Intracranial Pressure and Cerebral Perfusion

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Questions and Answers

What is the normal range for intracranial pressure (ICP)?

15-25 mmHg

20-30 mmHg

0-5 mmHg

5-15 mmHg (correct)

Which of the following does NOT contribute to the autoregulation of cerebral perfusion pressure (CPP)?

Decrease in intracranial blood volume (correct)

Increase in blood volume

Increased intracranial pressure (ICP)

Decrease in mean arterial pressure (MAP)

What two disorders are known to cause an increase in intracranial pressure (ICP)?

Anemia and dehydration

Postoperative edema and meningitis (correct)

Ischemia and migraines

Hypertension and diabetes

How is cerebral perfusion pressure (CPP) calculated?

MAP - ICP Signup and view all the answers

What is a potential effect of hypotension on intracranial pressure?

Leads to increased dilatation of cerebral vessels Signup and view all the answers

Which method is NOT used to assess for increased intracranial pressure (ICP)?

Blood glucose level check Signup and view all the answers

What factor can lead to an increase in ICP due to cell behavior?

Hyponatremia causing cell expansion Signup and view all the answers

Which of the following categories in the Glasgow Coma Scale (GCS) is NOT included?

Eye movement Signup and view all the answers

When assessing a neuro patient, how should a nurse adjust their communication tone?

Lower the tone to a calmer level Signup and view all the answers

Which response category indicates severe impairment on the Glasgow Coma Scale (GCS)?

3-8 Signup and view all the answers

What does the absence of doll's eyes signify?

Brainstem dysfunction Signup and view all the answers

What is the primary cause of brain herniation?

Rapid increase in intracranial pressure (ICP) Signup and view all the answers

What indicates widening pulse pressure?

Systolic increases as diastolic decreases Signup and view all the answers

What is the primary function of an intraventricular catheter (IVC)?

To drain excess fluid from the ventricles Signup and view all the answers

What is considered a common treatment for chronic subdural hematomas?

Surgery or JP drain Signup and view all the answers

What type of saline infusion is recommended for increased ICP?

Hypertonic saline (2-3%) Signup and view all the answers

What is a key characteristic of status epilepticus?

Seizures lasting longer than 5 minutes Signup and view all the answers

What does propofol infusion primarily aim to decrease?

Intracranial pressure (ICP) Signup and view all the answers

What occurs with increased intracranial pressure affecting the hypothalamic-pituitary system?

Diabetes insipidus Signup and view all the answers

Which of the following is NOT a treatment for SIADH?

Desmopressin Signup and view all the answers

What common complication can arise from untreated chronic subdural hematomas?

Increased intracranial pressure and risk of membrane formation Signup and view all the answers

In case of seizures due to increased ICP, which of the following is considered a potential cause?

Meningitis Signup and view all the answers

What role do benzodiazepines play in seizure management?

Enhance GABA inhibition Signup and view all the answers

What is a typical finding in the urine specific gravity of a patient with diabetes insipidus?

Low urine specific gravity Signup and view all the answers

Study Notes

Cerebral Perfusion Pressure (CPP)

CPP is a measure of the pressure gradient that drives blood flow to the brain.
CPP is calculated by subtracting intracranial pressure (ICP) from mean arterial pressure (MAP).
Normal CPP is 50-60 mmHg.
Decreased CPP can be caused by decreased MAP or increased ICP.

Increased Intracranial Pressure (ICP)

Increased ICP can occur due to various disorders, including tumors, trauma, stroke, post-operative edema, and meningitis.
The brain compensates for small rises in ICP by displacing cerebrospinal fluid (CSF) and shrinking brain tissue.
Hyponatremia can increase ICP by causing cells to expand.
Hypotension can increase ICP by causing cerebral vessels to dilate and blood shunting.
Hyperthermia can increase ICP by causing vasodilation.

Assessment of Increased ICP

Assessing for increased ICP involves monitoring the patient's level of consciousness (LOC), pupils (size and reactivity), motor strength, and performing a Glasgow Coma Scale (GCS).
The GCS has three categories: eye opening, verbal response, and motor response.
Scores range from 3-15, with scores of 3-8 indicating severe brain injury, 9-12 indicating moderate brain injury, and 13-15 indicating mild brain injury.
Noxious stimuli, such as sternal rub or nailbed pressure, can be used to assess the patient's response to pain.

