intracranial pressure (icp)

Intracranial Pressure

(ICP) Megan McClintock, MS, RN

11/4/11

Normal Values

ICP 5-15 mm Hg CPP 60-100 mm Hg (< 50 is bad) CSF 20-30 mL/hr

Factors Affecting ICP

Arterial & venous pressure (high or low) Intrabdominal/intrathoracic pressure Posture Temperature Blood gases (acidosis, hypoxia, high CO2)

All are potent vasodilators

Compensation

Change in CSF volume Absorption/production Movement of CSF to the spinal subarachnoid space

Change in intracranial blood volume Collapse of cerebral veins/dural sinuses Cerebral vasoconstriction/dilation Change in venous outflow

Change in brain tissue volume Distension of dura Compression of brain tissue

Symptoms of ICP

Change in LOC Most sensitive & reliable indicator of neuro status

Change in VS Cushing’s triad

Change in pupils Response to light, blurred vision, diplopia, eye

movements, papilledema

Change in motor function Hemiparesis/hemiplegia, decorticate or decerebrate

posturing

Headache Vomiting

Diagnostic Testing

CT MRI Angiography Transcranial Doppler EEG, Evoked Potentials PET NO LP!!!!!!!!

ICP Monitoring

LICOX

Assessment

Glasgow Coma Scale Pupils Cranial Nerves Eye movement Motor strength Vital signs (including respiratory pattern -

pg 1435)

Treatment CSF drain, ICP monitoring ET tube/trach to keep PaO2 at 100, PaCO2 30-

35 Surgical removal of mass Hemicraniectomy Only light sedation (ie. Versed, Ativan) Be careful with drugs that alter the neuro state

Rapid-acting opioids (Morphine, Fentanyl) are best

Propofol is good (rapid-acting, short half-life) Avoid benzodiazepines

Drugs

Mannitol Osmotic diuretic given intravenously Decreases ICP by plasma expansion and osmotic

effect

Hypertonic saline (3%) Can be as effective as mannitol or used concurrently Raises the osmolality of the ECF in the brain

Corticosteroids Used for vasogenic edema around tumors and

abscesses but not for head-injured patients

Barbiturates Reduce metabolic rate decreasing CBF and ICP

Interventions

No fever or shivering (or agitation, pain, seizures) No Valsalva, coughing, sneezing Avoid restraints Family member at bedside Seizure precautions Quiet, non-stimulating environment Light touch and talk even if in a coma

Interventions

Respiratory Patent airway Watch breathing patterns Side-lying Watch for snoring Careful use of suctioning HOB 30 degrees Prevent abdominal distension (NG tube – depends on

injury) Monitor ABGs

Nutrition

Interventions

Fluid & Electrolytes Monitor closely (esp. Na, Gl, K, Mg, osmo) Watch for diabetes insipidus & SIADH (pg

1437)

Body position HOB 30 degrees No neck flexion Turn gently and slowly Avoid extreme hip flexion Prevent pain