Post-test: PFT

Question 1

Which of the following tests is most appropriate next for a COPD patient with FEV1 1.4 L (43% predicted) and DLCO 14.5 mL/min/mmHg?
a. Lung volumes by body plethysmograph
b. Room air ABG
c. Treadmill exercise test with pulse oximetry
d. Post bronchodilator spirometry

Answer 1

Correct answer: a — Rationale: Lung volume measurement is indicated to determine hyperinflation severity and restriction when DLCO is low.

Question 2

After inhalation of methacholine, which spirometry change indicates a positive bronchial challenge test?
a. FEV1 decreased 10%, sGAW increased 10%
b. FEV1 decreased 15%, sGAW increased 35%
c. FEV1 decreased 25%, sGAW decreased 50%
d. FEV1 increased 5%, sGAW decreased 25%

Answer 2

Correct answer: c — Rationale: A ≥20% fall in FEV1 and decreased sGAW confirms airway hyperresponsiveness.

Question 3

When measuring DLCO, which statement is true?
a. Oxygen is better test gas than CO
b. The unit of measure is mL/min/mmHg or mL of CO
c. The test gas must be capable of combining with hemoglobin
d. Diffusion is independent of perfusion gradients

Answer 3

Correct answer: c — Rationale: CO diffusion measurement relies on rapid hemoglobin binding.

Question 4

Normal values of PFT depend on which factors?
I. Height
II. Weight
III. Age
IV. Lung condition
a. 1 and 3 only
b. 1, 2, and 3 only
c. 1, 3, and 4 only
d. 1, 2, 3, and 4

Answer 4

Correct answer: b — Rationale: Height, age, and sex are primary determinants; weight has minimal effect.

Question 5

Which anthropometric measurement is NOT essential for pulmonary function testing?
a. Height
b. Gender
c. Age
d. Percent body fat

Answer 5

Correct answer: d — Rationale: Body fat is irrelevant to predicted PFT values.

Question 6

Lack of bronchodilator response in severe emphysema is most likely due to:
a. Severe bronchospasm
b. Passive airway compression/collapse
c. Air trapping
d. Insensitivity to bronchodilators

Answer 6

Correct answer: b — Rationale: Emphysema causes airway collapse during exhalation, limiting reversibility.

Question 7

Regarding DLCO test results, which combination is correct?
1. Emphysema increases DLCO
2. Chronic bronchitis decreases DLCO
3. Exercise increases DLCO
4. Asbestosis decreases DLCO
a. 1 and 3 only
b. 3 and 4 only
c. 1, 2, and 3 only
d. 1, 2, 3, and 4

Answer 7

Correct answer: b — Rationale: DLCO increases with exercise; decreases in emphysema and interstitial disease.

Question 8

Which pulmonary function test best evaluates ability to cough?
a. VT
b. FRC
c. Alveolar minute ventilation
d. MIP

Answer 8

Correct answer: d — Rationale: Maximum inspiratory pressure assesses respiratory muscle strength.

Question 9

A man with smoking history shows TLC↑, RV↑, DLCO↓. Most probable diagnosis?
a. Emphysema
b. Pneumonia
c. Sarcoidosis
d. Pneumoconiosis

Answer 9

Correct answer: a — Rationale: Hyperinflation + RV↑ + DLCO↓ strongly indicate emphysema.

Question 10

Data set shows: FEV1/FVC 37%, RV/TLC high, MIP reduced. Most consistent disease entity?
a. COPD
b. Obesity
c. Pulmonary fibrosis
d. Neuromuscular disease

Answer 10

Correct answer: d — Rationale: Weak MIP + preserved RV/TLC pattern suggests neuromuscular weakness.

Question 11

Which statement regarding myasthenia gravis is FALSE?
a. FEV1 decreases
b. TLC decreases
c. VC decreases
d. FEV1/FVC markedly decreased

Answer 11

Correct answer: d — Rationale: MG is restrictive—FEV1/FVC is normal or increased.

Question 12

A 20-yr-old shows FVC +20% post-BD, FEV1 +10%. Interpretation?
a. Normal spirometry
b. Significant bronchodilator response
c. Moderate obstruction without reversibility
d. Test must be repeated

Answer 12

Correct answer: b — Rationale: ≥12% and ≥200 mL increase confirms bronchodilator response.

Question 13

Absolute contraindication for bronchoprovocation testing?
a. Pregnancy
b. Cardiovascular impairment
c. Recent caffeine
d. Lack of bronchodilator washout

Answer 13

Correct answer: b — Rationale: Bronchoprovocation poses risk in unstable cardiovascular disease.

Question 14

Back-extrapolated volume exceeds limit—what instruction is correct?
a. “Don’t hesitate”
b. “Blow out longer”
c. “Blow out faster”
d. “Breathe deeper before blowing”

Answer 14

Correct answer: c — Rationale: Rapid initial blast minimizes back-extrapolation.

