Chapter 9
Neurologic Physiology and Anesthesia
726. Following clipping of an anterior communicating artery aneurysm, a 59-yearold man is admitted to the intensive care unit (ICU). Serum sodium is 115 mEq/L, 24
hour urine sodium collection 350 mmol (normal range 40 to 117 mmol/24 h) and
central venous pressure (CVP) is 1 cm H2O. The most likely cause of these findings
is:
A. Tubular necrosis
B. Diabetes insipidus
C. Cerebral salt wasting syndrome
D. Syndrome of inappropriate antidiuretic hormone (SIADH)
E. Primary hyperaldosteronism
727. Intracranial hypertension is defined as a sustained increase in intracranial
pressure (ICP) above
A. 5 mm Hg
B. 15 mm Hg
C. 25 mm Hg
D. 40 mm Hg
E. None of the above
728. Calculate cerebral perfusion pressure from the following data: Blood pressure
(BP) 100/70, heart rate (HR) 65 beats/min, central venous pressure (CVP) 20 mm
Hg, ICP 15 mm Hg
A. 60 mm Hg
B. 65 mm Hg
C. 70 mm Hg
D. 75 mm Hg
E. Cannot be determined
729. The afferent input for somatosensory evoked potentials (SSEPs) is carried
through which spinal cord tract?
A. Spinocerebellar
B. Spinothalamic
C. Dorsal columns
D. Corticospinal
E. Vestibulospinal
730. By what percentage does cerebral blood flow (CBF) change for each mm Hg
increase in PaCO2?
A. 1%
B. 2%
C. 7%
D. 10%
E. 25%
731. Which of the following intravenous anesthetics is contraindicated in patients
with intracranial hypertension?
A. Propofol
B. Fentanyl
C. Thiopental
D. Midazolam
E. Ketamine
732. The term luxury perfusion refers to a situation that occurs in the brain when
A. Blood flow has resumed after a period of ischemia
B. Blood flow is directed from a normal region of the brain to an ischemic region
C. Vasoparalysis exists
D. The Robin Hood phenomenon exists
E. A zone of ischemic penumbra exists
733. A 62-year-old patient is scheduled to undergo resection of a frontal lobe
intracranial tumor under general anesthesia. Preoperatively, the patient is alert and
oriented, and has no focal neurologic deficits. Within what range should PaCO2 be
maintained?
A. 15 and 20 mm Hg
B. 20 and 25 mm Hg
C. 25 and 30 mm Hg
D. 40 and 45 mm Hg
E. None of the above
734. A 2-year-old child is anesthetized for resection of a posterior fossa tumor.
Preoperatively, the patient is lethargic and disoriented. Which of the following is
most likely to adversely alter ICP?
A. 5% dextrose in water
B. Normal saline
C. Lactated Ringer’s solution
D. 5% albumin
E. Fresh frozen plasma
735. A 22-year-old patient is anesthetized for resection of a temporal lobe tumor.
Preoperatively, he is lethargic and confused. After induction of general anesthesia,
which of the following would be the most appropriate drug to control systemic
arterial blood pressure during direct laryngoscopy and tracheal intubation?
A. Esmolol
B. Nitroglycerine
C. Hydralazine
D. Isoflurane
E. Nitroprusside
736. Normal global CBF is
A. 25 mL/100 g/min
B. 50 mL/100 g/min
C. 75 mL/100 g/min
D. 100 mL/100 g/min
E. 150 mL/100 g/min
737. The lower and upper mean arterial blood pressure limits of CBF autoregulation
are, respectively
A. 25 and 125 mm Hg
B. 25 and 200 mm Hg
C. 40 and 250 mm Hg
D. 60 and 160 mm Hg
E. 50 and 200 mm Hg
738. How much will CBF increase in a patient whose PaCO2 is increased from 35 to
45 mm Hg?
A. There is no relationship between PaCO2 and CBF
B. 10 mL/100 g/min
C. 25 mL/100 g/min
D. 40 mL/100 g/min
E. 50 mL/100 g/min
739. Select the FALSE statement concerning autonomic hyperreflexia. A. Distention
of a hollow viscus below the level of the spinal cord transection can elicit autonomic
hyperreflexia B. Up to 85% of patients with a spinal cord transection above the T6
dermatome will exhibit autonomic hyperreflexia under general anesthesia C.
