pulmonary function test Flashcards
what are the metric used for pulmonary function test
pft lung volume
tidal vol - normal breathing
breath in forcefully - inspiratory reserve volume
breathing out forcefully - expiratory reserve volume
residual volume - volume of air left in the lung
functional residulal capacity - expiratory reserve volume and residual volume
vital capcity - tidal volume , erv , irv
total lung capsity -vital capcity , residual volume
what is the operator that used for the plumbery function test
body plethysmography- patient placed in a sealed chamber
after normal expiration asked to take and inspiratory effort
what is diffusing lung capacity carbon monoxide ?
breath in carbon monoxide
and breath it back out - how much you actually transferred - proportional to how well your gas transfer is taking place
low dico , normal spirometry - pulmonary vascular disease
or early interstitial lung disease
low dico ,obstructive spirometry -emphysema
low dico , restrictive spirometry -chest wall deformity - neuromuscular disease
interstitial lung disease
severe congestive heart failure
what is a test for measuring anatomical dead space ?
100 percent 02 inhaled and exhales through one way valve measuring the nitrogen content
what are the results for obstructive spirometry
decreased fev1 , and ratio
increased total lung capacity , increased residual vol
decreased VC
copd
bronchial asthma
bronchiectasis
what are the restrictive pattern for spirometry ?
decreased TLC and VC and RV
fev1 /fvc higher than 80 percent because cvc is greater than fever even though fev1 is reduced
flow rates normal
interstitial lung disease
decreased chest wall compliance - kyphoscoliosis
ankylosing spondylitits
pleural effusion
how many times should the spirometry test be repeated ?
three
how can you asses the reliability of the spirometry after three times of repeating the spirometry
two largest FVC within 0.15L of each other
two largest fev1 WITHIN 0.15L WITHIN each other
what is considered an early diagnosis of obstruction in small airways ?
FEV (25-75percent -small)
what are the normal fev1/fvc ratio
0.75-0.80
how do we know the difference between asthma and copd in spirometry ?
copd FEV1 AND FVC reduced
asthma FEV1 only reduced in attack FVC is nearly normal
what are the confirming techniques we use to say its asthma
bronchidilatory test
bronchoprovacation
bronchoprovacation - give direct stimuli - such as methcholine , histamine
or indirect stimule - exercise , cold air , hypersonic saline
it is used in subsequent doses of two fold increase until FEV1 falls by 20 percent from baseline
and brochoconstrictor test
methycholine to constrict the airways and usually asthma patients are more hypersensitive and there is a 20 percent drop in breathing ability
what are contraindication to broncho provocation ?
FEV1 is less than 50 percent
recent upper or lower respiratory tract infections
acute coronary syndrome or stroke
how do we perform bronchodilation ?
application of relaxants for the bronchial wall in dyspnea episodes
if the bronchial constriction is reversible with SABA it is positive
high negative predictive value - if negative it is not asthma
but if positive - can have differential diagnosis
