3. B. CPP = MAP − ICP or CVP, whichever is higher.
Thus, CPP = 70 − 15 = 55 mm Hg.
4. A. Mannitol, a six-carbon sugar, is the most commonly used diuretic in
neuroanesthesia practice. It is an osmotic diuretic and undergoes little or no
reabsorption. It also improves renal blood flow. Side effects include an initial
increase in circulatory volume, which can cause pulmonary edema. Diuresis
attributed to mannitol can lead to hypovolemia and hypokalemia.
5. C. Treatment of intracranial hypertension includes hyperventilation to PaCO2 of
25 to 30 mm Hg, improving CSF drainage by elevating the head by 30 degrees or
surgical placement of CSF drain, using an osmotic diuretic (mannitol), hypertonic
saline, decompression craniectomy, barbiturates, and corticosteroids. The latter have
been used to decrease cerebral edema, and take a few hours to have effect, but
routine use of corticosteroids in managing intracranial hypertension is not
is the most potent physiologic determinant of cerebral blood flow.
Maximal reductions in ICP can be achieved by decreasing PaCO2
and the reduction in ICP lasts up to 24 to 36 hours.
7. B. ECT is commonly used for treatment of refractory major depression. It
involves using electricity to shock one or both cerebral hemispheres to induce a
seizure lasting 30 to 60 seconds. Contraindications to ECT include
pheochromocytoma, recent myocardial infarction (<3 months), recent stroke (<1
month), intracranial mass or increased ICP, angina, poorly controlled heart failure,
significant pulmonary disease, bone fractures, severe osteoporosis, pregnancy,
glaucoma, and retinal detachment.
8. A. Clinical signs of venous air embolism include a decrease in end-tidal CO2
decrease in arterial oxygen saturation, sudden hypotension, mill wheel murmur, and
even sudden circulatory arrest. Presence of a patent foramen ovale, which has an
incidence of 20% in adults, can lead to paradoxical air embolism, with the potential
of causing coronary ischemia or a stroke.
9. A. For posterior fossa tumor resection, the patient is frequently placed in the
sitting or prone position. Monitoring of the patient includes arterial blood pressure
line, a central venous catheter (for access, pressure monitoring, aspiration of any air
—if required), and a precordial Doppler to detect intracardiac air (venous air
embolism). Operations on posterior fossa tumors can injure vital brain-stem
respiratory and circulatory nuclei, resulting in hemodynamic fluctuations or
depression of ventilation. The surgeon should be informed at the first sign of cardiac
10. D. Nitrous oxide can diffuse into closed air spaces, which may be of significant
clinical consequences. The blood/gas coefficient of nitrous oxide is 0.47, whereas
that of nitrogen is 0.015. This means that nitrous oxide is about 33 times more
diffusible than nitrogen. As a result, at any given partial pressure, far more nitrous
oxide can be carried into a closed gas space than nitrogen removed. Thus, nitrous
oxide can quickly expand closed gas spaces, such as middle ear or a pneumothorax.
11. C. In a patient undergoing craniotomy, intravenous fluid replacement should be
performed by using glucose-free isotonic crystalloid or colloid solutions.
Hyperglycemia is known to worsen ischemic brain injury.
12. A. The most sensitive intraoperative monitor for detecting venous air embolism is
TEE. The second best monitor is precordial Doppler sonography, which can detect as
little as 0.25 mL of air. Changes in end-tidal respiratory gas concentrations, such as
nitrogen and carbon dioxide, and changes in pulmonary artery pressures are less
sensitive. Hypotension and mill wheel murmur are late manifestations of venous air
13. D. Hypothermia is one of the most effective methods for protecting the brain
against ischemia. Hypothermia decreases both basal and electrical metabolic
requirements throughout the brain, unlike intravenous anesthetic agents or
14. D. Propofol, barbiturates, and etomidate produce dose-dependent decreases in
cerebral metabolic rate and CBF. Ketamine is the only induction agent that dilates
the cerebral vasculature and thus increases CBF (50% to 60%).
15. C. In a seated patient, the arterial pressure in the brain differs significantly from
left ventricular pressure. Cerebral perfusion pressure is determined by setting the
transducer to zero at the level of the ear, which approximates the circle of Willis.
