vent perf Flashcards
1
Q
what is normal VQ ratio
A
0.8
2
Q
what happens when there is a left bronchial block and left pulmonary embolism
A
-good VQ ratio and normal gas exchange
3
Q
what happens when there is a right bronchus block and right pump artery block
A
VQ mismatch
no ventilation or perfusion
4
Q
what occurs when the VA:Q ratio is zero and infinity
A
zero: L R shunt
inf: dead space
5
Q
how can deoxy blood be adde to LHS circulation in a L to R shunt
A
- bronchial veins: carry deoxy blood from bronchioles to arteries
- thesbian veins: drain LV walls
6
Q
what are 3 abnormal R to L shunts
A
- collapsed lung: atelectasis
- consilidaded lung: lung pneumonia
- congenital heart defect: fallot’s tetralogy
7
Q
what happens in ventricular septal defect
A
- blood forced from LV to RV
- high pressure in RV (pulm circulation) =
- pulm vascular hypertension and R ventricular hypertrophy
- ventricle remodelling and deoxy blood enters LHS
8
Q
what’s an example of R ventricular hypertrophy and explain the consequences
A
VSD
- pulmonary stenosis by infundibulum
- LHS and RHS blood mix
- lower O2 saturation leaving aorta
9
Q
respones to low arterial PO2 and high PCO2 in LR shunt
A
- chemorceptors –> more ventilation
- ventilated areas lose more CO2 but gain little extra O2 (Hb saturated)
- shunt blood unaffected
