Monro-Kellie Doctrine and Intracranial Pressure
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Questions and Answers

What is the normal range for Intracranial Pressure (ICP)?

  • 15-20 mmHg
  • 0-5 mmHg
  • 5-15 mmHg (correct)
  • 20-25 mmHg

    • Which herniation type is associated with decerebrate posturing and bilateral pupil dilation?

  • Subfalcine Herniation
  • Uncal Herniation
  • Upwards Herniation (correct)
  • Central Tentorial Herniation

    • What is the calculated value of Cerebral Perfusion Pressure (CPP) if the Mean Arterial Pressure (MAP) is 64 and ICP is 14?

  • 78
  • 64
  • 50 (correct)
  • 80

    • What is the recommended normal minimum MAP for neuro patients?

    <blockquote> <p>80</p> </blockquote> Signup and view all the answers

    During hyperosmolar therapy, what is the sodium goal when administering hypertonic saline?

    <p>150-155 mEq/L</p> Signup and view all the answers

    Which of the following options is a criteria for ICP monitoring?

    <p>Severe traumatic brain injury (TBI)</p> Signup and view all the answers

    What is the upper limit for normal Cerebral Perfusion Pressure (CPP) recommended by the Brain Trauma Foundation?

    <p>70 mmHg</p> Signup and view all the answers

    What immediate action should be taken if a patient exhibits signs of an ischemic stroke?

    <p>Follow the FAST protocol.</p> Signup and view all the answers

    Which treatment is commonly used for reversing anticoagulation in hemorrhagic stroke?

    <p>Vitamin K</p> Signup and view all the answers

    What should be the blood pressure goal for treating intraparenchymal hemorrhage?

    <p>~140 mmHg systolic</p> Signup and view all the answers

    What does the Monro-Kellie Doctrine state regarding intracranial volume?

    <p>The total volume of the skull is constant.</p> Signup and view all the answers

    What is the significance of Cushing’s Triad with respect to elevated ICP?

    <p>It is a late sign of brain herniation.</p> Signup and view all the answers

    Which calculation is used to determine Mean Arterial Pressure (MAP)?

    <p>MAP = Diastolic + 1/3(Systolic - Diastolic)</p> Signup and view all the answers

    Which condition is indicated by an ICP measurement greater than 20 mmHg for more than 5 minutes?

    <p>Increased risk of cerebral ischemia.</p> Signup and view all the answers

    Which of the following is NOT an indication for ICP monitoring?

    <p>Mild cognitive impairment</p> Signup and view all the answers

    Which of the following therapies is primarily used to decrease ICP?

    <p>Hyperosmolar therapy</p> Signup and view all the answers

    Which clinical sign is most associated with uncal herniation?

    <p>Ocular motor dysfunction</p> Signup and view all the answers

    What is the main goal when treating ischemic strokes regarding blood pressure management?

    <p>Allow permissive hypertension targeting systolic 140-160 mmHg.</p> Signup and view all the answers

    Which of the following accurately describes the clinical presentation of subarachnoid hemorrhage?

    <p>Acute onset, often described as the 'worst headache of life'.</p> Signup and view all the answers

    What is the primary goal of controlled hyperventilation in the treatment of increased intracranial pressure (ICP)?

    <p>To reduce carbon dioxide levels and decrease ICP</p> Signup and view all the answers

    What therapy is most likely used in conjunction with supportive care during the management of an ischemic stroke?

    <p>tPA for thrombolysis</p> Signup and view all the answers

    Which condition is characterized by tearing of the pituitary gland during increased ICP?

    <p>Central tentorial herniation</p> Signup and view all the answers

    What is the serum osmolality monitoring during mannitol use important for?

    <p>To monitor for potential complications of therapy</p> Signup and view all the answers

    What is the recommended treatment approach for patients displaying signs of hemorrhagic stroke?

    <p>Aggressive blood pressure control and reversing anticoagulation</p> Signup and view all the answers

    Which of the following best defines the term 'penumbra' in relation to ischemic strokes?

    <p>A region surrounding an infarct with salvageable tissue</p> Signup and view all the answers

    What does a normal range for Cerebral Perfusion Pressure (CPP) indicate about brain health?

    <p>Adequate blood flow and oxygen delivery to the brain</p> Signup and view all the answers

    Which of the following is NOT a common change on an EKG associated with increased ICP?

