Important Equations

Question 1

MAP =

Answer 1

SBP + 2DBP/3

Question 2

What is SVR?

Answer 2

80(MAP-CVP)/CO

Question 3

Arterial O2 content

Answer 3

Hb X 1.36 X SaO2 + (PaO2 X 0.003)

Question 4

Allowable blood loss

Answer 4

Hct (start) - Hct (allowed) X EBV/Hct start

Question 5

Volume to transfuse

Answer 5

Hct (desired) - Hct (current) X EBV/ Hct (transfused)

Question 6

What is the alveolar gas equation?

Answer 6

PAO2= FiO2 (Patm-Ph2o) -PaCO2/RQ
= .21(760-47) - 40/.8
= 100

Question 7

Mixed venous O2 content

Answer 7

O2Hb (1.36 X SvO2 X Hb) + Dissolved oxygen

Question 8

Oxygen delivery

Answer 8

DO2= CO X CaO2

Question 9

Oxygen consumption (Fick principle)

Answer 9

VO2= CO (CaO2 - CvO2)

CO is 5L/min
CaO2 is 20 cc
CvO2 is 15 cc

Question 10

O2 extraction ratio

Answer 10

(VO2/DO2) 100

Normal is 22-30%

Question 11

Minutes until hypoxemia

Answer 11

FRC/O2 consumption X %O2

Oxygen consumption in an adult is 3-4ml/kg/min
FRC is 30 ml/kg

Question 12

What is the equation for calculating the amount of liquid anesthetic delivered?

Answer 12

% volatile = Volume of anesthetic vapor/ V+ FG

Question 13

Liquid volatile anesthetic

Answer 13

3 X FGF X % anesthetic vapor

Question 14

SvO2

Answer 14

SaO2 - (VO2/(CO X Hgb X 1.36)

Question 15

Ideal body weight for men

Answer 15

49.9 + 0.89 (Height -152.4)

Question 16

Ideal body weight for women

Answer 16

45.4 + 0.89(height -152.4)