Propranolol is effective in treating hypertension associated with autonomic
hyperreflexia D. Spinal anesthesia is effective in preventing autonomic hyperreflexia
E. Cutaneous stimulation below the level of the spinal cord transection can elicit
autonomic hyperreflexia 740. What is the normal cerebral metabolic rate for oxygen
(CMRO2) per minute? A. 0.5 mL/100 g brain tissue B. 2.0 mL/100 g brain tissue C.
3.5 mL/100 g brain tissue D. 7.5 mL/100 g brain tissue E. 10 mL/100 g brain tissue
741. A 14-year-old girl with severe scoliosis is to undergo spine surgery. Anesthesia
is maintained with fentanyl, N2O 50% in O2, vecuronium, and isoflurane. Neurologic
function of the spinal cord is monitored by SSEPs. In reference to the SSEP
waveform, spinal cord ischemia would be manifested as
A. Increased amplitude and increased latency
B. Decreased amplitude and increased latency
C. Decreased amplitude and decreased latency
D. Increased amplitude and decreased latency
E. Increased amplitude and no change in latency
742. For each 1° C decrease in body temperature, how much will CMRO2 be
diminished?
A. 3%
B. 5%
C. 6%
D. 10%
E. 20%
743. A 24-year-old carpenter is treated for a closed head injury sustained 3 days
earlier after falling from a roof. He has been hemodynamically stable, but despite
aggressive efforts to pharmacologically reduce ICP, he is now unconscious and
unresponsive to painful stimuli. All of the following are clinical criteria consistent
with a diagnosis of brain death in this patient EXCEPT
A. Persistent apnea for 10 minutes
B. Absence of pupillary light reflex
C. Persistent spinal reflexes
D. Decorticate posturing
E. Absence of oropharyngeal reflex
744. Which of the following is the most sensitive means of detecting venous air
embolism (VAE)?
A. Electroencephalography (EEG)
B. Pulmonary artery catheter
C. Transesophageal echocardiography
D. Mass spectrometry
E. Right atrial catheterization
745. When intracranial hypertension exists, the main compensatory mechanism
from the body is
A. Increased absorption of cerebrospinal fluid (CSF) at the arachnoid villi
B. Increased absorption of CSF in the spinal arachnoid villi
C. Shifting of CSF from intracranial to spinal subarachnoid space
D. Reduction of cerebral blood volume due to compression of intracranial arteries
E. Decreased production of CSF at the choroid plexus
746. Select the correct order from greatest to least for the sensitivity of the
following neurophysiologic monitoring techniques to volatile anesthetics (SSEP
[somatosensory evoked potential]; VEP [visual evoked potential]; BAEP [brainstem
auditory evoked potential]).
A. SSEP > VEP > BAEP
B. VEP > SSEP > BAEP
C. BAEP > VEP > SSEP
D. SSEP > BAEP > VEP
E. SSEP = VEP > BAEP
747. Patients can be safely imaged in the magnetic resonance imaging (MRI) scanner
with conventional versions of which of the following monitors?
A. Pulmonary artery catheter with cardiac output probe
B. Foley catheter with temperature probe
C. Electrocardiogram (ECG) electrodes
D. Pulse oximeter
E. Arterial line
748. What is the minimum quantity of intracardiac air that can be detected by a
precordial Doppler?
A. 0.25 mL
B. 5.0 mL
C. 10 mL
D. 25 mL
E. 50 mL
749. With regard to regulation of blood flow, the correct order of vascular
responsiveness to PaCO2 from most to least sensitive is
A. Cerebrum > spinal cord > cerebellum
B. Cerebrum > cerebellum > spinal cord
C. Cerebellum > cerebrum > spinal cord
D. Cerebellum > spinal cord > cerebrum
E. Spinal cord > cerebrum > cerebellum
750. Select the TRUE statement concerning administration of glucose-containing
solutions to the patient with a closed head injury versus a patient with a spinal cord
injury.
A. Glucose-containing solutions are contraindicated in both patient groups
B. Glucose-containing solutions are contraindicated in patients with closed head
injury but acceptable in patients with spinal cord injuries
C. Glucose-containing solutions are acceptable in patients with closed head injuries
but contraindicated in patients with spinal cord injuries
D. Glucose-containing solutions may be given to either patient group if blood
glucose concentrations do not exceed 200 mg/dL
E. Glucose-containing solutions are acceptable in both patient groups.
751. A 67-year-old patient is scheduled to undergo posterior cervical fusion in the
sitting position under general anesthesia. A central venous catheter is inserted from
the right basilic vein and advanced toward the heart. Intravascular
electrocardiography (ECG; with the exploring electrode attached to the V lead) is
used to aid in placement of the catheter. After the catheter is advanced 45 cm, the
tracing shown in the figure is noted on the ECG.
