Advanced Care of Adults in Acute Settings I | Questions and
Verified Answers | Pass Guaranteed - A+ Graded
Foundations of Mechanical Ventilation and Acute Respiratory Failure
Q1: A 68-year-old man with severe pneumonia develops respiratory distress. His arterial
blood gas on room air shows pH 7.25, PaCO₂ 68 mmHg, PaO₂ 52 mmHg, and HCO₃ 28
mEq/L. Which type of respiratory failure is present?
A. Hypoxemic respiratory failure only
B. Hypercapnic respiratory failure only
C. Both hypoxemic and hypercapnic respiratory failure [CORRECT]
D. Compensated respiratory alkalosis
Rationale: This patient meets criteria for both hypoxemic (PaO₂ <60 mmHg) and
hypercapnic (PaCO₂ >45 with pH <7.35) respiratory failure. The elevated bicarbonate
indicates metabolic compensation for chronic CO₂ retention, but the pH remains
acidemic indicating acute-on-chronic failure. Respiratory alkalosis would show
decreased PaCO₂ and elevated pH.
Correct Answer: C
Q2: A 58-year-old woman with ARDS is being initiated on mechanical ventilation.
According to lung-protective ventilation principles, which tidal volume setting is most
appropriate for her predicted body weight of 60 kg?
,A. 480 mL (8 mL/kg)
B. 420 mL (7 mL/kg)
C. 360 mL (6 mL/kg) [CORRECT]
D. 600 mL (10 mL/kg)
Rationale: Lung-protective ventilation for ARDS targets 6 mL/kg predicted body weight
(PBW), not actual body weight. This reduces volutrauma and ventilator-induced lung
injury. While 6-8 mL/kg is acceptable for non-ARDS patients, ARDS specifically requires
the lower tidal volume. 10 mL/kg is associated with increased mortality in ARDS.
Correct Answer: C
Q3: A 72-year-old man with COPD exacerbation has refractory hypoxemia on high-flow
nasal cannula. He is somnolent but protectable, with copious secretions. Which finding
is the strongest indication for endotracheal intubation?
A. PaO₂ of 58 mmHg on 60% FiO₂
B. Inability to protect airway with depressed mental status [CORRECT]
C. Respiratory rate of 28 breaths per minute
D. pH of 7.30 with PaCO₂ of 60 mmHg
Rationale: Failure to protect the airway (inability to handle secretions, depressed gag
reflex, altered mental status) is an absolute indication for intubation regardless of
oxygenation or ventilation status. While the other findings indicate respiratory failure,
they may be manageable with noninvasive ventilation if the airway is protected.
Correct Answer: B
,Q4: A patient on AC/VC ventilation has the following settings: tidal volume 400 mL, rate
16, FiO₂ 0.50, PEEP 5. The patient is anxious and breathing at 24 breaths per minute.
Which statement about this scenario is most accurate?
A. The patient receives 400 mL for all 24 spontaneous breaths
B. The patient receives 400 mL only for the 16 set breaths, spontaneous breaths get
minimal support
C. The patient receives 400 mL for every triggered breath regardless of rate [CORRECT]
D. The ventilator will alarm and require mode change
Rationale: In Assist-Control (AC) mode, every breath triggered by the patient (or
time-triggered) receives the full set tidal volume (400 mL in this case). The backup rate
is 16, but if the patient breathes faster, each breath still gets the full tidal volume. This
can cause respiratory alkalosis if the patient is over-triggering.
Correct Answer: C
Q5: A 55-year-old man with status asthmaticus is intubated. On ventilator check, the
expiratory flow tracing does not return to baseline before the next breath begins. Which
complication is occurring?
A. Pneumothorax
B. Auto-PEEP (intrinsic PEEP) [CORRECT]
C. Mainstem intubation
D. Ventilator disconnect
, Rationale: Incomplete exhalation with flow not returning to baseline indicates air
trapping and auto-PEEP (intrinsic PEEP), common in obstructive lung disease. This
increases intrathoracic pressure, reduces venous return, and can cause hemodynamic
compromise. Treatment includes increasing expiratory time, reducing respiratory rate,
and bronchodilator therapy.
Correct Answer: B
Q6: A patient with acute hypoxemic respiratory failure is placed on mechanical
ventilation. Initial settings are AC/VC, tidal volume 500 mL (6 mL/kg PBW), rate 18, FiO₂
0.80, PEEP 10. The plateau pressure is measured at 32 cm H₂O. Which adjustment is
most appropriate?
A. Increase PEEP to 15 cm H₂O
B. Decrease tidal volume to 400 mL (4.8 mL/kg) [CORRECT]
C. Increase respiratory rate to 22
D. Switch to pressure control ventilation
Rationale: Plateau pressure should be maintained <30 cm H₂O to prevent barotrauma
and volutrauma. A pressure of 32 cm H₂O exceeds this threshold. Decreasing tidal
volume (even below 6 mL/kg if necessary) is the appropriate response. Increasing PEEP
would further increase plateau pressure. Mode change does not address the pressure
issue.
Correct Answer: B