PFTs, D KInder, DSA Flashcards
What is definition of obstructive ventilatory defect
FEV1/FVC less than 70%
What is definition of restrictive ventilatory defect
TLC of 80% or less
FEV1/FVC is increased
What are msot important mortality predictors in COPD
postbronchodilator FEV1 and age
What is predictive of O2 desaturation with exercise
DLCO less than 50%
Best test to evaluate obstructive lung disease
spirometry
What FEV1 indicates severe obstruction? mild?
mild is greater than 2L
less than 1L is severe
Cuases of obstructive lungs
COPD, asthma, CF, bronchiolitis obliterans
When is methacholine challenge used
intermittent obstruction from bronchospasm may not be manifested as dec in FEV1/FVC if at time with no bronchospasm
What decrease in FEV1 with methacholine means there is bronchial hyperreactivity
20%
Is methacholine test specific?
can have false positives. 95% negative predictive value
What can differentiate extrathoracic obstructions from intrathoracic
present of truncated inspiratory curves
What data is obtained from spirometry
maximal inhalation followed by maximal exhalation, measuring volume of air and time
What do you obtain from helium lung volume test
RV, ERv, IRV, TC with calculation of tLC, VC, FRC and IC
What is key factor in restrictive lung diseases
TLC
what indicates mild vs severe restrictive lung disease
65-80% mild
less than 50% severe
A restrictive ventilatory defet with normal FRC should raise suspicion for what
neuromuscular disease
A decrease in FRC indicates what
either noncompliant lung or chest wall pathological condition(obesity or kyphoscoliosis)
What does CO diffusion depend on
pp of CO in albeolus
What can cause low DLCO
interstitial lung disease and emphysema
CHF with pulm edema, pulmonary HTN and PE
What can cause increase in DLCO
polycythemia, pulmonary hemorrhage, early CHF, L-R cardiac shunts
What values do you obtain from spirometry
FVC, FEV1, FEV1/FVC, FEF 25-75%
maximal voluntary ventilation
The primary abnormality detected by spirometry is what
airway obstruction
What is necessaroy to accurately Dx restrictive pathology of lungs
measure lung volumes
what are techniques to measure RV
nitrogen washout tecnhique
helium dilution technique
body plethysmography
What is the only technique for RV that measures the non-ventilated regions
body plethysmography
which lung pathologies have decreased VC
restrictive disease and obstructive disease
steady state PCO2 is normally what
38-42
steady state HCO3
22-28 mM
what is a volatile acid
CO2
where does 80-90% HCO3 resorption take place
proximal tubule
hypokalemia and high PCO2 stimulate what of HCO3
increased reabsorption
