a cerebral aneurysm after an initial bleed is common, and can result in secondary subarachnoid hemorrhage (SAH). Secondary SAH increases intracranial pressure (ICP) and may result in greater neurologic damage and more symptoms. Rebleeding frequently occurs within the first 24 hours of an initial bleed and may be fatal.

The arachnoid mater, beneath the subdural space, is a weblike membrane. In the subarachnoid space there are veins and arteries, and cerebrospinal fluid (CSF).

The pia mater, beneath the subarachnoid space, is a delicate membrane containing small blood vessels. The pia mater directly adheres to the brain.

Cerebral vasospasm can cause a variety of signs and symptoms, including neurological deficits, paresis or paralysis, restlessness, motor weakness, speech difficulties, and an increase in intracranial pressure (ICP). Prompt attention to onset of symptoms is imperative in avoiding stroke from severe ischemia.

Transcranial doppler (TCD) ultrasound, which measures blood flow velocities, may identify cerebral vasospasm even before ischemic symptoms appear.

It has already been documented that Mrs. Thorne has nuchal rigidity, stiffness of the neck. Nuchal rigidity and Kernig's and Brudzinski's signs reflect meningeal irritation, and with subarachnoid hemorrhage (SAH), are due to the presence of blood in the subarachnoid space.

With a subarachnoid hemorrhage, Mrs. Thorne has an increased intracranial pressure (ICP), which is causing some signs and symptoms. The skull is a non-compliant cavity filled to capacity with brain, blood, and cerebrospinal fluid (CSF). Anything that increases volume or mass within the cavity (such as blood) causes ICP to increase. With an elevated ICP, increased pressure on delicate cerebral cells creates an ischemic event within the cells, interferes with cerebral function, and results in neurologic deficits.

2. Which of the following describes the correct procedure for testing for Kernig's sign?

a. Passively flex one of the patient's legs at the hip and knee and then extend her knee while observing for pain or resistance Rationale: Kernig's sign is elicited by slightly flexing one of the patient's legs at the hip and knee and then extending the knee while observing for pain or resistance. Brudzinski's sign is elicited by passively flexing the neck forward and observing for hip and knee flexion.

3. You note that Mrs. Thorne arrived from the Emergency Department (ED) with a peripheral IV line through which dextrose 5% in water is slowly infusing at 75 mL per hour. Which of the following is indicated?

a. Question the infusion solution Rationale: Infusion of dextrose 5% in water should be questioned. Infusion of dextrose 5% in water could increase intracranial pressure (ICP). It is likely that Mrs. Thorne, who has a subarachnoid hemorrhage (SAH), has an increased intracranial pressure (ICP). It is important to prevent further increases in ICP. Dextrose 5% in water, although an isotonic solution, becomes hypotonic in the body after the dextrose in the solution is metabolized. Subsequently, when infused, dextrose 5% in water can ultimately cause fluid to be drawn by osmosis from intravascular to interstitial and intracellular spaces. This can result in an increase in intracranial pressure (ICP).

1. SAH resulting from a cerebral aneurysm is characterized by:

arterial bleeding into the subarachnoid space.

taking the______ _______ ______ Nimotop (nimodipine) every four hours. This drug is useful in minimizing the effects of vasospasm (preventing ischemic injury) if it occurs.

calcium channel blocker

9. You also check pupil response to light. Brisk consensual pupil __________ in response to light is observed, which is normal.

constriction When checking pupil response to light, brisk consensual pupil constriction in response to light is normal.

4. After subarachnoid hemorrhage (SAH) due to bleeding from a cerebral aneurysm, patients like Mrs. Thorne are at high risk for complications. Besides re-bleeding, complications include:

hydrocephalus, cerebral vasospasm, seizures Hydrocephalus (an increase in fluid in the ventricles) is a complication of subarachnoid hemorrhage (SAH). Blood in the subarachnoid space interferes with absorption of cerebrospinal fluid (CSF). Hydrocephalus may develop within a few days following SAH (acute hydrocephalus) or, more commonly, slowly over weeks or months (chronic hydrocephalus). It may develop before or after treatment to correct a cerebral aneurysm. Intracranial pressure (ICP) increases with hydrocephalus. Progressive drowsiness, incontinence, gait problems, and abulia (lack of initiative, inability to make decisions, slowed mentation) accompany hydrocephalus. Ventriculostomy, drainage of fluid from the ventricles, may be needed to correct intracranial hypertension. Cerebral vasospasm is a predictable major complication after subarachnoid hemorrhage (SAH). Cerebral vasospasm involves constriction of the large arteries at the base of the brain, and is probably due to the presence of blood. Cerebral vasospasm typically begins within 3-5 days after the initial subarachnoid bleed, may progressively increase, and gradually resolves over a 2-4 week period. Cerebral vasospasm causes cerebral ischemia and may result in cerebral infarction (stroke). It is a major cause of delayed morbidity and mortality after subarachnoid hemorrhage (SAH). Early treatment of aneurysms that have bled, when possible, allows for the safe use of preferred techniques for treating vasospasm, if it occurs. With subarachnoid hemorrhage (SAH), risk for seizure is increased. Blood acts as an irritant in the subarachnoid space.

12. In caring for Mrs. Thorne, you use interventions aimed at preventing/controlling increases in intracranial pressure (ICP). These include:

maintaining head of bed elevation avoiding neck flexion spacing patient care activities maintaining a relaxed physical and emotional environment

7. Which of the following clinical signs and symptoms would you expect in a patient with a total Glasgow Coma Scale (GCS) score of 15?

spontaneous opening of the eyes, alert and oriented behavior, appropriate response to commands