AMS Exam 2 Questions – Study Guide, Practice Questions & Revision
Notes
A patient has coronary artery bypass graft surgery and is transported to the surgical intensive
care unit at noon and is placed on mechanical ventilation. Interpret the initial arterial blood gas
levels
pH: 7.31
PaCO2: 48 mm Hg
Bicarbonate: 22 mEq/L
PaO2: 115 mm Hg
O2 saturation: 99%
a. Normal arterial blood gas levels with a high oxygen level
b. Partly compensated respiratory acidosis; normal oxygen
c. Uncompensated metabolic acidosis with high oxygen levels
d. Uncompensated respiratory acidosis; hyperoxygenated - ANS ✔✔d. Uncompensated
respiratory acidosis; hyperoxygenated
The high PaO2 level reflects hyperoxygenation; the PaCO2 and pH levels show respiratory
acidosis. The respiratory acidosis is uncompensated as indicated by a pH of 7.31 (acidosis) and a
normal bicarbonate level. No metabolic compensation has occurred.
The provider orders the following mechanical ventilation settings for a patient who weighs 75
kg. The patient's spontaneous respiratory rate is 22 breaths/min. Which arterial blood gas
abnormality may occur if the patient continues to be tachypneic at these ventilator settings?
Settings:
,Tidal volume: 600 mL (8 mL per kg)
FiO2: 0.5
Respiratory rate: 14 breaths/min
Mode assist/control
Positive end-expiratory pressure: 10 cm H2O
a. Metabolic acidosis
b. Metabolic alkalosis
c. Respiratory acidosis
d. Respiratory alkalosis - ANS ✔✔d. Respiratory alkalosis
Assist/control ventilation may result in respiratory alkalosis, especially when the patient is
breathing at a higher rate that the ventilator rate. Each time the patient initiates a spontaneous
breath—in this case 22 times per minute—the ventilator will deliver 600 mL of volume.
A patient's ventilator settings are adjusted to treat hypoxemia. The fraction of inspired oxygen is
increased from 0.6 to 0.7, and the positive end-expiratory pressure is increased from 10 to 15
cm H2O. Shortly after these adjustments, the nurse notes that the patient's blood pressure
drops from 120/76 mm Hg to 90/60 mm Hg. What is the most likely cause of this decrease in
blood pressure?
a. Decrease in cardiac output
b. Hypovolemia
c. Increase in venous return
d. Oxygen toxicity - ANS ✔✔a. Decrease in cardiac output
Positive end-expiratory pressure increases intrathoracic pressure and may result in decreased
venous return. Cardiac output decreases as a result, and is reflected in the lower blood
pressure. It is essential to assess the patient to identify optimal positive end-expiratory
,pressure—the highest amount that can be applied without compromising cardiac output.
Although hypovolemia can result in a decrease in blood pressure, there is no indication that this
patient has hypovolemia. As noted, higher levels of positive end-expiratory pressure may cause
a decrease, not an increase, in venous return. Oxygen toxicity can occur in this case
secondary to the high levels of oxygen needed to maintain gas exchange; however, oxygen
toxicity is manifested in damage to the alveoli.
The nurse is caring for a patient with an endotracheal tube. The nurse understands that
endotracheal suctioning is needed to facilitate removal of secretions and that the procedure
a. decreases intracranial pressure.
b. depresses the cough reflex.
c. is done as indicated by patient assessment.
d. is more effective if preceded by saline instillation. - ANS ✔✔c. is done as indicated by patient
assessment.
Suctioning is performed as indicated by patient assessment. Suctioning is associated with
increases in intracranial pressure; therefore, it is important to hyperoxygenate the patient
before suctioning to reduce this complication. Suctioning can stimulate the cough reflex rather
than depress this reflex. Saline instillation is associated with negative physiological outcomes
and is not recommended as part of the suctioning procedure; it does not loosen secretions,
which is a common misperception.
