N470: Cerebral perfusion (exam 2)

Elements of neuro assessment

- Level of consciousness

- Pupillary reaction

- Vital signs (MAP)

Examples of motor impairments (5)

- apraxia- cannot execute movement

- ataxia- poor coordination

-Dyskinesia- impaired voluntary movement

-Hemiplegia

-Nystagmus

Examples of sensory impairments (2)

-Anesthesia

-Paresthesia

cranial nerves

I- olfactory (sensory)

II- optic (sensory)

III- oculomotor (motor)

IV- trochlear (motor)

V- trigeminal (both)

VI- abducens (motor)

VII- facial (both)

VIII- acoustic/vestibular (sensory)

IX- glossopharyngeal (both)

X- vagus (both)

XII- accessory (motor)

XII- hypoglossal (motor)

(Oh Oh Oh To Touch And Feel Very Good Velvet AH)

AND

(Some say marry money but my brother says big brains matter most)

Olfactory (I) function

sensory: smell

Optic (II) function

sensory: vision

oculomotor (III) function

motor: eye movement

trochlear (IV) function

motor: downward and outward eye movement

trigeminal (V) function

sensory: face, sinuses, teeth

motor: muscles of mastication

Abducent (VI) function

motor: outward eye movement (abducts eye)

Facial (VII) function

Sensory: taste

Motor: facial expression, salivation

vestibulocochlear (VIII) function

sensory: hearing and balance

Glossopharyngeal (IX) function

motor: pharyngeal muscle

sensory: posterior tongue, tonsils, pharynx

Vagus (X) function

motor: heart, lungs, bronchi, GI tract

sensory: heart, lungs, bronchi, trachea, larynx, pharynx, GI tract, external ear

Accessory (XI) function

Motor: neck and back muscles

Hypoglossal (XII) function

motor: tongue muscles

Which populations have the highest risk for TBI?

- 75+ yo

- males

PRIORITY neuro assessment pieces for TBI

1) Airway

2) breathing

3) circulation

Airway assessment for TBI (4)

- C-spine precautions

- Loose teeth, vomitus, bleeding obstruction

- edema, neck swelling

- LOC

Breathing assessment for TBI (5)

- Skin color

- Breathing spontaneously

- Respiratory rate/pulse oximetry/ ETCO2

- Chest rise/fall symmetric

- Breath sounds

Breathing assessment for TBI (4)

- Skin color/ temperature

- Pulse

- Blood pressure

- Obvious bleeding

What tool do we use to assess LOC?

Glasgow coma scale

Three categories assessed with GCS

- eye opening

- verbal response

- motor response

How is eye opening scored on GCS?

4: Spontaneous

3: To command

2: To pain

1: None

How is verbal response scored on GCS?

5: Oriented

4: Confused conversation

3: Inappropriate words

2: Incomprehensible

1: None

How is motor response scored on GCS?

6: Obeys command

5: Localizes pain

4: Withdraws from pain

3: Abnormal flexion to pain

2: Abnormal extension to pain

1: None

Mild head injury GCS score

GCS 13-15

Moderate head injury GCS score

GCS 9-12

-mortality 2.5%

Severe head injury GCS score

GCS 3-8

-GCS 5-8 - 12% mortality

-GCS 3-5 - 60% mortality

-GCS 3 - 80% mortality

If over 60 y.o. mortality 75% for any severe head injury

Causes of altered cerebral perfusion (10)

- trauma

- stroke

- tumors

- aneurysms

- seizures

- infections

- hypertension

- hypotension

- drugs

- cardiopulmonary bypass

two types of traumatic brain injury

blunt and penetrating

traumatic brain injury with no opening in the skin or communication with the environment; motor vehicle crash, assault, fall

blunt traumatic injury

traumatic brain injury in which a foreign object penetrates the body; gunshot, stabbing, impalement

penetrating traumatic injury

Examples of blunt traumatic injury

- Skull fracture

- Concussion

- Contusion

- Hematoma (Epidural, Subdural, Intracerebral)

- Diffuse axonal injury (DAI)