At this time the anesthesiologist should
A. Advance the catheter 5 cm
B. Advance the catheter slightly
C. Leave the catheter in the present position
D. Withdraw the catheter 1 cm
E. Remove the catheter and defibrillate the heart
752. Critical CBF in patients anesthetized with isoflurane is
A. 5 mL/100 g/min
B. 10 mL/100 g/min
C. 18 mL/100 g/min
D. 25 mL/100 g/min
E. 32 mL/100 g/min
753. What effect does cerebral ischemia have on CBF autoregulation?
A. CBF autoregulation is ablated
B. CBF autoregulation is ablated at low cerebral perfusion pressures but remains
intact at high cerebral perfusion pressures
C. CBF autoregulation is ablated at high cerebral perfusion pressures but remains
intact at low cerebral perfusion pressures
D. The CBF autoregulatory curve is shifted to the right
E. The CBF autoregulatory curve is shifted to the left
754. The most rapid maneuver available for lowering ICP in a patient with a large
intracranial mass is
A. Mannitol, 1 g/kg IV
B. Ketamine, 1 mg/kg IV
C. Hyperventilation to 25 mm Hg PaCO2
D. Furosemide, 1 mg/kg IV
E. Methylprednisolone, 30 mg/kg IV
755. What effect does thiopental have on the CO2 responsiveness of the cerebral
vasculature?
A. Thiopental attenuates the effect of hypocarbia on CBF
B. Thiopental attenuates the effect of hypercarbia on CBF
C. Thiopental augments the effect of hypercarbia on CBF
D. Thiopental augments the effect of hypocarbia on CBF
E. Thiopental does not affect CO2 reactivity at a dose used clinically
756. Each of the following is a relative contraindication to the sitting position
EXCEPT
A. Ventriculoatrial shunt
B. Platypnea-orthodeoxia
C. Right-to-left intracardiac shunt
D. Ventriculoperitoneal shunt
E. Patent foramen ovale
757. A 72-year-old patient undergoing resection of an astrocytoma in the sitting
position suddenly develops hypotension. Air is heard on the precordial Doppler
ultrasound. Each of the following therapeutic maneuvers to treat VAE is appropriate
EXCEPT
A. Discontinue N2O
B. Apply jugular venous pressure
C. Implement positive end-expiratory pressure (PEEP)
D. Administer epinephrine to treat hypotension
E. Flood the surgical wound with saline
758. Which of the following is the LEAST likely sequela of venous air embolism
during posterior fossa surgery in the upright position?
A. Arterial hypoxemia
B. Bronchoconstriction
C. Stroke
D. Hypertension
E. Increase in pulmonary dead space
759. A 55-year-old business executive is scheduled for colonoscopy and
polypectomy under general anesthesia. A bruit is auscultated over the right carotid
artery on physical examination. The patient is otherwise healthy. Which of the
following would be the most appropriate course of action?
A. Cancel surgery and obtain coronary angiogram
B. Cancel surgery and obtain Doppler ultrasound carotid blood flow studies
C. Cancel surgery and obtain dobutamine stress echocardiogram
D. Proceed with surgery and obtain a carotid angiogram postoperatively
E. Proceed with surgery
760. How long after a stroke can anesthesia for surgery be carried out with about
the same risk of a perioperative occlusive vascular accident as existed immediately
before the previous stroke?
A. 1 week
B. 6 weeks
C. 6 months
D. 9 months
E. 1 year
761. A 13-year-old boy is anesthetized with 0.5% isoflurane, 50% N2O, and fentanyl
for scoliosis repair. Somatosensory evoked potentials (SSEP) monitoring is
conducted during the procedure. Which of the following structures is NOT involved
in conveyance of the stimulus from the posterior tibial nerve to the cerebral cortex?
A. Corticospinal tract
B. Medial lemniscus
C. Brain stem
D. Internal capsule
E. Dorsal root ganglion
762. A 19-year-old woman is undergoing surgery for a Harrington rod placement.
General anesthesia is administered with desflurane, nitrous oxide, and fentanyl.
