Formulas

Question 1

Qp/Qs

Answer 1

Ao-RA/PV-PA

Question 2

Laplace

Answer 2

Wall tension = pressure * radius / 2*h
h= wall thickness
Wall tension = determinant of myocardial oxygen deman

Question 3

Valve area

Answer 3

Valve area = CO/HR * SEP * K (44.3) * sqr (mPG)

sqr: square root
mpg: mean pressure gradient

Question 4

Fick

Answer 4

CO = oxygen consumption / arteriovenous difference
O2 consumption (ml/min)
AV diff (ml O2/L blood) = O2 sat * theoretical oxygen carrying capacity of Hg
AV diff = Art sat - venous sat (%) * Hg (g/dL) * 10 * 1.36 ml O2/g Hg

Question 5

Strain:

Langragian formula

Answer 5

E = L-L0/L0
E = strain
L = length (current)
L0 = initial length

Question 6

Poiseuille

Answer 6

Vascular resistance: 
R = 8nl/pi*r^4 
n = viscosity
l = vessel length
8/pi = constant
r= radius

R = P/Q
Q = P/R
P = Q*R

Question 7

Ohm

Answer 7

R = dP/CO

Question 8

SVR

Answer 8

SVR = Ao-RA/Qs (mean systemic arterial pressure, mean RA pressure, systemic blood flow).

Question 9

PVR

Answer 9

PVR = PA - LA/Qp (mean PA pressure, mean LA pressure, pulmonary blood flow)

Question 10

Hemisphere surface

Answer 10

2pir^2

Question 11

Doppler

Answer 11

V = (C x fd)/[2(f0) x cos θ]
Fd - frequency shift (reflected frequency minus transmitted frequency) 
F0 - frequency of the transducer
Cos - angle (cos 0 = 1)
C - constant

Question 12

Strain rate

Answer 12

(V2-V1)/D

v: velocity
d: distance

Question 13

Gorlin for aortic valve

Answer 13

AVA (cm^2)= CO (ml/min) / (SEP * HR * 44.3 * sqrmPG)

CO has to be in ml

Question 14

Gorlin for mitral valve

Answer 14

MVA (cm^2) = CO (ml/min) / (DFP * HR * 0.85(44.3) * sqrmPG)

CO has to be in ml

Question 15

Simplified Gorlin for valve area

Answer 15

VA = CO/sqrmPG

Question 16

Oxygen content

Answer 16

O2 = 1.36 * Hg * 10 * SaO2

Question 17

Indicator dilution technique

• Name the equation
• What is the equation

Answer 17

Stewart-Hamilton
CO = indicator / C * t
CO (l/min) = indicator * 60 (60sec/min) / integral of C (concentration of indicator at sampling site) * t (sec)

Question 18

Reynolds

Answer 18

Reynolds number = area * velocity * density / viscosity
Aorta usual : 1600
Critical number for murmur: 2300

Question 19

3 parts of Bernouilli

Answer 19

1) Convective acceleration
2) Flow acceleration
3) Viscous friction

Question 20

QT bazzet

Answer 20

QTc = QT/RR^1/2

Question 21

QT Fridericia

Answer 21

cQT = QT/RR^1/3

Question 22

QT van der Water

Answer 22

QTc = QT = 0.087(rr-1000)

Question 23

Teicholz

Answer 23

7*LVV^3/2.4+LVV

Question 24

Myocardial performance index/Tei

Answer 24

(IVC + IVR) / ET
isovolumic times
ejection time
Also (MCO – LVET)/LVET

Question 25

Valve area for MS

Answer 25

220/PHT

PHT = 0.29 * deceleration time