Prodigy Questions

Question 1

What is the normal cerebrospinal fluid pressure?

Answer 1

When lying in a horizontal position, the normal cerebrospinal fluid pressure is about 130 mm of water or 10 mmHg.

Question 2

What are some common causes of increased cerebrospinal fluid pressure?

Answer 2

brain tumor can result in the decreased reabsorption of the CSF, which can result in an increased CSF pressure. Hemorrhage or infection are other potential causes as the appearance of red blood cells or white cells can obstruct the absorption channels in the arachnoid villi. Hydrocephalus is an inborn cause of increased CSF pressure.

Question 3

What is the rate of formation of cerebrospinal fluid?

Answer 3

About 500 mL of CSF is formed each day. This translates into about 21 mL/hour.

Question 4

Where in the brain are the choroid plexuses located? Which locations are associated with the greatest quantity of cerebrospinal fluid produced?

Answer 4

The choroid plexuses are located in the four ventricles. The ones located in the two lateral ventricles produce the greatest quantity of cerebrospinal fluid.

Question 5

About how much cerebrospinal fluid is in the subarachnoid space at any given time?

Answer 5

About 150 mL

Question 6

How does secretion of cerebrospinal fluid by the choroid plexus occur?

Answer 6

It is dependent upon the active transport of sodium through the epithelium of the choroid plexus. As the sodium is transported out, chloride is pulled outward as well because of its electrochemical attraction to sodium. The combination of sodium and chloride increases the osmotic pressure on the outside of the plexus which results in the osmosis of water through the plexus membrane. It is the fluid that forms the principal constituent of cerebrospinal fluid.

Question 7

Where is the cerebrospinal fluid secreted and where is it absorbed?

Answer 7

Cerebrospinal fluid is secreted by the choroid plexus and absorbed by the arachnoid villi.

Question 8

What percentage of cardiac output goes to the brain?

Answer 8

The brain only comprises about 2% of body mass but receives about 15% of the cardiac output.

Question 9

What are the four arteries that supply blood to the brain?

Answer 9

The left and right carotid arteries and left and right vertebral arteries.

Question 10

What is the normal cerebral blood flow?

Answer 10

The normal blood flow to the brain is about 50-65 milliliters per 100 grams of brain tissue per minute. This amounts to about 750-900 milliliters/minute in the average adult.

Question 11

About what percent of the cardiac output does the brain receive?

Answer 11

About 15 percent of the cardiac output goes to the brain, or about 50 mL/100g/min

Question 12

What are evoked potentials?

Answer 12

Electrical potentials that are measured in response to some type of stimulus. The purpose is to improve or preserve neurologic structures that are at risk, and to also prevent damage that is irreversible.

Question 13

What is the purpose of SSEP’s?

Answer 13

SSEP’s monitor various neural structures along the central and peripheral somatosensory pathways.

Question 14

How is the stimulation for SSEP’s created?

Answer 14

Through electrical stimulation of peripheral nerves

Question 15

How does carbon dioxide affect cerebral blood flow?

Answer 15

Hypocapnia decreases cerebral blood flow. This effect usually lasts for about 4-6 hours. PaO2 has little effect on CBF until it reaches a tension of 50 mmHg at which point it dramatically increases CBF.

Question 16

Are most strokes ischemic or hemorrhagic?

Answer 16

Most CVAs are ischemic in nature. Only about 10 percent are hemorrhagic.

Question 17

How is blood glucose related to stroke outcomes?

Answer 17

Hyperglycemia is associated with poor outcomes in patients with ischemic stroke. Intravenous administration of glucose should be avoided in stroke patients

Question 18

What is electroconvulsive therapy (ECT)?

Answer 18

ECT is the induction of a generalized seizure via electrodes placed on the cranium.

Question 19

What psychiatric disorders is ECT used to treat?

Answer 19

Mania, affective disorders, and major depression disorders that are resistant to medical therapy.

Question 20

What are the two most common causes of death related to electroconvulsive therapy?

Answer 20

Cardiac dysrhythmias and myocardial infarction are the two most common causes of death related to ECT treatment.

Question 21

What are the anesthetic goals for ECT?

Answer 21

Provide airway support, prevent any recall of the procedure, and attenuate the hemodynamic response to ECT.

Question 22

What type of anesthesia is administered for ECT?

