Equation Review

Question 1

Odds ratio (for case-control studies)

Answer 1

a/c / b/d = ad/bc

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

NNT

Answer 4

1/absolute risk reduction

Question 5

Number needed to harm

Answer 5

1/Attributable risk

Question 6

Volume of distribution

Answer 6

Vd = amt of drug in body / plasma drug concentration

Question 7

Half life

Answer 7

t1/2 = 0.7 x Vd / Clearance

Question 8

Drug clearance

Answer 8

Clearance = rate of elimination / plasma drug concentration

= Vd x Ke (elimination constant)

Question 9

Loading dose

Answer 9

LD = Cp x Vd / F

Question 10

Maintenance Dose

Answer 10

D = Cp x CL x tau / F

Question 11

MAP

Answer 11

MAP = CO x TPR

= 2/3 diastolic + 1/3 systolic

Question 12

Stroke Volume

Answer 12

SV = EDV - ESV

Question 13

EF %

Answer 13

EF = SV /EDV

Question 14

Effective renal plasma flow

Answer 14

ERPF = UpahxV/Ppah = Cpah

Question 15

Renal blood flow

Answer 15

RBF = RPF / 1-hct

Question 16

Henderson Hassalbach equation

Answer 16

pH = 6.1 + log [HCO3-]/0.03 Pco2

Question 17

Physiologic dead space

Answer 17

Vd = Vt x PaCO2 - PeCO2 / PaCO2

Question 18

Pulmonary vascular resistance

Answer 18

PVR = P pulm artery - P left atrium / CO

Question 19

Alveolar gas equation

Answer 19

PA O2 = PI O2 - PaCO2/R