Equation Review Flashcards
(35 cards)
Sensitivity
Sensitivity = TP / (TP + FN)
Specificity
Specificity = TN / (TN + FP)
Positive predictive value
PPV = TP / (TP + FP)
Negative predictive value
NPV = TN / (FN + TN)
Odds ratio (for case-control studies)
OR = (a/c) / (b/d) = ad / bc
Relative risk
RR = (a/(a+b) / (c/(c+d)
Relative risk reduction
RRR = 1 - RR
Absolute risk reduction
ARR = (c/c+d) - (a/a+b)
Number needed to treat
NNT = 1/ARR
Number needed to harm
NNH = 1/AR
Hardy-Weinberg equilibrium
p^2 + 2pq + q^2 = 1 OR p + q = 1
Volume of distribution
Vd = amount of drug in the body / plasma drug concentration
Half-life
t1/2 = 0.693 x Vd / CL
Drug clearance
CL = rate of elimination of drug / plasma drug concentration = Vd x Ke (Ke = elimination constant)
Loading dose
LD = Cp x Vd / F
Maintenance dose
D = Cp x CL x tau / F
Cardiac output
CO = rate of O2 consumption / arterial O2 content - venous O2 content
OR
CO = stroke volume x heart rate
Mean arterial pressure
MAP = cardiac output x total peripheral resistance
OR
MAP = 2/3diastolic + 1/3systolic
Stroke volume
SV = EDV - ESV
Ejection fraction
EF = SV/EDV = (EDV - ESV)/EDV
Resistance
Resistance = driving pressure (ΔP) / flow (Q) = 8η (viscosity) x length / πr^4
Capillary fluid exchange
Jv = net fluid flow = Kf[(Pc-Pi) - ς(πc - πi)]
Renal clearance
Cx = UxV/Px Cx: clearance of X (mL/min) Ux: Urine concentration of X (mg/mL) Px: Plasma concentration of X (mg/mL) V: Urine flow rate (mL/min)
if Cx > GFR: net tubular secretion of X
if Cx < GFR: net tubular absorption of X
If Cx = GFR: no net secretion or reabsorption
Glomerular filtration rate
GFR = [Xurine]*V /[Xplasma] GFR = excretion rate/plasma concentration