Answer 22

General anesthesia is induced with an intravenous agent, succinylcholine is administered to provide muscle relaxation in preparation for the seizure, and positive-pressure ventilation by mask is performed via mask (or via ETT if the patient is at risk for aspiration).

Question 23

Historically, what has been the preferred intravenous anesthetic agent for ECT? Why?

Answer 23

Methohexital is considered the gold standard induction agent for ECT. All intravenous anesthetics reduce seizure activity, but methohexital reduces it the least.

Question 24

What are the hemodynamic effects of ECT?

Answer 24

ECT treatments result in stimulation of the autonomic nervous system resulting in a short-lived bradycardia followed by a surge in endogenous catecholamines causing potentially dangerous hypertension and tachycardia.

Question 25

What is the minimum seizure duration recommended to ensure adequate antidepressant efficacy when performing electroconvulsive therapy?

Answer 25

Seizures often last several minutes and minimum seizure duration of 25 seconds is recommended to ensure adequate antidepressant efficacy.

Question 26

What anesthetic agents do not produce a change in latency or amplitude in regards to SSEP's?

Answer 26

Ketamine, etomidate, and opiates.

Question 27

What are brainstem auditory evoked potentials and when are they used?

Answer 27

Brainstem auditory evoked potentials assess the integrity of the 8th cranial nerve and the auditory pathways above the pons and are best for monitoring during posterior fossa surgery.

Question 28

Blood flow to the brain is provided by what arteries?

Answer 28

2 vertebral arteries, 2 carotid arteries, and collateral circulation is provided by the Circle of Willis. The circular pattern helps ensure even blood flow to the brain even if one side is impeded.

Question 29

How do inhalational agents affect CBF?

Answer 29

Inhalational agents cause vasodilation in a dose-related fashion. At low doses, little to no change is seen, however with higher doses, CBF is increased.

Question 30

The IV agents thiopental and propofol exert what effects on CMRO2 and CBF?

Answer 30

Thiopental and propofol reduce metabolism and cause cerebral vasoconstriction (lower CBF).

Question 31

How does Ketamine affect cerebral blood flow and metabolism?

Answer 31

Ketamine increases both cerebral blood flow and metabolism.

Question 32

What is the most common psychiatric disorder?

Answer 32

Depression

Question 33

In order for ECT treatments to elicit a therapeutic effect, how long must the electrically-induced seizure last?

Answer 33

At least 25 seconds

Question 34

Why is succinylcholine used during anesthesia for ECT?

Answer 34

To lessen the magnitude of skeletal muscle contractions and associated bone fractures that occur during seizure activity.

Question 35

Are the cardiovascular side effects seen with ECT caused by stimulation of the sympathetic or parasympathetic nervous system?

Answer 35

Both. There is a 10-15 second stimulation of the parasympathetic nervous system in which bradycardia and hypotension occur, followed by hypertension and tachycardia that lasts for several minutes as a result of sympathetic nervous system activation.

Question 36

List side effects associated with ECT.

Answer 36

Hypotension and bradycardia (caused by parasympathetic activation), tachycardia and hypertension (caused by sympathetic activation), increased intragastric pressure, increased ICP, increased IOP, an increase in cerebral blood flow, cardiac dysrhythmias

Question 37

What is the disadvantage to the use of propofol during ECT?

Answer 37

It has anticonvulsant properties, thus reducing the duration of the induced seizure.

Question 38

What is the most common long-term effect associated with the use of ECT?

Answer 38

Memory impairment

Question 39

Why is methohexital the preferred induction drug used with ECT?

Answer 39

It has very little anticonvulsant effects, and it has a rapid onset and recovery. Because of difficulty getting barbiturates in the US, propfol is commonly used.

Question 40

Which type of seizure is defined as two consecutive tonic-clonic seizures without regaining consciousness or seizure activity that is unabated for 30 minutes or more?

Answer 40

Status epilepticus is defined as two consecutive tonic-clonic seizures without the patient regaining consciousness in between or seizure activity that lasts for 30 solid minutes or more.

Question 41

Where do partial seizures originate?

Answer 41

They originate from a localized segment of neurons in a single cerebral hemisphere.

Question 42

From where do generalized seizures originate?

Answer 42

The originate in neurons in both cerebral hemispheres.

