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
How can you differentiate etiologies of multiple small lung nodules?
Sarcoid- perilymphatic in subpleural and along interlobular septa, clustered and mostly upper lobe
Metastatic cancer/miliary infections- along pleural/perifissural locations in a random distribution and along bronchovascular bundles, may have feeding vessels and more basilar
TB/MAC- centrilobular, TiBO in clusters
HP/RB/LIP- centrilobular without TiBO, GGO, mixed bronchiolar-peribronchiolar
How do you calculate vaccine efficacy?
1- risk ratio
Risk ratio= risk of disease in vaccinated / risk of disease in unvaccinated
What are the features of pulmonary Langerhans cell histiocytosis?
Histo- stellate appearance, centered on small airways, stain S-100 and are CD1a +
Risk- smokers
Features-
Imaging- multiple ill defined micronodules, centrilobular, cavities of bizarre shape
Tx- smoking, maybe immunosuppressants, maybe cladribine
What are the features of LAM?
Histo- smooth muscle like cells, HMB-45 staining
Risk- women of child bearing age
Features- PTX, cysts, progressive decline in function, hemoptysis,
Imaging- diffuse, thin walled cysts, no nodules, chylous effusions
Mutations in TSC1/2 via MTOR signaling pathway
VEGF-D above 800
Tx- sirolimus for FEV1 <70%, avoid estrogens (OCPs, oopherectomy), transplant but can recur
What are the features of LIP?
Histo- infiltration of alveolar septa with polyclonal lymphocytes and plasma cells
Risk- middle-aged women with autoimmune/immunodeficiency (Sjogrens)
Features- cough, dyspnea, fatigue
Imaging- GGO, centrilobular micronodules, thickened bronchovascular bundle, few thin walled cystic airspaces that are subpleural
What are the features of Birt-Hogg-Dube syndrome?
Histo- + folliculin stain
Risk- autosomal dominient
Features- fibrofolliculomas on the face/head/upper torso, kidney tumors, recurrent PTX, irregularly shapped thin walled cysts mostly lower and medial
How do you calculate absolute risk reduction and relative risk reduction?
ARR the absolute difference in event rates= absolute risk in control - absolute risk in treatment
RR= absolute risk in treatment/ absolute risk in control
RRR the proportional reduction in event rates = ARR/ (1-RR)
NNT= 1/ ARR
What are the goals of different types of prevention?
Primary- prevent health problem before it arises
Secondary- reduce severity/spread
Tertiary- reduce chronic effects
Quarternary- prevent overmedication/polypharmacy
What are some factors that may affect 6MWT?
Increase distance- repeat measurement, outside, circular track, wheeled walker, oxygen, patient carries oxygen, encouragement, walk as fast as possible as opposed to as far
Decrease distance- treadmill
What is the power of a study? Confidence level? Type I/II errors?
Power- the probability that the test will reject the null hypothesis (results are purely from chance) when, in fact, it is false. A high value above 0.8 is good.
Confidence level- when the test accepts the null hypothesis when it is true
Type I error- occurs when the researcher rejects a null hypothesis when it is true
Type II error- occurs when the researcher accepts the null hypothesis when it is false
How has GLI developed the comprehensive set of spirometric reference values?
Modeled from datasets used in multiple reference equations in the published literature
What are the features of bronchopulmonary sequestration?
A malformation where a portion of the lung is detached from the remaining normal lung and receives its own blood supply from a systemic artery.
Intralobar sequestration will also lack their own visceral pleural, usually posterior basal of LLL.
See frequent infections, cystic spaces, treated with resection
What are the features of Mounier-Kuhn Syndrome?
Tracheobronchomegaly. Inefficient cough and mucus clearance leads to frequent infections and bronchiectasis. Tracheal diameter 3+cm when measured 2cm above aortic arch
Airways may dilate on inspiration and narrow on expiration
How is a bronchogenic cyst managed?
Elective resection as they grow and develop mass effects. Resection gets more difficult as it grows
Where is the safest place for thoracentesis?
Mid-axillary line as posterior intercostal artery can have a tortuous and unpredictable course
What are the features of a traumatic pulmonary pseudocyst?
Resulting from blunt or non-penetrating trauma, shear forces with elastic recoil can lacerate alveoli with subsequent air filling forming cavities. Observe for resolution
What are different kinds of studies?
Cross-sectional: descriptive study, analyzes an entire population at a specific point in time
Case-control: have the disease compared with non-disease and look backward at exposure
Cohort: identify exposure and non-exposure and look forward or backward to see if disease happens
What is a likelihood ratio?
Helps put something into context with your pretest probability
LR+= TP/FP
LR-= FN/TN
How do you calculate attributable risk?
AR= Incidence in exposed - Incidence in unexposed
How do improved treatment regimens affect NNT/NNS in lung cancer screening programs?
NNS goes down due to improved survival with early diagnosis