After completion of spinal instrumentation, a wake-up test is undertaken. Four
thumb twitches are present when the nerve stimulator attached to the ulnar nerve
is activated. The volatile anesthetic and nitrous oxide have been discontinued for 10
minutes when the patient is asked to move her hands and feet. After repeated
commands, the patient still does not move her hands or feet. The most appropriate
intervention at this time would be
A. 3 mg neostigmine plus 0.6 mg glycopyrrolate IV
B. 20 μg naloxone IV
C. 0.1 mg flumazenil IV
D. Institute SSEP monitoring
E. Reduce the distraction on the rods
763. A 75-year-old patient is undergoing craniotomy for resection of a large
astrocytoma. During administration of isoflurane anesthesia, arterial blood gas
sampling reveals a PaCO2 of 30 mm Hg. At this time, this patient’s global cerebral
blood flow would be approximately
A. 10 mL × 100 g brain weight-1 × min-1
B. 20 mL × 100 g brain weight-1 × min-1
C. 30 mL × 100 g brain weight-1 × min-1
D. 40 mL × 100 g brain weight-1 × min-1
E. 50 mL × 100 g brain weight-1 × min-1
764. A 24-year-old patient is brought to the intensive care unit after sustaining a
closed head injury in a motor vehicle accident. Each of the following would be useful
in managing intracranial hypertension in this patient EXCEPT
A. Corticosteroids
B. Barbiturates
C. Hyperventilation to a PaCO2 of 35 mm Hg
D. Osmotic diuretics
E. Placement of the patient in reverse Trendelenburg position
765. Preoperative treatment of subarachnoid hemorrhage (SAH) patients, without
concomitant cerebral vasospasm, might include any of the following EXCEPT
A. Induced hypertension (to 20% above baseline)
B. Administration of nimodipine
C. Sedation
D. Analgesic therapy
E. Administration of antiepileptic drugs
766. Which of the following pharmacologic agents would have the LEAST effect on
somatosensory evoked potentials?
A. Isoflurane
B. Nitrous oxide
C. Sodium thiopental
D. Etomidate
E. Vecuronium
767. A 75-year-old patient with signs and symptoms of a leaking cerebral aneurysm
is brought to the emergency room for evaluation. T-wave inversion, a prolongation
of the QT interval, and U waves are noted on the preoperative ECG. Appropriate
action at this point would be
A. Begin infusion of nitroglycerin
B. Check serum calcium and potassium
C. Administer esmolol
D. Place a pulmonary artery catheter
E. Delay surgery until myocardial infarction has been ruled out
768. Which of the following pharmacologic agents would have the LEAST effect on
transcranial motor evoked potentials (MEPs)?
A. Isoflurane
B. Nitrous oxide
C. Etomidate
D. Diazepam
E. Fentanyl
769. Ketamine
A. Decreases cerebral blood flow (CBF)
B. Augments the CO2 responsiveness of the cerebral vasculature
C. Reduces cerebral metabolic rate (CMR)
D. Increases cerebral blood volume (CBV)
E. Blunts cerebral autoregulation
770. CMR is decreased by
A. Isoflurane
B. Seizure
C. Hyperthermia
D. Ketamine
E. Corticosteroids
771. Which of the following is LEAST likely to impair CBF autoregulation?
A. Halothane 1 minimum alveolar concentration (MAC)
B. Intracranical tumors
C. Nitrous oxide 50%
D. Cerebral ischemia
E. Sevoflurane 2 MAC
772. An 18-year-old patient is brought to the intensive care unit after sustaining a
cervical spine injury and quadriplegia during a motor vehicle accident. In the first
24 hours after the injury, the patient is at risk for
A. Hypothermia, hypotension, pulmonary edema
B. Fever, hypertension
C. Fever, hypotension, hypoglycemia
D. Autonomic hyperreflexia
E. Impaired cerebral autoregulation
773. Signs and symptoms of intracranial hypertension include
A. Papilledema
B. Headache
C. Nausea and vomiting
D. Decreased mentation
E. All of the above
774. An 89-year-old man with a history of transient ischemic attacks is scheduled to
undergo a carotid endarterectomy under general anesthesia. Which of the following
would be appropriate in the anesthetic management of this patient?