Question 15

Starting from end-expiration, the correct breathing volume for nitrogen washout FRC measurement is:
a. TLC
b. RV
c. VT
d. Maximal inhalation

Answer 15

Correct answer: c — Rationale: N2 washout begins from resting FRC (end-expiration).

Question 16

Before performing FVC testing, the water-sealed spirometer must NOT contain which of the following?
a. Airtight circuit
b. Soda lime absorber
c. 3-L syringe leak check
d. Calibration volume marker

Answer 16

Correct answer: b — Rationale: CO₂ absorbers are unnecessary and interfere with gas composition.

Question 17

Sarcoidosis usually produces which defect?
a. Restrictive
b. Obstructive
c. Combined
d. Hyperreactive airways

Answer 17

Correct answer: a — Rationale: Sarcoidosis decreases lung compliance and volumes.

Question 18

In which condition is PFT contraindicated?
a. Vocal cord dysfunction
b. CHF
c. Untreated pneumothorax
d. Bronchiolitis obliterans

Answer 18

Correct answer: c — Rationale: Forced maneuvers risk worsening pneumothorax.

Question 19

Vocal cord dysfunction affects flow-volume loop by:
a. Blunting expiratory limb
b. Blunting both limbs
c. Blunting inspiratory limb
d. Causing stridor only

Answer 19

Correct answer: c — Rationale: VCD primarily obstructs inspiratory flow.

Question 20

Peak flow measurement records:
a. Peak flow
b. Vital capacity
c. FEV1
d. FEF25–75%

Answer 20

Correct answer: a — Rationale: It measures the highest instantaneous expiratory flow.

Question 21

Acceptable MEP test value includes:
a. –20 to –25 cmH₂O
b. –20 to –40 cmH₂O
c. +20 to +25 cmH₂O
d. +40 cmH₂O

Answer 21

Correct answer: b — Rationale: Normal MEP usually exceeds 40 cmH₂O; –20 to –40 indicates adequate effort.

Question 22

67-yr-old COPD patient post-BD: FEV1 66% predicted. Stage?
a. Mild
b. Moderate
c. Severe
d. Very severe

Answer 22

Correct answer: b — Rationale: GOLD staging: 50–79% = moderate.

Question 23

For DLCO trials, PFT tech should:
a. Average first two trials only
b. Average all trials
c. Report best DLCO
d. Repeat until three match

Answer 23

Correct answer: c — Rationale: Highest acceptable DLCO is reported.

Question 24

Formula for MVV:
a. FEV1 × 35
b. FEV1 × 40
c. MVV = 125 × panting rate
d. None

Answer 24

Correct answer: a — Rationale: MVV ≈ FEV1 × 35.

Question 25

RV/TLC >135% indicates: a. Hyperinflation b. Air trapping c. Increased resistance d. Severe obstruction

Answer 25

Correct answer: b — Rationale: Elevated RV/TLC means retained gas volume (air trapping).

Question 26

SRAW >120 indicates: a. Hyperinflation b. Air trapping c. Increased resistance d. Increased compliance

Answer 26

Correct answer: c — Rationale: Specific airway resistance increases with obstructive disease.

Question 27

FEV1/FVC 95% predicted; FVC 50% predicted. Diagnosis? a. Fibrosis b. Cystic fibrosis c. Emphysema d. Bronchitis

Answer 27

Correct answer: a — Rationale: Preserved ratio + low FVC = restrictive disease.

Question 28

Maximal inspiration + maximal expiration measures: a. Inspiratory reserve b. Tidal breath c. Vital capacity d. Inspiratory capacity

Answer 28

Correct answer: c — Rationale: Max inspiration to max expiration = VC.

Question 29

Supine DLCO effect: a. Decrease b. Increase c. No change d. Unpredictable

Answer 29

Correct answer: b — Rationale: Supine position increases pulmonary blood volume.

Question 30

Body box operates based on: a. Charles’ law b. Poiseuille’s law c. Boyle’s law d. Dalton’s law

Answer 30

Correct answer: c — Rationale: Plethysmography uses pressure–volume relationship (Boyle’s).

Question 31

Closed-circuit gas dilution shows ↑ tidal volume during test—why? a. CO₂ absorber missing b. Excess expiratory effort c. Bronchospasm d. Fatigue

Answer 31

Correct answer: a — Rationale: CO₂ accumulation triggers deeper breathing.

Question 32

Which maneuver measures VC? a. Inspiratory reserve b. Tidal breath c. Vital capacity d. Inspiratory capacity

Answer 32

Correct answer: c — Rationale: VC requires max inhale then max exhale.

