NUR1211 MEDSURG EXAM 1 & 2 WITH CORRECT
QUESTIONS AND ANSWERS
Cerebral blood flow: - -the amount of blood that passes through 100g of brain
tissue in
... [Show More] 1 minute.
*Normal CBF= 50mL/min/100g bran tissue*
*autoregulation
Autoregulation: - -the brain's ability to alter its blood flow in response to its need
for oxygen and glucose
-also by which brain can alter its vasculature to accommodate for changes in ICP
cerebral perfusion pressure (CPP) - -the pressure gradient that drives CBF to
provide adequate blood flow to the brain
*autoregulation*
Elevated ICPs are defined as: - -those sustained at greater than 20 mmHg.
*At approximately 25 mmHg, increased ICPs begin to manifest as decreased CBF,
decreased CPP, and distortion of brain tissue.*
Drivers of increased ICP include: - o The vasodilatory cascade, triggered by
hypoxia
o Ischemia in acute brain injury
Intracranial pressure (ICP) - -pressure exerted by the volume of the intracranial
contents within the cranial vault; brain tissue, blood, and cerebrospinal fluid (CSF).
*Monroe-Kellie Doctorine*- foundation for understand increased ICP
-changes in volume in one component must reciprocate change in other
components
What is normal ICP? Why must the volume remain constant? - -Normal ICP= 0-15
mmHg
-The fixed nature of the skull is reason the volume of its contents must remain
constant
Examples of structural disruption: *5* - head injury
brain tumor
intracranial hemorrhage
infection
stroke
The presence of space-occupying lesions will cause.. - -compression or
displacement of the other componentgs
hematoma
tumors
edema
hydrocephalus
Compensatory mechanisms to maintain normal ICP: - 1. Changing the volume of the
CSF by decreasing production or altering absorption
2. Compression of brain tissue
3. Alterations in blood volume caused by local changes in cerebral vasculature,
cerebral perfusion pressure, and cerebral blood flow
Conditions that can cause increased ICP include: - o Craniocerebral trauma
o Vascular abnormalities
o Tumors
o Edema
Cerebral edema: - -increase in water content of the brain
Two forms of cerebral edema: - 1. cytotoxic edema
2. vasogenic edema
Results in increased ICP, regardless of form
Cytotoxic edema: - -the accumulation of intracellular water.
-Occurs as a result of a hypoxic or toxic event that damages cells
•Examples include anoxic events such as cardiac arrest or asphyxiation
•Also seen in severe water intoxication caused by hyponatremia
Vasogenic edema (brain) - -an alteration in vascular permeability, with disruption
of the blood-brain barrier. [Show Less]