A patient is admitted to the progressive care unit with a diagnosis of community-acquired
pneumonia. The patient has a history of chronic obstructive pulmonary disease and diabetes. A
set of arterial blood gases obtained on admission without supplemental oxygen shows pH 7.35;
PaCO2 55 mm Hg; bicarbonate 30 mEq/L; PaO2 65 mm Hg. These blood gases reflect:
a. hypoxemia and compensated metabolic alkalosis.
b. hypoxemia and compensated respiratory acidosis.
, c. normal oxygenation and partly compensated metabolic alkalosis.
d. normal oxygenation and uncompensated respiratory acidosis. - ANS ✔✔b. hypoxemia and
compensated respiratory acidosis.
The PaO2 of 65 mm Hg is lower than normal range (80 to 100 mm Hg), indicating hypoxemia.
The high PaCO2 indicates respiratory acidosis. The elevated bicarbonate indicates metabolic
alkalosis. Because the pH is normal, the underlying acid-base alteration is compensated.
Given the patient's history of chronic pulmonary disease and a pH that is at the lower end of
normal range, it can be determined that this patient is hypoxemic with fully compensated
respiratory acidosis.
A patient's status worsens and needs mechanical ventilation. The pulmonologist wants the
patient to receive 10 breaths/min from the ventilator but wants to encourage the patient to
breathe spontaneously between the mechanical breaths at his own tidal volume. This mode of
ventilation is called
a. assist/control ventilation.
b. controlled ventilation.
c. intermittent mandatory ventilation.
d. positive end-expiratory pressure. - ANS ✔✔c. intermittent mandatory ventilation.
The intermittent mandatory ventilation mode allows the patient to breathe spontaneously
between breaths. The patient will receive a preset tidal volume at a preset rate. Any additional
breaths that he initiates will be at his spontaneous tidal volume, which will likely be lower than
the ventilator breaths. In assist/control ventilation, spontaneous effort results in a preset tidal
volume delivered by the ventilator. Spontaneous effort during controlled ventilation
results in patient/ventilator dyssynchrony. Positive end-expiratory pressure (PEEP) is
application of positive pressure to breaths delivered by the ventilator. PEEP is an adjunct to both
intermittent mandatory and assist/control ventilation.
Notes
A patient has coronary artery bypass graft surgery and is transported to the surgical intensive
care unit at noon and is placed on mechanical ventilation. Interpret the initial arterial blood gas
levels
pH: 7.31
PaCO2: 48 mm Hg
Bicarbonate: 22 mEq/L
PaO2: 115 mm Hg
O2 saturation: 99%
a. Normal arterial blood gas levels with a high oxygen level
b. Partly compensated respiratory acidosis; normal oxygen
c. Uncompensated metabolic acidosis with high oxygen levels
d. Uncompensated respiratory acidosis; hyperoxygenated - ANS ✔✔d. Uncompensated
respiratory acidosis; hyperoxygenated
The high PaO2 level reflects hyperoxygenation; the PaCO2 and pH levels show respiratory
acidosis. The respiratory acidosis is uncompensated as indicated by a pH of 7.31 (acidosis) and a
normal bicarbonate level. No metabolic compensation has occurred.
The provider orders the following mechanical ventilation settings for a patient who weighs 75
kg. The patient's spontaneous respiratory rate is 22 breaths/min. Which arterial blood gas
abnormality may occur if the patient continues to be tachypneic at these ventilator settings?
Settings:
,Tidal volume: 600 mL (8 mL per kg)
FiO2: 0.5
Respiratory rate: 14 breaths/min
Mode assist/control
Positive end-expiratory pressure: 10 cm H2O
a. Metabolic acidosis
b. Metabolic alkalosis
c. Respiratory acidosis
d. Respiratory alkalosis - ANS ✔✔d. Respiratory alkalosis
Assist/control ventilation may result in respiratory alkalosis, especially when the patient is
breathing at a higher rate that the ventilator rate. Each time the patient initiates a spontaneous
breath—in this case 22 times per minute—the ventilator will deliver 600 mL of volume.
