Assessment and nursing management of neurological compromise Flashcards
When the body is resting it uses what percentage? of oxygen and glucose?
20-25%
Interruption to blood blow causes irreversible damage within how much time?
3-8mins
What is autoregulation?
It is a way of maintaining brain blood flow despite changes in cerebral perfusion pressure. it is a major physiological regulatory process, whereby an increase in blood flow to an organ or tissue engenders vasoconstriction and a sustained increased vascular resistance.
What is cerebral perfusion pressure?
The pressure required to deliver adequate oxygen and glucose
How do we detect when autoregulation is lost?
When CPP (Cerebral perfusion pressure) is outside the range of 60-160mmhg.
What type of pressure test do we do to check if autoregulation is lost?
The CPP - Cerebral perfusion pressure
If autoregulation is lost what does the brain do to compensate?
The brain relies on mean arterial pressure (MAP) to maintain its blood supply. This will mean that if this patient sustains a brain injury and their blood pressure drops too low, there will not be enough pressure to drive the blood around the brain hence cause brain tissue hypoxia and furthermore death
Severely low levels of oxygen and glucose in the brain will cause what?
Brain tissue hypoxia and death
What are the main elements that generate intracranial pressure?
Brain tissue, blood volume and cerebrospinal fluid (CSF)
What happens when there is increased intracranial pressure?
A sudden increase in the pressure inside a person’s skull is a medical emergency. Left untreated, an increase in the intracranial pressure (ICP) may lead to brain injury, seizure, coma, stroke, or death.
If brain tissue increases what elements will counteract and decrease and why does this occur?
Intracranial blood and cerebrospinal fluid will decrease to maintain a normal intracranial pressure
If intracranial blood increases what elements will counteract and decrease and why does this occur?
Brain tissue and cerebrospinal fluid decrease to maintain normal intracranial pressure
If cerebrospinal fluid increases what elements will counteract and decrease and why does this occur?
Brain tissue and intracranial blood decrease to maintain a normal intracranial pressure
What is the Monro-Kellie doctrine?
The Monro-Kellie doctrine, or hypothesis, is that the sum of volumes of brain, CSF, and intracranial blood is constant. An increase in one should cause a decrease in one or both of the remaining two.
What is a brain herniation?
Brain herniation occurs when something inside the skull produces pressure that moves brain tissues. This is most often the result of brain swelling or bleeding from a head injury, stroke, or brain tumor.
What is cushings triad?
Cushing’s triad refers to a set of signs that are indicative of increased intracranial pressure (ICP), or increased pressure in the brain.
What does cushings triad consist of?
Bradycardia, irregular respirations, and a widened pulse pressure. A widened pulse pressure occurs when there is a large difference between the systolic and the diastolic.
Increasing ICP (Intracranial pressure) results in what?
A lack of oxygen in brain tissue and a restriction of cerebral blood flow in the brain.
Increasing ICP (Intracranial pressure) is caused by what?
Head injurys, bleeding in the brain, tumors, infections, strokes, excess cerebrospinal fluid or swelling in the brain
Increasing ICP (Intracranial pressure) activates which reflex?
The cushing reflex
As ICP (intracranial pressure) increases it eventually becomes greater than - what other pressure?
The mean arterial pressure which typically must be greater that intracranial pressure in order for the brain to be adequately oxygenated.
What is brain ischemia?
a condition that occurs when there isn’t enough blood flow to the brain to meet metabolic demand. This leads to limited oxygen supply or cerebral hypoxia and leads to the death of brain tissue, cerebral infarction, or ischemic stroke.
When the brain is not receiving enough oxygen it activates which nervous system and does what?
The sympathetic nervous system
This increases system blood pressure and an initial increase in heart rate.
The increase in BP signals the cartoid and aortic baroreceptors
Which activate the parasympathetic nervous system
Causing the heart rate to decrease
What are some indications of a worsening prognosis of increasing intracranial pressure?
Irregular respirations followed by periods where breathing ceases completely