Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
45 Cards in this Set
- Front
- Back
|
What is normal intracranial pressure and what are the normal values? Lewis pg 1492
|
ICP is the presure that 3 different components (brain, tissue, CSF, & cerebral blood volume) exert inside the rigid, unyeilding skull.
Normal ICP values: 0-15mmHg Normal values: 60-150 mmHg/H2O |
|
|
What is the significance of IICP? Lewis pg 1493
|
IICP is a life-threatening situation that results from an increase in any or all of the 3 components (brain tissue, blood, CSF) of the skull. Cerebral edema is an important factor contributing to IICP.
|
|
|
what are 3 types of cerebral edema, explain briefly. Lewis pg 1493-1494
|
Vasogenic Cerebral Edema: (Most common type of edema)occurs mainly in the white matter and is attributed to changes in the endothelial lining of the cerebral cappilaries.
Cytotoxic Cerebral Edema: results from local disruption of the functional or morphologic integrity of cell membranes and occurs most often in the gray matter. Interstitial Cerebral Edema: is the result of periventricular diffusion of ventricular CSF in a patient with uncontrolled hydrocephalus. It can also be caused by enlargement of the extracellular space as a result of systemic water excess (hyponatremia) |
|
|
What is CPP and how do changes effect the patient?
*Class notes and Lewis pg1492 |
CPP or cerbral perfusion pressure is the pressure needed to ensure blood flow to the brain or simply the pressure at which the blood perfuses the brain cells.
MAP<50mmHg will reduce CPP and may result in hypoxia, vascular collapse, and cellular death. CPP below 60mmg will result in irreversible ischemia. When cerebral perfusion falls to 0 there is no cerebral blood flow. |
|
|
What is the formula to calculate CPP?
Lewis pg 1492 |
CPP=MAP-ICP
MAP=SBP+2(DBP)/3 |
|
|
What is the effects of cerebral blood flow in regards to the factor of: CO2
Lewis pg 1493 |
The partial pressure of arterial carbon dioxide (PaCO2) is a potent vsoactive agent. An increased in PaCO2 relaxes smooth muscles, dilates cerebral vessels, decreases cerebrovascular resistance and increases CBF. Alternately, a decrease in PaCO2 reverses this process and decreases CBF.
|
|
|
What is the effects of cerebral blood flow in regards to the factor of: Oxygen
lewis pg 1493 |
Cerebral oxygen tension below 50mmHg results in cerebral vascular dilation. This dilation decreases cerebral vascular resistance, increases CBF, and raises oxygen tension. However, if oxygen tension is not raised, anaerobic metabolism begins, resulting in an accumulation of lactic acid.
|
|
|
What is the effects of cerebral blood flow in regards to the factor of: Hydrogen ion concentration
Lewis pg 1493 |
As lactic acid increases and hydrogen ions accumulate, the environment becomes more acidic. Within this acidic environment, further vasodilation occurs in a continued attempt to increase blood flow. The combination of a severly low arterial oxygen pressure (PaCO2) and an elevated hydrogen ion concentration (acidosis), which are both potent cerebral vasodilators, may produce a state where in autoregulation is lost and compensatory mechanisms fail to meet tissue metabolic demands.
|
|
|
Decribe how a change in LOC is related to an increase in ICP
Lewis pg 1494 |
Occur as a result of compression of the ascending reticular activating system pathways and the resulting hypoxia of the cells of these tissues as well as the cells of the cortex. As compression increases the patient becomes more difficult to arouse. Assessment is based on the extent to which he is oriented and able to respond.
|
|
|
Decribe how a change in VS is related to an increase in ICP
lewis pg 1495 |
Occur very late in the process of cellular hypoxia and indicate that pressure is being exerted on the lower brain stem and medulla. If not relieved, these changes quickly accelerate and death ensues.
|
|
|
Decribe how a change in ocular signs is related to an increase in ICP
lewis pg 1495 |
Changes in pupil size, equality, and reaction to light, and extraocular movements are indicative of compression of the third, fourth, and sixth cranial nerves.
