3 ICP STUDENTS

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Focus on Intracranial Pressure : 

Focus on Intracranial Pressure

Intracranial Pressure (ICP) : 

Intracranial Pressure (ICP) Factors that influence ICP Arterial pressure Venous pressure Intraabdominal and intrathoracic pressure Posture Temperature Blood gases (CO2 levels) Carotid Bodies Aortic Bodies

Intracranial Pressure : 

Intracranial Pressure Skull has three essential components Brain tissue Blood Cerebrospinal fluid (CSF)

Components of the Brain : 

Components of the Brain Fig. 57-1

Intracranial Pressure : 

Intracranial Pressure Intracellular and extracellular fluids of brain tissues make up 78% of the volume Blood makes up 12% Remaining 10% is CSF Balance of these components maintains the ICP under normal conditions

Intracranial Pressure : 

Intracranial Pressure Degree to which these factors ↑ ICP depends on the ability of the brain to accommodate to the changes

Intracranial PressureRegulation and Maintenance : 

Intracranial PressureRegulation and Maintenance Normal intracranial pressure Pressure exerted by the total volume from the brain tissue, blood, and CSF Modified Monro-Kellie doctrine: Describes relatively constant volume within skull structure

Intracranial PressureRegulation and Maintenance : 

Intracranial PressureRegulation and Maintenance Normal intracranial pressure If volume in any one of the components increases within cranial vault and volume from another component is displaced, the total intracranial volume will not change

Intracranial PressureRegulation and Maintenance : 

Intracranial PressureRegulation and Maintenance Normal compensatory adaptations Alteration of CSF absorption or production Displacement of CSF into spinal subarachnoid space Dispensability of the dura Ability to compensate is limited If volume increase continues, ICP rises

Intracranial PressureCerebral Blood Flow : 

Intracranial PressureCerebral Blood Flow Autoregulation of cerebral blood flow Automatic alteration in diameter of cerebral blood vessels to maintain constant blood flow to brain Ensures a consistent CBF to provide the metabolic needs of brain tissue and maintain cerebral perfusion pressure

Intracranial PressureCerebral Blood Flow : 

Intracranial PressureCerebral Blood Flow Cerebral perfusion pressure (CPP) Pressure needed to ensure blood flow to the brain CPP = MAP – ICP Normal is 70 to 100 mm Hg <50 mm Hg is associated with ischemia and neuronal death MAP 85 150/100 ICP=25 CPP= MAP 66 100/50 ICP=40 CPP= MAP 100 120/90 ICP=15 CPP=

Increased Intracranial PressureCerebral Edema : 

Increased Intracranial PressureCerebral Edema Increased accumulation of fluid in the extravascular spaces of brain tissue Three types of cerebral edema: Vasogenic Cytotoxic Interstitial

Increased Intracranial PressureCerebral Edema : 

Increased Intracranial PressureCerebral Edema Vasogenic cerebral edema Most common type Occurs mainly in white matter Associated with changes in the endothelial lining of cerebral capillaries

Increased Intracranial PressureCerebral Edema : 

Increased Intracranial PressureCerebral Edema Cytotoxic cerebral edema Results from local disruption of functional integrity of cell membranes Occurs mainly in gray matter

Increased Intracranial PressureCerebral Edema : 

Increased Intracranial PressureCerebral Edema Interstitial cerebral edema Result of periventricular diffusion of ventricular CSF in a patient with uncontrolled hydrocephalus Can also be caused by enlargement of the extracellular space as a result of systemic water excess

Slide 16: 

Fig. 57-3

Herniation : 

Herniation Fig. 57-4

Increased Intracranial PressureMechanisms of Increased ICP : 

Increased Intracranial PressureMechanisms of Increased ICP Sustained increase in ICP results in brainstem compression and herniation of brain from one compartment to another

Increased Intracranial PressureClinical Manifestations : 

Increased Intracranial PressureClinical Manifestations Change in level of consciousness Change in vital signs Cushing’s triad Ocular signs

Traumatic Brain Injury : 

Traumatic Brain Injury

Increased Intracranial PressureClinical Manifestations : 

Increased Intracranial PressureClinical Manifestations ↓ In motor function Decerebrate posturing (extensor) Indicates more serious damage Decorticate posturing (flexor)

