Week 5: Cerebral dysfunction Flashcards
Brain uses what for metabolism?
glucose and oxygen
Autoregulation is the brains ability to? When does it shut down
- maintain constant cerebral blood flow
- less than 60, greater than 160 systolic, or cerebral perfusion suboptimal
Arterial is the ? system in the brain
High Pressure System
Thinner & more fragile
Carotid & Vertebral arteries supply blood to the brain
Circle of Willis: where blood flows up and is able to flow over to the oppposite side
Venous is the ? Pressure System
Low pressure system
- Lack valves
- Compress easily with Increase Pressure
Cerebral Perfusion Pressure
- CPP= MAP –ICP
- Normally greater than 50
- Less than 50 indicates loss of autoregulation
Monro Kellie Hypothesis
Changes in the brain volume result in
Increased ICP
(or) decrease in one of the other volumes
VIC
Volume brain + Volume of Blood + Volume of CSF + Volume of Lesion
Compliance is the attempt to ?
- Compliance is the attempt to maintain the ICP between 5-15 mm/hg
- CSF displacement
- CSF reabsorption
- Venous compression and blood shunting
Cerebral Autoregulation helps?
ensure optimal CBF
Decrease in CBF leads to?
- Ischemia
- Build-up Lactate (does not cross blood brain Barrier)
- Ultimately cerebral acidosis
Hyperemia
- Is increased blood flow to brain. Causes arterial congestion
- Luxury Perfusion
- Progressive vasodilation
- Increased CBF
- Loss of Autoregulation: Increased ICP
Conditions That Affect CBF & CBV
Increase CBF/CBV
- Hypertension
- Fever
- Pain
- Hypercapnia
- Ischemia
- Cerebral vasodilation
Decrease CBF/CVP
- Hypotension
- Sedation
- Paralysis
- Hypocapnia
- Cerebral edema
- Decrease CO
- Cerebral vasoconstriction
Cerebral Spinal Fluid
What percent of volume?
How much volume
Pressure?
functions?
- Approximately 10% of Cerebral Volume
- Volume = 150 ml
- Pressure = 3-13 mm/Hg
- Functions: Cushion brain & spinal Cord, Stable chemical milieu, Assist in the excretion of toxic waste
Confusion
Disorientation differences?
disorientations: agitation and anxiety plus the confusion
obtunded
responses are slower
stupor
only respond with painful stimuli
coma
don’t respond to painful stimuli
Vowel- TIPPS
Common Reasons for altered LOC
Vowel-Tipps
- Alcohol
- Epilepsy
- Insulin
- Opiates/drugs
- Uremia
- Trauma
- Temperature
- Infection
- Psychogenic
- Poisin
- Shock-Stroke
Glascow coma scale
- Looks at eye opening, verbal response, motor response.
- Higher the score the higher the function
- Score less than 9=concern
Neuro Checks how often and what?
- Vital Signs Q15 minutes
- Glasgow Coma Score Q15 minutes
Reasons for pupil abnormalities
- hypoxia
- hypothermia
- orbital trauma
- pharmacological treatement (atropine)
- cataract surgery
- seizures
- hypotension
- illegal drug use
- toxic exposure
- artificial eye
- cerebral edema
- congenital abnormality
- severe TBI
decerebate
decorticate
as intercranial pressure increases what happens to pupils?
- 1st decrease in one sided response
- then fixed pupils that are not bilateral or responsive to light. Usually dilated
What is a positive Dolls Eyes?
turn the patient and the eyes stay fixed straight. Head goes sideways and eyes go sideways too
Caloric Ice Test negative and positive findings?
- insert 20 ml of cold water into the ear. You expect to see the eyes start moving, and then they fix over to the side you put the ice water in. This would be a normal response and a negative eyes test
- abnormal response is the eyes staying fixed
Cranial Nerve Assessment
- Corneal: stick something on cornea, they blink (normal)
- Gag
- Swallow
- Cough
Type of breathing assoc with problem:
- Cheyne-Stokes
- Cheyne-Stokes variant
- Central neurogenic hyperventilation
- Apneustic
- Ataxic
- Cheyne-Stokes: large bilateral supratentorial
- Cheyne-Stokes variant:large unilateral
- Central neurogenic hyperventilation: large bilateral partial
- Apneustic: large bilateral midpontine
- Ataxic: large bilateral posterior fossa
S/S of Increased ICP infants, children
Infants
- Bulging fontanel
- Separated cranial sutures
- Cracked-pot sign: bang on head, sounds like a hollow pot (extra fluid)
- Setting-sun sign: eyes are low set and whites are showing above it
- Positive transillumination
Children
- c/o headaches, projectile vomiting, and new seizure onset activity
Late signs for infants and children of increased ICP
- Bradycardia
- Decreased sensory/motor response
- Alterations in PERRLA
- Cheyne –stokes respirations
- Papilledema
- Decreased LOC/ Coma
Early Signs of ↑ ICP
- Slight LOC changes ***MOST IMPORTANT****
- Pupils sluggish / Impaired eye movement
- Limb strength changes
- Headache
ICP Peaks?
