random Flashcards
describe pulmonary oedema
lack of blood going from pulmonary circuit into left side of heart
why do you get a drop in BP following transfusion
explained by circulatory shock:
sustained ischemia results in microcirculation changes that aren’t easily reversed
loss of vascular tone due to:
• inadequate vessel wall perfusion (by vasa vasorum)
• impaired adrenergic transmission due to NEP depletion in nerve terminals
• perivascular accumulation of vasodilating metabolites & local vasomediator release
(reduced flow in venous circuit may result in stasis & clogging of microcirculation)
net fluid transfer to interstitium:
• capacity to maintain smooth m. activity in pre capillary vessels drops, post-capillary tone maintained → higher capillary hydrostatic P
• loss of capillary integrity due to accumulation of cytokines & autocoids → leaking of plasma proteins into interstitium
results in failure to maintain BP
why does MAP decreased upon standing up from a sitting down position
theres a decreased EDV upon standing up due to distention and collection of blood in the venous system (gravity).
Decreased EDV = decreased SV = Decreased CO = decreased MAP
explain why a patient with aortic stenosis feels dizzy or faint when exercising
exercising muscles need extra blood, hence vasodilation occurs within skeletal muscles. However, due to aortic stenosis (narrowing) the heart cant deliver the extra blood flow rate.
MAP = flow x resistance
therefore if you decrease resistance (vasodilate) and flow rate doesnt change MAP will decrease
this can lead to fainting due to reduced brain perfusion
what are the indications for pacemaker
- high-grade AV block
- sinus node disease
- only treats bradycardia
indications for cardiac re-synchronisation therapy (CRT)
- cardiomyopathy (poor ventricular performance)
- LBBB - with symptoms
indications for cardiac re-synchronisation therapy (CRT)
- cardiomyopathy (poor ventricular performance)
- LBBB - with symptoms
- helpful in patients who dont have a standard bradycardiac issue (no pacemaker use)
describe 2nd heart sound in pulmonary hypertension
2nd heart sound is split due to pulmonary valve closing second
when you breath in, right side of heart has increased blood and pressure, meaning it takes longer to close
someone with pulmonary hypertension will have even more blood and pressure on heart. Takes even longer for valve to close and will be more dramatic due to high pressures
explain when and why you would hear a more prominent S2 split
Cor pulmonale - R sided HF
- increased pulmonary hypertension
- increased RV afterload
- takes longer for RV to empty
- valve closes later
- S2 split greater time apart (aortic then pulmonary)
mitral stenosis heart sound
opening snap & prolonged diastolic murmur, accentuated S1
best heard at apex using bell (low Hz) with patient lying on their left side