Question 43

What is the Jacksonian March?

Answer 43

A partial seizure that evolves into a generalized seizure.

Question 44

Which test is used to determine the location of seizure foci and describe its electrical properties?

Answer 44

Standard EEG

Question 45

What is the method of choice for studying the brain structure of patients with epilepsy?

Answer 45

MRI

Question 46

What is often used in conjunction with an EEG to document clinical and electrical seizure activity at the same time?

Answer 46

Videography

Question 47

What is electrocorticography?

Answer 47

Electrocorticography is type of monitoring in which electrodes are placed surgically on the cerebral cortex. Seizure foci are more accurately determined and electrical events can be mapped in relation to brain anatomy.

Question 48

What are the most common adverse effects associated with the use of antiepileptic drugs?

Answer 48

Dose-dependent neurotoxic effects and depression of cerebral function.

Question 49

What is a conservative surgical approach to seizures that do not respond to antiepileptic drug therapy?

Answer 49

Implantation of a left vagal nerve stimulator

Question 50

Why is the vagal nerve stimulator used to treat seizures placed on the left side?

Answer 50

Cardiac innervation is usually controlled by the right vagus nerve. Implantation on that side could result in severe dysrhythmias.

Question 51

Should glucose be administered to a patient in status epilepticus before a glucose level is determined?

Answer 51

No. Hyperglycemia could potentially exacerbate brain injury in an instance such as this.

Question 52

Name two considerations in the management of anesthesia in patients taking antiepileptic drugs.

Answer 52

1. Antiepileptic drugs that cause enzyme induction can alter the pharmacodynamics and pharmacokinetics of anesthesia drugs and 2. There can be an additive effect between anesthetic drugs and antiepileptic drugs that produces excess sedation.

Question 53

What is the formula for cerebral perfusion pressure (CPP)?

Answer 53

CPP = MAP - ICP (or CVP if it's higher than ICP)

Question 54

``` Which of the following agents does not decrease CSF production? DES Acetazolamide Corticosteroids Furosemide ```

Answer 54

DES can increase CSF production.

Question 55

``` Which of the following will decrease CSF production? Etomoidate Isoflurane Fentanyl Meperidine ```

Answer 55

Etomidate ISO - increases absorption DES increases secretion Fentanyl increases absorption

Question 56

``` What is the normal tissue PO2 in the brain? 10-15 mmHg 20-25 mmHg 35-40 mmHg 70-90 mmHg ```

Answer 56

35-40 mmHg

Question 57

``` Intracranial hypertension is defined as a sustained increased in intracranial pressure above: A. 6-8 mmHg B. 10-15 mmHg C. 20-25 mmHg D. 35-40 mmHg ```

Answer 57

10-15 mmHg

Question 58

``` Methods to decrease the intracranial pressure should be employed when there is a sustained increase in pressure to at least 10 cm H2O 10 mmHg 20 cm H2O 20 mmHg ```

Answer 58

20 mmHg

Question 59

at is the term for a seizure that continues for 30 minutes or more?

Answer 59

Status epilepticus

Question 60

``` Wich of the following will decrease intracranial pressure? Dexmedetomidine Hyperventilation Droperidol Midazolam ```

Answer 60

Hyperventilation

Question 61

``` In adults, how many milliliters of cerebrospinal fluid are produced each day? 20-30 100-200 300-400 500-750 ```

Answer 61

In adults, about 21 ml/hour of CSF is produced by the choroid plexus of the cerebral ventricles every day. This will average around 500 mL a day.

Question 62

``` Which of the following interventions will not help decrease intracranial pressure? Ventriculostomy Hypoventilation Administration of mannitol 30 degree head-up position ```

Answer 62

Hypoventilation

Question 63

``` Under normal conditions, the mechanism of autoregulation maintains constant cerebral blood flow over a range of mean arterial pressures from _____ to _____ mm Hg. A. 30-80 B. 40-100 C. 60-140 D. 70-120 ```

Answer 63

60-140

Question 64

RR: 24; ICP: 29 Calculate your answer in mm Hg to the nearest whole number.

Answer 64

98 mmHg

Question 65

``` Which type of seizure is characterized by a sudden and brief loss of consciousness and postural tone? A. Grand mal B. Petit mal C. Akinetic D. Status epilepticus ```

Answer 65

Akinetic

Question 66

Cerebrospinal fluid normally flows from the lateral ventricles to the third ventricle via the:

Answer 66

Foramen of Monroe

Question 67

Where is cerebrospinal fluid produced?