|
|
|
Decribe how a change in decrease in motor function is related to an increase in ICP lewis pg 1495
|
As the ICP continues to rise, the patient manifests changes in motor ability. A contralateral hemiparesis or hemiplegia may be seen, depending on the location of the source of the increased ICP. If painful stimuli are used to elicit a motor stimuli, the patient may exibit localization to the stimuli or a withdrawl from stimuli. Decorticate (flexor) and decerebrate (extensor) posturing may also be elicited by noxious stimuli.
|
|
|
Decribe how a change in headache is related to an increase in ICP
lewis pg 1496 |
Compression of intracranial structures such as the walls of the arteries and veins and the cranial nerves can cause a headache. Ususally worse in the morning.
|
|
|
What is normal intracranial pressure and what are the normal values? Lewis pg 1492
|
ICP is the presure that 3 different components (brain, tissue, CSF, & cerebral blood volume) exert inside the rigid, unyeilding skull.
Normal ICP values: 0-15mmHg Normal values: 60-150 mmHg/H2O |
|
|
Decribe how a change in vomiting is related to an increase in ICP
Lewis pg 1496 |
Usually not proceded by nausea.
Nonspecific sign of IICP |
|
|
What is the significance of IICP? Lewis pg 1493
|
IICP is a life-threatening situation that results from an increase in any or all of the 3 components (brain tissue, blood, CSF) of the skull. Cerebral edema is an important factor contributing to IICP.
|
|
|
What diagnostic test is contraindicated for the patient with increased ICP and why?
|
Lumbar puncture is contraindicated in the patient with IICP because of the risk for cerebral herniation from the sudden release of the pressure in the skull from the area above the lumbar puncture.
Herniation involves processes whereby a portion of the brain is displaced through openings with the cranial cavity. When herniation occurs, the vascular system is compressed, destroyed, or lacerated, resulting in ischemia, necrosis, and ultimately death. |
|
|
what are 3 types of cerebral edema, explain briefly. Lewis pg 1493-1494
|
Vasogenic Cerebral Edema: (Most common type of edema)occurs mainly in the white matter and is attributed to changes in the endothelial lining of the cerebral cappilaries.
Cytotoxic Cerebral Edema: results from local disruption of the functional or morphologic integrity of cell membranes and occurs most often in the gray matter. Interstitial Cerebral Edema: is the result of periventricular diffusion of ventricular CSF in a patient with uncontrolled hydrocephalus. It can also be caused by enlargement of the extracellular space as a result of systemic water excess (hyponatremia) |
|
|
What is CPP and how do changes effect the patient?
*Class notes and Lewis pg1492 |
CPP or cerbral perfusion pressure is the pressure needed to ensure blood flow to the brain or simply the pressure at which the blood perfuses the brain cells.
MAP<50mmHg will reduce CPP and may result in hypoxia, vascular collapse, and cellular death. CPP below 60mmg will result in irreversible ischemia. When cerebral perfusion falls to 0 there is no cerebral blood flow. |
|
|
What is normal intracranial pressure and what are the normal values? Lewis pg 1492
|
ICP is the presure that 3 different components (brain, tissue, CSF, & cerebral blood volume) exert inside the rigid, unyeilding skull.
Normal ICP values: 0-15mmHg Normal values: 60-150 mmHg/H2O |
|
|
What is the formula to calculate CPP?
Lewis pg 1492 |
CPP=MAP-ICP
MAP=SBP+2(DBP)/3 |
|
|
What is the significance of IICP? Lewis pg 1493
|
IICP is a life-threatening situation that results from an increase in any or all of the 3 components (brain tissue, blood, CSF) of the skull. Cerebral edema is an important factor contributing to IICP.
|
|
|
What is the effects of cerebral blood flow in regards to the factor of: CO2
Lewis pg 1493 |
The partial pressure of arterial carbon dioxide (PaCO2) is a potent vsoactive agent. An increased in PaCO2 relaxes smooth muscles, dilates cerebral vessels, decreases cerebrovascular resistance and increases CBF. Alternately, a decrease in PaCO2 reverses this process and decreases CBF.
|
|
|
what are 3 types of cerebral edema, explain briefly. Lewis pg 1493-1494
|
Vasogenic Cerebral Edema: (Most common type of edema)occurs mainly in the white matter and is attributed to changes in the endothelial lining of the cerebral cappilaries.
