Cardio, renal, pulm equations Flashcards
πBS
Usually equals zero
(shouldn’t have any protein in BS)
HH equation
pH = 6.1 + log(HCO3-/0.03xPCO2)
CO x O2 content =
O2 delivery to tissues
GFR x Px =
Filtered load
(Pc - PBS) - (πc - πBS) =
Net filtration pressure (Pnet)
Clearance =
UxV/Px
RPF/(1-HCT)=
RBF
PVR =
Ppulm artery- PLA
CO
(b/c R = change in P/Q)
RPF =
UPAH- V/PPAH
Excretion rate =
Ux x V
Respiratory quotient =
CO2 produced/O2 consumed
Hb x 1.34
Oxygen binding capacity
2/3(DBP) + 1/3(SBP)
MAP
CO/SV
HR
PAo2 =
~ 150 - PaCO2/0.8
PI02 - (PaCO2/R)
Here, R is the respiratory quotient
Net filtration pressure (Pnet) =
(Pc - PBS) - (πc - πBS)
Accuracy of CRT as measurement of GFR?
Overestimates because CRT is slightly secreted
LaPlace’s Law
Wall tension = Pressure x radius/2 x wall thickness
Accuracy of PAH as measurement of RPF?
Underestimates by ~10% b/c not 100% is excreted
(VT - VD) x RR =
VA
Oxygen content =
(O2 binding capacity x O2 sat) + dissolved O2
Rate of O2 consumption
Arterial O2 - Venous O2
Cardiac output
(Fick principle)
Use inulin or CRT clearance to estimate:
GFR
Changes in CO in early vs. late exercise
Early = increase in HR and SV maintatin CO
Late = only increase in HR maintains CO b/c SV plateaus
GFR =
Uinulin x V/Pinulin
Kf[(Pc-PBS) - (πc-πBS)
FF =
GFR/RPF
What happens to resistance as the length of the vessel increases?
Increases
(R = viscosity x length/r4)
Winter formula
Predicts respiratory compensation for metabolic acidosis
PCO2 = 1.5[HCO3-] + 8 +/- 2
What happens to resistance to blood flow in larger vessels?
Decreases
(R = viscosity x length/r4)
VD=
VT [PaCO2- PECO2/PaCO2]
Ppulm artery- PLA/CO
PVR
EDV-ESV/EDV
EF
What is used to calculate GFR vs RPF?
GFR = inulin clearance
RPF = PAH clearance
6.1 + log(HCO3-/0.03xPCO2) =
pH
Net fluid flow (J) =
Kf(Pnet)
Ux x V =
Excretion rate
VT x RR =
VE (mintue ventilation)
EF =
SV/EDV
EDV-ESV/EDV
RBF =
RPF/(1-HCT)
SV =
EDV - ESV
EDV - ESV
SV
Pulse pressue =
SBP - DBP
MAP =
CO x TPR
2/3(DBP) + 1/3(SBP)
O2 binding capacity =
Hb x 1.34
CO x TPR
MAP
CO/HR
SV
SBP - DBP =
PP
QxR=
Change in pressure
How can you know if a patient is adequately compensating for metabolic acidosis?
Winter formula
PCO2 = 1.5[HCO3-] + 8 +/- 2
)O2 binding capacity x O2 sat) + dissolved O2 =
Oxygen content
CO =
SV x HR
Use PAH clearance to estimate:
RPF
UxV/Px =
Clearance
SV x HR
CO
VE =
VT x RR
VA=
(VT - VD) x RR
150 - (PaCO2/0.8) =
Alveolar pressure of oxygen (PAo2)
O2 delivery to tissues =
CO x O2 content
Filtered load =
GFR x Px
P =
QxR
SV/EDV
EF
Wall tension=
Pressure x radius/2 x wall thickness
(LaPlace’s Law)
GFR/RPF
FF
