Important Equations Flashcards
1
Q
Q =
A
Q (flow) = CO (cardiac output)
Q = Change in P/R (resistance)
2
Q
P =
A
CO x TPR
3
Q
Resistance =
A
R = 8Ln / pi*r^4 Resistance is inversely proportional to radius Rseries = R1 + R2 +. . .Rn and 1/Rparalell = 1/R1 + 1/R2 + . . . 1/Rn
4
Q
CO =
A
HR X SV
5
Q
SV =
A
(stroke volume) = EDV (end diastolic volume) - ESV (end systolic volume)
6
Q
What is Fick’s Principle?
A
Used to determine a tissue’s steady-state consumption (or production) of any substance. Xtc is the transcapillary efflux rate of X, [X]a,v is the arterial and venous concentrations of X, and Q is the blood flow rate.
7
Q
Fick’s Equation
A
Xtc = Q x ([X]a - [X]v)
8
Q
What can approximate P = CO x TPR?
A
MAP (mean arterial pressure) = Pdiastole + 1/3(Psystolic - Pdiastole)
9
Q
What are two methods for calculating the mean electrical axis?
A
- Find the lead with the largest R wave and follow that dipole. (If wave is negative, then dipole is in the opposite direction)
- Determine what lead contains the most equiphasic QRS complex.
Then determine which lead lies 90deg away from the most equiphasic lead and look at the tracing (remember if wave is negative, then dipole is in the opposite direction)
10
Q
Cardiac Index =
A
CO / Body surface area
11
Q
EF (ejection fraction) =
A
SV/EDV
