Tuesday, November 28, 2006

ICP to start


  • ICP
    Skull volume= brain tissue + blood + CSF.
    MONROE-KELLIE HYPOTHESIS
    There is a limited space inside the skull for expansion and an increase in any of the components will lead to a change in the volume of the other components.
    TO COMPENSATE
    There will be an increased absorption of the CSF and a decreased cerebral blood volume.
    UNCOMPENSATED
    The ICP will rise leading to decreased cerebral perfusion which will lead to edema. Then the brain tissue will shift through openings in the rigid dura leading to herniation and death.
    Remember that an increased ICP leads to decreased cerebral blood flow…leading to ischemia and cell death.
    The systemic response---vasomotor centers are stimulated which increase the BP
    ***Slow bounding pulse and irregular respirations***
    How the body deals with cerebral edema…..
    The goal is to maintain blood flow and prevent tissue damage. 2 ways the body deals= Auto regulation of blood vessel diameter, and decreasing production of the CSF.
    CUSHINGS TRIAD
    Bradycardia
    Hypertension
    Bradypnea
    Seen with pressure on the medulla from brain stem herniation.
  • Pathological Conditions that can cause ICP
    Head injury, CVA, brain tumor, intracranial Sx, meningitis, encephalitis, subarachnoid hemorrhage.
  • Early symptoms of ICP= a change in the LOC= slow speech, delayed responses, irritable, restless and increased effort of resps. Change in pupils, weakness on one side, headache that increases.
  • Late symptoms of ICP= Worsening LOC leading to coma. Sluggish pupil response, decreased HR, decreased RR. Bradycardia to tachycardia. BP and temp will rise. The pulse pressure widens, Cheyne stokes resps, PROJECTILE VOMITING, hemiplegia, decorticate or decerebrate posture, flaccid before death. Loss of brain stem function. Increased systolic pressure.
    ASSESS
    LOC, pupil response, VS, motor activity
    VS=pulse decreases, resps decrease, BP increases, Temp increases.
    Diagnostics= CT scan, MRI, PET
    MANAGEMENT
    Goal is to relieve the ICP by decreasing edema, decrease volume of CSF, decrease cerebral blood volume while still maintaining adequate perfusion.
    Monitoring the ICP
    Intraventricular catheter= ventriculostomy.into lateral ventricle. Allows for drainage. Meds can be instilled. Risks are infection and ventricle collapse.
    Subarachnoid bolt=or screw…hollow device through the skull and dura mater into the cranial subarachnoid space. No ventricle puncture. Negative aspect = blockage leading to decreased accuracy of reading.
    Epidural/subdural catheter= non electrical basis. Low incidence of infection. Can not withdrawal CSF for analysis.
    ***Remember the ventricles are the storage tanks for CSF***
    To decrease the cerebral edema
    Mannitol=and osmotic diuretic to dehydrate the brain tissue. This works by drawing the water across intact membranes. Need strict I&O
    Corticosteroids--dexamethasone is given to reduce the edema
    Fluid restrictions--- to lead to dehydration and hem concentration which is again drawing fluid across the osmotic gradient which will decrease the edema.
    Maintain the cerebral perfusion
    Manipulate cardiac output to provide enough perfusion to the brain. Improve Cardiac output. This is done by fluid volume and inotropic agents= dobutamine hydrochloride. This is checked by monitoring the cerebral perfusion pressure and it should be maintained at 70mmHg or greater.
    Reduce the CSF and intracranial blood volume with drains…but be careful of over drainage can lead to collapse. Hyperventilation of patients is only used for patients that do not respond to the other therapies.
    Control the fever….shivering increases ICP…fever increases cerebral metabolism and edema.
    Reduce metabolic demands
    Barbiturates= Nembutal, pentothal, diprivan. When administering paralyzing agents…..require intubation, arterial pressure monitoring…ICP monitoring.
    ASSESSMENTS based on location in the brain
    ICP on the frontal lobes will lead to Cheyne stokes resps
    ICP in midbrain will lead to hyperventilation
    ICP in stem (pons, medulla) leads to irregular resps and apnea.
    INTERVENTIONS
    Elevate the head of the bead 30-40 degrees as prescribed.
    Avoid Trendelenburg’s position
    Prevent flexion of neck and hips
    Monitor resp status and hypoxia
    Avoid morphine sulfate
    Maintain PaCO2 at 30-35mmHg. This will result in vasoconstriction of the cerebral blood flow vessels, decreased blood flow and a decreased ICP.
    Maintain body temp--anti pyretics ,
    Prevent shivering.
    Decrease environmental stimuli
    Monitor lyte and fluid balance
    I&O
    Limit fluid intake 1200mL/day--decrease edema
    Avoid straining, coughing sneezing
    Avoid valsalva maneuver.
    Seizure precautions--pad rails, have O2 and suction.
  • Avoid straining, coughing sneezing
    Avoid valsalva maneuver.
    Seizure precautions--pad rails, have O2 and suction.


2 comments:

Patti said...

THANK you for taking the time to post this info. helps this stressed out nursing student!

maya said...

Thank you Laura...this is great. will pass on to classmates