16. D. Jugular venous bulb oximetry involves placing a sampling catheter in the
internal jugular vein (IJV). The normal range for mixed venous oxygen saturation at
IJV is 50% to 75%. It gives an estimate of balance between oxygen supply and
demand of the brain, and measures global cerebral oxygenation (not focal).
17. D. SSEPs reflect the integrity of neuronal pathway from the peripheral nerves
through the spinal cord (dorsal columns) to the brain. SSEPs are electrical
manifestations of the central nervous system response to external stimulation.
Intraoperative changes in amplitude or latency or complete loss of waveforms are
indicators of compromised sensory pathway integrity. SSEP amplitude loss greater
than 50% or a latency increase greater than 10% is considered significant.
18. A. In the early management of acute spinal injury patients, particular emphasis
should be placed on preventing further spinal damage, which may occur during
patient movement, airway manipulation, and positioning. High-dose corticosteroids
are often administered to help improve neurological outcome. The head and neck
should be stabilized using manual inline stabilization, and awake fiberoptic intubation
should be considered in high cervical injuries. Patients with high cord transections
may have impaired airway reflexes, hypotension, and bradycardia and may be prone
to hypothermia in view of generalized vasodilation. Succinylcholine can be used
safely in first 24 hours following spinal injury.
19. C. Somatosensory- and motor-evoked potential monitoring is commonly used to
detect ischemia of spinal cord in spine surgeries. Brain-stem auditory–evoked
responses monitor ischemia during posterior fossa surgeries. Inhalational agents in
general increase the latency and decrease the amplitude of evoked potentials (if used
at more than 0.5–0.75 MAC). The effect of inhalational anesthetics on evoked
potentials in decreasing order is visual > motor > somatosensory > brain-stem
20. C. Awake neurological status is the most reliable method to detect cerebral
ischemia. In patients undergoing carotid endarterectomy under local anesthesia and
mild sedation, global and focal neurological status can be continuously assessed. In
patients undergoing carotid endarterectomy under general anesthetic indirect methods
to detect cerebral ischemia can be used. These include EEG monitoring, transcranial
Doppler, arteriography, and measurement of blood flow using xenon.
21. B. MS is characterized by progressive demyelination in the brain and spinal cord.
Stress, anesthesia, and surgery can have detrimental effects on the course of the
disease. Elective surgery should be avoided in acute relapse of MS. Regarding the
effect of anesthetic technique on MS, spinal anesthesia can exacerbate MS
symptoms, epidural anesthesia usually does not affect MS, succinylcholine should be
avoided to prevent hyperkalemia, and hyperthermia should be avoided as an increase
in temperature may block nerve conduction. Advanced MS may be associated with
22. D. GBS affects about 2/100,000 people. It is characterized by a sudden onset
ascending motor paralysis, areflexia, and paresthesias. Bulbar involvement with
respiratory failure is a frequent complication. Succinylcholine should be avoided in
these patients, as it can cause hyperkalemia. Regional anesthesia may make GBS
worse. Anesthetic management may be complicated by liability of the autonomic
nervous system (hypotension or hypertension).
23. B. Autonomic hyperreflexia is seen in patients with spinal cord injury at or above
T6. It is characterized by acute generalized sympathetic hyperactivity in response to
a triggering stimulus. The triggering stimulus can be any stimulus occurring below
the level of the lesion, and is most commonly a distension of hollow viscera (bowel
or bladder). Clinical signs include severe hypertension, bradycardia, arrhythmias,
profuse sweating, vasodilation above the level of lesion, and pallor and
vasoconstriction below the level of lesion. Antihypertensives may have to be utilized
to treat the hypertension. Spinal anesthesia (not preferred because of technical
difficulty and unpredictable level) or deep general anesthesia has been used in
preventing autonomic hyperreflexia.
24. C. LSD is a hallucinogen and causes CNS excitation, sensory distortion, delusions,
hallucinations, and euphoria. Autonomic effects, mediated via the hypothalamus,
include tachycardia, hypertension, mydriasis, piloerection, salivation, lacrimation,
and vomiting. In view of hypertension and tachycardia that can be caused by LSD,
25. B. Propofol when used for induction in patients undergoing ECT can increase the
seizure threshold and decrease the duration of the seizure. Hyperventilation and
administration of caffeine or etomidate can increase seizure duration. Muscle
relaxants do not affect the threshold or duration of the seizure.