Answer 67

Choroid plexus

Question 68

Which meningeal layer is thin and is in direct contact with the outer surface of the spinal cord?

Answer 68

Pia mater

Question 69

``` Which of the following values most accurately represents the normal average total cerebral blood flow? A. 10% of cardiac output B. 50 mL/100g/min C. 1500 mL/min D. 20 mL/100g/min ```

Answer 69

50 mL/100g/min

Question 70

What is the approximate CSF volume (in mL)?

Answer 70

150 mL

Question 71

Which of the following statements regarding respiratory gas tension and cerebral blood flow (CBF) is true? A. CBF decreases in response to hypocapnia B. CBF is not related to carbon dioxide tension C. CBF is directly proportional to PaO2 between tensions of 50 and 100 mmHg D. PaO2 tension has no effect on CBF

Answer 71

CBF decreases in response to hypocapnia

Question 72

``` A patient has been diagnosed with an ischemic stroke. Which agent should be avoided in the care of this patient? A. Glucose B. Labetolol C. Tissue plasminogen activator D. Heparin ```

Answer 72

Glucose

Question 73

Which of the following statements regarding cerebrospinal fluid is TRUE? A. Total CSF volume is about 250 mL B. CSF is produced by the cerebromedullary cistern C. CSF is absorbed by arachnoid tissue over the cerebral hemispheres D. CSF is produced at a rate of 120 cc/hour

Answer 73

CSF is absorbed by arachnoid tissue over the cerebral hemispheres

Question 74

Per hour how much CSF if produced?

Answer 74

21 mL/hr

Question 75

Which of the following statements regarding the formation of cerebrospinal fluid (CSF) is true? . CSF passes into the fourth ventricle via the foramen of Monro B. CSF is formed primarily by the choroid plexuses in the cerebromedullary cistern C. Normal CSF production is about 50 mL a day D. The total volume of CSF at any given time is about 140-150 mL

Answer 75

The total volume of CSF at any given time is about 140-150 mL

Question 76

``` You are preparing to induce a patient with uncorrected hydrocephalus for placement of a ventriculoperitoneal shunt. Which of the following agents would be least appropriate for this patient? A. Spironolactone B. Isoflurane C. Desflurane D. Acetazolamide ```

Answer 76

DES

Question 77

``` Select two factors that may increase the specific gravity of CSF. A. Hyperglycemia B. Uremia C. Hypoglycemia D. Jaundice ```

Answer 77

Hyperglycemia and uremia

Question 78

Which of the following represents a primary aim of the treatment of Parkinson's disease? A. Increasing the amount of dopamine in the basal ganglia B. Increasing the neuronal effects of acetylcholine C. Increasing the amount of serotonin in the neuronal synapse D. Preventing systemic hypertension

Answer 78

Increasing the amount of dopamine in the basal ganglia

Question 79

``` Which of the following will decrease intracranial pressure? A. Dexmedetomidine B. Hyperventilation C. Droperidol D. Midazolam ```

Answer 79

Hyperventilation

Question 80

Parkinson's disease is associated with A. A decrease in dopamine levels in the basal ganglia B. A decrease in dopamine levels in the cerebellum C. An increase in dopamine levels in the basal ganglia D. An increase in dopamine levels in the cerebellum

Answer 80

decrease in dopamine levels in the basal ganglia

Question 81

``` What is the primary area for relay of afferent chemoreceptor and baroreceptor information from the vagus and glossopharyngeal nerves? A. Pons B. Hypothalamus C. Nucleus tractus solitarius D. White ramus ```

Answer 81

Nucleus tractus solitarius

Question 82

APEX Select the true statements regarding cerebral blood flow. (select 2). Maximal cerebral vasoconstriction occurs when PaCO2 is 25 mmHg The pH of the CSF around the arterioles controls the cerebral vascular resistance A 1mmHg increase in PaCO2 increases CBF by 3-4mL/100g/min Respiratory alkalosis increases CBF

Answer 82

Maximal cerebral vasoconstriction occurs when PaCO2 is 25 mmHg The pH of the CSF around the arterioles controls the cerebral vascular resistance

Question 83

A Patient has a mAP of 95 mmHg, ICP of 15 mmHG and a CVP of 20 mmHg. Calculate the CPP.