Neurological Examinations

At shift change, the incoming nurse should perform a neurological assessment and compare findings with the previous nurse.
The NIHSS (National Institutes of Health Stroke Scale) should be performed at baseline in the emergency room, in conjunction with tPA or other therapies, and then per policy.
Doll's eyes is performed in patients in a coma with a clear spinal cord. Positive doll's eyes are when the eyes move in the opposite direction of the head. Absence of doll's eyes indicates brainstem dysfunction.

Herniation of the Brain

Herniation of the brain occurs when there is a rapid increase in ICP.
Herniation can cause Cushing's response, which is characterized by bradycardia, hyperventilation, Cheyne-Stokes respirations, widening pulse pressure, and hypertension.

Traumatic Brain Injury (TBI)

TBI can be classified as concussion, coup (acceleration injury), contrecoup (deceleration injury), skull fracture, and bleeding of arteries or veins.
Mild concussions resolve with rest.
Vascular brain injuries from trauma include epidural hematoma, subdural hematoma, subarachnoid hemorrhage, and intracerebral hematoma.
Subdural hematomas are the most common type of vascular brain injury.

ICP Monitoring

ICP monitoring may be indicated for patients with severe head injury, subarachnoid hemorrhage, tumor, or stroke.
An intraventricular catheter (IVC) is typically placed in patients requiring ICP monitoring and brain drainage.

Care of IVCs

The IVC drainage should be turned off when the patient is supine and brought toward the patient.
IVC dressing changes require at least two people.
The brain drain should be leveled correctly to prevent over-drainage or increased ICP.
Hourly neuro assessments should be performed along with checking ICP monitor readings and IVC output.

Nursing Considerations for Neuro Patients

Neuro patients require aseptic, not sterile, care.
Clustered care should be avoided because excessive stimuli can increase ICP.
IVCs are zeroed right after insertion.

Management of Increased ICP

Hypertonic saline (2-3%) is given slowly to reduce ICP.
Dexamethasone IVP is used to decrease inflammation.
Hyperventilation can worsen ICP because it decreases CO2, which is a vasodilator.

Seizures

Anticonvulsants may be started to prevent seizures in patients with increased ICP, seizures within 24 hours of injury, hematomas, depressed skull fractures, or penetrating head wounds.
Seizures can be caused by increased ICP, electrolyte imbalance, hyper/hypoglycemia, meningitis, brain tumors, drug/alcohol intoxication/withdrawal, and fever.
Partial seizures are characterized by focal symptoms such as lip smacking or rhythmic hand movements.
Seizures are diagnosed through an electroencephalogram (EEG).
Tonic-clonic seizures have two phases: a tonic phase, where extremities extend for 20 seconds, and a clonic phase, where rhythmic movements occur for 30 seconds.
Status epilepticus is defined as a seizure lasting longer than 5 minutes.

Treatment of Seizures

Seizures can cause anoxia to brain tissue by exceeding cerebral glucose and oxygen supply.
Benzos, such as Ativan or Valium, are given to stop a seizure immediately.
Dilantin (phenytoin), Cerebyx (fosphenytoin), and IVP benzos are used in the treatment of seizures.
Dilantin is alkaline and should be administered slowly post-mixing.
Cerebyx (fosphenytoin) is an alternative to Dilantin that is not as harsh on veins.
Benzos stop seizures by enhancing GABA inhibition, which makes neurons less excitable.

Sodium Imbalances in Neuro Patients

Increased ICP can affect the hypothalamic-pituitary system, leading to sodium imbalances.
Diabetes insipidus is characterized by the absence of ADH, leading to large volumes of dilute urine and increased serum sodium.
SIADH involves too much ADH, causing dilutional hyponatremia.
Diabetes insipidus is treated with Desmopressin (DDAVP).
SIADH is treated with fluid restriction, hypertonic saline solutions, and vaptans.

Aspiration and Pneumonia in Neuro patients

Patients with head injuries are at high risk for aspiration and pneumonia due to a decreased LOC and inability to protect their airways.

Epilepsy

Epilepsy is diagnosed after experiencing two unprovoked seizures.
Pseudoseizures do not have a postictal phase.
Increasing fat intake can reduce seizures.

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Description

This quiz focuses on the concepts of Cerebral Perfusion Pressure (CPP) and Increased Intracranial Pressure (ICP). It covers the mechanisms behind CPP calculation, the effects of increased ICP on brain function, and methods of assessment. Enhance your understanding of critical neurophysiological parameters.