A. Hyperventilation of the lungs to a PaCO2 of 30 mm Hg to reduce ICP
B. Injection of local anesthetic around the carotid body to prevent bradycardia
C. Initiation of deliberate hypotension (after induction of anesthesia) to reduce
bleeding
D. Induction of anesthesia with sodium thiopental
E. Permissive hypercapnia to a PaCO2 of 50 mm Hg to promote the Robin Hood
phenomenon
775. Anesthetics that decrease ICP include
A. Isoflurane
B. Nitrous oxide
C. Propofol
D. Sevoflurane
E. Fentanyl
776. Therapy that is useful in the treatment of cerebral vasospasm includes all of the
following EXCEPT
A. Blood pressure elevation
B. Hemodilution
C. Diuretics
D. Calcium channel blockers
E. Avoiding hyperglycemia
777. All of the following are associated with acromegalic patients undergoing
transsphenoidal hypophysectomy EXCEPT
A. Enlargement of the tongue and epiglottis
B. Narrowing of the glottic opening
C. Nasal turbinate enlargement
D. 20% to 30% incidence of difficult intubation
E. Increased need for postop continuous positive airway pressure (CPAP) because
obstructive sleep apnea (OSA) is more common
778. The CBF autoregulatory curve is shifted to the right by
A. Hypoxia
B. Volatile anesthetics
C. Hypercarbia
D. Chronic hypertension
E. Fentanyl
779. Autoregulation is abolished by
A. Hyperbaric oxygen
B. Cardiopulmonary bypass with a core temperature 27° C
C. Chronic hypertension
D. 3% isoflurane
E. Diabetes insipidus
780. Etomidate does all of the following EXCEPT
A. Abolishes CO2 reactivity
B. Reduces CMRO2
C. Produces direct cerebral vasoconstrictor
D. Reduces CBF
E. Increases both SSEP amplitude and latency
781. Following a motor vehicle accident, a 25-year-old male patient is brought to the
operating room for repair of facial lacerations and fractures, and abdominal
exploration. The patient is extremely micrognathic and weighs 150 kg (330
pounds). Acceptable techniques for securing the airway include
A. Mask technique
B. Awake fiberoptic intubation
C. Direct laryngoscopy after rapid sequence induction
D. Blind nasal intubation
E. Laryngeal mask airway
782. After resection of a grade II astrocytoma in a 60-year-old patient, the serum
sodium is 127 mEq/L. Urine sodium is 25 mEq/L. Therapy could include which of
the following?
A. Intranasal or IV vasopressin (DDAVP)
B. 500 mL 5% saline over 30 minutes
C. Chlorpropamide
D. Leave intubated and hyperventilate
E. Demeclocycline
783. A 48-year-old, 110-kg, man with history of meningioma is scheduled for
craniotomy for tumor debulking. His wife states he has been somnolent and
confused. On exam he is noted to be hyperventilating, sleepy, but arousable and
hypertensive. Useful measures for his anesthetic include
A. Rapid sequence induction using succinylcholine
B. Premedication with 2 mg IV morphine to lower BP and slow breathing
C. 10 cm H2O PEEP to reduce atelectasis
D. Esmolol to reduce response to intubation
E. Hyperventilation to 25 mm Hg
784. If during an MRI scan a patient were to become pinned by a large (50 kg)
metallic object, the appropriate course of action would be to
A. Stop the scan immediately to release the magnet
B. Summon enough people to pull the object away
C. Interrupt electrical power for 60 seconds to release the magnetic force
D. Cut up the metal object and remove piecemeal
E. None of the above
785. A 45-year-old man is undergoing a posterior cervical fusion in the sitting
position. Induction of anesthesia and tracheal intubation are uneventful. Anesthesia
is maintained with N2O, 50% in O2, and sevoflurane. Suddenly, air is heard on the
precordial Doppler ultrasound. Other observations consistent with venous air
embolism include
A. Decreased PaO2
B. Increased end-tidal nitrogen
C. Decreased arterial blood pressure
D. Decreased end-tidal CO2
E. All of the above
786. In patients with increased ICP, hyperventilation is typically limited to a PaCO2
of 30 to 35 mm Hg because additional hyperventilation
A. Is virtually impossible
B. Causes brain ischemia due to a rightward shifting of the oxyhemoglobin
dissociation curve
C. May be associated with a worsening of neurologic outcome
D. Could result in paradoxical cerebral vasodilation
E. May result in clinically significant hyperkalemia
787. Of the measures below, which is the LEAST useful in response to suspected
VAE during a neurosurgical procedure in the upright position?
A. Application 10 cm H2O PEEP
B. Discontinuation N2O
C. Placement of wax on cut bone edges
D. Trendelenburg position
E. Flooding surgical field with saline