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ผศ.ดร.กรองได อุณหสูต
คณะพยาบาลศาสตร ์มหาวิทยาลัยมหิดล
Approach to
Head-Injured Patient
Cerebral Blood Flow (CBF)
CO2 CO2
vasodilator
dilation of cerebral vessels
BF
Blood volume
vasoconstriction
BF
Blood volume
O2 concentration
CBF
ผศ.ดร.กรองได อุณหสตู
Intracranial Pressure (ICP)
Cranial vault: Brain 80% + Blood 10% +
Cerebrospinal fluid 10%
Normal intracranial pressure 10 mmHg
Pressure > 20 mmHg is abnormal
ICP CBF and cerebral perfusion
“Monro-Kellie hypothesis”
one volume expands…
one or both of the other 2 volumes must decrease
ผศ.ดร.กรองได อุณหสตู
Cerebral Perfusion Pressure
CPP = MAP - ICP
CPP < 70 mmHg is associated with poor
outcome brain injury.
A systemic mean arterial pressure is 60-180
mmHg
Cushing response = cerebral ischemia; SBP,
wide PP, reflex bradycardia
SBP, maintain CPP do not ICP
ผศ.ดร.กรองได อุณหสตู
Mechanism of injury Injury to the head
Shearing, tensile,
compressive stresses
Hemorrhage,
hematomas, contusions
Sudden deceleration
Impact pressure wave
Coup injury Contrecoup injury
ผศ.ดร.กรองได อุณหสตู
Pathophysiology Injury
Primary injury
Fracture, hematoma
Secondary injury
Autoregulation
Hypercarbia,
cerebral edema,
ICP,
hypotension,
hypoxemia,
Initial damage Compensatory
mechanism
ผศ.ดร.กรองได อุณหสตู
Pathophysiology of head injury
Primary injury
• Directly by the
external force
• Injury evident
on P/E and CT
scan
Secondary injury
• Occurs in the hours
to days following the
primary injury
• Cellular damage;
• Lack of oxygen
delivery
• Increased ICP
ผศ.ดร.กรองได อุณหสตู
Secondary injuries
Hypoxia
Deceased oxygen supply increased cerebral blood volume, increasing ICP
Hypercapnia
CO2 is a potent cerebrovasodilator, increase cerebral blood flow and increased ICP
Hypotension
Overall blood loss contributes cerebral hypoperfusion
Intracranial hypertension
Cerebral edema leads to increased ICP
ผศ.ดร.กรองได อุณหสตู
Cerebral ischemia CPP
Autoregulation
Vasoconstriction / Vasodilation
ICP & CPP
Maintain CPP
Failure of autoregulation
• cerebral vasodilation,
• blood brain volume,
• cerebral engorgement
• cerebral edema,
• blood brain volume,
• ICP, CPP
Cerebral ischemia
ผศ.ดร.กรองได อุณหสตู
Cerebral ischemia
CO2 concentration / O2 concentration
CO2 dilates cerebral blood vessels
blood brain volume
Cerebral ischemia
ICP
Early signs & symptoms
Late signs
• Headache
• Nausea, vomiting
• Amnesia
• Altered LOC
• Restless, change
in speech, loss of
judgment
• Dilate,
nonreactive pupil
• Unresponse to
V/P
• Abnormal motor
• Change in RR
• SBP
• Widened PP
• PR
ผศ.ดร.กรองได อุณหสตู
Categories of traumatic brain injury
Focal brain
injury
• Cerebral
contusion,
epidural,
subdural,
intracerebral
hematoma
Diffuse brain
injury
• concussion,
• Diffuse
axonal injury
Skull fractures
• Linear,
depressed,
comminuted,
basilar
ผศ.ดร.กรองได อุณหสตู
Epidural hematoma Is a focal brain injury resulting in a collection
of blood between the skull & dura mater
Require immediate surgical intervention.
Signs & symptoms:
Initial LOC followed lucid interval rapid
unconscious
Persistent LOC
Hemiparesis or hemiplegia
Unilateral fixed or dilated pupil.
ผศ.ดร.กรองได อุณหสตู
Subdural hematoma
Is a focal brain injury beneath the dura mater
Signs & symptoms:
Steady decline in LOC
Hemiparesis or hemiplegia
Unilateral fixed or dilated pupil.
ผศ.ดร.กรองได อุณหสตู
Subdural hematoma Acute SDH
• Occurs within 48
hrs of initial injury
• Present with loss
of consciousness
and deteriorating
GCS
• Required
emergent
craniotomy for
evacuate of the
thick, coagulated
blood
Sub acute SDH
• Develops 2-24
days after initial
injury
Chronic SDH
• Apearent several
weeks to months
after initial injury
• Headache,
confusion,
speech deficits
be developed if
hematoma
enlarges
ผศ.ดร.กรองได อุณหสตู
Category of head injury
Mild
head injury
• GCS = 13-15
• associated with
loss of
consciousness
or amnesia for
less
• than 1 hour
Moderate
head injury
• GCS = 9-12
• associated with
a loss of
consciousness
for up to a day
Severe
head injury
• GCS less than
or equal to 8
• associated with
loss of
consciousness
for more than
24 hours
ผศ.ดร.กรองได อุณหสตู
1survey to head-injured patient
Step 1
ABCDE
Step 2
Immobilize
Step 3 Brief
neurological exam
Step 1
Inspect
entire head
Step 2
Palpate
entire head
Step 3
Inspect
all scalp
Step 4
Determine
GCS
Step 5
Examine
cervical spine
Step 6
Document
Step 7
Reassess
& observe
2survey to head-injured patient
Those older than 65 years of age
• are at increased risk of bleeding from head
injury because the aging brain shrinks away
from the skull, causing the veins that bridge
from the skull to the brain surface to be more
easily torn.