26. A. Contraindications to ECT include recent myocardial infarction (<3 months), a
recent stroke (<1 month), an intracranial mass and raised intracranial pressure,
angina, poorly controlled congestive heart failure, significant pulmonary disease,
bone fractures, severe osteoporosis, pregnancy, glaucoma, and retinal detachment.
27. C. The cerebral metabolic rate is reflected by oxygen consumption, which is about
3 to 3.8 mL/100 g/min. Total CBF averages 50 mL/100 g/min. In normal individuals,
CBF remains nearly constant between mean arterial pressures of about 60 and 160
mm Hg. The cerebral autoregulation curve is shifted to right in patients with chronic
arterial hypertension. ICP by convention means supratentorial CSF pressure
measured in the lateral ventricles or over the cerebral cortex, and the normal CSF
28. C. CSF is formed by the choroid plexuses of cerebral lateral ventricles. In adults,
normal CSF production is about 20 mL/hour with a total volume of 150 mL. The
CSF is absorbed in arachnoid granulations over cerebral hemispheres. CSF formation
involves active secretion of sodium in the choroid plexuses, and not passive
29. B. A precordial Doppler can detect as little as 0.25 mL of intracardiac air. A
precordial Doppler is the next best sensitive indicator to detect intracardiac air after
a transesophageal echocardiogram.
30. A. Isoflurane can produce an isoelectric EEG at 2 to 2.5 MAC, while enflurane
typically produces a spike and wave pattern at 2 to 3 MAC. Seizure activity may be
seen on EEG with 3% enflurane in a hypocapnic patient. Halothane causes slowing of
EEG activity with increasing concentration until 4 MAC, after which it produces
uniform activity. Increasing sevoflurane concentration from 2 to 5 MAC changes the
cortical EEG pattern from a high-amplitude slow wave to burst suppression to an
isoelectric EEG interspersed with spikes.
31. D. Intraoperative management of cerebral aneurysms should include availability of
blood, avoidance of hypertension during induction, central venous pressure and
arterial blood pressure monitoring, mannitol after the dura is opened to help surgical
exposure, elective hypotension as it decreases transmural pressure across the
aneurysm (avoiding rupture), administration of thiopental and mild hypothermia for
cerebral protection, and awake extubation depending on neurological status.
32. C. The transsphenoidal or bifrontal craniotomy approach may be used to gain
access to pituitary gland. The former (transsphenoidal approach) has several
advantages including elimination of frontal lobe retraction, microsurgical removal of
small adenomas, reduced blood loss, and shorter hospital stay. Patients are intubated
endotracheally (oral), and oropharyngeal packing is done to prevent bleeding into the
esophagus. Additionally, epinephrine or cocaine may be injected submucosally to
reduce bleeding. The cavernous sinus forms the lateral border of the sella turcica and
includes the internal carotid artery, venous structures, and cranial nerves III, IV, V,
and VI. Therefore, visual-evoked potentials may be monitored in the OR for early
detection of visual pathway damage.
33. A. Parkinson disease is a movement disorder that affects individuals 50 to 70 years
of age. It is caused by progressive loss of dopamine in the nigrostriatum. Patients
phenothiazines, and metoclopramide can worsen symptoms and thus these should be
34. D. Ketamine, etomidate, and enflurane can cause seizurelike activity on the EEG.
Thiopental increases the threshold and decreases the duration of seizure activity.
35. C. In a patient with increased intracranial pressure, a nondepolarizing muscle
relaxant is commonly used to facilitate controlled ventilation and tracheal intubation.
Rocuronium and vecuronium are commonly used as they provide the greatest
hemodynamic stability. Succinylcholine and atracurium (due to associated histamine
release) may increase ICP, particularly if intubation is attempted before deep general
anesthesia. Hyperventilation prior to intubation is utilized to decrease the ICP.
