Formulas Flashcards
Expression for pressure with respect to surface tension
P=4T/r
What is Tidal volume?
Amount breathed in/out during a normal breath
What is inspiratory reserve volume?
The amount you can breath in past a normal breath
What is expiratory reserve volume?
The amount you can breath out past a normal breath
What is residual volume?
The amount always left in your lungs
What is vital capacity? (Equation)
Tidal volume+inspiratory reserve volume+expiratory reserve volume
What is functional residual capacity? (Equation)
Expiratory reserve volume+residual volume
What is inspiratory capacity? (Description+equation)
Tidal volume+inspiratory reserve volume. The maximum amount you can breath in after exhaling to FRC
What is total lung capacity? (Equations with only 2 values)
FRC+IC=VC+RV
Expression for VE
VE=VT x f
VT = tidal volume, f = number of breaths per minute
Expression for Px
Px = PFx
P = total pressure, Px = partial pressure of gas, Fx = fractional concentration in dry gas
Expression for VO2 (measured by comparing [O2] in the expired gas collected in a large spirometer)
VO2= Q (CaO2 - CVO2) or Q= VO2/ (CaO2 – CVO2)
VO2: measured by comparing [O2] in the expired gas collected in a large spirometer, [O2] in inspired gas; CaO2: measured from an artery; CVO2: measured via a catheter from the pulmonary artery. Q=cardiac output
Expression for compliance
C = V / P (change in volume/change in pressure)
Expression for Elastance
Elastance= 1/compliance
Transpulmonary Pressure expression
Pl = Palv - Ppl
Chest Wall Pressure expression
Pw = Ppl - Pbs (therefore Pbs = Ppl - Pw)
Expression for flow with respect to Palv and Patm.
Flow=deltaP/R=(Palv-Patm)/R
Resistance of airways expression with respect to Palv and Pao
Raw = (Palv – Pao)/Flow
Raw = resistance of the airways, Pao = Pressure of the airway opening pressure
Expression for flow (Fick’s law of diffusion)
Flow: = D x (Cout - Cin)/d x A
D: diffusion coefficient
Cout: Concentration out
Cin: Concentration in
d: Thickness of the membrane
A: Surface Area
Expression for flux in the cardio unit.
Flux = Flow/Area = D x (Cout - Cin)/d
Normal blood volume value
5L or 75mL/kg
1 unit of blood value
450mL
Stroke Volume (SV)
70 mL
Normal cadiac output value
5000mL/min or 5L/min
Expression for flow (with respect to volume)
delta V/t
Expression for flow (with respect to velocity)
mean velocity*area
General expression for pressure
Pressure=Force/Area
Normal blood pressure value
120/80mmHg (The first value is systolic, the second is diastolic)
Central venous pressure value
5-10 cm H20
Expression for volume–>general
Volume = A x h (Area x Height)
Expression for mass
Mass = density x volume = ρV = ρAh
Expression for force
Force = mass x acceleration = ρAhg
Expression for pressure–>general
Pressure = Force/Area = ρhg
Perfusion Pressure expression
ΔP = Pin - Pout
Across an organ, it’s specifically… ΔP = Pa - Pv
Flow with respect to perfusion pressure
Flow = Perfusion Pressure/Resistance
Poiseuille’s Law
R = 8νL/πr^4
ν = viscosity
r = radius
L = length of the vessel
Resistance in Series
R = R1 + R2 (flow is the same)
What is the same in series?
Flow
What is the same in parallel?
deltaP
Expression for Resistance in Parallel
1/R = 1/R1 + 1/R2
How do you find lead 1?
Lead 1=VLarm - VRarm
How do you find lead 2?
Lead 2=VLleg - VRarm
How do you find lead 3?
VLleg - VLarm=Lead 3
VLarm + VRarm + VLleg = ….
0
Expression for transmembrane voltage.
ΔV = Vinside -Voutside
Expression for stroke volume
SV = End diastolic volume - end systolic volume = EDV - ESV
Expression for ejection fraction
Ejection fraction = SV/EDV
Expression for cardiac output
CO = Heart rate x SV
Expression for MAP (mean arterial pressure) with respect to CO
MAP= CO x TPR (total peripheral resistance)
Expression for MAP (mean arterial pressure) with respect to SV and HR
MAP = SV x HR x TPR
Expression for MAP with respect to relevant pressures
MAP = Diastolic Pressure + ⅓ (pulse pressure)
DCO2 with respect to DO2
DCO2=20DO2
Time constant expression.
t=RC
Max HR?
220-age in years
Fick’s principle for VO2.
VO2=CO*(arterialO2-venousO2)
