23. C. The tip of the pulmonary artery catheter typically enters the pulmonary artery at
around 35 to 45 cm. This can vary from patient to patient, especially with patients at
24. B. Mixed venous oxygen tension can provide valuable information on the balance
between oxygen consumption and delivery. Typical mixed venous oxygen tension in
a healthy adult is 40 mm Hg, yielding a saturation of approximately 75%. Reduction
in oxygen delivery can be due to a reduction in oxygen content per deciliter leaving
the left ventricle, or a reduction in overall cardiac output. Increased oxygen
consumption (low mixed venous oxygen) occurs during periods of elevated metabolic
states, such as during vigorous exercise or sepsis.
25. A. In the clinical scenario, low central venous, pulmonary artery, and pulmonary
artery occlusion pressures support the diagnosis of hypovolemia. Increasing
intravascular volume would be the most beneficial intervention at this time.
26. C. The patient’s history and clinical scenario suggest right heart failure due to
pulmonary hypertension. Milrinone may be beneficial in decreasing pulmonary
vascular resistance as well as increasing cardiac output.
27. C. Interpreting physiologic data from a pulmonary artery catheter and guiding
therapy requires having an intimate knowledge of baseline values. On average,
normal physiologic vascular resistance falls between 900 and 1500 (dynes)(s)/cm5
28. A. Normal pulmonary vascular resistance ranges between approximately 50 and
29. C. Normal cardiac index in a healthy adult ranges between 2.2 and 4.2 L/min/m2
Cardiac index is often used over cardiac output in estimating cardiac function, since
it is more reliable with extremes of height.
30. B. Serious complications with TEE have been reported in approximately 0.1% of
cases, or approximately 1 in 1,000 patients. Strict contraindications to TEE include
but are not limited to esophageal spasm, esophageal stricture, esophageal laceration,
esophageal perforation, and esophageal diverticulum. Relative contraindications
include but are not limited to upper GI bleed, dysphagia or odynophagia, mediastinal
radiation, large diaphragmatic hernias, atlantoaxial disease, and difficult intubation
due to possibility of unintentional extubation with probe manipulation.
31. C. The current guidelines recommend a Nyquist limit of 50 to 60 cm/s when
evaluating regurgitant lesions. Setting the limit to low could result in overestimating
the regurgitant lesion, and setting the limit to high could result in underestimating the
and the location of the signal can be calculated. Continuous-wave Doppler, on the
other hand, uses two separate crystals to send and receive ultrasound energy. This
allows the echo machine to detect higher velocities and energy shifts; however, the
exact location of the signal cannot be determined. Color-wave Doppler is used to
33. B. Pulse oximetry uses two wavelengths of light to calculate oxygen saturation.
These wavelengths are 660 nm of red light (well absorbed by oxygenated
hemoglobin) and 940 nm of infrared light (well absorbed by deoxygenated
34. B. The accuracy of pulse oximetry can be affected by many factors. These include
but are not limited to low blood flow conditions, patient movement, ambient light,
dysfunctional hemoglobin molecules, dyes such as methylene blue and indigo
carmine, and altered relationships in the hemoglobin dissociation curve (severe
acidosis). Intravenous heparin bolus is not known to distort the accuracy of pulse
35. D. Many different clinical situations will cause pulse oximetry to read in
characteristic patterns. Methemoglobinemia absorbs both wavelengths of light and
tends to converge around a saturation of 85%. Carboxyhemoglobin only absorbs red
light, but not infrared light, and can vary widely in saturation readings. Methylene
blue, a common dye used during surgery, tends to cause saturations to converge
36. A. Many different clinical situations will cause pulse oximetry to read in
characteristic patterns. Methemoglobinemia absorbs both wavelengths of light and
tends to converge around a saturation of 85%. Carboxyhemoglobin only absorbs red
light, but not infrared light, and can vary widely in saturation readings. Methylene
blue, a common dye used during surgery, tends to cause saturations to converge
37. B. The corticospinal tracts responsible for motor function travel along the anterior
spinal cord, and can be monitored using motor-evoked potentials. Sensory tracts, on
the other hand, travel along the posterior spinal cord, and can be monitored using
somatosensory-evoked potentials. Electroencephalography is commonly used to
measure cerebral activity during neurovascular surgeries, such as carotid
endarterectomies, looking for decreased cerebral blood flow. Bispectral index or
Sedline monitoring is somewhat controversial, but is used to monitor the adequacy of
38. B. SSEPs monitor the posterior spinal column, which would be affected by damage
to the posterior spinal arteries or compression of the posterior spinal cord. A light
plane of anesthesia would not cause a drop in SSEPs, nor would the administration of
a neuromuscular blocking agent (the latter would hinder the use of motor-evoked
39. C. Halogenated anesthetics as well as nitrous oxide (especially when combined
together) can decrease amplitude and increase latency. For this reason, it is
recommended to minimize the use of volatile anesthetics to below 1 MAC, or to use
a total intravenous technique when monitoring SSEPs.