48 – 72 hours after injury
Cushing’s Triad: Signs of ↑ ICP
Blood Pressure
- Systolic BP Increases - Diastolic BP Decreases - Pulse Decreases
Widening Puse Presure
Bradycardia
Might also see cheyne-stokes breathing and elevated temperature
Brain Herniation occurs when
a part of the brain pushes downward inside the skull through the opening that leads into the neck
(Foramen Magnum)
Burr holes
Will burr holes in skull to allow pressure to be relived and the fluid will come out through the burr holes
How To Minimize Cerebral Edema?
Maintain
- Cerebral perfusion pressure
CPP of 50 – 70 mm Hg
- Prevents Hypoxia (Hypercarbia)
UNCAL Herniation Early, mid, and late
_Early herniation (potentially reversible):_ -LOC may not be impaired initially
Herniation to the Midbrain/Upper Pons:
-Deep Coma, Dolls eyes, pupils fixed, posturing, hyperventilation, wide pulse pressure
Herniation to the Medulla (Late phase of Uncal Herniation):
- irreversible (terminal)
- Deep Coma
- no pupillary response
- cluster or apneic
- pulse pressure starts to narrow again
Lumbar Puncture
Used to diagnose:
- Meningitis
- Guillain-Barre syndrome
- multiple sclerosis
- Cancers of the brain & spinal cord.
-Insert large bore needle, it’s a sterile proceedure. Keep them laying flat after and watch them for headache (very severe). If happens, they’ll do a blood patch to put fluid back into the space to reduce the headache
Ventricular Puncture
Used to remove excess CSF and reduce ICP pressure
EEG
Used to:
- Electrical Activity
- Identify seizure activity
- Determine Brain Death
Nuclear Brain Scan
Used to
- Identify brain lesions, encephalitis, and subdural hematomas
Encephalography
Used to
- Identify shifts from midline
- May show ventricular dilation
Radiography
Used to
- Show Fractures
- Suture separation pediatric population
*
CT Scan
Show Horizontal and Vertical Cross Sections
PET Scan
Used to
Show Blood Volume
MRI
Show tissue discrimination
Intercranial monitoring indications
- Severe Head Injury
- GCS 3-8 (less than 9)
- Abnormal Imaging
- SBP less than 90 mm/hg
- Subarachnoid hemorrhage
- Hydrocephalus
- Brain tumors
- Stroke
- meningitis
contraindications for ICP
- Central nervous system infection
- Coagulation defects
- Anticoagulant therapy
- Scalp infection
- Severe midline shift resulting in ventricular displacement
- Cerebral edema resulting in ventricular collapse
Intraventricular monitoring advantages and disadvantages
*gold standard*
Advantages
- Allows for CSF drainage
- Provides direct measurement of CSF pressure
Disadvantages
- Most Invasive
- High risk for infection/ hemorrhage/ infection
- Contraindicated with coagulopathies
subarachnoid advantages/disadvantages
Advantages
- Less invasive
- Easy to place
- Low risk of infection
- Able to sample CSF
- Can be used if ventricles are not able to be cannulated
Disadvantages
- Unable to drain CSF
- Decreased accuracy with time
- Needs frequent recalibration
- Easy to be obstructed with bone/tissue
Intraparenchymal advantages/disadvantages
advantages
- Easy placement
- Low risk of infection
- Highly accurate
disadvantages
- Unable to drain CSF
- Needs a separate monitoring system
- Catheters kink easy
- Risk of hemorrhage/ infection
- Can not be re-zeroed
Epidural Probe advantages/disadvantages
advantages
- Easy placement
- Low risk of infectin
disadvantages
- Unable to drain CSF
- Can not be re-zeroed
- Accuracy questionable
Noninvasive ICP Monitoring
new technique
- uses special glasses and measures icp, you can also visualize the waveform
- applies pressure to the eye
- accurate, safe, easy to use
- can actually measure one side versus the other
- Disadvantage is you cannot remove fluids
normal icp for adults
normal is 15
maintaning ICP
- Q 1hour Neuro Checks
- Monitor MAP, ICP, CPP (MAP-ICP)
- Monitor ICP wave Forms
- Strict Asepsis
- Assess ICP site
- Watch for CSF leaks (ear, see halo with the fluid)
- Watch for Blood in the ICP monitoring system (should never see blood in there)
Never use a ? for ICP monitoring
- never use a flush device. Use only sterile 0.9% NaCl to fill the pressure tubing.
- Never use a heparinized solution.
Patients are maintained in a ? head up and neutral position when necessary to minimize the ICP.
30-45 degree
Avoid ? of the neck and positioning the patient in a Trendelenberg position, all of which may increase ICP.
flexion and hyperextension of the neck
simultaneous drainage and pressure monitoring is ?