    <p>Prolonged QT interval</p> Signup and view all the answers

    What does the term Cushing's Triad signify in a clinical context?

    <p>A set of symptoms suggesting elevated ICP</p> Signup and view all the answers

    What is the purpose of SjVO2 monitoring in a neurocritical care setting?

    <p>To assess cerebral blood flow and oxygen delivery</p> Signup and view all the answers

    What is the consequence of maintaining an Intracranial Pressure (ICP) greater than 20 mmHg for longer than 5 minutes?

    <p>Increased risk of herniation</p> Signup and view all the answers

    Which of the following describes the calculation for Cerebral Perfusion Pressure (CPP)?

    <p>CPP = MAP - ICP</p> Signup and view all the answers

    What is the target blood pressure range for permissive hypertension in treating ischemic stroke?

    <p>Systolic 140-160 mmHg</p> Signup and view all the answers

    Which type of herniation is characterized by cerebral artery compression?

    <p>Subfalcine (cingulate) herniation</p> Signup and view all the answers

    What is the recommended dosage and method of administration for hypertonic saline in treating increased ICP?

    <p>3% saline, bolus 250 mL over 10-30 minutes</p> Signup and view all the answers

    In the context of EKG changes associated with increased ICP, which condition is most likely indicated by ST depressions?

    <p>Intracranial hypertension</p> Signup and view all the answers

    Which class of medications is primarily used to treat hypertension during a hemorrhagic stroke?

    <p>Antihypertensives</p> Signup and view all the answers

    What is the normal range for Cerebral Perfusion Pressure (CPP) recommended by the Brain Trauma Foundation?

    <p>50-90 mmHg</p> Signup and view all the answers

    What is the primary goal of elevating the head of the bed in a patient with increased ICP?

    <p>Reduce intracranial pressure</p> Signup and view all the answers

    Which of the following methods is NOT indicated for monitoring cerebral oxygen supply in neurocritical care?

    <p>Optic Ultrasound</p> Signup and view all the answers

    What is the primary reason to monitor intracranial pressure (ICP) in severe traumatic brain injury (TBI) patients?

    <p>To guide therapy in order to prevent secondary brain injury</p> Signup and view all the answers

    Which of the following EKG changes is most commonly associated with increased intracranial pressure (ICP)?

    <p>ST depressions</p> Signup and view all the answers

    What is the implication of a Cerebral Perfusion Pressure (CPP) below 60 mmHg?

    <p>Increased risk of brain ischemia</p> Signup and view all the answers

    In the context of managing increased ICP, what is the function of hyperosmolar therapy?

    <p>To decrease brain tissue swelling</p> Signup and view all the answers

    What does the calculation of Mean Arterial Pressure (MAP) help determine in neurocritical care?

    <p>The adequacy of cerebral blood flow</p> Signup and view all the answers

    Which of the following treatments is indicated for managing elevated ICP?

    <p>Barbiturate therapy for sedation</p> Signup and view all the answers

    Which type of herniation is characterized by unilateral dilated pupils and posturing?

    <p>Uncal herniation</p> Signup and view all the answers

    What does a score on the NIH Stroke Scale help determine?

    <p>Baseline neurological function and improvement</p> Signup and view all the answers

    What is the most critical step in acknowledging a stroke under the FAST protocol?

    <p>Call emergency services immediately</p> Signup and view all the answers

    What is a key goal of controlling hyperventilation in a patient with elevated ICP?

    <p>Reduce carbon dioxide levels in the brain</p> Signup and view all the answers

    Study Notes

    Monro-Kellie Doctrine

    • The Monro-Kellie Doctrine describes the relationship between the brain, blood, and cerebrospinal fluid (CSF) within the closed cranial vault.
    • The total volume of these three components is fixed, so an increase in one component must be compensated for by a decrease in another.

