# Equations Flashcards

Alveolar Gas Equation

PAO2 = ((Pb-H2O)xFiO2)-(PaCO2/0.8)

Shunt Equation

QS/QT = (CcO2-CaO2)/(CcO2-CvO2)

Pulmonary Vascular Resistance

PVR = ((MPAP - PCWP) x 80) / CO

Plasma Osmolarity

2(Na + K) + Glucose + Urea

Anion Gap

(Na + K) - (Cl + HCO3)

Bohr Equation

VD/VT = (PaCO2 - PECO2)/PaCO2

Oxygen Delivery

DO2 = CO x (1.34 x Hb x SpO2) + (0.003 x PaO2)

Respiratory Compliance

1/(C Total) = 1/(C Chest) + 1/(C Lung)

Clearance

Cl x Cp = Cu x Vu

Cl - Clearance

Cp - Plasma Concentration

Cu - Urine Concentration

V - Urine flow (ml/min)

pH

pH = -log(H+)

Fick’s Law

Q = (ΔP x A x D) / T

Q - flow

ΔP - Pressure difference

A - Surface area

D - Diffusion constant (gas specific)

T - membrane thickness

Boyle’s Law

P1V1 = P2V2

Assuming temperature is constant

Charle’s Law

V1/T1 = V2/T2

Assuming pressure is constant

Gay-Lussac’s Law

P1/T1 = P2/T2

Assuming V is constant

Henry’s Law

C = kP

The amount of dissolved gas in a liquid is proportionate to the partial pressure of the gas above the liquid