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Question 1. Which structure primarily functions as a humidifier and filter for inspired air? A) Trachea B) Nasal mucosa C) Bronchi D) Alveolar sac Answer: B Explanation: The nasal mucosa contains ciliated epithelium and mucus that humidify, warm, and filter inhaled air before it reaches the lower airways. Question 2. The primary muscle of quiet inspiration is: A) Internal intercostals B) Diaphragm C) Scalene muscles D) Abdominal muscles Answer: B Explanation: The diaphragm contracts during quiet breathing, generating most of the negative intrathoracic pressure needed for inspiration. Question 3. Which lung volume is measured directly by a spirometer during a forced vital capacity maneuver? A) Residual volume (RV) B) Functional residual capacity (FRC)
C) Inspiratory reserve volume (IRV) D) Forced vital capacity (FVC) Answer: D Explanation: Spirometry directly records the volume of air exhaled during a forced maneuver, which is the FVC. Question 4. Thoracic compliance is best described as: A) The resistance of the airway to airflow B) The elastic recoil of lung tissue C) The change in volume per change in pressure D) The ratio of alveolar ventilation to perfusion Answer: C Explanation: Compliance is the change in lung volume for a given change in transpulmonary pressure (ΔV/ΔP). Question 5. According to Fick’s law, diffusion of a gas across the alveolar‑capillary membrane is directly proportional to: A) Membrane thickness B) Surface area of the membrane C) Partial pressure gradient squared D) Molecular weight of the gas Answer: B
A) Arterial PO₂ B) Arterial PCO₂ (as H⁺) C) Blood pH in the peripheral tissues D) Ambient temperature Answer: B Explanation: Central chemoreceptors in the medulla respond to changes in cerebrospinal fluid pH, which reflects arterial CO₂ levels. Question 9. The primary function of the mucociliary escalator is to: A) Facilitate gas exchange B) Maintain alveolar surfactant C) Remove inhaled particles and pathogens D) Regulate airway resistance Answer: C Explanation: Ciliated epithelium and mucus trap particles and move them toward the pharynx for clearance. Question 10. In chronic obstructive pulmonary disease (COPD), the hallmark physiologic change is: A) Decreased total lung capacity (TLC) B) Increased residual volume (RV) C) Decreased airway resistance
D) Increased diffusion capacity (DLCO) Answer: B Explanation: Air trapping in COPD leads to an elevated RV and often increased TLC due to hyperinflation. Question 11. Which of the following best characterizes restrictive lung disease? A) Decreased FEV₁/FVC ratio with normal TLC B) Normal FEV₁/FVC ratio with reduced TLC C) Increased airway resistance with normal RV D) Elevated DLCO with normal lung volumes Answer: B Explanation: Restriction reduces lung volumes including TLC, but the FEV₁/FVC ratio is typically normal or high. Question 12. The primary effect of smoking on lung function is: A) Increased elastic recoil B) Decreased airway resistance C) Chronic inflammation leading to airway narrowing D) Enhanced surfactant production Answer: C Explanation: Cigarette smoke causes inflammation, mucus hypersecretion, and structural changes that narrow airways.
B) Boyle’s law (P₁V₁ = P₂V₂) C) Dalton’s law of partial pressures D) Graham’s law of diffusion Answer: B Explanation: Plethysmography measures pressure changes in a sealed box; Boyle’s law relates pressure and volume to compute VTG. Question 16. Which gas analyzer principle is commonly used for measuring helium dilution lung volumes? A) Infrared absorption B) Thermal conductivity C) Mass spectrometry D) Photoacoustic detection Answer: B Explanation: Helium’s thermal conductivity differs from nitrogen, allowing its concentration to be measured by a thermal conductivity sensor. Question 17. According to ATS/ERS standards, daily calibration of a spirometer should be performed using: A) A calibrated pressure transducer B) A 3‑liter syringe at a flow of 300 mL/s C) A calibrated flow‑meter at 500 mL/s D) A nebulized saline solution
Answer: B Explanation: The 3‑L syringe is the reference device for checking volume accuracy and linearity of spirometers. Question 18. A common cause of a “leak” error during spirometry is: A) Using a mouthpiece that is too large B) Inadequate patient seal around the mouthpiece C) Over‑inflating the pneumotachometer D) Excessive ambient humidity Answer: B Explanation: An inadequate seal allows air to escape, resulting in reduced recorded volumes and flow rates. Question 19. During a forced expiratory maneuver, the “smooth start” criterion refers to: A) Immediate achievement of peak expiratory flow within the first 0.5 s B) Absence of hesitation or cough at the beginning of exhalation C) A gradual increase in flow over the first 2 seconds D) A plateau in volume after 6 seconds of exhalation Answer: B Explanation: A smooth start means the patient begins a rapid, uninterrupted exhalation without hesitation.