    Intracranial Pressure (ICP)

    • Normal ICP: 5–15 mmHg
    • Elevated ICP: >20 mmHg for longer than 5 minutes
    • Cushing's Triad: A classic sign of increased ICP, characterized by:
      • Hypertension
      • Bradycardia
      • Irregular breathing

    Increased ICP EKG Changes

    • Common EKG changes associated with increased ICP include:
      • ST depressions
      • Intracerebral T-waves (deep T-waves in anterior leads)

    Herniation

    • Herniation occurs when increased ICP forces brain tissue to shift through the opening in the skull, compressing vital structures.
    • Types of herniation:
      • Uncal herniation: Posturing, blown pupil
      • Subfalcine (cingulate) herniation: Cerebral artery compression
      • Central tentorial herniation: Diabetes insipidus (tearing of pituitary gland)
      • Upwards herniation: Bilateral pupil dilation, decerebrate posturing
      • Cerebellar (tonsillar) herniation: Herniation, altered mental status, respiratory arrest

    Mean Arterial Pressure (MAP)

    • Calculation: MAP = Diastolic + 1/3 (Systolic – Diastolic)
    • Normal minimum MAP for neuro patients: >80 mmHg
    • Absolute minimum for brain perfusion: >60 mmHg

    Cerebral Perfusion Pressure (CPP)

    • Calculation: CPP = MAP – ICP
    • Normal CPP: 50-90 mmHg (Brain Trauma Foundation recommends 60-70 mmHg)

    Treating Increased ICP

    • Supportive care:
      • Maintain ABCs
      • Elevate head of bed ~30 degrees
      • Treat seizures
      • Provide sedation
      • Treat fever
    • Neuro ICU interventions:
      • Consider deep sedation (barbiturates)
      • Hyperventilation
      • Hyperosmolar therapy (mannitol, hypertonic saline)

    Stroke

    • Ischemic stroke: Occurs when a blood clot blocks an artery in the brain, depriving tissue of oxygen.
    • Hemorrhagic stroke: Occurs when a blood vessel in the brain ruptures, causing bleeding into brain tissue.
    • Penumbra: The salvageable area around a dead area of brain tissue in an ischemic stroke.

    Ischemic Stroke Treatment

    • Supportive care:
      • Maintain SpO2 > 94%
      • Check blood glucose
      • Monitor EKG
    • BP Management:
      • Permissive hypertension: Generally target systolic BP 140-160 mmHg, diastolic 70-90 mmHg
    • Thrombolysis:
      • tPA (tissue plasminogen activator) may be administered within 4.5 hours of stroke onset.**

    Hemorrhagic Stroke

    • High mortality rate: ~3% of strokes annually in the US.
    • Incidence doubles every 10 years after age 35.
    • High rate of associated problems: Seizures, hydrocephalus, fever, infection.

    Hemorrhagic Stroke Treatment

    • Reversing anticoagulation: Vitamin K, K-Centra
    • BP control: Labetalol, Nicardipine
    • Pain management

    Intraparenchymal Hemorrhage

    • Caused by hypertension
    • BP management: Target ~140 mmHg systolic

    Subarachnoid Hemorrhage

    • Acute onset, known as the "worst headache of life"
    • Hypertension management: Target BP:
      • Systolic < 140 mmHg in the first 24 hours.
      • Systolic < 160 mmHg after the first 24 hours.
      • Lower goal if high risk of re-bleeding.

    Monro-Kellie Doctrine

    • This doctrine describes the relationship between the volume of the brain, blood, and cerebrospinal fluid (CSF) within the skull.
    • The total volume of these three components is constant, so an increase in one component must be compensated for by a decrease in another to maintain a normal intracranial pressure (ICP).

    Intracranial Pressure (ICP)

    • Normal ICP is between 5-15 mmHg.
    • Elevated ICP is a serious condition that can lead to brain damage.
    • Cushing’s Triad is a classic sign of elevated ICP and is characterized by hypertension, bradycardia, and irregular respirations.

    Herniation

    • Herniation occurs when the brain tissue is displaced from its normal position due to increased pressure.
    • An ICP greater than 20 mmHg for longer than 5 minutes is a risk factor for herniation.
    • Different types of herniations include uncal, subfalcine, central tentorial, upwards, and cerebellar (tonsillar).
    • Each type has specific symptoms and clinical consequences.

    Mean Arterial Pressure (MAP)

    • MAP is a measure of the average pressure in your arteries during a single cardiac cycle.
    • MAP is calculated using the formula: Diastolic + 1/3 (Systolic – Diastolic).
    • A normal minimum MAP for neuro patients is greater than 80 mmHg.
    • An absolute minimum MAP for brain perfusion is greater than 60 mmHg.

    Cerebral Perfusion Pressure (CPP)

    • CPP is the pressure gradient that drives blood flow to the brain.
    • CPP is calculated by subtracting ICP from MAP: CPP = MAP – ICP.
    • Normal CPP is 50-90 mmHg with the Brain Trauma Foundation recommending a CPP of 60-70 mmHg.

