Med Math Conversions/ Tips

Question 1

lb in kg

Answer 1

2.2lb in 1kg
ex) pt is 160lb / 2.2 = 72.72 kg

Question 2

cm in inches

Answer 2

2.54cm in 1in
Ex) pt is 5’7 = 67in x 2.54 = 170.18 cm

Question 3

Equation for how many L left in O2 tank based on PSI=

Answer 3

0.33 x PSI in the tank = L of gas left in the tank

ex) tank reads 750PSI
750 * 0.33 = 247.5 L

Question 4

Equation for how many minutes left in tank if volume is known=

Answer 4

Given PSI x .33 = L of gas left in tank

Divide total L by flow/min = minutes remaining

ex) The known volume remaining in a tank is 247.5L and the pt is receiving 4L/min. How many minutes remaining does the tank have at that rate?

247.5L / 4L/min = 61.87 ~ 62 min

Question 5

1:100,000 Epi means what?

Answer 5

This means there is 1g in 100,000 mL of solution.

1g/100,000mL = 1,000,000mcg/100,000mL=
10mcg/mL

Question 6

How many mg/mL in a % conc solution?

Answer 6

Whatever the percent is, just move decimal one space to the right for mg/mL

Ex) 0.75% Bupivicaine = 7.5mg/mL

Question 7

How to get % conc of a solution from mg/mL?

Answer 7

If in mg/100mL already, just move decimal one place to left to get the % concentration

Must be in g/100mL to equal % concentration.

Ex) 500mg/mL solution= 0.5gm/mL = 50gm/100mL

50gm/100mL=50% solution

Ex)500mg/mL solution = 50%

Question 8

How to get mg/mL from a premixed bag?

Answer 8

Multiple dose to equal 1000mL then divide total concentration by 1000mL to find concentration per 1mL

Ex) 4mg norepinephrine in 250mL bag
4 in 250 x 4 = 16mg/1000mL = 0.016mg/mL

Ex) Mag sulfate 2g in 100mL
2g in 100mL x 10 = 20g/1000mL = .02g/mL

.02g/mL = 20mg/mL

Question 9

How to: Double dilute Epi

Answer 9

Take 1mg/mL dose and dilute it in 9mL diluent(saline) to get new dose. Then do that again with another 9mL of diluent.

(In real life, epi comes in the brown box CPR amp we are all familair with that has a concentration of 1mg in 10mL(1:10,000) or it often comes in 1mg/mL vials (1:1,000). Pay attention to the concentration!! They are not always the same.)

ex) Someone hands you a vial of Epi that has 1:1,000 on it. Double dilute it and give dose in mcg/mL.

Step1: Figure out mg/mL from concentration.
-Epi vial 1:1,000 = 1g/1,000mL = 1,000mg/1,000mL = 1mg/mL OR 1,000mcg/mL

Step 2: Take 10ml syringe and draw up the 1mL of Epi, then draw up 9mL diluent(saline), giving you100mcg/10mL OR 100mcg/mL

Step 3: Take another 10mL syringe and draw up 1mL of that mixture, followed by another 9mL of saline, giving you 100mcg/10mL OR 10mcg/mL

Question 10

MAP Equation

Answer 10

MAP = [SBP+ (DBPx2)] / 3

Question 11

IDEAL BW

Answer 11

women = 100lb + (5lb x inches over 5’)
men = 105lb + (6lb x inches over 5’)

Question 12

Lean BW =

Answer 12

=IBW x 1.3

Question 13

1g = ____ mg = _____ mcg

Answer 13

1,000mg, 1,000,000mcg

Question 14

1:1000 means?

Answer 14

1g in 1000mL

Question 15

% concentration is equal to what?

Answer 15

g/100ml

ex: 2% lido = 2g in 100mL = 2000mg in 100ml = 20mg/mL

Question 16

Celsius to farenheit conversion

Answer 16

F = (C x 1.8) +32

Question 17

Farenheit to celsius conversion

Answer 17

C = (F - 32) x (5/9)