Trauma

Question 1

Question:
Initiation of enteral nutrition in mechanically ventilated patients within 24 to 48 hours of admission
to the intensive care unit has been strongly associated with reduction of which of the following?
Answers:
A. Bowel perforation
B. Venous thromboembolisms
C. Mean arterial blood pressure
D. Mortality
E. Pneumonia

Answer 1

D. Mortality

Early initiation of enteral nutrition has been associated with reduced ICU and hospital mortality,
especially in the sickest patients. However, an increased risk of ventilator associated pneumonia
has been associated with early initiation of enteral nutrition.

Question 2

A 55-year-old man sustains severe multisystem injuries in a motor vehicle collision. On the fourth
day postinjury, PaO2 is 75 mmHg on 100% oxygen, with 10 cm H2O positive end-expiratory
pressure. Pulmonary capillary wedge pressure is 8 mmHg. Chest x-ray is shown. Which of the
following is the most likely diagnosis?
A. Pulmonary contusion
B. Pneumothorax
C. Pleural effusion
D. Empyema
E. ARDS

Answer 2

E. ARDS

This patient fits the Berlin criteria for acute respiratory distress syndrome. His respiratory distress
began within 1 week of clinical insult and the chest x-ray demonstrates bilateral opacities. The low
wedge pressure is not consistent with fluid overload or cardiac failure. The PaO2/FiO2 is <= 100
mmHg on more than 5 cm H20 PEEP, which is consistent with severe ARDS. Using a consensus
process, a panel of experts convened in 2011 (an initiative of the European Society of Intensive
Care Medicine endorsed by the American Thoracic Society and the Society of Critical Care
Medicine) developed the Berlin Definition, focusing on feasibility, reliability, validity, and objective
evaluation of its performance. Using the Berlin Definition, stages of mild, moderate, and severe
ARDS were associated with increased mortality (27%; 95% CI, 24%-30%; 32%; 95% CI,
29%-34%; and 45%; 95% CI, 42%-48%, respectively; P < .001) and increased median duration of
mechanical ventilation in survivors (5 days; interquartile [IQR], 2-11; 7 days; IQR, 4-14; and 9 days;
IQR, 5-17, respectively; P < .001).
The Berlin definition of acute respiratory distress syndrome
Timing: Within 1 week of a known clinical insult or new or worsening respiratory symptoms
Chest imaging: Bilateral opacities — not fully explained by effusions, lobar/lung collapse, or
nodules
Origin of edema: Respiratory failure not fully explained by cardiac failure or fluid overload.
Need objective assessment (e.g., echocardiography) to exclude hydrostatic edema if no risk factor
present
Oxygenation:
Mild 200 mmHg < PaO2/FIO2 ≤300 mmHg with PEEP or CPAP ≥5 cmH2Oc
Moderate 100 mmHg < PaO2/FIO2 ≤200 mmHg with PEEP ≥5 cmH2O
Severe PaO2/FIO2 ≤100 mmHg with PEEP ≥5 cmH2O

Question 3

The use of positive end-expiratory pressure during mechanical ventilation produces which of the
following effects?
Answers:
A. Increased intrathoracic pressure
B. Increased cardiac output
C. Decreased risk of pulmonary barotruma
D. Increased ventilation-perfusion mismatch
E. Decreased DLCO

Answer 3

Increased intrathoracic pressure

Extrinsic positive end-expiratory pressure (PEEP) during mechanical ventilation increases
oxygenation, decreases work of breathing, and can improve areas of ventilation-perfusion (V/Q)
mismatch. However, PEEP can cause increase in intrathoracic pressure and pulmonary
barotrauma. PEEP can also decrease cardiac output, preload, and venous return.

Question 4

A 45-year-old man in the ICU is recovering from a severe head injury and being considered for
extubation. He demonstrates spontaneous breathing and maintains oxygenation during a two-hour
continuous positive airway pressure trial. Which of the following factors is most likely to result in
failure of extubation and the need for reintubation?
Answers:
A. Normal chest x-ray
B. Presence of a cuff leak
C. Serum pH of 7.40
D. PaO2 > 60
E. Rapid Shallow Breathing Index > 105

Answer 4

E. Rapid Shallow Breathing Index > 105

The Rapid Shallow Breathing Index (RSBI) was originally described as a physiological
measurement that could be used to predict successful extubation in mechanically ventilated
patients ready to be liberated from the ventilator. It is calculated by dividing the respiratory rate by
the tidal volume. Patients that were likely to fail extubation had a RSBI > 105. Higher values for the
RSBI signify a pattern of breathing often seen in patients with respiratory muscle fatigue who tend
to have weak inspiratory efforts and consequently higher respiratory rates. However, the observed
RSBI value can be increased by recent suctioning, anxiety, fever, and the size of the endotracheal
tube.