36. B. Somatosensory-evoked potentials are transmitted through the following
peripheral stimulus → peripheral nerve → dorsal root ganglia → first-order fibers in the
ipsilateral posterior column to dorsal column nuclei → second-order fibers crossing to the
opposite side → medial lemniscus to the thalamus → third-order fibers continuing to the
frontoparietal sensory-motor cortex.
37. D. Brain death is irreversible cessation of all brain activity. Generally accepted
clinical criteria for brain death include presence of coma, absence of motor activity,
absence of brain-stem reflexes (papillary, corneal, vestibule–ocular, and gag/cough),
absence of ventilatory effort (PaCO2 >60 mm Hg), exclusion of hypothermia or effect
of sedatives, isoelectric EEG, and absence of cerebral perfusion by angiography.
38. B. Cerebral metabolic rate decreases by 6% per degree Celsius decrease in body
temperature below 37°C. Hence, a 3°C drop in temperature will decrease the
cerebral metabolic rate by 18%.
39. D. The incidence of venous air embolism in sitting craniotomies is about 20% to
40%. The presence of right-to-left shunt can cause paradoxical air embolism. Air
embolism can have catastrophic consequences, such as coronary ischemia and
stroke. Thus, sitting position should be avoided in patients with a right-to-left shunt,
patent foramen ovale, or ventriculoatrial shunt.
40. B. Regional blood flow and metabolic rate are normal after 2 weeks following a
responsiveness and blood–brain barrier abnormalities
require more than 4 weeks to be corrected. Thus, most clinicians postpone elective
surgery for at least 6 weeks following stroke.
41. A. Definitive treatment of intracranial hypertension is ideally directed at the
underlying cause. Treatment modalities include fluid restriction, head elevation,
osmotic agents and loop diuretics, moderate hyperventilation (up to 24–36 hours),
avoidance of hypotension, hypoxia and hypercarbia, and corticosteroids. The latter is
used to decrease cerebral edema in patients with known intracranial tumors, and take
42. A. Inhalational volatile anesthetics produce an increase in latency and decrease in
amplitude of evoked potentials. Nitrous oxide produces a decrease in amplitude with
no change in latency. Propofol decreases amplitude and an increase in latency of
SSEPs. Muscle relaxants have no effect on SSEPs. Narcotics cause dose-dependent
decrease in amplitude and increase in latency.
43. B. Increased intracranial pressure (ICP) can lead to altered mental status,
intractable vomiting, and focal or global neurological deficits. Clinical signs include
hypertension, bradycardia, irregular respiration, and pupillary changes (papilledema
may be seen on fundoscopy). Cushing triad consists of raised ICP, hypertension, and
44. A. Etomidate decreases cerebral metabolic rate, CBF, leading to a decrease in
intracranial pressure. It enhances SSEP. It is a sedative hypnotic but lacks analgesic
properties. Ventilation is affected to a lesser extent with etomidate when compared to
barbiturates or benzodiazepines. Induction doses usually do not result in apnea.
45. A. Increased metabolic activity leads to an increase in CBF. Regional CBF
parallels metabolic activity and can vary from 10 to 300 mL/100 g/min. For example,
motor activity of a limb is associated with a rapid increase in regional blood flow of
the corresponding motor cortex.
46. A. CO2 gas tension has the greatest influence on cerebral blood flow (CBF).
Between a PaCO2 of 20 and 80 mm Hg, CBF changes approximately 1 to 2 mL/100
47. B. Marked changes in PaO2 affect cerebral blood flow (CBF), although minimally.
Hyperoxia is associated with only minimal decreases in CBF. On the other hand,
hypoxemia (PaO2<50 mm Hg) greatly increases CBF.
48. A. The acromegalic patient suffers from general overgrowth of skeletal, soft, and
connective tissues. This results in coarse facial features and enlarged hands and feet.
Patients may also have a difficult airway because of overgrowth of soft tissues of
upper airway, enlargement of tongue and epiglottis, overgrowth of mandible with
increased distance from lips to vocal cords, and glottic and subglottic narrowing.
These changes may also lead to obstructive sleep apnea. Patients also are prone to
hyperglycemia, hypertension, congestive heart failure, increased lung volumes,
increased ventilation–perfusion mismatch, peripheral neuropathy, skeletal muscle
weakness, osteoarthritis, and osteoporosis.
