Posts: 3,675,937
Threads: 734,344
Joined:
Sep 2021
Reputation:
5
hmmm. but how does increased vascular resistance bring arterial pressure down?
hey sami, in what context is the decrease in CO asked? is it with pooling of blood in pulmo circulation (congestive heart failure) or without pooling of blood in pulmo (hemorrhage outside pulmo circ)?
Posts: 3,675,937
Threads: 734,344
Joined:
Sep 2021
Reputation:
5
Well resistance is inversely proportional to flow and thus as resistances increases flow will decrease and since flow is directly proportional to the change in pressure and hence pressure will decrease.
Most common cause of decreased CO is CHF which in turn may cause Pulm. odema.
Posts: 3,675,937
Threads: 734,344
Joined:
Sep 2021
Reputation:
5
Pulm edema will result in increase pulm artery pressure due to increase blood due to bckflow so I dont think in this case it can be due to decrease CO is due to CHF.It is most probably due to haemorrhage so in order to increase sytemic circulation pulmonary vessels will constrict and this will increase pulmonary vessel resistance but due to decrease blood flow in Pulm artery that cn decrease the Pulmonary artery pressure.
Posts: 3,675,937
Threads: 734,344
Joined:
Sep 2021
Reputation:
5
Pulm edema is due to :-
(1) CHF
(2) Valvular diseases
(3) A-V malformations
(3) Left atrial tumors
(4) Fluid overload
(5) Repurfusion injury (Lung transplantation)
(6) ARDS
Posts: 3,675,937
Threads: 734,344
Joined:
Sep 2021
Reputation:
5
yes mohitmd, i was thinking the same thing. they both increase in CHF. the backflow of blood to the lungs will increase resistance to flow and the increased hydrostatic pressure in pulmo veins will lead to transudation of fluid to alveoli leading to pulmonary edema. so my bet would have been on hemorrhage when sami mentioned it.
but i guess if no conditions were mentioned, the easier way to think about it would be physiologic mechanisms. (never forego normal before abnormal.) either decrease stroke volume or decrease heart rate = decrease CO. and since it's focusing on CO relationship to pulmo circulation, then the stroke volume could easily be the factor affected. with decrease preload, like systemic venodilation leading to decreased flow to pulmo circulation. then both resistance and pressure need not be increased at the same time, unlike CHF.
Posts: 3,675,937
Threads: 734,344
Joined:
Sep 2021
Reputation:
5
hmm...in my opinion
R=p/Q
so if flow decreases resistance will increase
secondly
PAP=(co into pulmonary vascular resistance) + pulmonary venous pressure
so if we decrease cardiac output PAP will also decrease
obviously decrese in pvr or pvp will also decrease pap
bt that wud b compensation...
Posts: 3,675,937
Threads: 734,344
Joined:
Sep 2021
Reputation:
5
CO decreased due to hemorrhage ,what will happen to be the pulmonary vascular resistance and pulmonary arterial pressure? THAT IS THE QUESTION
Posts: 3,675,937
Threads: 734,344
Joined:
Sep 2021
Reputation:
5
can i ask one qs...
if co decreases...
wt will happen to map and tpr
