Cardiovascular compensations

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PART 1

Page 2

Part 2

Hypovolaemia - decreased volume of circulation blood

hypovolaemic shock -- dec blood vol

--not enough return to hear

-lower preload

-less filling

-less stroke volume

-hyper tension

---over time organ failure

Baroreflex kicks in

-vasocontriction

-Stream

-inc arterial pressure

--splenic contraction -- ejects blood into circulation

--starlings law of capillaries -- reduction of hydrostatic pressure

--more absorption of water into capilaries

--RAAS - ADH produced

- aldosterone produced more h2o from liver

- vasoconstriction

- makes you feel thirsty

-if whole blood lost initially PCV and TP same

-these reduce as replacement of fluid causes dilution of blood

Forward and backward heart failure -- often both found at once as one turns into the other.

--refer to side of heart in failure i.e. left/right sided forward

Forward heart failure

-systolic failure reduced CO, reduced mean arterial pressure

-cardiac tamponade - external pressure preventing filling (a cause)

signs-- fainting - especially on exercise

--gums pale

--thready pulse

-slow return to colour

Backwards heart failure

-valve disease (a cause)

-congestive heart failure

-inability of heart to cope with preload

-inc venous pressure -- inc capillary pressure - oedema

-pulmonary oedema LHF

- abdomen swelling RHF

see flow charts for compensation

Baroreflex and starlings mechanism not meant for long time use

----decompensation -- stream

Viscious cycle stream

Natriuretic peptides - substances make you pee sodium -- therefore water

-AtrialNP BrainNP (in ventricles mostly)

-peripheral vasodilation

-reduce renin and aldosterone

-test for them to see myocardial stretch