Question 5

Positive pressure ventilation most commonly affects cardiac function through which of the following
mechanisms?
Answers:
A. Increased SVR
B. Decreased pulmonary vascular resistance
C. Decreased LV function
D. Decreased venous return
E. Increased venous return

Answer 5

Decreased venous return

In contrast to spontaneous breathing, mechanical ventilation with positive pressure results in a
positive pleural pressure during inspiration. The positive intrathoracic pressure induced by
mechanical ventilation will decrease the pressure gradient needed for venous return to the right
atrium. Reductions in cardiac output after initiation of positive pressure ventilation may be
particularly prominent in patients who are not adequately volume resuscitated and are preload
dependent. This decrease in cardiac output may be offset by increased left ventricular function
occurring due to a lower transmural gradient caused by increased intrathoracic pressure.
Mechanical ventilation should not have significant effects on SVR but may result in a small
increase in pulmonary vascular resistance, affecting RV afterload.

Question 6

Which of the following molecules has been most strongly implicated in the large vessel
vasoconstriction seen following aneurysmal subarachnoid hemorrhage?
Answers:
A. Interleukin-4 (IL-4)
B. Hypoxia-inducible factor-1alpha (HIF-1alpha)
C. Nuclear factor erythroid 2-related factor 2 (Nrf2)
D. Interleukin-17a
E. Endothelin-A

Answer 6

E. Endothelin-A

Subarachnoid Hemorrhage (SAH) results in transient global ischemia due to Intracranial Pressures
(ICPs) that near Mean Arterial Pressure (MAP). In addition to triggering a catecholamine surge,
this ischemic event has been shown to result in vascular dysfunction. This results in the stimulation
of the endothelin-1 pathway. Data have suggested that plasma endothelin-1 concentrations have
correlated with delayed cerebral ischemia (DCI) and inhibition seemed to reverse SAH induced
vasospasm. Clinical trials have been conducted using the endothelin-1 antagonist clazosentan.
While the CONSCIOUS-1 trial showed some improvment in radiographic vasospasm,
CONSCIOUS-2 and CONSCIOUS-3 showed no improvement in outcomes after SAH with a
possible increase in pulmonary complications, anemia, and hypotension. HIF-1a and Nrf2 have
been shown to play a role in stroke pathophysiology. While systemic cytokines have been shown
to play a role in the pathophysiology of DCI and vasospasm after SAH, IL-4 and IL-17a have not
been shown to be the major effectors.

Question 7

A 68-year-old woman returns to the intensive care unit in respiratory distress two weeks after a
large left middle cerebral artery stroke. Based on the chest x-ray shown, which of the following is
the most appropriate initial management?
A. Retract the tracheostomy.
B. Emergent bedside bronchoscopy.
C. Start empiric broad spectrum antibiotics.
D. Left side thoracostomy tube placement.
E. Right side thoracostomy tube placement.

Answer 7

B. Emergent bedside bronchoscopy.

The chest radiograph shows significant atelectasis of the left lung; the mediastinum and the right
subclavian central line is seen pulled towards the same side of the radiopaque abnormality seen.
Bedside flexible bronchoscopy is a common procedure in the ICU; atelectasis and presence of
retained secretions are some of the most common indications for bedside bronchoscopy.
Thoracostomy (on the left or right side) will not help, given the pathology causing the shift of the
mediastinum and white-out of the left lung is likely in the airway and not outside the lung. There is
no pneumothorax on the right side because lung vasculature can be seen throughout the right
lung. The patient will likely require antibiotic therapy, but antibiotics will not improve her acute
respiratory distress, which is likely caused by a mucus plug in the left bronchus which can be
resolved by bedside flexible bronchoscopy.

Question 8

Glutamate excitotoxicity is most commonly mediated by which of the following processes?
Answers:
A. Neurokinin A receptor stimulation
B. Gamma-aminobutyric acid receptor inhibition
C. N-methyl-D-aspartate receptor stimulation
D. N-methyl-D-aspartate receptor inhibition
E. Gamma-aminobutyric acid receptor stimulation

Answer 8

N-methyl-D-aspartate receptor stimulation

N-methyl-D-aspartate receptors are glutamate-gated ion channels widely expressed in the central
nervous system, with high density in the hippocampus and the cerebral cortex, that have key roles
in excitatory synaptic transmission. The NMDA receptor, along with other glutamate-gated ion
channels, plays an important part in synaptic plasticity and thus in cognitive performance.
Glutamate excitotoxicity is a cell death mechanism triggered by excessive glutamate release from
neurons, causing persistent activation of glutamate-gated ion channels (i.e. NMDA receptor),
resulting in influx of extracellular calcium. Other options are not mediated by glutamate.

