FA Rapid review- equations

Question 1

SN

Answer 1

TP / (FN+TP)

Question 2

SP

Answer 2

TN / (FP + TN)

Question 3

PPV

Answer 3

TP / (TP+FP)

Question 4

NPV

Answer 4

TN / (TN+FN)

Question 5

Odds ratio (for case control studies)

Answer 5

a/c / b/d = ad/bc

Question 6

relative risk

Answer 6

a/(a+b) / c/(c+d)

Question 7

attributable risk

Answer 7

a/(a+b) - c/(c+d)

Question 8

NNT

Answer 8

1/absolute risk reduction

Question 9

NNH

Answer 9

1/attributable risk

Question 10

Vd

Answer 10

amount of drug in body / plasma drug concentration

Question 11

half life

Answer 11

( 0.693xVd) / CL

Question 12

CL

Answer 12

rate of elimination / plasma concentration = Vd x Ke

Question 13

loading dose

Answer 13

Cp x Vd / F

Question 14

maintenance dose

Answer 14

Cp x CL x tau / F

Question 15

CO

Answer 15

rate of O2 consumption / arterial O2 - venous O2

Question 16

MAP

Answer 16

CO x TPR

or

2/3 DBP + 1/3 SBP

Question 17

SV

Answer 17

EDV - ESV

Question 18

EF

Answer 18

SV / EDV

Question 19

resistance

Answer 19

P/Q

or

( 8n x length) / (pi x r^4)

Question 20

renal clearance

Answer 20

proportion of X in urine/plasma times urine flow

Question 21

filtration fraction

Answer 21

GFR / RPF

Question 22

HH for pH

Answer 22

pH = 6.1 + log [HCO3]/(0.03xPCO2)

Question 23

Winters

Answer 23

PCO2 = 1.5[HCO3] + 8 +/- 2

Question 24

physiologic dead space

Answer 24

TV x PaCO2-PeCO2 / PaCO2

the proportion of tidal volume that’s not used in gas exchange

PeCO2 is expired CO2 … so whatever is used will be PaCO2 - PeCO2

Question 25

Pulmonary vascular resistance

Answer 25

((P in pulm art) - (P in LA)) / CO

deltaP = IxR … or deltaP = COxPVR

Question 26

alveolar gas equation

Answer 26

PalvO2 = PiO2 - PaO2/R