RPFT Lung Volume Measurement & Diffusing Capacity 2

Question 1

The single-breath diffusing capacity (DLCO) test primarily measures the transfer of which gas across the alveolar-capillary membrane?

Accepted Answer

Carbon monoxide

Answer

Oxygen

Answer

Carbon dioxide

Answer

Helium

Question 2

During a single-breath DLCO maneuver, how long does the patient hold their breath at TLC after a rapid inhalation of test gas?

Accepted Answer

10 seconds

Answer

2 seconds

Answer

5 seconds

Answer

20 seconds

Question 3

Which of the following conditions is most likely to cause a DECREASED DLCO with NORMAL spirometry?

Accepted Answer

Pulmonary arterial hypertension

Answer

Asthma

Answer

Obesity

Answer

Vocal cord dysfunction

Question 4

The DLCO result must be adjusted (DLCO/VA or KCO) when a patient cannot perform a full inhalation to TLC. What does VA represent in this equation?

Accepted Answer

Alveolar volume calculated from the helium dilution during the breath hold

Answer

Vital capacity measured on the same maneuver

Answer

Total lung capacity from a prior plethysmography session

Answer

The anatomical dead space volume

Question 5

A patient with significant anemia is found to have a low DLCO. What correction should be applied to interpret the result accurately?

Accepted Answer

Correct DLCO for hemoglobin concentration

Answer

Correct for body surface area

Answer

Apply the BTPS correction

Answer

Adjust for barometric pressure only

Question 6

Which of the following is an absolute contraindication to performing a DLCO test?

Accepted Answer

Carbon monoxide poisoning or recent exposure to high CO levels

Answer

A mild respiratory infection with stable vitals

Answer

Patient age over 70 years

Answer

Mild claustrophobia

Question 7

According to ATS/ERS quality criteria, the minimum number of acceptable DLCO maneuvers required for a valid test session is:

Accepted Answer

2

Answer

1

Answer

3

Answer

5