Calculations

Question 1

liklihood ratio (+)

Answer 1

LR + = sensitivity / (1-specificity)

Question 2

liklihood ratio (-)

Answer 2

LR (-) = (1-SENSITIVITY) / SPECIFICITY

Question 3

ATRIBUTABLE RISK

Answer 3

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

Question 4

cardiac output

Answer 4

CO = SV X HR

Question 5

MAP

Answer 5

MAP = CO X SVR

Question 6

stroke volume

Answer 6

SV = EDV - ESV

Question 7

ejection fraction

Answer 7

EF = SV (EDV-ESV) /EDV

Question 8

filtration fraction

Answer 8

FF = GFR / RPF

Question 9

GFR

Answer 9

GFR = Urinary inulin x V/ plasma inulin

Question 10

anion gap

Answer 10

Na - (Cl + HC03)

Question 11

pulmonary vascular resistance

Answer 11

PVR = (P pulm artery - P left atrium) / cardiac output

Question 12

absolute risk reduction

Answer 12

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

Question 13

relative risk

Answer 13

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

Question 14

number needed to treat

Answer 14

NNT = 1 /ARR

Question 15

number needed to harm

Answer 15

NNH = 1/AR

Question 16

sensitivity

Answer 16

sensitivity = TP / (TP+FN)

Question 17

specificity

Answer 17

specificity = TN / (TN + FP)

Question 18

volume of distrubution

Answer 18

Vol distrubution = amount of drug in the body / vol distrubution

Question 19

loading dose

Answer 19

LD = desired plasma conc x vol distrubution / bioavailability

Question 20

maintenance dose

Answer 20

MD = desired plasma con x Cr cl x dosage interval / bioavailability

Question 21

half life

Answer 21

0.7 x volume distrubution / Cl

Question 22

drug clearance

Answer 22

drug clearance = rate of elimination / plasma conc of drug

Question 23

therapeutic dose

Answer 23

TD = mean toxic dose / mean therapeutic dose

Question 24

odds ratio

Answer 24

odds ratio = (a/c) / (b/d)