Equation Review

Question 1

Odds ratio

Answer 1

Case control studies

AD/BC) = (A/C)/(B/D

Question 2

Relative risk

Answer 2

[A/(A+B)]/ [C/(C+D)]

Question 3

Attributable risk

Answer 3

[A/(A+B)]- [C/(C+D)]

Question 4

Number needed to treat

Answer 4

1/(absolute risk reduction)

Question 5

Number needed to harm

Answer 5

1/(attributable risk)

Question 6

Volume of distribution

Answer 6

(amount of drug in the body) / (plasma concentration)

Question 7

Half-life

Answer 7

0.693 * (volume of distribution) / (drug clearance)

Question 8

Drug clearance

Answer 8

(rate of elimination of drug) / (plasma drug concentration) = (volume of distribution) * (elimination constant)

Question 9

Cardiac output

Answer 9

SV * HR

rate of O2 consumption) / (arterial O2 content - venous O2 content

Question 10

Mean arterial pressure

Answer 10

CO * TPR

DBP + (1/3)*(SBP-DBP)

Question 11

Ejection fraction

Answer 11

(stroke volume) / (end diastolic volume)

Question 12

Resistance

Answer 12

(pressure difference) / (flow)

8 * nu * viscosity * length / (pi * r^4)

Question 13

Renal clearance

Answer 13

Ux * V / Px

Question 14

GFR

Answer 14

U(inulin) * V / P(inulin)

Question 15

Filtration fraction

Answer 15

GFR/RPF

Question 16

Winters formula

Answer 16

PCO2 = 1.5(HCO3-) + 8 +/- 2

Question 17

Physiologic dead space

Answer 17

Tidal volume * (PaCO2 - PeCO2)/(PaCO2)

Question 18

Pulmonary vascular resistance

Answer 18

P (pulmonary artery) - P (L atrium) / CO

Question 19

Alveolar gas equation

Answer 19

PAO2 = PIO2 - PaCO2/R