Answer 83

75

Question 84

CSF is reabsorbed into the venous circulation via the:

Answer 84

Arachnoid villi

Question 85

``` Order the flow from the aorta to the circle of willis (1-4) Basilar artery Subclavian artery Vertebral artery Posterior cerebral artery ```

Answer 85

Subclavian Vertebral Basilar Posterior cerebral

Question 86

``` Which spinal tract is monitored by somatosensory evoked potentials? Dorsal column Spinothalmic Corticospinal Vestibulospinal ```

Answer 86

Dorsal column

Question 87

``` Loss of somatosensory evoked potentials during spinal fusion is most likely due to interruption of the: posterior spinal artery artery of Adamkiewicz anterior spinal artery azygous artery ```

Answer 87

posterior spinal artery

Question 88

``` Prolonged thoracic aortic cross clamp time most likely to result in loss of: (select 2) Bowel control movement sensation proprioception ```

Answer 88

Bowel control | movement

Question 89

List the name and function of the 4 lobes of the cerebral cortex

Answer 89

Frontal - contains the motor cortex Parietal - contains somatic sensory cortex Occipital - contains vision cortex Temporal - contains auditory cortex and speech centers wernicke's area = understanding speed broca's area = motor control of speech

Question 90

What is the function of CSF, and where is it located?

Answer 90

Cushions the brain, provides buoyancy, and delivers optimal conditions for neurologic function. It is located in the: ventricles (laterals, third and fourth), cisterns around the brain, subarachnoid space in the brain and spinal cord

Question 91

What regions of the brain are not protected by the BBB?

Answer 91

chemoreceptor trigger zone, posterior pituitary gland, pineal gland, choroid plexus, and parts of the hypothalamus

Question 92

What is the normal volume and specific gravity of CSF?

Answer 92

Volume 150 mL | SG 1.002-1.009

Question 93

Describe production, circulation, and absorption of CSF

Answer 93

Production: ependymal cells of the chorioid plexus at a rate of 30 mL/hr Circulation: Lateral ventricles - Monroe - 3rd ventricle - aqueduct of sylvius - 4th ventricle - lusaka and magendie Reabsorption: venous circulation via arachnoid villi in the superior sagittal sinus

Question 94

?Formula for cerebral blood flow?

Answer 94

CBF = CPP/cerebral vascular resistance

Question 95

What is the normal value for CMRO2? What factors causes it to increase? To decrease?

Answer 95

3.0-3.8 mL/100g/min Increase: hyperthermia, seizures, ketamine, N2O Decrease: hypothermia, halogenated anesthetics, propofol, etomidate, barbiturates

Question 96

What is the formula for CPP? What is normal?

Answer 96

CPP = MAP - ICP (or CVP whichever is higher) | 50-150 mmHg

Question 97

What is the relationship between PaCO2 and CBF?

Answer 97

Linear

Question 98

What is the relationship between CMRO2 and CBF?

Answer 98

As a general rule things that increase the amount of O2 the brain uses tend to cause cerebral vasodilation

Question 99

What is normal ICP? What values are considered abnormal?

Answer 99

Normal is 5-15 mmHg | Cerebral hypertension ICP > 20 mmHg

Question 100

How does hyperventilation affect CBF?

Answer 100

Hyperventilation constricts the cerebral vessels, increases cerebral vascular resistance, decreasing CBF and decreasing ICP

Question 101

Describe the anterior and posterior circulation of the brain. Where do these pathways converge?

Answer 101

Anterior: aorta - internal carotids - circle of willis - cerebral hemispheres Posterior: aorta - subclavian - vertebral a. - basilar a. - posterior fossa and cervical spinal cord. Converge at the circle of willis

Question 102

What is the primary function of the circle of willis

Answer 102

to provide redundancy of blood flow to the brain

Question 103

What is the relationship between hyperglycemia and cerebral hypoxia?

Answer 103

During cerebral hypoxia, glucose is converted to lactic acid. Cerebral acidosis destroys brain tissue and is associated with worse outcomes.

