# Medical Calculator with Equations and Interpretations

Click on name of equation to see formula and edit input boxes to automatically calculate result.

## Convert between Pounds and Kilograms and between Inches and Centimeters

kg * 2.2 = lbs
cm = 2.54 * inches

= FiO2 * (pAtm - pH2O) - paO2 - pCO2 / RQ = _____
pAtm = 760 mmHg * exp(-altitude / 7000)
pH2O = 47 mmHg @ 37 degrees Celcius
FiO2 (%):
altitude (Sacramento is 7 meters):
paO2 (mmHg):
pCO2 (mmHg):
RQ (respiratory quotient):

## Anion Gap

= Na - (Cl + HCO3) = _____
Na:
Cl:
HCO3:
Interpretation: Normal range is 8 - 16. If high, remember MUDPILES (Methanol, Uremia, Dka, Paraldehyde, INH/Iron, Lactic acid, Ethanol, Salicylates)

## APGAR

= _____
color: pink extremities blue body blue
tone: active some flexion limp
pulse: HR >= 100 < 100 no pulse
respiration: crying irregular respirations or slow absent
response to suction: sneeze or cough grimace no reaction
Interpretation: most babies 7-10, points off for color and tone

## Body Mass Index, (BMI)

= weight / square of height = _____
weight (kg):
height (m):
Interpretation:
less than 18.5 => underweight
18.5 - 25 => normal weight
25 - 30 => overweight
greater than 30 => obese

## Basal Metabolic Rate (Harris-Benedict)

(male) = 13.7516 * kg + 5.0033 * cm - 6.755 * yrs + 66.473
(female) = 9.5634 * kg + 1.8496 * cm - 4.6756 * yrs + 655.095
= ________ kcal/day
weight (kg): , height (cm): , age (yrs): , gender: Male   Female

## Corrected Calcium

= Ca + 0.8 * (4 - Alb) = _____ Ca: Alb:

## Child-Pugh Score

= _____
 Bilirubin: <2 2-3 >3 Albumin: >3.5 3.5-2.8 <2.8 PT prolongation (INR): <4 seconds (<1.7) 4-6 seconds (1.7-2.3) >6 seconds (>2.3) Ascites: Absent Mild-Moderate Severe/Refractory Encephalopathy: Absent Mild (I-II) Severe (III-IV)

## Creatinine Clearance (Cockcroft-Gault)

(male) 1.23 * kg * (140 - years) / Cr
(female) 1.03 * kg * (140 - years) / Cr
= _____
gender: Male   Female
weight (kg):
age (years):
Creatinine (mg/dL):

## Corrected Na

= Na + (glc - 5) / 3.5 = _____
Na (mmol/L): glc (mg/dL):

## Fractional Excretion of Sodium, (FENa)

= (UNa / UCr) * (PCr / PNa) = _____%
Na, plasma (mmol/L):
Cr, plasma (mmol/L):
Na, urine (mmol/L):
Cr, urine (mmol/L):
Interpretation: less than 1% implies Prerenal azotemia

## Free Water Deficit

(Male) = 0.5 * kg * ((Na / 140) - 1)
(Female) = 0.4 * kg * ((Na / 140) - 1)
= _____
gender: Male Female
weight (kg):
Na (mmol/L):
Interpretation: max 1/2 deficit replace in 1st 24hrs

## Fluid Replacement, Parkland formula

= weight * % BSA burned * 4 = _____(L)
weight (kg):
% Body Surface Area burned (%):
Interpretation: 1/2 first 8hrs, 1/2 next 16hrs

## Glomerular Filtration Rate, (GFR)/CKD Staging

(female, black) = 186 * Cr ^ -1.154 * age^-0.203 * 1.210 * 0.742
(??, ??) = 170 * Cr ^ -1.007 * age^-0.180 * 1.178 * 0.755 * BUN ^ 0.169
(??, ??) = 170 * Cr ^ -0.999 * age^-0.176 * 1.180 * 0.762 * BUN ^ 0.17 * alb ^ 0.318
= _____
gender: Male Female
African-American ethnicity:
age (years):
BUN (units):
Cr (mg/dL):
alb (units):

## Osmotic Gap

= measured osmolals - 2 * Na + BUN / 2.8 + glc = _____
measured Osmolals (units):
Na (mmol/L):
BUN (units):
glc (mg/dL):

## Delta-Delta Gap

delta HCO3 = 24 - HCO3 =
expected AG = albumin x 2.5 =
AG = Na - (Cl + HCO3) =
delta AG = AG - expected AG =
delta-delta = delta HCO3 - delta AG
= _____
Na:
Cl:
HCO3 (units):
alb:
Interpretation:
delHCO3 ~ delAG, ~0 --> pure AG metabolic acidosis
delHCO3 > delAG, >0 --> simultaneous non-AG acidosis
delHCO3 < delAG, <0 --> simultaneous metabolic ALKalosis

= _____
Eye opening (none/pain/speech/spontaneous)
Verbal communication (none/sounds/words/confused/oriented)
Motor (none/abnormal extension/abnormal flexion/withdraw pain/localize pain/spontaneous or obeys commands)
Interpretation: less than 8 is coma.

## LDL goals from ATP III

Major CHD Risk Factors: Cigarette smoking, Hypertension, HDL<40, age (man >45, female >55), family history of premature CHD (male age <55, female age <65)
LDL goals based on # risk factors:
0-1 => less than 160
2+ => less than 130
CHD => less than 100
DM => less than 70
Criteria for choosing a lipid lowering agent:
Drug%LDL reduction%HDL increase%TG reductionSide Effects (monitoring & contraindications)
statin18-555-157-30myopathy, increased LFT
sequestrant15-303-5nil - increaseGI, constipation, decreased drug absorption
Niacin5-2515-3520-50flushing, hyperglc, gout, LFT, UGI
fibric acid5-2010-2020-50dyspepsia, gallstones, myopathy, (LFT, Cr)

## Severe I Respiratory Syndrome, (SIRS)

2 or more of HR>90, T<36 or T>38, RR >20 or PaCO2 <32, WBC <4 or >12

## Ideal Body Weight, (IBW), (Robinson Formula)

(men) = 52 + 1.9 * (in - 60)
(women) = 49 + 1.7 * (in - 60)
= _____