Critical Care Exam 3 Guide
Neuro Basics
· Brain metabolism
o Soul source of energy for the brain is glucose. Brain needs glucose to function. Brain cannot
store it, but needs a constant supply. If glucose levels start to fall you will some changed.
o Cerebral glucose < 70 mg/dL = confusion
o Cerebral glucose < 20 mg/dL = damage
· Cerebral blood flow
· Autoregulation
o Changes in pressure
o Changes in CO2
▪ Alters cerebral blood volume with change in blood vessel size
o Ability of the blood vessel in the brain to either constrict or dilate in response to pressure or
CO2 levels
▪ Hypotension or hypoventilating causing hypercapnia BV in brain will dilate and vice
versa try to send more blood and oxygen to brain.
▪ If hypertension or hypocapnia blood vessels in the brain will constrict.
▪ Systolic less than 50 or greater than 160 BV in brain lose the ability to autoregulate.
Neuro Assessment
o GCS, LOC, Memory, speech, Reflexes (babinski with brain injury) which only babies should
have if adult has it this is not good, motor response, sensation , look for aphasia, motor
strength
▪ Concerned with GAS or 8 or lower
o Posturing
▪ Decorticate
· Extremities go toward the body
▪ Decerebrate
· Extremities pull away from the body, more severe, damage to brainstem – this
is the worse posturing
· Cranial nerves
o 1 – Olfactory - Smell
o 2 – Optic - vison, pupil response, visual fields – PERRLA - need flashlight or pen light dim the
lights in room
o 3, 4, 6 - Oculomotor, Trochlear, Abducens - eye movement – 6 fields of gaze “EOM’S”
, o 5,7 – Trigeminal, Facial - corneal reflex touch patients eyeball, on unresponsive patients-
corneal reflex, use gauze or cotton. Touch the eyeball – you want the person to blink as a re-
sponse. Only do the corneal reflex on someone who is unresponsive.
o 8 – Acoustic – hearing - whisper test or just ask the patient questions Just talk to the patient
o 9,10 – Glossopharygeal, Vagus – swallow and gag reflex cough and gag – assess gag take a
tongue depressor. If patient is intubated use suction to assess gag reflex.
o 11 – Accessory – shoulder and neck movement
o 12 – Hypoglossal – tongue movement
· Oculocephalic Reflex (Doll’s Eyes Reflex)
o Usually absent or negative
o Only done on unconscious patients when trying to asses brainstem functioning
o Not done on if spinal cord injury is present or suspected
o Look forward and then move head side to side,
▪ Normal (negative) - eyes will move contralateral (opposite) to the direction the
head moves
▪ Irregular (positive) – eyes do not move, stay fixed. (Sign of brain death)
· Oculovestibular Reflex (Cold Caloric)
o Done on unresponsive patients trying to Asses brainstem functioning. We say its normal or
abnormal.
o Must have intact tympanic membrane
o You need a 50 ml syringe and cool saline
▪ Instill 50ml of cool saline into patients ear
▪ Normal – Eyes will turn toward side you are putting water and go back to center
▪ Abnormal – Eyes do not move (brain death)
Intracranial Pressure
o Components of ICP: brain tissue, blood, CSF fluid
▪ Monro-Kellie doctrine
· Increase in any one component requires a reduction in one or both of other
components to sustain normal ICP.
o Normal ICP: 0-15 mm Hg
o Cerebral Perfusion Pressure (CPP)
▪ How well brain is being profuse
▪ Dependent upon ICP and MAP (CPP = MAP – ICP) Systolic + 2(Diastolic) / 3 =
, · Optimal is 70-100 mmHg
· If less then 70 you can develop ischemia to brain tissue.
· If under decrease BP or increase ICP
▪ If CPP is inadequate, ischemia or infarction can occur
· Increased Intracranial Pressure
Increased metabolic de-
o Associated with many neurological problems mands, fevers, seizures
can also increase in-
o ICP 20mm Hg or greater for 5 minutes or longer
tracranial pressure.
o Results from an increase in any one of the three com- po-
nents:
▪ Increased Blood Volume
· Loss of Autoregulation
· Decreased Oxygenation
· Hypercapnia – cause blood vessels in brain to dilate sending more blood to
brain which can increase pressure
· Obstruction – Ex: Tumor
▪ Increased Brain Volume
· Cerebral Edema
▪ Increased Cerebrospinal Fluid
· Hydrocephalus
o Cardinal (early) sign is changes in LOC
o Pupil changes, respiratory changes are late sign
o Herniation = he dead
▪ Brain usually comes out of foramen magnum
▪ Nurse needs to identify signs early. Prevention es muy importante.
▪ If ICP > 20 for 5 minutes or more herniation can occur.
▪ We need to know the signs to look for to prevent herniation to occur.