B) Underestimation in the presence of trapped gas C) Inability to measure dead space D) Requirement for arterial blood sampling Answer: B Explanation: Helium dilution cannot equilibrate with non‑communicating (trapped) alveolar gas, leading to an underestimate of TLC in obstructive disease. Question 23. Compared with plethysmography, gas‑dilution techniques generally: A) Provide higher values for RV B) Underestimate RV in obstructive disease C) Overestimate TLC in restrictive disease D) Are unaffected by airway resistance Answer: B Explanation: Gas‑dilution methods miss trapped air, resulting in a lower measured RV and TLC in obstructive patients. Question 24. The single‑breath DLCO test requires a breath‑hold of approximately: A) 2 seconds B) 5 seconds C) 10 seconds D) 15 seconds
Answer: B Explanation: A 5‑second breath‑hold allows sufficient time for CO diffusion without causing significant CO uptake changes. Question 25. When correcting DLCO for hemoglobin concentration, a lower than normal Hb will: A) Increase the corrected DLCO value B) Decrease the corrected DLCO value C) Have no effect on DLCO calculation D) Require a change in the CO concentration of the test gas Answer: A Explanation: Low Hb reduces CO uptake; correcting for it raises the DLCO to reflect the true diffusing capacity of the alveolar membrane. Question 26. A positive bronchodilator response is defined as an increase in FEV₁ of at least: A) 5% or 100 mL B) 10% or 150 mL C) 12% and ≥ 200 mL D) 15% and ≥ 300 mL Answer: C Explanation: ATS/ERS criteria require a ≥12% and ≥200 mL increase in FEV₁ (or FVC) after bronchodilator administration.
B) The 5th percentile (or – 1.64 Z‑score) of the predicted distribution C) 80% of predicted value D) The median of the reference data set Answer: B Explanation: LLN corresponds to the value below which only 5% of healthy individuals fall, i.e., – 1.64 Z‑score. Question 30. Which reference standard incorporates ethnicity, age, height, and sex to generate predicted values for lung function? A) ATS/ERS 1995 equations B) NHANES III C) Global Lung Function Initiative (GLI) 2012 D) European Coal and Steel Community (ECSC) equations Answer: C Explanation: The GLI 2012 provides multi‑ethnic reference equations covering a wide age range. Question 31. In a flow‑volume loop, a “scooped” appearance of the expiratory limb is most indicative of: A) Restrictive disease B) Upper airway obstruction C) Obstructive airway disease (e.g., COPD) D) Normal lung function
Answer: C Explanation: The concave (scooped) expiratory curve reflects a reduced flow at mid‑lung volumes typical of obstruction. Question 32. An increase in residual volume (RV) with a normal TLC suggests: A) Pure restriction B) Air trapping due to obstructive disease C) Pleural effusion D) Neuromuscular weakness Answer: B Explanation: In obstruction, air gets trapped, raising RV while TLC may remain normal or slightly increased. Question 33. Variable extrathoracic obstruction is best demonstrated on a flow‑volume loop by: A) Flattened inspiratory limb only B) Flattened expiratory limb only C) Both limbs flattened equally D) No change in loop shape Answer: A Explanation: Extrathoracic lesions (e.g., vocal cord dysfunction) affect inspiratory flow more, flattening the inspiratory limb.