Question 33

Spirometry + N₂ washout shows: RV 186%, RV/TLC 136%. Interpretation? a. Severe hyperinflation + air trapping b. Normal volumes c. Restriction d. Normal RV

Answer 33

Correct answer: a — Rationale: RV% and RV/TLC extremely elevated.

Question 34

Recommended breath-hold time for DLCO: a. 12 s b. 10 s c. 7 s d. 5 s

Answer 34

Correct answer: b — Rationale: Standard single-breath DLCO uses 10-sec breath hold.

Question 35

Patient data: FVC 63% predicted, FEV1/FVC 97%. Interpretation? a. Emphysema b. Sarcoidosis c. Asthma d. Normal PFT

Answer 35

Correct answer: b — Rationale: Restrictive pattern + preserved ratio = parenchymal disease (sarcoid).

Question 36

Pulmonary function results: FEV1 55% predicted, DLCO 40% predicted. Most likely? a. Chronic bronchitis b. Kyphoscoliosis c. Emphysema d. Silicosis

Answer 36

Correct answer: c — Rationale: DLCO reduced with obstruction = emphysema.

Question 37

Which method determines lung volume? a. Body box b. N₂ washout c. Spirometry d. Helium dilution

Answer 37

Correct answer: a — Rationale: Body box is gold standard for TLC.

Question 38

Final methacholine report must include: a. PC20 FEV1 b. Patient weight c. Drug concentration only d. Symptoms only

Answer 38

Correct answer: a — Rationale: PC20 defines degree of airway hyperreactivity.

Question 39

From forced expiratory spirogram, which can be determined? I FEV1 II FEF200–1200 III FRC IV Diffusing capacity a. 1 only b. 1 and 2 only c. 3 and 4 only d. 1, 2, 4

Answer 39

Correct answer: b — Rationale: FRC & DLCO cannot be obtained from FVC maneuver.

Question 40

Earliest sign of respiratory impairment in GBS? a. PaO₂ b. PaCO₂ c. MIP d. MVV

Answer 40

Correct answer: c — Rationale: MIP falls first as neuromuscular weakness develops.

Question 41

MIP should be measured at: a. FRC b. RV c. End-inspiration d. TLC

Answer 41

Correct answer: b — Rationale: Max inspiratory pressure is most accurate at RV.

Question 42

Wright respirometer measures: a. Tidal volume b. Vital capacity c. FVC d. Peak flow

Answer 42

Correct answer: a — Rationale: It measures low flow volumes (VT).

Question 43

Which PFT best fits: FEV1 55%, FEV1/FVC 55%, FEF25–75 40%, DLCO normal? a. Silicosis b. Kyphoscoliosis c. Emphysema d. Chronic bronchitis

Answer 43

Correct answer: d — Rationale: Obstruction with normal DLCO is chronic bronchitis.

Question 44

Correct nitrogen washout test requires: a. 7 min or final N₂ 10% b. 10 min or final N₂ 5% c. 3 repeated final values at 10% d. 3 repeated final values at 1.5%

Answer 44

Correct answer: d — Rationale: Test ends when final N₂ ≤1.5% for 3 breaths.

Question 45

In emphysema DLCO is reduced due to: a. Low FEV1 b. Low lung volume c. Low pulmonary pressure d. Loss of alveolar surface area

Answer 45

Correct answer: d — Rationale: DLCO loss = destruction of alveolar-capillary membrane.

Question 46

DLCO test mixture contains: a. 0.1% CO, 10% helium, 20% O₂, rest air b. 0.1% CO, 15% helium, rest O₂ c. 0.3% CO, 10% helium, nitrogen balance d. 0.5% CO, 20% helium, rest air

Answer 46

Correct answer: c — Rationale: Standard mixture uses ~0.3% CO + inert tracer gas.

Question 47

Methacholine results: FEV1 drop from 4.1 to 3.0 L (≈27% drop). Interpretation? a. Negative b. Positive after first dose c. Positive after second dose d. Patient does not have asthma

Answer 47

Correct answer: c — Rationale: ≥20% fall confirms positive challenge.

Question 48

Which physical measurement is correct before PFT? a. Actual weight only b. Standing height without shoes c. Arm span only d. Sitting height only

Answer 48

Correct answer: b — Rationale: Predicted PFT values require accurate standing height.

Question 49

33-yr-old with exertional SOB shows FVC 73%, FEV1 70%, PEF 45%, MVV 43%. Interpretation? a. Mild obstruction b. Normal c. Severe restriction d. Muscle weakness/poor effort

Answer 49

Correct answer: d — Rationale: Low PEF + low MVV with near-normal ratio suggests poor effort or weakness.

Question 50

Maximal inspiratory pressure assesses which? a. Ventilatory status b. Pulmonary mechanics c. Oxygenation d. Acid-base balance

Answer 50

Correct answer: b — Rationale: MIP evaluates muscle strength for breathing.