ICP Monitoring
· Indications
o Severe head injury, severe neurologic disorder, GCS < 8, Post brain surgery, tumors, strokes
· Purpose
Neuro Basics
· Brain metabolism
o Soul source of energy for the brain is glucose. Brain needs glucose to function. Brain cannot
store it, but needs a constant supply. If glucose levels start to fall you will some changed.
o Cerebral glucose < 70 mg/dL = confusion
o Cerebral glucose < 20 mg/dL = damage
· Cerebral blood flow
· Autoregulation
o Changes in pressure
o Changes in CO2
▪ Alters cerebral blood volume with change in blood vessel size
o Ability of the blood vessel in the brain to either constrict or dilate in response to pressure or
CO2 levels
▪ Hypotension or hypoventilating causing hypercapnia BV in brain will dilate and vice
versa try to send more blood and oxygen to brain.
▪ If hypertension or hypocapnia blood vessels in the brain will constrict.
▪ Systolic less than 50 or greater than 160 BV in brain lose the ability to autoregulate.
Neuro Assessment
o GCS, LOC, Memory, speech, Reflexes (babinski with brain injury) which only babies should
have if adult has it this is not good, motor response, sensation , look for aphasia, motor
strength
▪ Concerned with GAS or 8 or lower
o Posturing
▪ Decorticate
· Extremities go toward the body
▪ Decerebrate
· Extremities pull away from the body, more severe, damage to brainstem – this
is the worse posturing
· Cranial nerves
o 1 – Olfactory - Smell
o 2 – Optic - vison, pupil response, visual fields – PERRLA - need flashlight or pen light dim the
lights in room
o 3, 4, 6 - Oculomotor, Trochlear, Abducens - eye movement – 6 fields of gaze “EOM’S”
, o 5,7 – Trigeminal, Facial - corneal reflex touch patients eyeball, on unresponsive patients-
corneal reflex, use gauze or cotton. Touch the eyeball – you want the person to blink as a re-
sponse. Only do the corneal reflex on someone who is unresponsive.
o 8 – Acoustic – hearing - whisper test or just ask the patient questions Just talk to the patient
o 9,10 – Glossopharygeal, Vagus – swallow and gag reflex cough and gag – assess gag take a
tongue depressor. If patient is intubated use suction to assess gag reflex.
o 11 – Accessory – shoulder and neck movement
o 12 – Hypoglossal – tongue movement
· Oculocephalic Reflex (Doll’s Eyes Reflex)
o Usually absent or negative
o Only done on unconscious patients when trying to asses brainstem functioning
o Not done on if spinal cord injury is present or suspected
o Look forward and then move head side to side,
▪ Normal (negative) - eyes will move contralateral (opposite) to the direction the
head moves
▪ Irregular (positive) – eyes do not move, stay fixed. (Sign of brain death)
· Oculovestibular Reflex (Cold Caloric)
o Done on unresponsive patients trying to Asses brainstem functioning. We say its normal or
abnormal.
o Must have intact tympanic membrane
o You need a 50 ml syringe and cool saline
▪ Instill 50ml of cool saline into patients ear
▪ Normal – Eyes will turn toward side you are putting water and go back to center
▪ Abnormal – Eyes do not move (brain death)
Intracranial Pressure
o Components of ICP: brain tissue, blood, CSF fluid
▪ Monro-Kellie doctrine
· Increase in any one component requires a reduction in one or both of other
components to sustain normal ICP.
o Normal ICP: 0-15 mm Hg
o Cerebral Perfusion Pressure (CPP)
▪ How well brain is being profuse
▪ Dependent upon ICP and MAP (CPP = MAP – ICP) Systolic + 2(Diastolic) / 3 =
, · Optimal is 70-100 mmHg
· If less then 70 you can develop ischemia to brain tissue.
· If under decrease BP or increase ICP
▪ If CPP is inadequate, ischemia or infarction can occur
· Increased Intracranial Pressure
Increased metabolic de-
o Associated with many neurological problems mands, fevers, seizures
can also increase in-
o ICP 20mm Hg or greater for 5 minutes or longer
tracranial pressure.
o Results from an increase in any one of the three com- po-
nents:
▪ Increased Blood Volume
· Loss of Autoregulation
· Decreased Oxygenation
· Hypercapnia – cause blood vessels in brain to dilate sending more blood to
brain which can increase pressure
· Obstruction – Ex: Tumor
▪ Increased Brain Volume
· Cerebral Edema
▪ Increased Cerebrospinal Fluid
· Hydrocephalus
o Cardinal (early) sign is changes in LOC
o Pupil changes, respiratory changes are late sign
o Herniation = he dead
▪ Brain usually comes out of foramen magnum
▪ Nurse needs to identify signs early. Prevention es muy importante.
▪ If ICP > 20 for 5 minutes or more herniation can occur.
▪ We need to know the signs to look for to prevent herniation to occur.
ICP Monitoring
· Indications
o Severe head injury, severe neurologic disorder, GCS < 8, Post brain surgery, tumors, strokes
· Purpose
