NBRC TMC EXAM MASTERY REVIEW
QUESTIONS AND ANSWERS
1. A patient with ARDS is being ventilated in Pressure Control mode. The clinician notes a
sudden decrease in the exhaled tidal volume. Which of the following is the most likely cause?
A. An increase in lung compliance
B. A decrease in airway resistance
C. A decrease in lung compliance
D. An increase in the pressure limit
Answer: C
Conceptual Explanation: In Pressure Control ventilation, the pressure is constant. If lung
compliance decreases (stiffer lungs), the volume delivered by that specific pressure will
decrease.
2. While monitoring a patient with a Swan-Ganz catheter, the therapist notes a CVP of 12
mmHg and a PCWP of 6 mmHg. Which of the following conditions is most consistent with
these findings?
A. Left heart failure
,B. Hypovolemia
C. Right heart failure
D. Pulmonary edema
Answer: C
Conceptual Explanation: An elevated CVP (normal 2-6 mmHg) with a normal or low
PCWP (normal 4-12 mmHg) indicates a problem isolated to the right side of the heart, such
as right heart failure or pulmonary hypertension.
3. A 65-year-old male with COPD has the following ABG results: pH 7.36, PaCO2 62, PaO2 54,
HCO3 34. How would you interpret this blood gas?
A. Fully compensated respiratory acidosis with moderate hypoxemia
B. Acute respiratory acidosis with mild hypoxemia
C. Partially compensated metabolic alkalosis
D. Uncompensated respiratory acidosis
Answer: A
Conceptual Explanation: The pH is within normal range (7.35-7.45) but on the acidic side.
The PaCO2 is high, and the HCO3 is elevated to compensate. This indicates a chronic (fully
compensated) respiratory condition.
, 4. Calculate the Alveolar Oxygen Tension (PAO2) for a patient breathing 40% oxygen at sea
level with a PaCO2 of 40 mmHg. (Assume R = 0.8)
A. 235 mmHg
B. 285 mmHg
C. 250 mmHg
D. 220 mmHg
Answer: A
Conceptual Explanation: PAO2 = FiO2(Pb - PH2O) - (PaCO.8). PAO2 = 0.40(760 - 47)
- (.8) = 0.40(713) - 50 = 285.2 - 50 = 235.2 mmHg.
5. A patient is receiving volume-controlled ventilation. The peak airway pressure is 35 cmH2O
and the plateau pressure is 20 cmH2O. If the flow rate is 60 L/min, what is the airway
resistance?
A. 15 cmH2O/L/sec
B. 10 cmH2O/L/sec
C. 5 cmH2O/L/sec
D. 25 cmH2O/L/sec
Answer: A
Conceptual Explanation: Raw = (PIP - Plateau) / Flow in L/sec. Flow is 60 L/min, which is
1 L/sec. Raw = (35 - 20) / 1 = 15 cmH2O/L/sec.
QUESTIONS AND ANSWERS
1. A patient with ARDS is being ventilated in Pressure Control mode. The clinician notes a
sudden decrease in the exhaled tidal volume. Which of the following is the most likely cause?
A. An increase in lung compliance
B. A decrease in airway resistance
C. A decrease in lung compliance
D. An increase in the pressure limit
Answer: C
Conceptual Explanation: In Pressure Control ventilation, the pressure is constant. If lung
compliance decreases (stiffer lungs), the volume delivered by that specific pressure will
decrease.
2. While monitoring a patient with a Swan-Ganz catheter, the therapist notes a CVP of 12
mmHg and a PCWP of 6 mmHg. Which of the following conditions is most consistent with
these findings?
A. Left heart failure
,B. Hypovolemia
C. Right heart failure
D. Pulmonary edema
Answer: C
Conceptual Explanation: An elevated CVP (normal 2-6 mmHg) with a normal or low
PCWP (normal 4-12 mmHg) indicates a problem isolated to the right side of the heart, such
as right heart failure or pulmonary hypertension.
3. A 65-year-old male with COPD has the following ABG results: pH 7.36, PaCO2 62, PaO2 54,
HCO3 34. How would you interpret this blood gas?
A. Fully compensated respiratory acidosis with moderate hypoxemia
B. Acute respiratory acidosis with mild hypoxemia
C. Partially compensated metabolic alkalosis
D. Uncompensated respiratory acidosis
Answer: A
Conceptual Explanation: The pH is within normal range (7.35-7.45) but on the acidic side.
The PaCO2 is high, and the HCO3 is elevated to compensate. This indicates a chronic (fully
compensated) respiratory condition.
, 4. Calculate the Alveolar Oxygen Tension (PAO2) for a patient breathing 40% oxygen at sea
level with a PaCO2 of 40 mmHg. (Assume R = 0.8)
A. 235 mmHg
B. 285 mmHg
C. 250 mmHg
D. 220 mmHg
Answer: A
Conceptual Explanation: PAO2 = FiO2(Pb - PH2O) - (PaCO.8). PAO2 = 0.40(760 - 47)
- (.8) = 0.40(713) - 50 = 285.2 - 50 = 235.2 mmHg.
5. A patient is receiving volume-controlled ventilation. The peak airway pressure is 35 cmH2O
and the plateau pressure is 20 cmH2O. If the flow rate is 60 L/min, what is the airway
resistance?
A. 15 cmH2O/L/sec
B. 10 cmH2O/L/sec
C. 5 cmH2O/L/sec
D. 25 cmH2O/L/sec
Answer: A
Conceptual Explanation: Raw = (PIP - Plateau) / Flow in L/sec. Flow is 60 L/min, which is
1 L/sec. Raw = (35 - 20) / 1 = 15 cmH2O/L/sec.