49. D. The quickest way to reduce ICP in a patient is hyperventilation, often to a
PaCO2 of 25 mm Hg. Reduced PaCO2
(hypocarbia) causes cerebral vasoconstriction
leading to a reduction in cerebral blood flow and cerebral blood volume. However,
hyperventilation is only used as a temporizing measure only in periods of acute
50. A. Cerebral vasospasm occurs in about one-third of patients surviving the initial
aneurysmal rupture, and carries a high degree of morbidity and mortality. The degree
of vasospasm depends on the degree of initial subarachnoid hemorrhage. Vasospasm
usually develops 3 to 14 days postsubarachnoid hemorrhage results in narrowing of
cerebral blood vessels and decreased blood flow distally. This may lead to an
ischemic deficit and cerebral infarction, if left untreated. Therapies for cerebral
vasospasm include “triple-H therapy” (hypertension/hypervolemia/hemodilution),
balloon angioplasty, and intra-arterial nicardipine and other vasodilators.<CT>
Gastrointestinal, Liver, and Renal Diseases
1. A 38-year-old woman with a history of diverticulosis is scheduled for an exploratory
laparotomy for lysis of adhesions. Which of the following is the best way of
maintaining core body temperature during the initial hour of general endotracheal
A. Providing warm and humidified inspired gases
B. Increasing ambient temperature
C. Administration of warm intravenous fluids
D. Use of warm irrigating fluids
2. Each of the following would be expected in an otherwise-healthy 125-kg (BMI 40
) man undergoing open cholecystectomy, except
A. Decreased functional residual capacity
B. Increased intra-abdominal pressure and risk of reflux
C. Increased metabolism of volatile anesthetics
D. Decreased metabolism of atracurium
3. Which of the following has a dual effect of increasing gastric pH, and decreasing the
gastric volume to minimize risks associated with aspiration?
4. This finding is indicative of microatelectasis on the second postoperative day after
5. A morbidly obese 60-year-old man with a 65-pack year history of tobacco smoking
is awake after an uncomplicated general anesthetic with sevoflurane for routine
endoscopy and colonoscopy screening. After 45 minutes in the recovery room
(PACU), while breathing 6 L/min of oxygen via nasal cannula, his pulse oximetry
drops to 88%. His rest of the vital signs are stable, and the lungs are clear to
auscultation. The most effective management at this point is
A. Coughing with deep breathing
B. Reintubation of the trachea
C. Intravenous administration of doxapram
D. Continuous positive-airway pressure
6. During rapid-sequence induction of anesthesia for emergent laparotomy to explore
multiple stab wounds, a 45-year-old man vomits a large quantity of undigested food
particles. During intubation of the trachea, food particles are noted near the cords.
After instituting ventilation with 100% oxygen, the most appropriate next step in this
A. Place patient in Trendelenburg position
B. Ventilate with positive end–expiratory pressure of 15 cm H2O
7. A 71-year-old female develops a severe case of diarrhea with multiple loose bowel
movements since awakening this morning. When she arrives preoperatively for her
surgery, an arterial blood gas (ABG) is obtained. The most likely finding would be
A. pH = 7.30, PaCO2 = 50, PaO2 = 60, HCO3
B. pH = 7.35, PaCO2 = 32, PaO2 = 85, HCO3
C. pH = 7.45, PaCO2 = 30, PaO2 = 80, HCO3
D. pH = 7.40, PaCO2 = 45, PaO2 = 85, HCO3
8. A 65-year-old patient is noted to have excessive bleeding during a colectomy with
an activated clotting time (ACT) of 200 seconds. The most unlikely reason for this
A. Undiagnosed factor VII deficiency
B. Prior administration of heparin 5,000 U subcutaneously
C. Preoperative ingestion of aspirin and ibuprofen
D. Dilutional thrombocytopenia
9. During laparotomy, a patient has required infusion of 4 L of lactated Ringer’s and 4
U of packed red blood cells (pRBCs). As the fifth unit of pRBCs begins infusing,
patient has sudden onset of tachycardia and hypotension. Within a few minutes,
Foley bag reveals dark urine. The most likely cause of unexplained oozing is
A. Hemolytic transfusion reaction
C. Dilutional thrombocytopenia
A 26-year-old male patient with a history of severe ulcerative colitis, unresponsive to
conservative measures, presents for elective open total abdominal colectomy with end
ileostomy. He has been unable to eat for the last 2 weeks and was started on total
parenteral nutrition (TPN) several days prior.
