Lung testing Flashcards
if you increase resistance what disease could occur
obstructive
if you decrease compliance what disease could occur
restrictive
describe for a peak flow meter is and what is a normal value
rapid exhaled puff from a full inspiration, measures peak expiratory flow rate (PEFR) -
500-600l/min
why is a peak flow meter good for an obstructive disease
reproducible
expiration
what does a nebuliser do and what are the two types
convert solution of drug into fine spray
Brown- preventer e.g. corticosteroids -anti-inflammatory
Blue-reliever - bronchodilator e.g. salbutamol
vitalograph how does it work
sustained fced expiration from a full inspiration measure FVC FEV1- first second normal range of ratio is 75-85%
If FEV1/FVC<0.75 what disease is this indicative of
obstructive
compliance
expandability of the lungs
resistance
ease at which gas flows
In an obstructive disease such as asthma what would you see with the FVC,FEV1 and the ratio
FVC would stay more or less the same - takes longer but more effort to get out , same capacity of the lungs
FEV1 would decrease
FEV1/FVC ratio would decrease
In a restrictive disease such as pulmonary fibrosis what would you see with the FVC,FEV1 and the ratio
FVC would decrease as lungs cannot expand normally ( can’t create negative pressure )
FEV1 would also decrease
FEV1/FVC would either stay the same or increase
what do lung functions vary with
height, age , gender
Tidal volume ( Vt )
normal inspiration and expiration
IRV- inspiratory reserve volume
amount of extra air inhaled above tidal volume
ERV- expiratory reserve volume
extra air exhaled - force
RV - residual volume
air that remains in the lungs after fully exhale
TLC - total lung capacity
volume of air the lungs - max in
VC - vital capacity
max air that is expelled after inhalation
FVC - ( not forced vital capacity like In spirometry) functional residual capacity
vol of air in lungs after passive exhalation
capacities are sum of 2 or more volumes
how does fibrosis appear on X-ray
widely distributed throughout the lung fields - course or fine appearance
Inspiration is limited more by what type of disease
restrictive
does hyperinflation limit IRV
yes
also raises FRC and RV
In COPD what is destroyed
alveolar destruction and elastin broken down
what can you use to measure function residual capacity/residual volume
helium dilution and body plethysmography ( deep breath in and out measure Interhtoraic pressure)
why and when is a wheeze normally heard
lower airway obstruction, normally on expiration
at level of bronchioles increasing resistance - inflammation of or smooth muscle spasms , inside the thoracic cavity
Greater effort only increase Pip compressing small intrrathoracic airways further limiting air flow o expiration
on inspiration there Is a negative Pip so bronchioles increase in diameter
high pitched whistle like sound - deep and low pitched rumbling - hear breaths better than stridor
why and when is a stridor normally heard
upper airway obstruction heard on inspiration at level of larynx/trachea - tumours, croup or foreign body
outside thoracic cavity
on inspiration more negative pressure in thorax further narrows the obstructed part of the airway - on expiration the positive pressure increases the diameter
continuous high pitched crowing sound
crackles what are they
alveolar rales
fine and short and high pitched - caused by air passing through fluid puss or mucus - bases of lung lobes on inspiration
course crackles - low pitch and moist - bronchitis
Fien - fibrosis - hair rubbing on ear
pleural rub
movement of inflamed pleural surfaces against one another during chest wall movement
harsh grating like creaking
TB and pneumonia
lower anterior lung during both in and out
in an obstructive disease both RV and TLC increasing by about 20% what happens with a restrictive disease
both decrease by about 20%
in diffusion capacity DLCO/TLCO used CO to measure perfusion what does a decreased DLCO mean
obstructive ,pulmonary vascular os anemic disease
what does an increased diffusion capacity for for carbon monoxide indicate( extend to which oxygen passes from the air sacs into the blood)
pulmonary haemorrhage or left right shunt
what 3 things do flow volume loops allow movements of
upper airway obstruction - stridor or unexplained dyspnoea
variable extra thoracic obstruction ( above sternal notch) - vocal paralysis
Variable intrathoracic obstruction ( below sternal notch) chronic inflammatory disorders
what is a bronchodilator response
degree to which FEV1 improves with inhaled bronchodilator indication of reversible airflow obstruction
significant. if FEV1 increases by 12%
FEV1
and is reduced in what
(forced expiratory volume in 1 second) = max. volume of air exhaled in 1 second. Reduced w/ obstruction and restriction
FVC
FVC (forced vital capacity) = total volume exhaled after full inhalation. Reduced w/ restriction.
what test is good for asthma control and a test for obstructive disease
peak flow meter
how are restrictive and obstructive diseases impacted respectively
obstructive increases resistance
restrictive decreases compliance
how to determine the difference between asthma and COPD
Test for reversibility, give bronchodilator (salbutamol) obstruction reversed in asthma but not COPD
normal tidal volume
500ml
normal inspriaotry reserve volume
2.5L
normal expiratory reserve volume
1.5L
normal residual volume
1.5L
total lung capacity
6L
when does surfactant production markedly increase
after 34 weeks
what hormones stimulate surfactant production
Cortisol (most important by far)
Thyroxine
Prolactin
if a premature baby is born under 32 weeks do you give them corticosteroids
yes to combat affects of surfactant
in addition to surfactant what also helps to keep airways open in normal respiration
cartilage
Pulmonary shunt: ventilation is cut off in the lung so blood gets no oxygen so V/Q ration = 0
Dead space = blood supply to alveoli are cut off so V/Q ration is high
true or false
true