    Indications for ICP Monitoring

    • ICP monitoring is crucial for patients with severe traumatic brain injury (TBI).
    • It is recommended for comatose patients with abnormal CT scan findings, hydrocephalus with elevated ICP, and long-anticipated hospital stays with ICP concerns.

    Treating Increased ICP

    • Supportive care is essential in treating increased ICP, including ensuring adequate airway, breathing, and circulation (ABCs).
    • Elevating the head of the bed to 30 degrees, treating seizures, and providing sedation are important supportive measures.
    • Neuro ICU management includes fever control, deep sedation with barbiturates, and controlled hyperventilation.
    • Hyperventilation should not be used in the field or with a bag-valve mask (BVM).

    Hyperosmolar Therapy

    • Mannitol is an osmotic diuretic that helps to decrease ICP but requires monitoring of serum osmolality.
    • Hypertonic saline, typically 3%, is administered as a bolus of 250 mL over 10-30 minutes, targeting a sodium goal of 150-155 mEq/L.

    Stroke

    • Ischemic Stroke:
      • Occurs when a blood clot blocks an artery in the brain, causing a lack of blood flow and oxygen to the brain.
      • The FAST acronym can be used to quickly identify signs of stroke: Facial weakness, Arm weakness, Speech difficulty, Time to call 911.
      • Additional tools for stroke assessment include the Cincinnati Stroke Scale and National Institutes of Health (NIH) Stroke Scale.
      • The "penumbra" refers to the area surrounding the dead tissue which is still salvageable but at risk of dying.
    • Ischemic Stroke Treatment:
      • Supportive care includes maintaining SpO2>94%, checking blood glucose, and monitoring EKG.
      • Permissive hypertension is generally the preferred approach to blood pressure management, aiming for a systolic of 140-160 mmHg and a diastolic of 70-90 mmHg.
      • Tissue plasminogen activator (tPA) is a clot-busting medication administered within 48 hours of stroke onset.

    Hemorrhagic Stroke

    • General:
      • Represents a higher mortality rate compared to ischemic strokes, accounting for 3% of strokes annually in the USA.
      • Incidence doubles every 10 years after the age of 35.
      • Hemorrhagic stroke carries with it a high rate of associated problems including seizures, hydrocephalus, fever, and infection.
    • Treatment:
      • Reversing anticoagulation is vital. Vitamin K and K-Centra medications are commonly used.
      • Blood pressure control is crucial, and medications like labetalol and nicardipine are employed.

    Intraparenchymal Hemorrhage

    • Results from ruptured blood vessels within the brain tissue.
    • Hypertension is a common cause of intraparenchymal hemorrhage.
    • The target blood pressure for patients with intraparenchymal hemorrhage is approximately 140 mmHg systolic.

    Subarachnoid Hemorrhage

    • Leads to bleeding in the space surrounding the brain.
    • Often presents with an acute onset, described as a "worst headache of life."
    • Treatment focuses primarily on hypertension management, aiming for a target blood pressure of:
      • Within 24 hours of onset: 140-160 mmHg systolic and 70-80 mmHg diastolic
      • After the first 24 hours: 120-140 mmHg systolic and 70 mmHg diastolic

    Monro-Kellie Doctrine & Intracranial Pressure (ICP)

    • The Monro-Kellie doctrine describes the relationship between the volume of brain tissue, cerebrospinal fluid (CSF), and blood within the rigid skull. Any increase in one of these components will cause a decrease in the others to maintain equilibrium.
    • Normal intracranial pressure ranges between 5-15 mmHg.
    • Elevated ICP is a serious neurological emergency that can lead to brain damage if left untreated.
    • Cushing's triad, a classic symptom of elevated ICP, involves a widened pulse pressure, bradycardia, and irregular respirations.
    • EKG changes associated with increased ICP include ST depressions and deep T waves in anterior leads.
    • Herniation occurs when brain tissue is displaced, often due to increased ICP.
    • Herniation becomes a significant risk if ICP remains above 20 mmHg for longer than 5 minutes.
    • Types of herniation include uncal (posturing, blown pupil), subfalcine (cerebral artery compression), central tentorial (diabetes insipidus - tearing of pituitary), upwards (bilateral pupil dilation, decerebrate posturing), and cerebellar (tonsillar - herniation, altered mental status, respiratory arrest).