10. Intraoperative effect that should be expected and monitored for is
11. At the conclusion of the surgery, the patient fails to regain consciousness. The
metabolic complication of TPN (Table 14-1) that is likely is
Table 14-1 Metabolic Complications of TPN.
Glucose (hypoglycemia, hyperosmolar nonketotic coma)
Essential fatty acid deficiency
C. Hyperosmolar ketotic hyperglycemia
D. Hyperosmolar nonketotic hyperglycemia
12. Consider that the patient opens his eyes and is extubated in the operating room.
However, 15 minutes after arriving to the recovery room (PACU) he is unable to
maintain adequate ventilation and oxygenation. Physical exam reveals profound
global weakness with absent reflexes. The specific electrolyte abnormality that
should be evaluated considering his TPN requirement is
13. Each of the following statements about the preoperative management of an adrenal
pheochromocytoma is true, except
A. Adequate blockade can be assessed by in-house blood pressures <160/90 mm
Hg for 24 hours prior to surgery
B. β-Blockers should be administered only in conjunction with adequate αblockade
C. Administration of α-blocker can decrease operative mortality
D. Nasal congestion is a sign of inadequate α-adrenergic block
14. A 40-year-old man undergoing an open resection of a pheochromocytoma under
isoflurane general endotracheal anesthesia suddenly develops tachycardia,
hypertension, and multifactorial ventricular ectopy. Each of the following could be
considered an appropriate treatment option, except
A. Switching from isoflurane to sevoflurane
15. An otherwise-healthy 38-year-old female patient is undergoing repair of a large
ventral hernia under intrathecal anesthesia. A T2 sensory level is obtained with
hyperbaric bupivacaine prior to incision. A false statement concerning this situation
A. Effective cough is preserved
B. The cardioaccelerator nerves are blocked
C. Examination of the biceps reveals full strength bilaterally
D. Bupivacaine binds to the intracellular portion of sodium channels
16. A patient with cholestasis presents for preoperative evaluation with laboratory
findings revealing normal aspartate aminotransferase (serum glutamic–oxaloacetic
transaminase) and prothrombin time but with a markedly elevated alkaline
phosphatase. He will need a muscle relaxant for upcoming colon surgery. Which of
the following anesthetic scenarios should be considered?
A. Prolonged duration of vecuronium action
B. Increase intubating dose of atracurium
C. Prolonged duration of succinylcholine action
D. Shortened duration of pancuronium action
17. An alcoholic 62-year-old male patient is noted to have jaundice one day after a
laparoscopic cholecystectomy under halothane/fentanyl general endotracheal
anesthesia. Bilirubin and alkaline phosphatase are elevated, but alanine
aminotransferase (serum glutamic–pyruvic transaminase [SGPT]) and aspartate
aminotransferase (serum glutamic–oxaloacetic transaminase [SGOT]) are within
normal ranges. Of note, all values were within normal limits in this patient
preoperatively. The most likely cause of his jaundice is
A. Idiopathic halothane hepatic injury
B. Worsening of underlying chronic liver dysfunction
C. Posthepatic biliary obstruction
D. Intravenous acetaminophen administration
18. An initial bolus of pancuronium was administered to a patient with end-stage liver
disease with associated ascites for general anesthesia. Appropriate anesthetic
considerations include all of the following, except
A. Increased sympathomimetic activity due to vagolysis
B. Intense histamine release immediately after administration
C. Larger volume of distribution requiring initial larger doses
D. Longer duration of action requiring smaller maintenance doses
19. A chronic alcoholic patient with liver cirrhosis is likely to demonstrate all of the
following during administration of anesthesia, except
A. A high minimum alveolar concentration (MAC) for desflurane
Comments
Post a Comment
اكتب تعليق حول الموضوع