9 Gas Laws & Gas Cylinders Flashcards
PAO2 Equation
PAO2 = FiO2 x (PB - PH2O) - (PaCO2/RQ) RQ = 0.8
Alveolar/Arterial Ratios
Alveolar-arterial oxygen difference/gradient
(A - a)DO2 or PAO2 - PaO2
Normal 5-15mmHg
Arterial-alveolar ratio
PaO2/PAO2
Normal > 0.75
PaO2/FiO2
Normal >200
Henry’s Law
Cgas = Pgas / KH
Dissolved PaO2
0.003ml O2 dissolved in 100ml blood per 1mmHg PO2 applied
PAO2 = 100mmHg
PaO2 = 0.3ml O2
Dissolved CO2
0.067ml CO2 dissolved in 100ml blood per 1mmHg PCO2
Arterial O2 Content Equation
CaO2 = ((1.34ml O2/gm Hgb) x (15gm Hgb/100ml blood) x (% saturation)) + (0.003 x PaO2)
O2 Delivery
= CaO2 content x CO
Boyle’s Law
Gas pressure inversely proportional to volume at constant temperature
P1 x V1 = P2 x V2
Charles’ Law
Gas volume directly proportional to absolute temperature (°K) at constant pressure
V1/T1 = V2/T2
Gay-Lussac’s Law
Gas pressure directly proportional to absolute temperature (°K) at constant volume
P1/T1 = P2/T2
Combined Gas Laws
(P1xV1)/T1 = (P2xV2)/T2
Avogadro’s Law
Equal gas volumes at same temperature and pressure contain the same number molecules or atoms
V1/n1 = V2/n2
Avogadro’s Number
1 mole gas @ STP = 6.02 x 10^23 molecules
GMW 1 mole O2 = 32g
2kg tank N2O (44g) = 45.45 Mole
1 Mole Gas = x L
22.4L @ STP
Ideal Gas Law
Avogadro + Boyle + Charles + Dalton PV/T = Rn PV/nT = R PV = nRT V = nRT/P R (constant) = 62.36 L⋅mmHg/Mol⋅K