    Mean Arterial Pressure (MAP) & Cerebral Perfusion Pressure (CPP)

    • MAP, a measure of the average pressure in the arteries during a heart cycle, is calculated using the formula: Diastolic + 1/3 (Systolic - Diastolic).
    • A minimum MAP of >80 mmHg is required for adequate brain perfusion in critically ill patients.
    • CPP is the pressure gradient needed to deliver blood flow and oxygen to the brain. It's calculated as CPP = MAP - ICP.
    • A normal CPP range is 50-90 mmHg, with the Brain Trauma Foundation recommending 60-70 mmHg.

    Managing Increased ICP

    • Supportive care for patients with increased ICP includes airway management (A-B-C), elevating the head of bed ~30 degrees, seizure control, and sedation.
    • In the neuro ICU, fever management is critical, and deep sedation with barbiturates may be considered.
    • Controlled hyperventilation, increasing minute volume by 20% to target a PaCO2 of 28-30 mmHg, can be used to reduce ICP.
    • Hyperosmolar therapy, through the use of mannitol (osmotic diuretic) or hypertonic saline (3% saline bolus over 10-30 minutes), aims to draw fluid from the brain tissue and reduce ICP.

    Stroke

    • Ischemic stroke, caused by a blockage in an artery supplying blood to the brain, is a medical emergency.
    • The acronym FAST (Facial weakness, Arm weakness, Speech difficulty, Time to call 911) is a simple tool for identifying possible stroke symptoms.
    • The Cincinnati Stroke Scale (facial droop, pronator drift, speech abnormality) and NIH Stroke Scale (baseline, serial, post-intervention) are standardized assessment tools used in stroke evaluation.
    • tPA administration, a clot-busting drug, is a crucial treatment for ischemic stroke within 48 hours of onset.
    • Permissive hypertension (Systolic 140-160, Diastolic 70-90) is often a goal for managing blood pressure in ischemic stroke patients.

    Hemorrhagic Stroke

    • Hemorrhagic stroke, caused by bleeding into or around the brain, carries a high mortality rate and accounts for 3% of strokes annually in the United States.
    • The incidence of hemorrhagic stroke doubles every 10 years after the age of 35.
    • Treatment focuses on reversing anticoagulation (vitamin K, K-Centra), blood pressure control (labetalol, nicardipine), and pain management.
    • Intraparenchymal hemorrhage, a type of hemorrhagic stroke caused by hypertension, is treated with antihypertensives to achieve a systolic pressure of ~140 mmHg.
    • Subarachnoid hemorrhage, characterized by an acute onset of severe headache often described as the "worst headache of life," requires aggressive blood pressure management, aiming for a target BP of ______.

    Monitoring in the Neuro ICU

    • Indications for ICP monitoring include severe TBI, comatose patients with abnormal CT scans, hydrocephalus with elevated ICP, and patients anticipated to have a prolonged ICU stay with ICP concerns.
    • Optic ultrasound measures optic nerve diameter to estimate ICP.
    • SjVO2 monitoring assesses cerebral oxygen supply, perfusion, and consumption.
    • PbtiO2 monitoring tracks brain tissue oxygenation.
    • Intracerebral microdialysis measures brain neurochemistry.

    Monro-Kellie Doctrine

    • Describes the relationship between intracranial volume components: Brain tissue, Cerebrospinal fluid, and Blood
    • The total volume of these 3 components should remain constant
    • An increase in one component results in a compensatory decrease in another, maintaining a stable intracranial pressure

    Intracranial Pressure (ICP)

    • Normal ICP: 5-15 mmHg
    • Elevated ICP: Can lead to Cushing’s Triad (hypertension, bradycardia, irregular respirations)
    • EKG changes associated with increased ICP: ST depressions, intracerebral T waves
    • Herniation occurs when ICP exceeds the capacity of the skull, causing brain tissue to displace
    • Risk of herniation: ICP > 20 mmHg for longer than 5 minutes

    Types of Herniation

    • Uncal Herniation: Occurs when the uncus of the temporal lobe compresses the brainstem, causing posturing and blown pupil
    • Subfalcine (Cingulate) herniation: The cingulate gyrus gets pushed under the falx cerebri, compressing the cerebral artery
    • Central Tentorial Herniation: Upward displacement of the diencephalon through the tentorium cerebelli, often results in diabetes insipidus due to pituitary damage
    • Upward Herniation: Bilateral pupil dilation, decerebrate posturing
    • Cerebellar (Tonsillar) Herniation: Cerebellar tonsils herniate through the foramen magnum, causing AMS, respiratory arrest

