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ICP AND MANAGEMENT July 2014. OUTLINE Intracranial contents Intracranial contents Monroe-Kellie Doctrine Monroe-Kellie Doctrine ICP monitors and waveforms.

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Presentation on theme: "ICP AND MANAGEMENT July 2014. OUTLINE Intracranial contents Intracranial contents Monroe-Kellie Doctrine Monroe-Kellie Doctrine ICP monitors and waveforms."— Presentation transcript:

1 ICP AND MANAGEMENT July 2014

2 OUTLINE Intracranial contents Intracranial contents Monroe-Kellie Doctrine Monroe-Kellie Doctrine ICP monitors and waveforms ICP monitors and waveforms Calculate cerebral perfusion pressure Calculate cerebral perfusion pressure Types of edema and Herniation Syndromes Types of edema and Herniation Syndromes Management of ICP Management of ICP

3 VAULT CONTENTS

4 MONROE-KELLIE DOCTRINE An increase in the volume of any of the contents within the intracranial vault must be met with a decrease in the volume of another or the intracranial pressure will increase An increase in the volume of any of the contents within the intracranial vault must be met with a decrease in the volume of another or the intracranial pressure will increase V (vault)= V (CSF) + V (brain) + V (blood) + V (other) V (vault)= V (CSF) + V (brain) + V (blood) + V (other)

5 INTRINSIC COMPENSATORY MECHANISMS Brain- none Brain- none CSF- redistributed into compliant paraspinal CSF space CSF- redistributed into compliant paraspinal CSF space Blood- venous blood forced into internal jugular veins Blood- venous blood forced into internal jugular veins When compensatory mechanisms are exhausted, ICP rises more rapidly When compensatory mechanisms are exhausted, ICP rises more rapidly

6 CBF VIA AUTO-REGULATION Maintains CBF via auto-regulation over wide range of MAP by altering resistance of cerebral blood vessels This insures supply of oxygen and metabolic substrates to neurons are unaltered ICP > 20 has been shown in both adult and pediatric studies to be associated with increased morbidity and mortality Maximally Dilated Ischemia Ischemia, disrupted BBB, inc ICP

7 LOSS OF AUTO-REGULATION CPP = MAP – ICP Minimal CPP is age variant Infants 50 mmHg Children 60 mmHg Adults 70 mmHg

8 MAINTAINING ADEQUATE BRAIN OXYGENATION Hypoxia results in vasodilation therefore increasing CBF and potentially worsening ICP Hypoxia results in vasodilation therefore increasing CBF and potentially worsening ICP Another way of maintaining good oxygenation is to attack it from the consumptive end Another way of maintaining good oxygenation is to attack it from the consumptive end Decrease cerebral metabolism Decrease cerebral metabolism Keep patient adequately sedated Keep patient adequately sedated In extreme cases, use a pentobarbital induced coma In extreme cases, use a pentobarbital induced coma

9 ETIOLOGIES OF ELEVATED ICP Increased ICP can occur with any CNS pathology that results in a space Increased ICP can occur with any CNS pathology that results in a space occupying mass lesion, edema (osmotic, vasogenic, cytotoxic), or obstruction to occupying mass lesion, edema (osmotic, vasogenic, cytotoxic), or obstruction to CSF flow. Some common etiologies include: CSF flow. Some common etiologies include: Trauma: epidural, subdural bleeds, contusion, hematomas, diffuse axonal Trauma: epidural, subdural bleeds, contusion, hematomas, diffuse axonal injury, intraventricular hemorrhage injury, intraventricular hemorrhage Infection: meningitis, encephalitis, cerebritis Infection: meningitis, encephalitis, cerebritis VP shunt malfunction VP shunt malfunction Mass lesion: tumors, AVM Mass lesion: tumors, AVM Metabolic: hepatic encephalopathy, DKA Metabolic: hepatic encephalopathy, DKA Vascular or embolic disease, stroke with subsequent edema or mass effect Vascular or embolic disease, stroke with subsequent edema or mass effect

10 ICP MONITORS AND WAVEFORMS Intraventricular monitoring advantage of accuracy, simplicity of measurement, and the unique characteristic of drainage of CSF. disadvantage is infection, up to 20 percent of patients, hemorrhage Intraparenchymal (thin electronic or fiberoptic transducer) Advantages include ease of placement, and a lower risk of infection and hemorrhage (<1 percent) than with intraventricular devices Disadvantages include the inability to drain CSF for diagnostic or therapeutic purposes and the potential to lose accuracy (or "drift") over several days, since the transducer cannot be recalibrated following initial placement