Skull fracture types (5)

linear, depressed, comminuted, simple, compound, basilar

skull fracture type- A break in the bone but no displacement; usually from low velocity injury

linear

skull fracture type- Inward indentation of the skull, requires a powerful impact

depressed

skull fracture type- Can be linear or depressed; no fragmentation or communicating lacerations; from low/moderate impact

simple

skull fracture type- Multiple linear fractures with fragmentation of bone into many pieces; from direct, high momentum impact

comminuted

skull fracture type- Depressed fracture and scalp laceration with communicating pathway into the intracranial cavity, severe injury

compound

signs of a basilar skull fracture

1. Raccoon eyes

2. Battle sign- bruising behind ears

occurs after blow to the head hard enough to move the brain within the skull

concussion

occurs after a more severe injury when the brain rebounds against the skull from the force of a blow (a beating with a blunt instrument). Injury is directly beneath the site of impact.

contusion

How does a CT scan look for a concussion vs a contusion

Concussion: cannot see

Contusion: may see diffuse bleeding

Shearing damage to the pathways (axons) that connect the different areas of the brain; this occurs when there is twisting and turning of the brain tissue at the time of injury; brain messages are slowed or lost, torn axons cannot be repaired

Diffuse axonal injury (DAI)

a victim of assault who has been hit in the head with a baseball bat would most likely suffer which type of injury?

a) penetrating injury

b) deceleration injury

c) acceleration injury

d) rotational injury

c) acceleration injury- caused by movement of the brain within the unrestrained head (whiplash injury)

Types of stroke (+ which is most common?)

ischemic (most common) and hemorrhagic

causes of hemorrhagic stroke

- Aneurysms

- Drugs

- Hypertension

causes of ischemic stroke

- drugs

- hypotension

Which populations have the highest risk/incidence for stroke?

- 65+ yo

- stroke belt- southeastern US

types of ischemic stroke

- thrombotic: begins with a clot

- embolic: clot on the move

types of hemorrhagic stroke

- subarachnoid hemorrhage- rupture of stressed vessel, aneurysm or vascular malformation

- intracerebral

Stroke assessment (7)

- decreased consciousness, changing personality

- drooping mouth & eyelid

- paralysis or weakness on one or both sides

- arm Drift, possible seizures

- pupillary changes & B/P HR RR

- nausea & Vomiting

- pain

Stroke assessment tools (2)

- BE FAST- balance, eyes, facial droop, arm drift, speech difficulty, time to call

- National institute of health stroke scale (NIHSS)- higher number = more severe stroke

How is a stroke diagnosed? (7)

- CT Scans

- MRI

- Lumbar Puncture

- Doppler Ultrasonography & Duplex Imaging- assessing for Carotid Artery Disease, DVT; SAH: transcranial doppler for vasospasm

- Echocardiogram - PFO or other abnormalities

- 24 hours of continuous cardiac monitoring - paroxysmal atrial fibrillation

- CT Angiography - Assessing for Vasospasm

Medical management for a stroke (6)*

1) Optimize cerebral oxygenation – “maintain a patent airway”- restore cerebral blood flow!

2) Manage BP and Temp

3) Minimize risk of stroke recurrence–anti-coagulant, anti-platelet meds

4) Prevent aspiration

5) PT/OT as soon as possible

6) Seizure precautions

medical management of ischemic stroke (4)

1) Infusion of (rtPA) tissue plasminogen activator within 3 hours of onset

2) Mechanical Thrombectomy (surgical coil retriever or aspiration device)

3) Anticoagulant Medications

4) Cerebral Edema - Mannitol

Medical management for hemorrhagic stroke

- prevent vasospasm

- prevent obstructive hydrocephalus

- surgery- craniotomy, craniectomy, aneurysm clipping/coiling

- burr holes

how to prevent vasospasm in hemorrhagic stroke patients?

1) calcium channel blockers: Nimodipine, Verapamil injection

2) triple H therapy: Hypertension, hypervolemia, hemodilution

Medical management of Obstructive Hydrocephalus from hemorrhagic stroke

External Ventricular Drain (EVD) AKA "Ventriculostomy"

craniotomy vs craniectomy

Craniotomy-Bone flap returned

Craniectomy-Bone flap NOT returned

aneurysm clipping vs coiling

clipping- more durable

coiling- minimally invasive, shorter recovery time

Is the epidural hematoma a venous or arterial bleed?

arterial

what is the most common source of an epidural bleed?

middle meningeal artery?