    Mean Arterial Pressure (MAP)

    • Calculation: MAP = Diastolic + 1/3 (Systolic – Diastolic)
    • Minimum MAP for Neuro Patients: >80 mmHg
    • Absolute Minimum for Brain Perfusion: >60 mmHg

    Cerebral Perfusion Pressure (CPP)

    • Calculation: CPP = MAP – ICP
    • Normal CPP: 50-90 mmHg (Brain Trauma Foundation recommends 60-70 mmHg)
    • Example: Stroke patient post hemicraniectomy, BP: 92/50 mmHg, ICP: 14 mmHg
      • MAP = 50 + 1/3(92-50) = 64 mmHg
      • CPP = 64 - 14 = 50 mmHg
      • Conclusion: CPP is at the lower end of normal

    Indications for ICP Monitoring

    • Severe Traumatic Brain Injury (TBI)
    • Comatose patients with abnormal CT scan
    • Hydrocephalus with elevated ICP
    • Long anticipated hospital stay with ICP concerns

    Other Neuro ICU Monitoring Technology

    • Optic Ultrasound: Monitors ICP by measuring optic nerve diameter
    • SjVO2: Measures cerebral oxygen supply, perfusion, and consumption
    • PbtiO2: Brain tissue oxygenation monitoring
    • Intracerebral Microdialysis: Measures brain neurochemistry

    Treating Increased ICP

    • Supportive Care: A-B-C, Elevate head of bed ~30 degrees, Treat seizures, Provide sedation
    • Neuro ICU: Treat fever, Deep sedation (Barbiturates), Hyperventilation (Controlled/Targeted Hyperventilation: Increase minute volume 20%, target PaCO2 28-30)
      • Do not hyperventilate in the field with a BVM
    • Hyperosmolar Therapy: Mannitol (Osmotic diuretic, monitor serum osmolality), Hypertonic Saline (Usually 3% saline, bolus 250 mL over 10-30 min, sodium goal: 150-155 mEq/L)

    Stroke

    • Ischemic Stroke Signs & Symptoms: FAST (Facial weakness, Arm weakness, Speech difficulty, Time to call 911), Cincinnati Stroke Scale (Facial droop, Pronator drift, Speech abnormality), NIH Stroke Scale (Baseline, Serial, Post-intervention)
    • Penumbra: Salvageable hypoxic area surrounding dead tissue
    • Ischemic Stroke Treatment: Supportive care (SpO2 > 94%, Check blood glucose, Monitor EKG), Permissive hypertension (BP goal generally Systolic 140-160, Diastolic 70-90)
    • tPA: Thrombolytic therapy, given within 48 hours of stroke onset

    Hemorrhagic Stroke

    • High mortality rate (3% of strokes annually in USA)
    • Incidence doubles every 10 years after age 35
    • High rate of associated problems: Seizures, Hydrocephalus, Fever, Infection

    Hemorrhagic Stroke Treatment

    • Reversing Anticoagulation: Vitamin K, K-Centra
    • Blood Pressure Control: Labetalol, Nicardipine
    • Pain Management

    Intraparenchymal Hemorrhage:

    • Results from hypertension
    • Treated with antihypertensives
    • BP Goal: ~140 mmHg systolic

    Subarachnoid Hemorrhage

    • Acute onset, “Worst headache of life”
    • Treat hypertension, target BP: ~140 mmHg systolic

    Monro-Kellie Doctrine

    • The skull is a rigid container with three components: brain tissue, blood, and cerebrospinal fluid (CSF)
    • The total volume of these components is relatively fixed
    • An increase in one component must be compensated for by a decrease in another component to maintain normal intracranial pressure (ICP)

    Intracranial Pressure (ICP)

    • Normal ICP: 5-15 mmHg
    • Elevated ICP: Cushing’s Triad
      • Hypertension (elevated systolic blood pressure)
      • Bradycardia (slow heart rate)
      • Irregular respirations (Cheyne-Stokes)
    • Increased ICP EKG Changes
      • ST depressions
      • Intracerebral T waves (deep T-waves in anterior leads)