Question 104

Describe the pathophysiology of Parkinson's disease

Answer 104

The dopaminergic neurons in the basal ganglia are destroyed

Question 105

What arteries perfuse the spinal cord

Answer 105

1 anterior spinal artery 2 posterior spinal arteries 6-8 radicular arteries

Question 106

How much of the spinal cord is perfused by the anterior spinal artery?

Answer 106

2/3

Question 107

How much of the spinal cord is perfused by the posterior spinal arteries?

Answer 107

1/3

Question 108

What is the most important radicular artery? Which spinal segment does it typically enter the spinal cord?

Answer 108

Artery of Adamkiewicz | Most commonly originates between T11-T12

Question 109

What part of the spinal cord does the artery of Adamkiewicz supply?

Answer 109

Along with the anterior spinal artery, it supplies the anterior cord in the thoracolumbar region

Question 110

``` Anesthesia Hub: The EEG begins to flatten during carotid endarterectomy when regional cerebral blood flow (in ml/min/100 g brain) decreases to (A) 55 (B) 45 (C) 30 (D) 20 (E) 10 ```

Answer 110

20 mL/100g/min

Question 111

``` The most important factor regulating blood flow to ischemic cerebral tissue is (A) systolic blood pressure (B) PaO2 (C) cerebral perfusion pressure (D) PaCO2 (E) cerebral oxygen consumption ```

Answer 111

CPP

Question 112

``` Which of the following drugs increases cerebral blood flow while decreasing cerebral metabolic rate? (A) Etomidate (B) Fentanyl (C) Isoflurane (D) Lidocaine (E) Midazolam ```

Answer 112

Isoflurane

Question 113

``` Cerebral blood flow is decreased by (A) chronic respiratory acidosis (B) hypoxia (C) hypoglycemia (D) polycythemia (E) the postictal state ```

Answer 113

polycythemia

Question 114

Which of the following would be most likely to increase the duration of seizures during electroconvulsive therapy using a barbiturate and succinyleholine for general anesthesia? A) Administration of atropine prior to therapy (B) Changing to a benzodiazepine for induction (C) Changing to etomidate for induction (D) Adding phenytoin to preoperative medications (E) Decreasing the dose of barbiturate used for induction

Answer 114

Decreasing the dose of barbiturate used for induction

Question 115

Brain stem auditory evoked potentials are most likely to be absent during which of the following? (A) Anesthesia with 1.5 MAC isoflurane (B) Barbiturate coma (C) Hypotension to a mean arterial pressure of 50 mmHg (D) Surgical retraction of the temporal lobe (E) Surgical traction on the pons

Answer 115

Surgical traction on the pons

Question 116

Which of the following best explains the decreased effect of hyperventilation on cerebral blood flow when PaCO2 decreases below 20 mmHg? (A) Maximal constriction of cerebral vessels (B) Decreased cerebral perfusion pressure (C) Decreased cerebral metabolic rate for oxygen (D) Increased cardiac output (E) Increased cerebrospinal fluid pressure

Answer 116

Maximal constriction of cerebral vessels

Question 117

Which of the following best reflects findings of inadequate cerebral perfusion during carotid cross clamping? (A) Decreased frequency on EEG (B) Increased latency of brain stem auditory evoked potentials (C) Increased spectral edge frequency (D) Jugular bulb oxygen tension of 27 mmHg (E) Stump pressure of 50 mmHg

Answer 117

Decreased frequency on EEG

Question 118

Which of the following statements concerning brain stem auditory evoked responses is true? (A) They monitor cortical function (B) They are not affected by changes in PaCO2 (C) They are not affected by mild hypothermia (34°C) (D) They are more resistant to anesthetic effects than somatosensory evoked responses (E) They are abolished coincident with flattening of the EEG

Answer 118

They are more resistant to anesthetic effects than somatosensory evoked responses

Question 119

Each of the following statements about the blood supply of the spinal cord is true EXCEPT: (A) The anterior spinal artery is made up of branches from the vertebral, intercostal, and iliac arteries (B) The segmental blood supply of the cord depends upon the location of the arteria radicularis magna (Adamkiewicz) (C) The posterior spinal arteries supply most of the spinal cord (D) Obstruction of the inferior vena cava increases blood flow through the epidural venous plexus (E) The spinal cord is supplied by one anterior spinal artery and two posterior spinal arteries

Answer 119

The posterior spinal arteries supply most of the spinal cord