Intracranial Regulation Flashcards
Meninges
Membrane covering the brain and spinal cord and protects these structures
Blood brain barrier
Allows certain molecules to pass through to the brain and prevents neurotoxic substances from reaching the brain
Parts of the meninges
- Dura mater
- Arachnoid layer
- Pia mater
Cerebral spinal fluid (CSF)
Surrounds the brain to cushion and support brain and provide nutrients
CSF nutrients (6)
- Potassium
- Protein
- Sodium
- Chloride
- Bicarbonate
- Glucose
Autoregulation
- Brain alters its own vasculature to accommodate changes in ICP to ensure consistent CBF
- Doesn’t work if MAP is <65 or >150
Monro Kelli hypothesis
Brain, CSF, blood are contained in a fixed vault (skull) and total volume must remain constant and change in 1 component mandates change in the other components
Blood amount in brain
12%
Brain amount
80%
CSF amount in brain
8%
Intracranial pressure (ICP)
brain swelling or cerebral edema
Normal ICP
5-15
Elevated ICP
Sustained >20
Cerebral Perfusion Pressure (CPP)
Amount of pressure needed to maintain blood flow to the brain
CPP calculation
MAP - ICP
Goal CPP
60-70
What is associated with a CPP <50
Ischemia, neuronal death
Causes of increased CSF (3)
- Reduced CSF reabsorption
- Increased CSF production
- Obstructed CSF flow
Causes of increased blood (3)
- Hypercapnia
- Venous outflow obstruction
- Vasodilation of cerebral blood vessels
Causes of increased brain matter (4)
- Cerebral edema
- Space occupying lesions
- Abscesses
- Hematoma
Perfusion related ICR dysregulation (3)
- CVA
- Severe hypotension
- Trauma
Neurotransmission related ICR dysregulation (6)
- Alzheimer’s
- Drugs/toxins
- TBI
- Stroke
- Infection
- Genetic abnormalities
Pathological processes related to ICR dysregulation (3)
- Brain tumors
- Degenerative diseases
- Inflammatory conditions
Factors influencing ICP (9)
- BP
- Oxygenation
- Posture
- Coughing
- Hip flexion
- Temperature
- Blood gases
- Intra-abdominal pressure
- Intra-thoracic pressure
S/S of ICP (13)
- Headache
- Decrease LOC
- Nausea
- Projectile vomiting not preceded by nausea
- Altered breathing patterns
- Dilated pupils
- Pinpoint, non-reactive pupils
- Fixed, unilateral, dilated pupil (blown pupil)
- Diplopia
- Blurred vision
- Seizures
- Deteriorating motor function
- Cushing’s triad
Cushing’s triad
- Systolic HTN with widened pulse pressure
- Bradycardia
- Irregular respirations
Brain herniation
Shift of brain tissue from normal location into adjacent space
National Institute of Health Stroke Scale (NIHSS) components (12)
- LOC
- Best gaze
- Visual field testing
- Facial palsy
- Motor function arm
- Motor function leg
- Limb ataxis
- Sensory
- Best language
- Dysarthria
- Extinction and inattention
- Distal motor function
Decerebrate
Abnormal extension
Decorticate
Abnormal flexion
Glasgow coma scale: Eye opening response
- 4: spontaneous
- 3: to voice
- 2: to painful stimuli
- 1: no response
Glasgow coma scale: verbal response
- 5: oriented to person, place, time
- 4: confused
- 3: inappropriate words
- 2: incomprehensible sounds
- 1: no response
Glasgow coma scale: motor response
- 6: follows commands
- 5: moves to localized pain
- 4: flexion withdrawal from pain
- 3: abnormal flexion
- 2: abnormal extension
- 1: no response
ICP catheters are contraindicated in what patients
- Concurrent use of anticoagulants
- Bleeding disorders
- Scalp infection
- Brain abscess
Nonpharmacological ways to lower ICP (6)
- Elevate head of bed >30 degrees
- Keep head/neck midline
- Decrease stimulation
- Hyperventilate
- Adequate oxygenation
- NG tube suctioning
Pharmacological ways to lower ICP (7)
- Osmotic diuretic
- 3% hypertonic saline
- Sedatives
- Analgesics
- Antiepileptics
- Antipyretics
- Stool softeners
Osmotic diuretic (Mannitol)
Sugar alcohol that draws fluid from the brain into the blood to decrease cerebral edema
Nursing interventions for Mannitol
Monitor fluid and electrolytes
3% hypertonic saline
Moves water out of cells and into the blood to decrease cerebral edema