Question 9

Which of the following enzymes must be present for the formation of CSF?
Answers:
A. Gammaglutamyl transpeptidase
B. NADH dehydrogenase
C. Na+-K+ ATPase
D. Pyruvate kinase
E. Succinate dehydrogenase

Answer 9

Na+-K+ ATPase

CSF is formed primarily by the choroid plexus, with a smaller amount being formed
extrachoroidally. Water and ions are transferred into the ventricles by either intracellular movement
across epithelial cells or intracellular movement across apical tight junctions. A number of ion
transporters are necessary for CSF production by the four main choroid plexuses. The Na+-K+
ATPase is located in the apical membrane of epithelial cells from the choroid plexus and accounts
for the active transport of Na that is necessary for secretion of CSF. Small molecules that inhibit
the Na+-K+ ATPase, such as ouabain, have been shown to decrease CSF production. Several
other enzymes also play a critical role in CSF production, such as carbonic anydrase, which is
inhibited by acetazolamide.

Question 10

A 70-year-old man has a myocardial infarction after undergoing surgery. Echocardiogram shows
an ejection fraction of 60%. This finding indicates that which of the following is within the normal
range?
Answers:
A. Left ventricular diastolic function.
B. Left ventricular systolic function.
C. Aortic valve function.
D. Heart size.
E. Right ventricular systolic pressure.

Answer 10

B. Left ventricular systolic function.

The ejection fraction, or left ventricular ejection fraction (LVEF), is the measurement of the left
ventricular systolic function. Per the American College of Cardiology (ACC), a normal LVEF is
between 50% and 70%. LVEF is the fraction of chamber volume ejected in systole (stroke volume)
in relation to the volume of the blood in the ventricle at the end of diastole (end-diastolic volume).
Stroke volume (SV) is calculated as the difference between end-diastolic volume (EDV) and endsystolic
volume (ESV). LVEF is calculated from: [SV/EDV] x 100.
The simplest classification as per the American College of Cardiology (ACC) that is used clinically
as follows:
A. Hyperdynamic = LVEF greater than 70%
B. Normal = LVEF 50% to 70% (midpoint 60%)
C. Mild dysfunction = LVEF 40% to 49% (midpoint 45%)
D. Moderate dysfunction = LVEF 30% to 39% (midpoint 35%)
E. Severe dysfunction = LVEF less than 30%

Question 11

Which of the following sedative-hypnotic agents causes adrenal cortical suppression?
Answers:
A. Propofol
B. Phenobarbital
C. Ketamine
D. Etomidate
E. Pentobarbitol

Answer 11

Etomidate

Etomidate is a short-acting, sedative hypnotic that is commonly used for inducing short-term
anesthesia during rapid sequence intubation. It exhibits fewer detrimental side effects, mainly
hemodynamic compromise, when compared to other sedatives commonly used for induction such
as benzodiazepines.
A well-documented side effect of etomidate is suppression of the adrenal synthesis of cortisol. In a
dose dependent fashion, it inhibits adrenal mitochondrial 11-β hydroxylase, the enzyme
responsible for the final conversion of 11-deoxycortisol to cortisol. This side effect, shown to be a
risk factor for increased mortality, can be detrimental in septic patients who may have a baseline
adrenal insufficiency due to critical illness.
Barbiturates can cause induction of cortisol metabolism.

Question 12

In pulmonary physiology, which of the following describes the primary action of surfactant?
Answers:
A. Reduce the surface tension at the air-liquid interface in the alveoli.
B. Regulate air temperature during inhalation.
C. Stimulate movement of cilia within the bronchus.
D. Increase the surface tension at the air-liquid interface in the alveoli.
E. Inhibit alveolar macrophage activity.

Answer 12

A. Reduce the surface tension at the air-liquid interface in the alveoli.

The main functions of surfactant include: lowering surface tension at the air–liquid interface
preventing alveolar collapse at end-expiration, antimicrobial activity and modulating immune
response. Pulmonary surfactant is a mixture of lipids and proteins that is secreted into the alveolar
space by epithelial type II cells. The main function of surfactant is to lower the surface tension at
the air/liquid interface within the alveoli of the lung. This is needed to lower the work of breathing
and to prevent alveolar collapse at end-expiration. The more hydrophilic surfactant components,
SP-A and SP-D, participate in pulmonary host defense and modify immune responses.
Specifically, SP-A and SP-D bind and partake in the clearance of a variety of bacterial, fungal, and
viral pathogens and can dampen antigen-induced immune function of effector cells. Emerging data
also show immunosuppressive actions of some surfactant-associated lipids, such as
phosphatidylglycerol. Deficiencies of surfactant components are classically observed in the
neonatal respiratory distress syndrome, where surfactant replacement therapies have been the
mainstay of treatment. However, functional or compositional deficiencies of surfactant are also
observed in a variety of acute and chronic lung disorders.