Increased Intracranial PressureClinical Manifestations : 

Increased Intracranial PressureClinical Manifestations Headache Often continuous and worse in the morning Vomiting Not preceded by nausea Projectile

Increased Intracranial PressureDiagnostic Studies : 

Increased Intracranial PressureDiagnostic Studies Aimed at identifying underlying cause MRI CT Cerebral angiography EEG Brain tissue oxygenation measurement ICP measurement Transcranial Doppler studies Evoked potential studies PET

Slide 25: 

Cerebral Angiography

Slide 26: 

EEG

Evoked Potentials : 

Evoked Potentials

Intermittent Drainage System : 

Intermittent Drainage System Fig. 57-9

Increased Intracranial PressureMeasurement of ICP : 

Increased Intracranial PressureMeasurement of ICP The gold standard for ICP monitoring is the ventriculostomy LICOX brain tissue oxygenation catheter Jugular venous bulb catheter

Increased Intracranial PressureMeasurement of ICP : 

Increased Intracranial PressureMeasurement of ICP Infection is always a serious consideration with ICP monitoring ICP should be measured as a mean pressure at the end of expiration Waveform should be recorded Shaped similar to arterial pressure trace

Slide 31: 

“A” waves: > 50-100 mmHg “B” waves: 20-40 mmHg “C” waves: < 20 mmHg Sustained “A” waves may indicate irreversible brain damage ICP Monitor Waveforms

Increased Intracranial PressureMeasurement of ICP : 

Increased Intracranial PressureMeasurement of ICP Inaccurate readings can be caused by CSF leaks Obstruction in catheter Differences in height of bolt/transducer Kinks in tubing Incorrect height of drainage system relative to patient’s reference point

Nursing Management : 

Nursing Management Will be Discussed in Class! Come Prepared.

Increased Intracranial PressureNursing Management : 

Increased Intracranial PressureNursing Management Nursing assessment Subjective data from patient or family members Glasgow Coma Scale Neurologic assessment

Increased Intracranial PressureNursing Management : 

Increased Intracranial PressureNursing Management Motor strength and response Vital signs BP Pulse Respiratory rate Temperature

Increased Intracranial Pressure Nursing Management : 

Increased Intracranial Pressure Nursing Management Adequate oxygenation PaO2 maintenance at 100 mm Hg or greater ABG analysis guides the oxygen therapy May require mechanical ventilator

Increased Intracranial Pressure Nursing Management : 

Increased Intracranial Pressure Nursing Management Drug therapy Mannitol Corticosteroids Barbiturates Antiseizure drugs

Increased Intracranial Pressure Nursing Management : 

Increased Intracranial Pressure Nursing Management Hyperventilation therapy Was the mainstay treatment But now found that aggressive hyperventilation increases risk of focal cerebral ischemia and adversely affects outcome Brief periods may be useful for refractory intracranial hypertension

Increased Intracranial Pressure Nursing Management : 

Increased Intracranial Pressure Nursing Management Nutritional therapy Patient is in hypermetabolic and hypercatabolic state ↑ Need for glucose Keep patient normovolemic IV 0.9% NaCl

Pupillary Check for Size and Response : 

Pupillary Check for Size and Response Fig. 57-11

Increased Intracranial PressureNursing Management : 

Increased Intracranial PressureNursing Management Planning Overall goals Maintain a patent airway ICP within normal limits Normal fluid and electrolyte balance No complications secondary to immobility and decreased LOC

Increased Intracranial PressureNursing Management : 

Increased Intracranial PressureNursing Management Nursing implementation Respiratory function Fluid and electrolyte balance Monitoring of intracranial pressure

Increased Intracranial PressureNursing Management : 

Increased Intracranial PressureNursing Management Nursing implementation Body position maintained in head-up position Protection from injury Psychologic considerations

Conscious Exam : 

Conscious Exam What is your name? Where are you? What is the date? Show me 2 fingers. Stick out your tongue. How much us a quarter/nickel/dime Tell me about...

Motor Response : 

Motor Response Localizes to Pain Organized attempt to localize and remove painful stimuli. Withdraws to Pain Withdraws extremity from source of painful stimuli.