EQUATIONS

Tobacco Use

Pack years=

# packs a day X # of years packed

Cerebral Perfusion Pressure ( CPP )

CPP=

MAP - ICP

Estimating heart rate from an ECG tracing

HR=

300 divided by # of large boxes between R waves

or

1500 divided by # of small boxes between R waves

Pulse Pressure

systolic - diastolic pressure

MAP

2 x diastolic + systolic divided by 3

Cardiac Output ( Fick Equation )

QT=

VO2 divided by

C ( a-v) O2 ( 10 )

Cardiac Output ( stroke volume equation )

QT=

heart rate X stroke volume

Stroke Volume

QT ( total cardiac output ) divided by heart rate

Cardiac Index

CI=

QT divided by BSA

aka

cardiac output divided by body surface area

Systemic Vascular Resistance SVR

MAP- CVP divided by Cardiac Output

( to convert to dynes multiply by 80 )

Pulmonary Vascular Resistance

( MPAPA - PWP ) divided by cardiac output

( to convert to dynes multiply by 80 )

PAO2

( Pb - PH2O) X FIO2 - PACO2 / .8

OR

PACO2 X 1.25

A-aDO2

PAO2 - PaO2

PaO2 / FiO2 ratio or P/F ratio

PaO2 divided by FiO2

CaO2

( Hb x 1.34 X SaO2 ) + ( PaO2 × 0.003 )

CvO2

( Hb x 1.34 X SvO2 ) + ( PvO2 × 0.003 )

C( a-v )O2

CaO2 - CvO2

QT

VO2 divided by C ( a-v )O2 (10)

VO2