Head Injuries and Hypothermia Flashcards
1.7 million TBIs occur annually in the U.S.
__% are classified as concussion
Over half, 65%
Contributes significantly to the death of approximately half of all trauma victims
TBI
Leading causes of TBI
MVC
Falls in the elderly
Scalp contains the following layers
Skin
Connective tissue
Galea aponeurotica (thick fibrous layer that provides structural support)
Periosteum
Skull
Small openings for blood vessels and nerves to pass
Foramina
Brain stem and spinal cord passes through
Foramen magnum
Provides protection to the brain
Skull/cranium
Layers that cover the brain
Meninges
Meninges
Inside the skull, tough fibrous layer, epidural space
Dura mater
Meninges
Closely adhered to the brain
Pia mater
Layered on top of blood vessels adhered to pia
Arachnoid membranes
Surrounds the brain, produced in the ventricular system and functions to cushion the brain
CSF (150ml)
Exert a pressure within the brain, which is referred to as intracranial pressure (ICP)
Brain tissue, blood, and CSF
Portion of dura mater between cerebrum and cerebellum
Tentorium cerebelli
Cranial nerves originate from the:
Brain Stem
Controls pupillary constriction. Crosses surface of tentorium. Hemorrhage or edema that leads to herniation of the brain will compress the nerve. Leading to pupillary dilation.
CN III (oculomotor)
Mean arterial pressure (MAP) =
(systole + diastole x2/3) or diastole + 1/3 pulse pressure
Used to characterize pressure driving blood into the brain
Cerebral perfusion pressure (CPP)
Amount of pressure it takes to push blood through cerebral circulation to maintain oxygen, glucose delivery
Mean arterial pressure (MAP)
CPP =
MAP - ICP
Normal CPP =
70-80 mmHg
CPP
Decreased levels of CO2 lead to:
Vasoconstriction
CPP
Elevated levels of CO2 =
Dilation
Used to lower ICP
Decreases PaCO2 which in turn affects the acid base balance resulting in vasoconstriction
Hyperventilation
Direct trauma to the brain
Primary brain injury
Refers to ongoing injury processes set in motion from primary injury
Secondary brain injury
2-5% of TBI patients have _________ injury which can affect
patient’s ability to properly ventilate
C-spine
The hypoxic brain leads to vasoconstriction and subsequent stimulation of the sympathetic nervous system in an effort to raise BP
Therefore parasympathetic nervous system causes slowing of the heart rate in response
Cushing’s reflex