L5:physiological consequences of lung disease extra Flashcards
minute volume =
tidal volume x respiratory rate
alveolar ventilation=
(tidal volume-dead space) x respiratory rate
ventilatory demand=
the spontaneous minute ventilation required to maintain a normal PaCO2
rate of gas transfer proportional to
tissue area
difference in partial gas pressure
rate of gas transfer inversely proportional to
tissue thickness
which gas diffuses 20x faster
CO2
maximum diffusion is at
lung bases when upright
reduced ventilation/ normal perfusion –>
shunt of deoxygenated blood to systemic circulation
FVC=
forced vital capacity
FEV1=
forced expiratory volume in 1 sec
CT pulomary angiogram looks at
perfusion
oxygen saturation at normal PaO2
95
CO2 levels detected by
central chemoreceptors
type 1 respiratory failure
low O2
low/normal PaCO2
type 2 respiratory failure
low O2
high PaCO2
obstruction=
problem with airflow
ratio in obstruction
FEV1 reduced
FVC same
FEV1/FVC reduced
3 obstructive disease
Asthma
COPD
bronchiectasis
4 restrictive disorders
pulmonary fibrosis
obesity
chest wall deformities
neuromuscular disorders
asthma=
narrowing of airways
muscular hypertrophy
mucus secretion
reversible with treatment
obstructive disease effect on diffusion
normal (except emphysema)
type 2 compensated respiratory failure=
ph normal
PO2 low
PCO2 high
HCO3 high
pulmonary fibrosis=
thickened alveolar membranes
2 restrictive lung diseases causing type 2 respiratory failure
chest wall deformities
neuromuscular disorders