    Herniation

    • Occurs when increased ICP forces brain tissue to shift or bulge through an opening in the skull
    • Risk: ICP > 20 for longer than 5 minutes
    • Types:
      • Uncal: posturing, blown pupil (dilation of the pupil of one eye)
      • Subfalcine (cingulate): cerebral artery compression
      • Central Tentorial: Diabetes insipidus – tearing of pituitary
      • Upwards: bilateral pupil dilation, decerebrate posturing (extensor posturing)
      • Cerebellar (tonsillar): herniation, altered mental status (AMS), respiratory arrest

    Mean Arterial Pressure (MAP)

    • Calculation: MAP = Diastolic + 1/3 (Systolic – Diastolic)
    • Normal Minimum MAP for Neuro Patients: >80 mmHg
    • Absolute Minimum for Brain Perfusion: >60 mmHg

    Cerebral Perfusion Pressure (CPP)

    • Calculation: CPP = MAP – ICP
    • Normal CPP: 50-90 (Brain Trauma Foundation recommends 60-70)
    • Example: Patient with stroke post hemicraniectomy
      • BP: 92/50
      • ICP: 14
      • MAP = 50 + 1/3(92-50) = 64
      • CPP = 64 - 14 = 50
      • CPP is at the lower end of normal

    Indications for ICP Monitoring

    • Severe Traumatic Brain Injury (TBI)
    • Comatose patients with abnormal CT scan
    • Hydrocephalus with elevated ICP
    • Long anticipated course of stay with ICP concerns

    Neuro ICU Monitoring Technology

    • Optic Ultrasound: Monitors ICP by measuring optic nerve diameter
    • SjVO2: Measures cerebral oxygen supply, perfusion, and consumption
    • PbtiO2: Brain tissue oxygenation monitoring
    • Intracerebral Microdialysis: Measures brain neurochemistry

    Treating Increased ICP

    • Supportive Care
      • A-B-C (Airway, Breathing, Circulation)
      • Elevate head of bed ~30º
      • Treat seizures
      • Provide sedation
    • Neuro ICU
      • Treat fever
      • Consider deep sedation (Barbiturates)
      • Hyperventilation
        • Controlled/Targeted Hyperventilation: Increase minute volume 20%, target PaCO2 28-30
        • Do not hyperventilate in the field or with a BVM
      • Hyperosmolar Therapy
        • Mannitol: Osmotic diuretic, monitor serum osmolality
        • Hypertonic Saline: Usually 3% saline, bolus 250 mL over 10-30 min, sodium goal: 150-155

    Stroke - Ischemic Stroke

    • FAST: Facial weakness, Arm weakness, Speech difficulty, Time to call 911
    • Cincinnati Stroke Scale: Facial droop, Pronator drift, Speech abnormality
    • NIH Stroke Scale: Baseline, Serial, Post-intervention
    • Penumbra: Salvageable hypoxic area surrounding dead tissue
      • Treatment:
        • Supportive care: SpO2 > 94%, check blood glucose, monitor EKG
        • BP Management: Permissive hypertension (BP goal generally Systolic 140-160, Diastolic 70-90)
        • tPA: 16, within 48 hours of onset

    Stroke - Hemorrhagic Stroke

    • General
      • High mortality rate, 3% of strokes annually in USA
      • Incidence doubles every 10 years after age 35
      • High rate of associated problems (seizures, hydrocephalus, fever, infection)
    • Treatment
      • Reversing Anticoagulation: Vitamin K, K-Centra
      • Blood Pressure Control: Labetalol, Nicardipine
      • Pain Management

    Stroke - Hemorrhagic Stroke Types

    • Intraparenchymal Hemorrhage
      • Results from hypertension
      • Treat with antihypertensives
      • BP Goal: ~140 mmHg systolic
    • Subarachnoid Hemorrhage
      • Acute onset, “Worst headache of life"
      • Treat hypertension, target BP:
        • 140 mmHg systolic for 1st 24 hours
        • 120 mmHg systolic after 24 hours
      • Control ICP, prevent vasospasm, early surgical intervention may be necessary

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    Description

    This quiz explores the Monro-Kellie Doctrine, detailing the relationship between the brain, blood, and cerebrospinal fluid within the cranial vault. It also covers normal and elevated ICP, associated EKG changes, and different types of herniation related to increased ICP.

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