Equations Flashcards
What is the equation of oxygen delivery
D02= CO x CaO2 (1.34xHbxSa02) + (0.003 x Pa02)
Poiseuilles equation
Delta P= 8uLQ/ pie r to the power of 4
La place
P= 2T/R
A-a gradient
PA02= (PB-Ph20) *Fi02 -(PaC02/RQ)
Shortened to
PA02= 150-(PaC02/0.8)
Equation for BP
BP= CO x SVR
Equation for MAP
MAP= DAP + (SAP-DAP)/3
Henry’s Law
V= S x P
Boyles Law
V1P1= V2P2
Ficks Law
J= k (c1-c2)
Where K= DxAxP/T
PPV equation
PPV (%)= 100 x (PPmax-PPmin)/ (PPmax + PPmin)/2)
Free water deficit
BW (kg) x {[Current Na/Normal NA] -1} x 0.6
= free water deficit in Litres
What is the calculation for compliance?
C= deltaV / delta P
Equation of motion
Pvent + pmuscles= elastance x volume + resistance x flow
What is the equation for fractional shortening?
FS (%) = LVIDd-LVIDs/ LVIDd x100
What is the equation for ejection fraction?
EF (%) = SV/ EDV x100
Map equation
MAP= DAP + [(SAP-DAP)/3]
What is the calculation for free water deficit?
free water deficit (when NA too high)
FWD= 0.6 x BW(kg) x [(Na patient/Na normal) - 1]
Take normal sodium to be around 145
Ohms law
Q= deltaP / R
Flow= change in pressure divided by resistance
Reynolds number and it’s interpretation
Re= (D x p x V) / n
Reynolds number= (Diameter x density x velocity) divided by viscosity
< 2000 likely laminar flow
> 2000 likely turbulent flow
Modified Bernoulli equation
Delta P= 4V squared
Change in pressure= 4 times velocity squared
What is the equation for a shunt?
Qs/Qt= CcO2- CaO2/CcO2-CvO2
Oxygen index equation
Mean airway pressure x FiO2 x 100/PaO2
Oxygen saturation index
OSI= Mean airway pressure xFiO2 x 100/Sp02