Cytotoxic Cerebral Edema: results from local disruption of the functional or morphologic integrity of cell membranes and occurs most often in the gray matter. Interstitial Cerebral Edema: is the result of periventricular diffusion of ventricular CSF in a patient with uncontrolled hydrocephalus. It can also be caused by enlargement of the extracellular space as a result of systemic water excess (hyponatremia) |
|
|
What is the effects of cerebral blood flow in regards to the factor of: Oxygen
lewis pg 1493 |
Cerebral oxygen tension below 50mmHg results in cerebral vascular dilation. This dilation decreases cerebral vascular resistance, increases CBF, and raises oxygen tension. However, if oxygen tension is not raised, anaerobic metabolism begins, resulting in an accumulation of lactic acid.
|
|
|
What is CPP and how do changes effect the patient?
*Class notes and Lewis pg1492 |
CPP or cerbral perfusion pressure is the pressure needed to ensure blood flow to the brain or simply the pressure at which the blood perfuses the brain cells.
MAP<50mmHg will reduce CPP and may result in hypoxia, vascular collapse, and cellular death. CPP below 60mmg will result in irreversible ischemia. When cerebral perfusion falls to 0 there is no cerebral blood flow. |
|
|
What is the formula to calculate CPP?
Lewis pg 1492 |
CPP=MAP-ICP
MAP=SBP+2(DBP)/3 |
|
|
What is the effects of cerebral blood flow in regards to the factor of: Hydrogen ion concentration
Lewis pg 1493 |
As lactic acid increases and hydrogen ions accumulate, the environment becomes more acidic. Within this acidic environment, further vasodilation occurs in a continued attempt to increase blood flow. The combination of a severly low arterial oxygen pressure (PaCO2) and an elevated hydrogen ion concentration (acidosis), which are both potent cerebral vasodilators, may produce a state where in autoregulation is lost and compensatory mechanisms fail to meet tissue metabolic demands.
|
|
|
What is the effects of cerebral blood flow in regards to the factor of: CO2
Lewis pg 1493 |
The partial pressure of arterial carbon dioxide (PaCO2) is a potent vsoactive agent. An increased in PaCO2 relaxes smooth muscles, dilates cerebral vessels, decreases cerebrovascular resistance and increases CBF. Alternately, a decrease in PaCO2 reverses this process and decreases CBF.
|
|
|
Decribe how a change in LOC is related to an increase in ICP
Lewis pg 1494 |
Occur as a result of compression of the ascending reticular activating system pathways and the resulting hypoxia of the cells of these tissues as well as the cells of the cortex. As compression increases the patient becomes more difficult to arouse. Assessment is based on the extent to which he is oriented and able to respond.
|
|
|
What is the effects of cerebral blood flow in regards to the factor of: Oxygen
lewis pg 1493 |
Cerebral oxygen tension below 50mmHg results in cerebral vascular dilation. This dilation decreases cerebral vascular resistance, increases CBF, and raises oxygen tension. However, if oxygen tension is not raised, anaerobic metabolism begins, resulting in an accumulation of lactic acid.
|
|
|
Decribe how a change in VS is related to an increase in ICP
lewis pg 1495 |
Occur very late in the process of cellular hypoxia and indicate that pressure is being exerted on the lower brain stem and medulla. If not relieved, these changes quickly accelerate and death ensues.
|
|
|
What is the effects of cerebral blood flow in regards to the factor of: Hydrogen ion concentration
Lewis pg 1493 |
As lactic acid increases and hydrogen ions accumulate, the environment becomes more acidic. Within this acidic environment, further vasodilation occurs in a continued attempt to increase blood flow. The combination of a severly low arterial oxygen pressure (PaCO2) and an elevated hydrogen ion concentration (acidosis), which are both potent cerebral vasodilators, may produce a state where in autoregulation is lost and compensatory mechanisms fail to meet tissue metabolic demands.