Question 13

An 82-year-old woman receives an enteral feeding tube. Four hours later, she develops shortness
of breath and oxygen desaturation. She requires reintubation. A chest x-ray is shown. Which of the
following is the most appropriate next step in management?
A. Right sided thoracostomy tube placement.
B. Emergent bedside flexible bronchoscopy.
C. Left side thoracostomy tube placement.
D. Increase PEEP and tidal volume on ventilator.
E. Obtain emergent computed tomography angiography of the chest.

Answer 13

Right sided thoracostomy tube placement.

The chest radiograph is remarkable for moderate-sized pneumothorax on the right side. The
pneumothorax was likely iatrogenic after nasogastric tube placement. Emergent placement of a
right sided thoracostomy tube would be the most appropriate next step, after securing the airway.
To visualize a pneumothorax, one should look for a visible visceral pleural edge that is seen as a
thin sharp white line with no lung markings seen peripheral to this line. The peripheral space
should be radiolucent compared to the adjacent lung. The mediastinum should not shift away from
the pneumothorax unless a tension pneumothorax is seen.

Question 14

Which of the following treatments is indicated for the patient whose chest x-ray is shown?
Answers:
A. Pericardiocentesis
B. Observation
C. Tube thoracostomy with pigtail catheter
D. Bronchoscopy
E. Tube thoracostomy with large bore chest tube

Answer 14

Tube thoracostomy with pigtail catheter

The chest X-ray demonstrates a left pneumothorax in an intubated patient. The best option for
treating this patient is tube thoracostomy with placement of a pigtail catheter. Current evidence
suggests that placement of a pigtail catheter is preferable to a large bore chest tube (PMID:
29452099). Histroically, large bore chest tubes have been considered to be preferable in patients
with hemothoraces and emphyemas, however recent evidence has also challenged this (PMID:
33843831, PMID: 19820073). While conservative management is often an option for
pneumothoraces, positive pressure ventilation is thought to promote expansion of
pneumothoraces, and traditional practice is to intervene upon all pneumothoraces in mechanically
ventilated patients. The recent OPTICC trial has suggested that cautiously watching small, occult
pneumothoraces may be an option in patients receiving mechical ventilation (PMID: 33641940). As
the pneumothorax in this patient is large and 40% of patients requiring prolonged ventilation
require eventual drainage, insertion of a pigtail catheter is likely preferable to conservative
management in this case.

Question 15

In patients who have head injuries, the electrodiagnostic test that is most useful in assessing
damage to the brain stem is which of the following?
Answers:
A. EEG
B. BAERs
C. SSEPs
D. Q-SART
E. EMG

Answer 15

BAERs

Brainstem auditory evoked potentials (BAERs) can be used to assess brainstem function in
traumatic brain injury. There may be a role for somatosensory evoked potentials (SSEPs) in
selected patients. EMG, EEG, and Q-SART have no role in clinical assessment of brainstem
function. Changes in latency and amplitude represent either decreased number or efficiency of
axons. Therefore, BAERs provides a method for quantifying the extent of axonal damage. The
electrophysiological functioning of the early auditory network provides a model for understanding
how networks respond to injury more generally. The non-invasive technique allows for survival and
serial assessment, which can help elucidate the temporal evolution of recovery or persistent
dysfunction.

Question 17

A 60-year-old woman has been treated in the intensive care unit for ten days for Hunt and Hess
Grade 4 aneurysmal subarachnoid hemorrhage complicated by severe vasospasm and
pneumonia. Her temperature increases to 39.7°C (103.5°F), her white blood cell count increases
to 20 × 109/L, and her blood pressure decreases to 70/40 mmHg without response to fluid
resuscitation. Administration of which of the following agents is the most appropriate next step?
Answers:
A. Initiation of broad spectrum antibiotics and vasopressin.
B. Initiation of milrinone.
C. Initiation of broad spectrum antibiotics and norepinephrine.
D. Administration of hydrocortisone.
E. Initiation of broad spectrum antibiotics and low-dose dopamine.

Answer 17

Initiation of broad spectrum antibiotics and norepinephrine.

The patient is most likely in septic shock given the known pneumonia, new high fever, new
leukocytosis, and severe hypotension unresponsive to IV fluid resuscitation. If not already started,
the patient should be started on broad spectrum antibiotics and vasopressors. Based on the 2021
Surviving Sepsis Campaign, it is recommended to use norepinephrine as first line, with a target
MAP of 65 mmHg. Norepinephrine is a potent α-1 and β-1 adrenergic receptor agonist, which
results in vasoconstriction and increased MAP with minimal effect on heart rate. When compared
to dopamine, norepinephrine is a more potent vasoconstrictor and is associated with decreased
mortality and lower risk of arrhythmias in patients with septic shock.