Simultaneous drainage and pressure monitoring is not recommended. To ensure precise pressure measurements, perform only pressure monitoring while keeping the stopcock closed to the drainage system.
Peak 1
choroidal plexus pulsations: percussion wave
peak 2
tidal wave
high peaked wave with little differentiation between peak s means?
intercranial pressure is rising
peak 3
dicrotic wave
ICP monitor level
- head 30 degrees
- ear in line with transducer
- leveler is at 90 degrees (upright)
Dampened, absent, distorted waveform potential source and action
potential source
- Catheter occlusion
- Air bubbles in system
- Loose connections
- Need for recalibration
- Fiber optic cables broken
- Kinked tubing
- Dislodgement of catheter
action
- Remove any air from system
- Tighten all connectors
- Recalibrate and zero
- Check for kinks
- Replace transducer, fiber optic device, or monitoring device
ICP values suspect potential source and action
potential source
- Recalibration and zeroing needed
- Catheter/ transducer placement incorrect
action
- Recalibrate and zero
- Correct placement of transducer
leakage of fluid from tubing potential source and action
potential source
- Loosened connections
action
- Tighten all connectors
suctioning with ICP
- Contraindicated unless necessary: Cough & valsalva increase ICP
- If required: Be brief, Pre/post oxygenate with 100% FiO2
pharmacological interventions for ICP
Osmotic Diuretics
- Mannitol: Pulls fluid into the cerebral vascular space
- Reduces cerebral blood viscosity
- Increases cerebral blood flow
- Increased cerebral oxygen delivery
- Dosage: 1.0 gm/kg
- Nurse considerations: Watch serum osmolality
Pain control: Opioids
Sedatives: Used to reduce cerebral metabolic rate
- Benzodiazepines
- Propofol
Paralytics: to decrease workload deman
- Vecuronium
- atracuronium
Targeted Temperature Management in ICP
- Reduces ICP
- Decrease levels of excitatory neurotransmitters
- Cerebral edema
- Free radicals
- Cerebral metabolic rate
- 33 degrees celcius
Nursing management of targeted temperature management
Monitor for S/S of:
- Shivering
- Arrhythmias
- Coagulopathies
- Hypothermia-induced diuresis
- Electrolyte imbalance
- Hiccoughs
- Rewarming slowly
Seizure Precautions
-Seizures are very common with increased ICP
Phenytoin may be initiated with
- GCS less than 10
- Cortical Contusions
- Depressed skull fractures
- Subdural, epidural and intracerebral hematomas
- Penetrating head injuries
- A seizure within the first 24 hours post injury
Nursing considerations: Safety
- Oral airway
- Side rails padded
- Suction and oxygen set-up
- Patient/ family teaching
- Administration and monitoring of pharmacological interventions
ALL Cranial Injury things to do?
*ATLS (asvance trauma life support)evaluation & intervention
(ABCs / Foley / NG / oxygen / Maintain traction)
*Constant Monitoring
*Diagnosis:
- CT scan (FAST!)
- MRI
- PET Scan (brain function assessment)
*Medical interventions depend on severity:
- Endotracheal intubation / hyperventilation
- Sedation
- Diuresis
- Rapid surgical evacuation
Normal pupil reactivity prior to surgery is associated with ?
Normal pupil reactivity prior to surgery is associated with a favorable outcome in 84 -100% of patients
When both pupils are dilated, outcome?
When both pupils are dilated a poor outcome or death occurs in the great majority of individuals
Postoperative seizures are ? in ICP patients
Postoperative seizures are relatively common in these patients
In general, a favorable (functional) outcome is more likely in those patients who are?
In general, a favorable (functional) outcome is more likely in those patients who are treated very soon after injury, those who are younger adults, those with a higher GCS (above GCS of 6 or 7), those with reactive pupils, those without multiple cerebral contusions and those who do not develop difficult to control raised intracranial pressure
Nursing Interventions for Acute Head Injury
- Continuous monitoring of Vitals, PERRL and Glasgow Coma Score
- Report client condition changes ASAP
- Maintain airway patency- positioning, suctioning (if necessary)
- Minimize cerebral edema
- Maximize cerebral perfusion
- Implement seizure precautions / Siderails
- Provide emotional support
- Address all self-care deficits
how to optimize cerebral perfusion?
- Keep head position midline
- HOB elevated ( 30 - 60 degrees )
- Oxygen ****
- Sedate prior to activity
- Minimal ADL movement of client
What to teach client and family for ICP?
- Minimal stimulation environment
- No coughing, no straining, no hard laughing
- Head midline + Bedrest + HOB elevated
- S & S to report to nurse ASAP (Headache, drainage, etc)
- Purpose + frequency of neuro checks
- Medication regime (Narcotics, diuretics, stool softeners, etc)
- Medical interventions (Tests, traction, logrolling, surgery, etc)