|
|
|
Decribe how a change in ocular signs is related to an increase in ICP
lewis pg 1495 |
Changes in pupil size, equality, and reaction to light, and extraocular movements are indicative of compression of the third, fourth, and sixth cranial nerves.
|
|
|
Decribe how a change in LOC is related to an increase in ICP
Lewis pg 1494 |
Occur as a result of compression of the ascending reticular activating system pathways and the resulting hypoxia of the cells of these tissues as well as the cells of the cortex. As compression increases the patient becomes more difficult to arouse. Assessment is based on the extent to which he is oriented and able to respond.
|
|
|
Decribe how a change in decrease in motor function is related to an increase in ICP lewis pg 1495
|
As the ICP continues to rise, the patient manifests changes in motor ability. A contralateral hemiparesis or hemiplegia may be seen, depending on the location of the source of the increased ICP. If painful stimuli are used to elicit a motor stimuli, the patient may exibit localization to the stimuli or a withdrawl from stimuli. Decorticate (flexor) and decerebrate (extensor) posturing may also be elicited by noxious stimuli.
|
|
|
Decribe how a change in VS is related to an increase in ICP
lewis pg 1495 |
Occur very late in the process of cellular hypoxia and indicate that pressure is being exerted on the lower brain stem and medulla. If not relieved, these changes quickly accelerate and death ensues.
|
|
|
Decribe how a change in headache is related to an increase in ICP
lewis pg 1496 |
Compression of intracranial structures such as the walls of the arteries and veins and the cranial nerves can cause a headache. Ususally worse in the morning.
|
|
|
Decribe how a change in ocular signs is related to an increase in ICP
lewis pg 1495 |
Changes in pupil size, equality, and reaction to light, and extraocular movements are indicative of compression of the third, fourth, and sixth cranial nerves.
|
|
|
Decribe how a change in vomiting is related to an increase in ICP
Lewis pg 1496 |
Usually not proceded by nausea.
Nonspecific sign of IICP |
|
|
Decribe how a change in decrease in motor function is related to an increase in ICP lewis pg 1495
|
As the ICP continues to rise, the patient manifests changes in motor ability. A contralateral hemiparesis or hemiplegia may be seen, depending on the location of the source of the increased ICP. If painful stimuli are used to elicit a motor stimuli, the patient may exibit localization to the stimuli or a withdrawl from stimuli. Decorticate (flexor) and decerebrate (extensor) posturing may also be elicited by noxious stimuli.
|
|
|
What diagnostic test is contraindicated for the patient with increased ICP and why?
|
Lumbar puncture is contraindicated in the patient with IICP because of the risk for cerebral herniation from the sudden release of the pressure in the skull from the area above the lumbar puncture.
Herniation involves processes whereby a portion of the brain is displaced through openings with the cranial cavity. When herniation occurs, the vascular system is compressed, destroyed, or lacerated, resulting in ischemia, necrosis, and ultimately death. |
|
|
Decribe how a change in headache is related to an increase in ICP
lewis pg 1496 |
Compression of intracranial structures such as the walls of the arteries and veins and the cranial nerves can cause a headache. Ususally worse in the morning.
|
|
|
Decribe how a change in vomiting is related to an increase in ICP
Lewis pg 1496 |
Usually not proceded by nausea.
Nonspecific sign of IICP |
|
|
What diagnostic test is contraindicated for the patient with increased ICP and why? Lewis pg.
|
Lumbar puncture is contraindicated in the patient with IICP because of the risk for cerebral herniation from the sudden release of the pressure in the skull from the area above the lumbar puncture.
Herniation involves processes whereby a portion of the brain is displaced through openings with the cranial cavity. When herniation occurs, the vascular system is compressed, destroyed, or lacerated, resulting in ischemia, necrosis, and ultimately death. |