Question 18

Which of the following most accurately describes the relationship of pCO2, pO2, and cerebral blood flow?
A. Increase in the pCO2 will decrease cerebral blood flow. pO2 has minimal effect on
cerebral blood flow
B. Increase in the pO2 will decrease cerebral blood flow. pCO2 has minimal effect on
cerebral blood flow
C. Increase in pCO2 and increase in pO2 together will cause increase in the cerebral blood
flow.
D. Decrease in the pCO2 will decrease cerebral blood flow. pO2 has minimal effect on
cerebral blood flow
E. Decrease in the pO2 will decrease cerebral blood flow. pCO2 has minimal effect on
cerebral blood flow

Answer 18

D. Decrease in the pCO2 will decrease cerebral blood flow. pO2 has minimal effect on cerebral blood flow

Carbon Dioxide has a marked and reversible effect on cerebral blood flow. Hypercapnia will cause
marked dilation of the cerebral arteries and arterioles, thereby increasing cerebral blood flow.
Hypocapnia will cause vasoconstriction of the arteries and arterioles, decreasing cerebral blood
flow. The potent vasodilator effect of CO2 is demonstrated by the finding that in humans 5% CO2
inhalation causes an increase in cerebral blood flow by 50% and 7% CO2 inhalation causes a
100% increase in cerebral blood flow. Although several mechanisms involved in hypercapnic
vasodilation have been proposed, the major mechanism appears to be related to a direct effect of
extracellular H+ on vascular smooth muscle. pO2 has minimal effect on cerebral blood flow.

Question 19

Which of the following states is most likely to increase a patient’s susceptibility to ventricular
fibrillation?
Answers:
A. Low serum magnesium
B. QTc ≥ 492
C. Low serum potassium
D. Hypothyroidism
E. Hyperlipidemia

Answer 19

QTc ≥ 492

Among patients admitted to the neurocritical care unit, a QTc ≥ 492 has been strongly linked to the
development of ventricular fibrillaiton. Other risk factors included premature ventricular complexes,
atrial fibrillation, active myocardial infarction, CAD, and heart failure. Increased age, mechanical
ventilation, and sepsis have also been associated with ventricular fibrillation. Among neurological
disorders, supratentorial strokes have been most strongly associated with ventricular arrhythmias.

Question 20

A 45-year-old woman is intubated and mechanically ventilated after her severe pneumococcal
pneumonia progressed to acute respiratory distress syndrome (ARDS). During the next 24 hours,
her PaO2 decreases to 38 mmHg despite a ventilator FiO2 setting of 1.0 and PEEP of 20 cm H2O.
Which of the following is the most appropriate next step in management?
Answers:
A. Start veno-venous extracorporeal membrane oxygenation.
B. Start high dose inhaled steroids.
C. Increase PEEP.
D. Start inhaled nitric oxide at 40ppm.
E. Start continuous albuterol inhalation for 48 hours.

Answer 20

Start veno-venous extracorporeal membrane oxygenation.

The patient has severe ARDS (P/F Ratio < 100mmHg) with significant hypoxemia despite FiO2 of
100% and PEEP of 20 cmH2O. Mortality in severe ARDS is around 45%. Interventions that can
improve clinical outcome are low tidal volume ventilation (<6mL/Kg [predicted body weight] with
goal plateau pressures of < 30cmH2O), prone positioning for 16 hours in combination with low tidal
volume ventilation, and the use of ECMO. Ninety-day mortality was significantly lowered with the
use of ECMO compared to standard care. The most appropriate next step in management is
transitioning the patient to veno-venous ECMO for oxygenation and ventilator support. The use of
nitric oxide would minimally aid with oxygenation, given the degree of hypoxemia seen in this
patient. Increasing PEEP above 20 cmH2O will increase the risk of the ventilator induced lung
injury and increase the risk of spontaneous pneumothorax. Continuous albuterol is helpful in
patients with status asthmaticus, not in ARDS. There is some recent data that using high dose
steroids can decrease the alveolar inflammation seen in ARDS and length of ventilator use, but in
this case it will not help correct the acute hypoxemia seen in this patient.

