Calculations To Remember

Question 0

Pouiseulle law

Answer 0

Q(flow)= (pi * pressure change * radius ^4)/ (8* viscosity * vessel length)

Resistance to flow R= (8* viscocity* length)/ (pi r^4)
In otherwords PVR inverse relation to r ^4

Question 1

BP

Answer 1

CO * PVR

Question 2

Vcf velocity of circumferential fiber shortening

Answer 2

(End diastolic -endsystolic circumferences)/ (duration of shortening)

Question 3

LaPlace

Answer 3

Tension= (pressure*radius)/ (wall thickness)

Question 4

Reynolds number

Answer 4

(2*radius velocitydensity)/ viscosity

Question 5

EF

Answer 5

SV/ EDV

Question 6

CO

Answer 6

HR*SV
SV is affected by preload, after load, contractility, LV synchrony
Fick: O2 consumption/ change in arteriovenous O2

Question 7

Aortic elastance (stiffness)

Answer 7

Aortic pressure/aortic flow

Question 8

Valve area

Answer 8

CO/ [sq root] pressure gradient