40. A. Etomidate is known to increase the amplitude of somatosensory-evoked
potentials (SSEPs), and can sometimes be dramatic. Propofol is considered to have
minimal to no effect on amplitude, and is commonly used as an infusion for the
maintenance of anesthesia when monitoring SSEPs. Midazolam has been shown to
decrease amplitude, and this should be kept in mind when used for premedication.
As discussed in the previous question, sevoflurane would be expected to decrease
amplitude and increase latency of SSEPs.
41. A. Medications are not the only variables that affect somatosensory-evoked
potentials, as changes in physiology can also alter latency and amplitude. Amplitude
decreases during episodes of hypotension, hypoxia, and hyperthermia. Latency can
be increased during hypothermia, hypocarbia, and hemodilution/anemia.
42. A. A to B occurs during exhalation of anatomic dead space, B to C occurs during
mixing of exhaled dead space and alveolar gas, C to D reflects the exhalation of
alveolar gas, with point D correlating with end-tidal carbon dioxide, and D to E
represents the beginning of inspiration.
43. D. A to B occurs during exhalation of anatomic dead space, B to C occurs during
mixing of exhaled dead space and alveolar gas, C to D reflects the exhalation of
alveolar gas, with point D correlating with end-tidal carbon dioxide, and D to E
represents the beginning of inspiration.
44. A. It is important to remember that capnography will show a normal capnograph
immediately following endobronchial intubation. Anesthesia
providers must be vigilant to always listen for bilateral breath sounds and observe
bilateral chest rise to confirm tracheal intubation.
45. D. The classic image above is commonly referred to as a curare cleft, and occurs
when a patient begins to attempt inspiration during the expiratory phase of
mechanical ventilation. This is one of the indications that neuromuscular function is
46. C. On average, core temperature declines by approximately 1 to 1.5°C after the
induction of general anesthesia. This initial drop in core body temperature is
primarily due to redistribution (core to periphery) from the vasodilating properties of
many anesthetics. Temperature may continue to drop as processes of heat loss, such
as conduction, convection, radiation, and evaporation, occur (as opposed to
47. D. The current recommendations from the American Society of Anesthesiologists
state that temperature monitoring is required “when clinically significant changes in
body temperature are intended, anticipated, or suspected.” In addition to considering
the surgical procedure, it is also important to consider at risk populations such as the
elderly, infants, burn patients, and patients with autonomic dysfunction.
48. A. Uncontrolled hypothermia has many detrimental effects, including increased
oxygen utilization through shivering, impaired platelet function and coagulation,
delayed wound healing and increasing surgical site infections, as well as potential for
serious dysrhythmias. Cerebral oxygen consumption, however, decreases by
approximately 7% per degree Celsius decrease in temperature.
49. A. Numerous sites can be used to monitor temperature in the operating room. Of
the most common, tympanic membrane (perfused by carotid artery) and pulmonary
artery measurements tend to be the best reflectors of core temperature, followed by
bladder temperatures. Rectal temperatures overall tend to be a poor substitute, while
axillary and skin temperatures are highly prone to error.
50. C. Understanding the limitations of neuromuscular twitch monitoring devices is
fundamental for an anesthesia provider. At the point the fourth twitch reappears, still
up to 75% to 80% of acetylcholine receptors may be blocked. Adequate reversal
(neostigmine–glycopyrrolate) should be given, and clinical signs for return of
neuromuscular function should be used to gauge readiness for extubation.