Question 21

A 63-year-old woman becomes lethargic five days after undergoing clipping of a ruptured
aneurysm. Pulse is 90/min, blood pressure is 110/65 mmHg, and central venous pressure is 3
mmHg. Results of serum studies are shown: Na+ 129 mEq/L, K+ 3.9 mEq/L, Urea nitrogen 27
mg/dL, Creatinine 0.9 mg/dLTranscranial Doppler ultrasonography shows no abnormalities. Which
of the following is the most appropriate management for this patient’s condition?
Answers:
A. Intravenous nimodipine
B. Fluid restriction
C. Interarterial nimodipine
D. Fludrocortisone
E. Hypertonic saline

Answer 21

Hypertonic saline

Hyponatremia following aneurysmal SAH likely occurs via a different mechanism than with SIADH.
Increasing natriuresis may occur due to increased release of atrial natriuretic peptide (ANP) and
brain natriuretic peptide (BNP). Fluid restriction is not advised as first-line treatment of
hyponatremia in patients with aneurysymal subarachnoid hemorrhage (which could be due to
Cerebral Salt Wasting), as volume depletion could exacerbate hypotension and increase the risk of
vasospasm and ischemia. Nimodipine is not indicated as the transcranial doppler does not show
evidence of vasospasm. Fludrocortisone could be considered, but not as first-line treatment. The
best option is treatment with hypertonic saline.

Question 22

A 62-year-old man is three weeks status post left carotid endarterectomy when he suffers a
cardiac arrest. He is comatose and was not cooled. Which of the following is most predictive of
death or vegetative outcome in this patient?
Answers:
A. Unilateral absent Somatosensory Evoked Potential (SSEP) N20 wave 72 hours after
return of spontaneous circulation.
B. Absence of EEG activity within the first 12 hours after return of spontaneous circulation.
C. Absence of pupillary light reflex at 72 hours after return of spontaneous circulation.
D. Serum neuron specific enolase level < 30μg/L 48 hours after return of spontaneous
circulation.
E. Absence of vestibulo-ocular reflex 72 hours after return of spontaneous circulation.

Answer 22

Absence of pupillary light reflex at 72 hours after return of spontaneous circulation.

In post-cardiac arrest patients that remain comatose and did not undergo targeted temperature
management, presence of myoclonus at 24–48 hours, bilateral absence of SSEP N20 wave or
absence of EEG activity > 20–21 μV at 24–72 hours, and absence of pupillary light reflex at 72
hours after return of spontaneous circulation each predicted death or vegetative state.

Question 23

A patient with a severe closed head injury exhibits a decreasing serum sodium level over a 48-hour period to 125 mEq/L. Serum osmolality level is diminished, and urine sodium level is elevated. Monitoring of which of the following parameters is critical in the ensuing management of this patient?
Answers:
A. Volume status
B. Urine Potassium
C. Urine specific gravity
D. Serum ADH
E. Serum BNP

Answer 23

Volume status

Cerebral Salt Wasting is a syndrome defined by hyponatremia accompanied by elevated urine
sodium and hypovolemia in the setting of injury to the central nervous system. Careful monitoring
of volume status (via clinical examination, urine output, and laboratory testing) is required during
treatment of cerebral salt wasting syndrome. Bedside point of care ultrasonography assessment of
the inferior vena cava (IVC) and LV velocity time integral (VTI) can also assist in determining
volume status. Care should be undertaken to avoid inducing volume overload while correcting
serum sodium, which may exacerbate renal, cardiac, or pulmonary dysfunction. Conversely, undersupplementation
of blood volume may lead to clinical worsening in some conditions, notably
aneurysmal subarachnoid hemorrhage.

Question 24

Dysfunction of which of the following hypothalamic-pituitary axes is most likely after aneurysmal
subarachnoid hemorrhage?
Answers:
A. Hypothalamic-pituitary-gonadal
B. Hypothalamic-pituitary-adrenal
C. Hypothalamic-pituitary-mammary
D. Hypothalamic-pituitary-thyroidal
E. Hypothalamic-pituitary-muscle bone and other tissues

Answer 24

Hypothalamic-pituitary-mammary

Hypothalamic-pituitary axis dysfunction is common after aSAH. Pituitary dysfunction occurs in
nearly 50% of patients acutely after aSAH, decreasing to about 25% chronically. The pituitary is
perfused by branches of the internal carotid artery, which forms a plexus of capillaries near the
median eminence of the hypothalamus. Blood then reaches the anterior pituitary via long and short
portal veins. The middle and inferior hypophyseal arteries perfuse the pituitary stalk and
neurohypophysis. Growth hormone has been shown to be the most commonly decreased pituitary
hormone. The differences in blood suppy may explain why GH, which is produced by the anterior
pituitary, is commonly affected. Adrenal insuffiency is common in critically ill patients and often
seen in the context of sepsis.