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12 WAYS TO DECREASE ICP Size of the box Size of the box May increase size of vault with decompressive crainectomy May increase size of vault with decompressive crainectomy Decrease the volume of the contents Decrease the volume of the contents Remove “others”- tumors, crowbars, hematomas, bullets, etc. Remove “others”- tumors, crowbars, hematomas, bullets, etc. Must decrease volume of one of the components of the intracranial vault Must decrease volume of one of the components of the intracranial vault Brain Brain CSF CSF Blood Blood

13 TYPES OF EDEMA Vasogenic Increased permeability of brain capillary endothelium leads to edema and is usually seen around tumors, abscesses, intracerebral hematomas, encephalitis & meningitis. Neurons are not primarily injured. Reduction of this type of edema can minimize secondary injury Interstitial Edema results from increased CSF hydrostatic pressure and is usually seen in hydrocephalus or decreased CSF absorption by arachnoid villi, e.g. intraventricular hemorrhage. Cytotoxic Neuronal swelling occurs secondary to cell injury caused by failure of the ATPase – dependent pump as occurs in diffuse axonal injury. This type of injury is often irreversible.

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15 5 WAYS TO DECREASE INTRACRANIAL PRESSURE USING THE MONRO-KELLIE DOCTRINE Enhance venous drainage Enhance venous drainage Elevate head 30° Elevate head 30° If in a cervical collar, check fit If in a cervical collar, check fit Hyperosmolar therapy Hyperosmolar therapy Hyperventilation Hyperventilation CSF Drainage CSF Drainage Decompression Decompression

16 DECOMPRESSIVE CRANIECTOMY Done infrequently Done infrequently Usually done at an OSH prior to transfer OR in conjunction with hematoma evacuation Usually done at an OSH prior to transfer OR in conjunction with hematoma evacuation Remember to save the bone flap for reimplantation later Remember to save the bone flap for reimplantation later

17 CSF DRAINAGE Neurosurgical Procedure Neurosurgical Procedure Always push for an EVD, not just an ICP monitor Always push for an EVD, not just an ICP monitor Therapeutic AND diagnostic Therapeutic AND diagnostic Can stay in long-term (no drift) Can stay in long-term (no drift) Requires INR 100K Requires INR 100K

18 HYPEROSMOLAR THERAPY Increase serum osmolality to draw water out of brain parenchyma Increase serum osmolality to draw water out of brain parenchyma Mannitol Mannitol Decreases bld viscosity Decreases bld viscosity g/kg g/kg Maximal effect in 10 min, duration 75 min Maximal effect in 10 min, duration 75 min 3% Saline (500 mEq/L) 3% Saline (500 mEq/L) Osmotic, hemodynamic, vasoregulatory, and immunodmodulatory Osmotic, hemodynamic, vasoregulatory, and immunodmodulatory Every 1.5 cc/kg will increase Na by ≈ 1 mEq/L Every 1.5 cc/kg will increase Na by ≈ 1 mEq/L Known to have a longer lasting effect Known to have a longer lasting effect In general, check Na + and osmolality q6h In general, check Na + and osmolality q6h Target Na Target Na Target osmolality > 300 Target osmolality > 300

19 HYPERVENTILATION CAUSES A DECREASE IN CEREBRAL BLOOD FLOW Pic of blood flow with hypervent Pic of blood flow with hypervent Skippen. Crit Care Med Aug;25(8): Skippen. Crit Care Med Aug;25(8):1402-9

20 USE OF HYPERVENTILATION Worse long-term outcome Worse long-term outcome Target normocapnea Target normocapnea Works for acute spikes in ICP Works for acute spikes in ICP Target pCO 2 of about 35 Target pCO 2 of about 35 Avoid hypercapnea Avoid hypercapnea

21 AVOID THE BAD “H”S Hypotension Hypotension Hypoxia Hypoxia Hyponatremia Hyponatremia Hypervolemia Hypervolemia Hyperglycemia Hyperglycemia Hyperthermia Hyperthermia Hypermetabolism (seizures, agitation) Hypermetabolism (seizures, agitation)

22 SUMMARY OF KEY POINTS Many of the goals of increased ICP management are based using the Monro-Kellie Doctrine to our advantage Many of the goals of increased ICP management are based using the Monro-Kellie Doctrine to our advantage Goal ICP < 20 mmHg Goal ICP < 20 mmHg Hyperventilation is not a long-term strategy Hyperventilation is not a long-term strategy CPP = MAP – ICP; Maintain CPP > 40 mmHg CPP = MAP – ICP; Maintain CPP > 40 mmHg Goal Na Goal Na Avoid the bad “H’s” Avoid the bad “H’s”


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