B) Transcutaneous oximetry C) Arterial blood gas (ABG) analysis D) Venous blood gas analysis Answer: C Explanation: ABG directly measures PaO₂, PaCO₂, pH, and other parameters from arterial blood. Question 37. In ABG interpretation, a primary metabolic alkalosis is identified by: A) pH > 7.45, PaCO₂ > 45 mmHg, HCO₃⁻ > 26 mmol/L B) pH > 7.45, PaCO₂ < 35 mmHg, HCO₃⁻ < 22 mmol/L C) pH < 7.35, PaCO₂ > 45 mmHg, HCO₃⁻ > 26 mmol/L D) pH < 7.35, PaCO₂ < 35 mmHg, HCO₃⁻ < 22 mmol/L Answer: A Explanation: Metabolic alkalosis raises pH and bicarbonate; compensation raises PaCO₂. Question 38. During cardiopulmonary exercise testing (CPET), the ventilatory equivalent for CO₂ (VE/VCO₂) is used to assess: A) Cardiac output reserve B) Ventilatory efficiency C) Muscular oxygen extraction D) Anaerobic threshold
Answer: B Explanation: VE/VCO₂ reflects how effectively ventilation eliminates CO₂; an elevated ratio suggests ventilatory inefficiency. Question 39. The anaerobic threshold (AT) during CPET is identified when: A) VO₂ plateaus despite increasing workload B) VCO₂ rises disproportionately to VO₂ (V‑slope method) C) Heart rate exceeds 85% of predicted max D) Respiratory exchange ratio (RER) reaches 0. Answer: B Explanation: AT corresponds to the point where lactate accumulation causes excess CO₂ production, seen as a steeper VCO₂ vs. VO₂ slope. Question 40. High‑altitude simulation testing (HAST) primarily evaluates: A) Diffusing capacity at sea level B) Exercise tolerance in hypoxia C) The adequacy of supplemental oxygen delivery systems for patients with COPD D) Sleep‑related breathing disorders Answer: C Explanation: HAST simulates altitude‑induced hypoxia to determine whether a patient with chronic lung disease requires additional oxygen during air travel.
C) Increasing the inspiratory flow rate D) Administration of a bronchodilator mid‑test Answer: A Explanation: Significant desaturation indicates patient distress or hypoxemia; the test must be stopped and the patient assessed. Question 44. HIPAA compliance in pulmonary function testing primarily addresses: A) Calibration standards for equipment B) Confidential handling of patient health information C) Radiation safety protocols D) Sterilization of reusable mouthpieces Answer: B Explanation: HIPAA governs the privacy and security of protected health information, requiring proper documentation and storage. Question 45. The most appropriate way to document a bronchodilator test result is: A) Record only the post‑bronchodilator FEV₁ value B) List pre‑ and post‑values plus absolute and percent change for FEV₁ and FVC C) Note the patient’s subjective feeling of improvement D) Document the type of bronchodilator used without numeric values Answer: B
Explanation: Full documentation includes baseline and post‑treatment values and the calculated changes to assess significance. Question 46. In a patient with neuromuscular disease, the most common pattern on PFT is: A) Obstructive with reduced FEV₁/FVC B) Restrictive with reduced TLC and normal FEV₁/FVC C) Isolated reduction in DLCO D) Mixed obstruction and restriction with elevated RV/TLC Answer: B Explanation: Weak respiratory muscles limit lung expansion, producing a restrictive pattern with preserved ratios. Question 47. The “plateau” in the volume‑time curve at the end of an FVC maneuver indicates: A] Incomplete exhalation B] Adequate expiratory effort with less than 0.025 L change over 1 s C] Presence of a leak D] Need for a larger mouthpiece Answer: B Explanation: ATS/ERS accept a plateau when the volume change is ≤ 0.025 L (25 mL) over at least 1 second, confirming test completion.
