equations

E-Cylinder

0.28 x psig / liter flow

H-Tank

3.14 x psig / liter flow

oxygen content/carrying capacity equation

CaO2 = (Hb x 1.34 x SaO2) + (PaO2 × 0.003)

normal value for CaO2

16 to 20 vol %

CaO2

arterial oxygen content in vol %

Hb

hemoglobin in content g %

1.34

amount of oxygen that 1g of fully saturated Hb can hold

SaO2

arterial oxygen in %

PaO2

arterial tension in mmHg

0.003

amount of dissolved oxygen for 1mmHg of PaO2

example oxygen content equation

Hb= 15g%

SaO2= 98%

PaO2= 100mmHg

CaO2 = (15 × 1.34 × 98%) + (100 × 0.003)

= 20 vol %

PAO2

alveolar O2 tension or partial pressure of O2 in the alveoli

measures the amount of O2 available in the sacs of your lungs

PAO2

calculated. alveoli

PaO2

blood (get from abg) arterial

PAO2-PaO2 or P(A-a)O2

A-a gradient

tells us how much O2 was lost while moving from the alveoli INTO the blood

normal value for A-a gradient

10-20mmHg

V/Q mismatch (ventilation/perfusion)

21-350mmHg

shunting

more than 351mmHg

PAO2/alveolar gas equation

PAO2 = (PB - PH2O)FiO2 - (PaCO2 × 1.25)

PAO2

alveolar O2 tension (mmHg)

PB

barometric pressure (760mmHg)

PH2O

water vapor pressure (47mmHg at 37 degrees celsius)

FiO2

inspired O2 concentration in percent

PaCO2

arterial carbon dioxide tension in mmHg

1.25

1/normal respiration exchange rate (0.8)

percentage of personal best on peak flowmeter

current peak flow/personal best x 100

green - 80-100% good/continue meds

yellow - 50-79% caution: worsening symptoms

red - <50% medical alert intervention needed