equations

Question 1

Sensitivity

Answer 1

Sensitivity = TP / (TP + FN)

Question 2

Specificity

Answer 2

Specificity = TN / (TN + FP)

Question 3

Positive predictive value

Answer 3

PPV = TP / (TP + FP)

Question 4

Negative predictive value

Answer 4

NPV = TN / (TN + FN)

Question 5

Relative risk

Answer 5

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

Question 6

Attributable risk

Answer 6

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

Question 7

Number needed to treat

Answer 7

1/absolute risk reduction (ARR), 1/[Event Rate (control) - Event Rate (treatment)]

Question 8

Number needed to harm

Answer 8

1/attributable risk increase (ARI), 1/[Event Rate (treatment) - Event Rate (placebo)]

Question 9

Hardy-Weinberg equilibrium

Answer 9

p(exp)2 + 2pq + q(exp)2 = 1 , p + q = 1

Question 10

Henderson-Hasselbalch equation

Answer 10

pH = pKa + log ([HCO3-]/ 0.03 PCO2)

Question 11

Volume of distribution

Answer 11

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

Question 12

Clearance

Answer 12

CL = (rate of elimination of drug) / (plasma drug concentration) , or Vd x Ke (elimination constant)

Question 13

Half-life

Answer 13

t1/2 = 0.7 x Vd/CL

Question 14

Loading dose

Answer 14

LD = Cp x Vd/F

Question 15

Maintenance dose

Answer 15

MD = Cp x CL/F

Question 16

Cardiac output

Answer 16

CO = stroke volume x heart rate, CO = Rate of O2 consumption/(arterial O2 content - venous O2 content)

Question 17

Mean arterial pressure

Answer 17

MAP = cardiac output x total peripheral resistance, MAP = 1/3 systolic + 2/3 diastolic

Question 18

Stroke volume

Answer 18

SV = end diastolic volume - end systolic volume

Question 19

Ejection fraction

Answer 19

EF = (stroke volume / end diastolic volume) x 100

Question 20

Resistance

Answer 20

R = driving pressure/flow , R = 8 x (viscosity) x length / (pi x r^4)

Question 21

Net filtration pressure

Answer 21

Pnet = (Pc - Pi) - (pi c - pi i)

Question 22

Glomerular filtration rate

Answer 22

GFR = U inulin x (V/ P inulin) = C inulin

Question 23

Glomerular filtration rate (In terms of hydrostatic and oncontic pressures)

Answer 23

GFR = Kf [(P GC - P BS) - (pi GC - pi BS)]

Question 24

Effective renal plasma flow

Answer 24

ERPF = U PAH x (V/ P PAH) = C PAH

Question 25

Renal blood flow

Answer 25

RBF = RPF / (1 - Hct)

Question 26

Filtration fraction

Answer 26

FF = GFR/RPF

Question 27

Physiologic dead space

Answer 27

VD = VT x [(PaCO2 - PeCO2) / PaCO2]

Question 28

Renal Clearance

Answer 28

C = U x V/P

Question 29

Pulmonary vascular Resistance

Answer 29

PVR=[P(pulm artery) - P(L atrium)]/CO

Question 30

Alveolar gas equation

Answer 30

PAO2 = PIO2 - PaCO2/R

Question 31

Odds ratio (for case-control studies)

Answer 31

Odds ratio = (a/c)/(b/d) = (a x d)/(b x c)

Question 32

BMI - body mass index

Answer 32

BMI = weight in kg / (height in meters)exp2

Question 33

Alveolar Ventilation

Answer 33

Alveolar ventilation = (tidal volume - dead space) x Resp Rate