Misc Flashcards
What would you see on CPET for ventilatory mechanical constraint?
Impairment in end-exercise workload, aerobic capacity (peak Vo2) while exceeding predicted max ventilation. Also can have elevated end-expiratory lung volume at rest compared to end-exercise due to dynamic hyperinflation
What conditions cause calcification of the tracheobronchial tree?
Advanced age, HD, warfarin use (Matrix G1a protein is a vit K-dependent inhibitor of arterial calcification). Histo is calcified granulomas/LNs. DM and amyloidosis can cause partial calcification but not the entire airway
What are the features of marijuana use?
Pneumomediastinum, PTX, subQ emphysema due to deep inhalation. Severe bullous disease in upper lobes
What are the features of alpha-1-antitrypsin deficiency?
Basilar bullous emphysema, relatively young (but can also be apical predominent in older individuals)
How do you calculate negative predictive value?
TN / (FN + TN)
How do you calculate positive predictive value?
TP / (FP + TP)
How do you calculate sensitivity?
TP / (TP + FN)
How do you calculate specificity?
TN / (TN + FP)
How do you calculate prevalence Al pretext probability?
(TP + FN) / total
How do you calculate NNT?
1/ absolute risk reduction
ARR= risk in control - risk in treatment
For how long do you see the benefits of an 8 week pulmonary rehab program?
24 months, see improvement in dyspnea, QOL, exercise capacity, and decrease healthcare utilization.
Describe the different validation methods for “big data” analysis
Apparent- model tested on the sample used to derive the model
Split sample- random split of the cohort where derivation is from one set and validation from the other
Temporal- validate on more recently seen cohort
Geographic- tests at a different site from derivation site
How does altitude affect DLCO?
O2 competes with CO for Hgb binding sites. At higher altitude, PaO2 is lower so more CO is taken up, so DLCO increases with altitude by approx 0.53% per 100m altitude.
DLCO (Pb adjusted) = DLCO measured x (0.505 + 0.00065 Pb)
{Pb is barometric pressure, 760 at sea level)
Which order should PFTs measurements be recorded?
DLCO should be before lung volumes as the nitrogen washout for lung volumes will take time to dissipate and would affect DLCO measurement. Not affected if lung volumes measured by body plethysmography
How do you calculate person-time incidence for a disease?
When calculating person-time incidence rates for a disease, consider 1/2 person-years for patients that die or are lost to follow up and add to total