Pulmonary Diagnostic Tests
Pulmonary and Critical Care Medicine · Pulmonary Diagnostic Tests 🎯 Practice these cards
FEV1 severity grading (% predicted): mild ____, moderate ____, moderately severe ____, severe ____, very severe <____.
Obstruction severity by FEV1 % predicted: mild 70-79, moderate 60-69, moderately severe 50-59, severe 35-49, very severe <35.
DLCO severity: mild is below the LLN but above ____% of predicted, moderate is ____-____%, and severe is below ____%.
DLCO severity: mild = below the LLN but above 60% of predicted; moderate 40-60%; severe below 40%.
A positive bronchodilator response requires an increase in FEV1 or FVC of at least ____% AND at least ____ mL.
A positive bronchodilator response = an increase in FEV1 or FVC of at least 12% AND at least 200 mL from baseline. Both criteria must be met.
The ATS defines the lower limit of normal as below the ____th percentile of predicted, which roughly coincides with ____% of predicted.
The ATS defines the LLN as below the 5th percentile of the predicted value, which roughly coincides with 80% of predicted; values below it indicate impairment.
Methacholine challenge is positive when FEV1 falls by ____% or more from baseline; its chief value is a high ____ for ruling out asthma.
Bronchial challenge testing is positive when FEV1 falls by 20% or more from baseline. Its main strength is a high negative predictive value for ruling out asthma; positives are nonspecific (COPD, smoking, URI, rhinitis, bronchiectasis, CF).
FeNO above ____ ppb indicates glucocorticoid-sensitive airway inflammation; below ____ ppb makes eosinophilic inflammation unlikely.
ATS FeNO cutoffs: above 50 ppb indicates glucocorticoid-sensitive eosinophilic airway inflammation; below 25 ppb makes eosinophilic inflammation and steroid responsiveness unlikely. Recommended as an adjunct from age 5.
Three causes of elevated DLCO: diffuse alveolar ____, left-to-right ____, and ____ (also polycythemia).
DLCO rises with increased pulmonary capillary blood volume or intra-alveolar hemoglobin: diffuse alveolar hemorrhage, left-to-right shunts, asthma, and polycythemia.
Normal SpO2 is ____-____%; values below ____% indicate hypoxemia.
Normal SpO2 is 95-100%; values below 90% indicate hypoxemia. Erroneous readings come from carboxyhemoglobin (CO poisoning), methemoglobin (nitrates), methylene blue, cool extremities, poor perfusion, nail polish, and motion.
For interstitial lung disease order ____-resolution CT; it must NOT be used for lung ____ because it skips lung sections.
High-resolution CT (1 mm slices) is preferred for interstitial lung disease but skips lung sections, so it must NOT be used to evaluate lung nodules — use routine noncontrast CT (2-2.5 mm) for those. CT angiography (timed contrast bolus) is for pulmonary embolism.
PET cannot characterize nodules under ____ mm; two classic false-negative tumors are carcinoid and adenocarcinoma ____ ____.
PET is not useful for nodules under 8 mm. False positives: infection/inflammation. False negatives: low-metabolic tumors — carcinoid, adenocarcinoma in situ, rarely metastatic kidney/prostate/testicular cancer.
EBUS-TBNA sensitivity: ~____% for epithelial malignancies, ~____% for lymphoma, and at least ____% for sarcoidosis.
EBUS-TBNA is the initial procedure of choice for mediastinal/hilar lymph node tissue. Sensitivity: ~90% epithelial malignancies, ~70% lymphoma, >=80% sarcoidosis (higher combined with endobronchial/transbronchial biopsies).
Normal upright-to-supine FVC fall is ____-____%; a fall of 10% to more than ____% suggests diaphragmatic weakness.
Normal FVC falls 3-8% from upright to supine. A fall of 10% to more than 25% indicates diaphragmatic weakness, hemidiaphragm paralysis, or neuromuscular disease — a sensitive bedside screen.
The 2023 ATS statement recommends the single race-neutral "GLI ____" reference equation for all patients.
In April 2023 the ATS recommended replacing race-specific GLI equations with the single race-neutral "GLI Global" equation for all patients, reporting results with z-scores and the LLN rather than % predicted.
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