Why does the epidural hematoma form the shape of a lens (convex) on CT/MRI?

The expansion stops at skull's sutures, where the dura mater is tightly attached to the skull.

bleeding Between the skull and the outer endosteal layer of the dura mater

epidural hematoma

sources of epidural hematomas (4)

-Temperoparietal locus (most likely) - Middle meningeal artery

- Frontal locus - anterior ethmoidal artery

- Occipital locus - transverse or sigmoid sinuses

- Vertex locus - superior sagittal sinus

Symptoms of an epidural hematoma

finish

Is the subdural hematoma a venous or arterial bleed?

venous

Is the subdural hematoma acute, subacute or chronic?

finish

Are acute hematomas a surgical emergency?

finish

Bleeding between the dura and the arachnoid layers

Subdural Hematoma

Source of Bleed in a Subdural Hematoma

bridging veins

How does a Subdural Hematoma appear on a CT?

Crescent-shaped

symptoms of a Subdural Hematoma?

Gradually increasing headache and confusion

bleeding into the subarachnoid space.

Subarachnoid Hemorrhage

causes/ risk factors for a SAH?

-Smoking, heavy drinking, illicit drugs

-Genetics

-People between 30 and 40 years of age

-More common in women than men - unknown etiology

tests for SAH diagnosis

CT, CTA

Lumbar Puncture

MRI (later)

Treatment for a SAH

finish

Nursing care for SAH

finish

Other than trauma what causes an intracerebral bleed?

abnormalities of blood vessels like aneurysm or angioma

What is a brain shear?

finish

Internal bleeding can occur in any part of the brain

intracerebral hemorrhage

Shear forces from brain movement commonly cause vessel laceration and hemorrhage into the ______________.

parenchyma

A subarachnoid hemorrhage is the accumulation of blood between the:

a) dura and the arachnoid layers of the meninges

b) dura mater of the skull

c) parenchyma of the brain

d) meningeal arachnoid layer and the brain

d) meningeal arachnoid layer and the brain

diffused axonal injury occurs when the brain:

a) twists and turns during time of injury

b) shifts forward and back during injury

c) experiences coup-contrecoup injury

d) bleeds below the Dural layers of the brain

a) twists and turns during time of injury

A diffuse axonal injury may be difficult to visualize on a CT/MRI because:

a) the shearing is too small to notice

b) the injury does not disrupt the structure of neurons

c) it can occur without bleeding

d) this type of injury is not serious

c) it can occur without bleeding

The skull is a rigid compartment filled to capacity with essentially non-compressible contents; If volume rises in one compartment, there must be a decrease of volume in one of the remaining compartments for pressure to remain unchanged

Monroe-Kellie hypothesis

what are the components inside the cranium, and how much space do they take up? (Monroe-Kellie hypothesis)

Brain 80%

Blood 10%

CSF 10%

Types of brain herniation (6)

-Midline shift

-Uncal/Lateral (only time where pupillary changes are first sign)

-Transtentorial/Central

-Through Fracture

-Foramen Magnum (deadly)

-Space-occupying

normal ICP

0-15 mmHg

increased ICP

Persistent increase ≥20 mm Hg for >5 min

ICP must be maintained within normal limits to maintain adequate _____

CPP

a compensatory mechanism to keep cerebral blood flow constant; Cerebral blood vessels automatically constrict or dilate to maintain adequate cerebral perfusion pressure (CPP); MAP, CO2 & O2 levels drive this process

Auto-regulation

In auto-regulation, cerebral blood vessels constrict with ______ MAP, but dilate with _____ MAP; as CO2 rises and/or O2 falls, cerebral blood vessels _______ .... and vice versa

In auto-regulation, cerebral blood vessels constrict with high MAP, but dilate with low MAP; as CO2 rises and/or O2 falls, cerebral blood vessels dilate …. and vice versa

what is the zero point for the ICP transducer on the ventriculostomy?

lateral ventricles (tip of the ear)

CPP (cerebral perfusion pressure) formula*

CPP= MAP-ICP

MAP formula*

(SBP + 2DBP)/3

Normal CPP*

80-100 mmHg*

What does a CPP blow 70 lead to?*

ischemia and death*