Fluid Management and Blood Transfusion
Rebecca Kalman and Edward Bittner
1. All of the following are signs of dehydration, except
A. Progressive metabolic acidosis
B. Urinary specific gravity > 1.010
C. Urine osmolality < 300 mOsm/kg
2. Regarding central venous pressure (CVP) monitoring
A. Low values of <5 mm Hg may be considered normal in the absence of other
B. CVP readings can be interpreted independently of the clinical setting
C. CVP monitoring is never indicated in patients with normal cardiac and
D. In a patient with right ventricular dysfunction, a CVP of 10 mm Hg should be
3. In healthy patients, the lactate in lactated Ringer solution
B. Is converted to bicarbonate by the liver
C. Is rapidly bound by albumin
D. Causes a hyperchloremic metabolic acidosis
4. All of the following fluids are generally considered to be isotonic, except
5. All of the following statements regarding dextran solutions are true, except
A. Dextran 40 may improve blood flow through the microcirculation
B. Dextrans may have antiplatelet effects
C. Large-volume infusions of dextrans have been associated with renal failure
D. Dextran 40 is a better volume expander than dextran 70
6. Which of the following statements is true regarding fluid loss?
A. Substantial evaporative losses can be associated with large wounds and are
directly proportionate to the surface area exposed
B. Internal redistribution of fluids, “third spacing,” cannot cause massive fluid
C. Traumatized, inflamed, or infected tissues can only sequester minimal amounts
of fluid in the interstitial space
D. Cellular dysfunction as a result of hypoxia usually produces a decrease in
7. The probability of developing anti-D antibodies after a single exposure to the Rh
8. In a conventional crossmatch
A. Donor cells are mixed with recipient serum
B. Recipient cells are mixed with donor serum
C. Donor serum is tested against red cells of known antigenic composition
9. A leftward shift of the oxyhemoglobin dissociation curve may be related to
A. Low levels of 2,3-DPG in packed red blood cells
B. Hypothermia resulting from transfusion of blood
10. Which of the following statements regarding fresh-frozen plasma (FFP) is correct?
A. Contains all of the clotting factors except factor VIII
B. Should not be used in patients with antithrombin III deficiency
C. Carries the same infection risk as a unit of whole blood
D. Is contraindicated in the case of isolated-factor deficiencies
11. The most common cause of an acute hemolytic transfusion reaction is
A. An error during type and screen
B. An error during type and crossmatch
C. Misidentification of the patient, blood specimen, or transfusion unit
12. Evidence for the fact that leukocyte-containing blood products appear to be
immunosuppressive includes all of the following, except
A. Preoperative blood transfusions appear to improve graft survival in renal
B. Recurrence of malignant growths may be more likely in patients who receive a
blood transfusion during surgery
C. Transfusion of allogeneic leukocytes can activate latent viruses in a recipient
D. Blood transfusion may decrease the incidence of serious infection following
13. Bacterial infection due to a contaminated blood product is most likely with
14. All of the following qualities are advantages of crystalloid solutions, except
D. Have the ability to remain in the intravascular space for a relatively long
15. Administration of large volumes of normal saline can lead to
B. A hyperchloremic-induced nongap metabolic acidosis
C. An anion gap lactic acidosis
16. All of the following solutions contain potassium, except
17. The storage time for packed red blood cells at temperatures of 1 to 6°C is
18. Which of the following statements regarding transfusion of packed red blood cells is
A. The hematocrit of 1 unit is usually 30% to 40%
B. Transfusion of a single unit will increase an adult’s hemoglobin concentration
C. May cause clotting if the transfused packed red blood cells are mixed with
D. Their principle use as that of a volume expander
19. Blood products are tested for all of the following, except
20. Regarding assessment of surgical blood loss
A. Both surgeons and anesthesiologists tend to underestimate blood loss
B. Measurement of blood in the surgical suction container is all that is necessary
C. The use of irrigating solutions does not complicate assessment of blood loss
D. A soaked “lap” pad can hold 10 to 15 mL of blood
21. The most common nonhemolytic reaction to transfusion of blood products is
22. Types of autologous blood transfusion include all of the following, except
B. Intraoperative blood salvage
23. A patient with type O blood will have which of the following plasma antibodies?
24. After blood is collected, the preservative CPDA-1 is commonly added. This
contains all of the following, except
25. A 51-year-old patient was an unrestrained driver in a motor vehicle crash in which
he sustained multiple traumatic injuries. He is on mechanical ventilation, and has
received 8 units of packed red blood cells, 4 units of fresh-frozen plasma, and 6
units of platelets. His arterial blood gas reveals a metabolic alkalosis. The most
likely explanation for this finding is
A. Metabolism of citrate to bicarbonate
26. A 70-year-old patient with chronic renal failure is in the operating room undergoing a
kidney transplant. There has been more blood loss than expected, and he has
received 6 units of packed red blood cells and 3 units of fresh-frozen plasma. The
surgeons still complain that the patient “won’t clot.” All of the following are
potential contributors to his coagulopathy, except
C. Dilutional thrombocytopenia
D. Fibrinogen level of 250 mg/dL
27. The estimated maintenance fluid requirement for a 9-year-old, 35-kg patient is
28. Which of the following patients is least likely to need calcium supplementation due
to citrate-induced hypocalcemia related to blood transfusion?
