A pulmonary function technologist is performing daily quality control on a body plethysmograph using an isothermal lung analog. The known volume of the analog is 3.00 L. The three measured volumes are 3.15 L, 3.16 L, and 3.14 L. Ambient temperature is 22°C and barometric pressure is 760 mmHg. Which of the following is the most likely cause for this consistent overestimation?
A patient with suspected neuromuscular weakness is coached to perform a maximal inspiratory pressure (MIP) maneuver. The patient performs three efforts, generating pressures of -45 cmH2O, -65 cmH2O, and -62 cmH2O. According to ATS/ERS guidelines, what should the technologist report?
A patient's spirometry results are as follows: FVC = 2.5 L (55% pred), FEV1 = 1.0 L (35% pred), FEV1/FVC = 40%. After administration of a bronchodilator, the FEV1 increases to 1.25 L and FVC increases to 2.8 L. How should the technologist interpret the bronchodilator response?
A laboratory performs a linearity check on a new spirometer using a 3.0 L calibration syringe. Stepwise injections of 1.0 L are performed. The spirometer measures the volumes as 1.01 L, 2.03 L, and 3.05 L. Which ATS/ERS standard is being evaluated, and do these results meet the criteria?
A 6-minute walk test (6MWT) is performed on a patient with idiopathic pulmonary fibrosis. The patient begins the test with an SpO2 of 95% on room air. After 3 minutes, their SpO2 drops to 87% and they report severe dyspnea. According to ATS guidelines, which TWO actions should the technologist take? (Select TWO)
A technologist reviews the results from a helium dilution lung volume test. The initial and final helium concentrations are reasonable, and the test duration was 7 minutes. However, the calculated TLC is 130% of predicted, while the patient's spirometry shows a clearly restrictive pattern with an FVC of 45% predicted. What is the most likely technical error?
During a DLCO maneuver, the patient inspires the test gas from residual volume (RV) to total lung capacity (TLC). However, the inspired volume (IVC) is measured to be only 75% of the patient's previously measured best FVC. According to the 2017 ATS/ERS DLCO standard, is this maneuver acceptable?
A hospital's pulmonary function lab is located at an altitude of 5,000 feet (1524 meters). A DLCO test is performed on a patient, yielding a result of 25 mL/min/mmHg. The patient's hemoglobin is 14.5 g/dL. What is the most critical correction that must be applied to this result before interpretation?
A cardiopulmonary exercise test (CPET) is performed on a patient complaining of exertional dyspnea. The technologist notices that the patient's breathing reserve (BR) at peak exercise is 5 L/min (5% of MVV). The heart rate reserve is 40%. Which system is the primary limitation to exercise in this patient? ```mermaid graph TD A[Cardiopulmonary Exercise Test] --> B{Analyze Limiting Factors}; B --> C[Breathing Reserve (BR)]; B --> D[Heart Rate Reserve (HRR)]; C --> E{BR < 15%?}; D --> F{HRR < 15%?}; E -->|Yes| G[Ventilatory Limitation]; E -->|No| H[Non-Ventilatory Limitation]; F -->|Yes| I[Cardiovascular Limitation]; F -->|No| J[Non-Cardiovascular Limitation]; ```
When troubleshooting a blood gas analyzer that fails its high-level PCO2 quality control, which of the following actions should be performed FIRST?