Question 25

A 52-year-old woman is evaluated for peripheral vision loss and undergoes a right frontal craniotomy for resection of the lesion in the MR images shown. Four hours postoperatively, the urine output has increased to 950 mL/hour. Laboratory studies show: Serum Na+ 150 mEq/L, K+
3.9 mEq/L , serum osmolality 305 mOsm/kg, urine specific gravity 1.002, urine osmolality 145 mOsm/kg. Which of the following is the most appropriate management at this time?
A. Give 100mg of hydrocortisone IV
B. Administration of desmopressin
C. Administer 2L of hypotonic crystalloid solution
D. Bolus 2L of balanced crystalloid solution
E. Obtain STAT serum cortisol level.

Answer 25

Administration of desmopressin

Central diabetes insipidus (CDI) is a common complication following pituitary surgery. It is
frequently transient. Clinical manifestations include abnormally elevated serum osmolality (> 300
mOsm/kg), elevated serum sodium (≥145 mEq/L), polyuria (urinary volume greater than 4-5
mL/kg/hr for two consecutive hours after surgery) and an abnormally low urine osmolality (< 350
mOsm/kg). A urine specific gravity of <1.005, in the light of raised serum sodium and increased
urinary output, points strongly to a diagnosis of CDI. Treatment of choice is administration of
desmopressin.

Question 26

The ECG shown is obtained from an asymptomatic patient. Which of the following is the most
appropriate initial treatment?
Answers:
A. Digoxin
B. Adenosine
C. Amiodarone
D. Procainamide
E. Electrical cardioversion

Answer 26

Adenosine

The EKG demonstrates a narrow complex supraventricular tachycardia. In patients who are
unstable (hypotensive, heart failure, shock, AMS), synchronized cardioversion is indicated. In
patients who are stable and without symptoms, a trial of adenosine is indicated. Vagal maneuvers
and beta-blockers can also be considered. If these options fail, antiarrthymic medications such as
amiodarone and procainamide can be used.

Question 27

Which of the following is the major factor governing the transfer of a nonionized, lipid-soluble agent
from the blood to the brain?
Answers:
A. Clearance rate
B. Molecular weight
C. Tertiary structure
D. Accumulation in peripheral tissues
E. Protein binding

Answer 27

Molecular weight

While all of these factors may affect the ability of a lipid soluble molecule to cross the Blood-Brain
Barrier (BBB), molecular weight is the most important. The ability of a molecule to cross the BBB is
inversely related to the square root of its molecular weight with a cutoff of around 600 Da for
penetration of the BBB. While lipid solubility is an important factor in the ability of a molecule to
cross the BBB, molecules with very high lipid solubility may also become sequestered in capillary
beds and peripheral tissues, thereby lowering the amount available to be presented to the BBB.

Question 28

During seizure activity, which of the following changes in cerebral blood flow (CBF) and cerebral
oxygen utilization (CMRO2) occur?
Answers:
A. Increased CBF and decreased CMRO2
B. No change in CBF or CMRO2
C. No change in CBF but increase in CMRO2
D. Decreased Cerebral Blood Flow (CBF) and decreased CMRO2
E. Increased CBF and Increased CMRO2

Answer 28

Increased CBF and Increased CMRO2

Studies of cerebral blood flow and metabolism in animals and humans have revealed an ictal
increase in both blood flow and metabolic rate. Interictally, reduced blood flow and metabolism to
the epileptogenic focus can occur. These observations provide critical information for interpreting
scans which can be used in the localisation of epileptic foci. This postictal switch in blood flow
patterns may reflect the underlying metabolic processes of neuronal activation and recovery and
have implications for understanding the neurobiology of human epileptic seizures.

Question 29

Which of the following is the most appropriate initial treatment for the abnormality in the chest x-ray
film shown?
Answers:
A. Emergent right sided thoracostomy.
B. Increase positive end-expiratory pressure.
C. Emergent left sided thoracostomy.
D. Retraction of the endotracheal tube.
E. Bedside flexible bronchoscopy.

Answer 29

Retraction of the endotracheal tube.

The chest x-ray demonstrates a right endobronchial intubation, causing the left lung to not be
ventilated and subsequently collapsed. Manifestations of endobronchial intubation include
respiratory distress, elevated peak pressures, hypoxemia, tachypnea and, when severe, may lead
to tension pneumothorax. Once the chest radiograph confirmed mainstem intubation, the
endotrachial tube should be deflated and retracted to an appropriate position, the cuff re-inflated
and chest radiograph repeated to confirm new position.