A patient's ventilator settings are adjusted to treat hypoxemia. The fraction of inspired oxygen is
increased from 0.6 to 0.7, and the positive end-expiratory pressure is increased from 10 to 15
cm H2O. Shortly after these adjustments, the nurse notes that the patient's blood pressure
drops from 120/76 mm Hg to 90/60 mm Hg. What is the most likely cause of this decrease in
blood pressure?
a. Decrease in cardiac output
b. Hypovolemia
c. Increase in venous return
d. Oxygen toxicity - ANS ✔✔a. Decrease in cardiac output
Positive end-expiratory pressure increases intrathoracic pressure and may result in decreased
venous return. Cardiac output decreases as a result, and is reflected in the lower blood
pressure. It is essential to assess the patient to identify optimal positive end-expiratory
,pressure—the highest amount that can be applied without compromising cardiac output.
Although hypovolemia can result in a decrease in blood pressure, there is no indication that this
patient has hypovolemia. As noted, higher levels of positive end-expiratory pressure may cause
a decrease, not an increase, in venous return. Oxygen toxicity can occur in this case
secondary to the high levels of oxygen needed to maintain gas exchange; however, oxygen
toxicity is manifested in damage to the alveoli.
The nurse is caring for a patient with an endotracheal tube. The nurse understands that
endotracheal suctioning is needed to facilitate removal of secretions and that the procedure
a. decreases intracranial pressure.
b. depresses the cough reflex.
c. is done as indicated by patient assessment.
d. is more effective if preceded by saline instillation. - ANS ✔✔c. is done as indicated by patient
assessment.
Suctioning is performed as indicated by patient assessment. Suctioning is associated with
increases in intracranial pressure; therefore, it is important to hyperoxygenate the patient
before suctioning to reduce this complication. Suctioning can stimulate the cough reflex rather
than depress this reflex. Saline instillation is associated with negative physiological outcomes
and is not recommended as part of the suctioning procedure; it does not loosen secretions,
which is a common misperception.
A patient is admitted to the progressive care unit with a diagnosis of community-acquired
pneumonia. The patient has a history of chronic obstructive pulmonary disease and diabetes. A
set of arterial blood gases obtained on admission without supplemental oxygen shows pH 7.35;
PaCO2 55 mm Hg; bicarbonate 30 mEq/L; PaO2 65 mm Hg. These blood gases reflect:
a. hypoxemia and compensated metabolic alkalosis.
b. hypoxemia and compensated respiratory acidosis.
, c. normal oxygenation and partly compensated metabolic alkalosis.
d. normal oxygenation and uncompensated respiratory acidosis. - ANS ✔✔b. hypoxemia and
compensated respiratory acidosis.
The PaO2 of 65 mm Hg is lower than normal range (80 to 100 mm Hg), indicating hypoxemia.
The high PaCO2 indicates respiratory acidosis. The elevated bicarbonate indicates metabolic
alkalosis. Because the pH is normal, the underlying acid-base alteration is compensated.
Given the patient's history of chronic pulmonary disease and a pH that is at the lower end of
normal range, it can be determined that this patient is hypoxemic with fully compensated
respiratory acidosis.
A patient's status worsens and needs mechanical ventilation. The pulmonologist wants the
patient to receive 10 breaths/min from the ventilator but wants to encourage the patient to
breathe spontaneously between the mechanical breaths at his own tidal volume. This mode of
ventilation is called
a. assist/control ventilation.
b. controlled ventilation.
c. intermittent mandatory ventilation.
d. positive end-expiratory pressure. - ANS ✔✔c. intermittent mandatory ventilation.
The intermittent mandatory ventilation mode allows the patient to breathe spontaneously
between breaths. The patient will receive a preset tidal volume at a preset rate. Any additional
breaths that he initiates will be at his spontaneous tidal volume, which will likely be lower than
the ventilator breaths. In assist/control ventilation, spontaneous effort results in a preset tidal
volume delivered by the ventilator. Spontaneous effort during controlled ventilation
results in patient/ventilator dyssynchrony. Positive end-expiratory pressure (PEEP) is
application of positive pressure to breaths delivered by the ventilator. PEEP is an adjunct to both
intermittent mandatory and assist/control ventilation.