A. A 30-year-old trauma patient receiving massive blood transfusion through a
rapid transfuser at a rate of 75 mL/min
B. A patient with end-stage liver disease undergoing a complicated open shunt
procedure, who is hypothermic and has received greater than 2 blood volumes of
C. A neonate undergoing congenital diaphragmatic hernia repair
D. A 50-year-old patient with coronary artery disease undergoing an open femoral
popliteal bypass procedure, who has received 3 units of packed red blood cells
29. A medical student asks you if “young” blood is better for critically ill patients.
Which of the following statements regarding “young” blood is most correct?
A. Fresher blood has better ability to deliver oxygen to tissues
B. Blood from younger donors has lower risk of immunosuppression than blood
C. Older blood has a lower potassium content
D. Fresher blood can be transfused more rapidly than older blood
30. You are caring for an 18-year-old female trauma patient who was emergently
transported to the operating room for control of massive bleeding. Due to the
acuteness of the patient’s bleeding, there was no time for blood typing and she has
received 3 units of O-negative packed red blood cells. The blood bank notifies you
that the patient’s blood type is A-positive. If the patient requires further transfusion,
which of the following should be administered?
1. C. When dehydrated, patients with normal renal function will retain sodium and
produce a concentrated urine. Urine osmolality is typically greater than 450
mOsm/kg in this setting. Urine sodium will be low, and specific gravity will be high.
2. A. CVP measurements must be evaluated in context of the clinical setting. Factors
such as underlying cardiopulmonary disease, patient position, and anatomy can affect
the values. A CVP of <5 mm Hg can be normal in a healthy patient without signs of
hypovolemia. For surgical cases during which large fluid shifts are expected,
placement of a CVP monitor may be indicated. Patients with compromised right
ventricular function generally have high CVPs, and thus, a CVP of 10 mm Hg should
be considered normal to low depending on the degree of dysfunction.
3. B. In healthy patients the lactate in lactated Ringers solution is rapidly converted to
bicarbonate by the liver and does not cause a lactic acidosis. Administration of a
large volume of normal saline can cause a hyperchloremic metabolic acidosis.
Lactate is not bound by albumin.
4. C. An intravenous solution’s effect on fluid movement depends in part on its
tonicity. This term is sometimes used interchangeably with osmolarity, although they
are subtly different. Osmolarity is the number of osmoles or moles of solute per liter
of solution. Tonicity is the effective osmolality and is equal to the sum of the
concentrations of the solutes which have the capacity to exert an osmotic force
across the membrane. A solution is isotonic if its tonicity falls within (or near) the
normal range for blood serum—from 275 to 295 mOsm/kg. A hypotonic solution has
lower osmolarity (<250), and a hypertonic solution has higher osmolarity (>350)
Table 5-1 Osmolarity and tonicity of commonly used crystalloid solutions
D5 normalsaline 586 Hypertonic
5. D. While dextran 40 has a molecular weight of 40,000, dextran 70 has a molecular
weight of 70,000, and therefore, the latter is broken down more slowly, lasts longer,
and is a better volume expander. Dextran 40 appears to improve blood flow through
the microcirculation, and all dextrans may have antiplatelet effects. Infusion of large
volume of dextran (>20 mL/kg/day) has been associated with renal failure.
6. A. Substantial evaporative losses can be associated with large wounds and are
directly proportionate to the surface area exposed. Third spacing can cause massive
fluid shifts, and traumatized, inflamed, or infected tissue can sequester large amounts
of fluid. Cellular dysfunction as a result of hypoxia usually produces an increase in
7. C. The Rh blood group is second in importance only to the ABO blood group in
the field of transfusion medicine. It has remained of primary importance in obstetrics,
being the main cause of hemolytic disease of the newborn. The significance of the Rh
blood group is related to the fact that the Rh antigen (D antigen) is highly
immunogenic. In the case of the D antigen, individuals who do not produce the D
antigen will produce anti-D if they encounter the D antigen when transfused with
RBCs (causing a hemolytic transfusion reaction). For this reason, the Rh status is
routinely determined in blood donors, transfusion recipients, and mothers-to-be.
8. A. A crossmatch mimics a transfusion, where donor cells are mixed with the
recipient’s serum. This has three purposes: (1) confirms ABO/Rh typing, (2) detects
recipient antibodies to other blood group systems, and (3) detects antibodies in low
titers or those that do not agglutinate easily. Choice C describes an antibody screen.
9. C. The level of 2,3-DPG in stored blood is reduced, causing decreased oxygen
unloading to the tissues. Hypothermia also causes a leftward shift of the
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