Question 30

A 52-year-old woman with low grade subarachnoid hemorrhage presents with diffuse T-wave
inversion on ECG. Physical examination shows she is tachycardic, mildly hypotensive, and has
bilateral crackles on lung auscultation. Which of the following studies is most likely to indicate this
patient’s diagnosis?
Answers:
A. Cardiac catheterization
B. Echocardiogram
C. CT angiography of the chest with and without contrast
D. Lower extremity venous dopplers
E. Chest X-Ray

Answer 30

Echocardiogram

An echocardiogram is indicated to detect myocardial wall motion abnormalities, the presence of
which represents an independent risk factor for poor outcome in patients with aneurysmal
subarachnoid hemorrhage. Wall motion abnormalities could be indicative either of myocardial
infarction or Takotsubo stress cardiomyopathy, both of which can accompany aneurysmal
subarachnoid hemorrhage and increase morbidity. This may be related to catecholamine release.
Ischemic changes on ECG should raise suspicion for such a process. Pulmonary embolus, volume
overload, and pneumonia are all less likely in this clinical scenario.

Question 31

In a patient with a severe traumatic brain injury, the most appropriate time frame for resumption of
feeding and caloric replacement goal is which of the following?
Answers:
A. Attain basal caloric replacement after day 7 post-injury.
B. Attain basal caloric replacement once patient has lost 3-5lbs compared to admission
weight.
C. Attain basal caloric replacement, at least, by the end of day 1.
D. Attain basal caloric replacement, at least, by the 5th day post-injury.
E. Attain basal caloric replacement within the first 72 hours post-injury.

Answer 31

Attain basal caloric replacement, at least, by the 5th day post-injury.

After reviewing multiple RCTs and retrospective cohorts regarding timing of feeding, method of
feeding, glycemic control and the use of vitamins and supplements in the severe TBI population, in
the 4th edition of the Brain Trauma Foundation guidelines, it is recommended that patients should
be fed to “attain basal caloric replacement at least by the 5th day and at most by the 7th day postinjury”
to decrease mortality, with some studies showing a significant reduction in mortality at 2
weeks, and lower rates of ventilator associated pneumonia.

Question 32

A 35-year-old woman is diagnosed with diffuse axonal injury after she was ejected from her car
during a high-speed motor vehicle collision. Physical examination shows pulmonary atelectasis
and a head injury. She currently requires 100% FiO2. Which of the following ventilation methods is
most likely to help decrease this patient’s FiO2 requirement?
Answers:
A. Optimizing PEEP
B. Decreasing plateau pressure
C. Decreasing tidal volume
D. Decreasing expiratory time
E. Decreasing respiratory frequency

Answer 32

Optimizing PEEP

Optimization of positive end-expiratory pressure (PEEP) would help decrease the patient’s FiO2
requirement. PEEP can be extrinsic (applied via ventilator) and intrinsic. Intrinsic PEEP develops
with increasing minute ventilation or increasing expiratory time. PEEP maintains pressure in the
airway and alveoli, recruiting closed alveoli and preventing open ones from collapsing, thereby
improving oxygenation.

Question 33

When a patient on parenteral alimentation becomes hyperglycemic, the primary concern is that the
patient has also become?
Answers:
A. Delirious
B. Diabetic
C. Septic
D. Obese
E. Heart failure

Answer 33

Septic

Hyperglycemia is common after total parenteral nutrition (TPN). The association between the
development of hyperglycemia during TPN and poor clinical hospital outcome is well established.
Patients with hyperglycemia during TPN are more likely to be admitted to the ICU and have longer
lengths of stay, higher mortality rate, higher rates of systemic infections and renal failure. Tight
glycemic control has been demonstrated to reduce mortality in critically ill surgical patients and to
limit certain morbidities (acute renal failure, for example) in critically ill medical patients. Patients
experiencing the stress of trauma, critical illness or major surgery typically display endogenous
insulin resistance that is characterized by reduced insulin uptake in peripheral tissues, along with
an increase in glucose production. When combined with a large exogenous dextrose load such as
occurs with TPN, the glucose oxidation capacity can easily be exceeded, which predisposes
patients to develop significant hyperglycemia. It is thought that hyperglycemia contributes to
adverse outcomes associated with TPN in critically ill patients and other hospitalized patients.

Question 34

A 40-year-old man is evaluated because of slowly progressive headache, hoarseness, tongue
weakness, and pulsatile tinnitus associated with a glomus tumor. On presentation, pulse is
120/min and blood pressure is 220/110 mmHg. Which of the following is the most appropriate initial
treatment?
Answers:
A. Hydralazine
B. Observation
C. Enalapril
D. Clonidine
E. Phenoxybenzamine

Answer 34

Phenoxybenzamine

Patients with elevated catecholamine levels secreted by a glomus tumor typically present with
episodic hypertension and require surgical intervention. In this case, the patient has elevated blood
pressure and tachycardia, thus necessitating surgical management. Preoperative management of
elevated blood pressure is typically achieved with an alpha blocker, such as phenoxybenzamine or
doxazosin. Beta blockers such as propranolol may be necessary if tachycardia persists despite
alpha blockers.