Help with dosage calculations

8mg x

---- = ----

250ml 3.7 ml

cross multiply

8*3.7 = 250x

(8*3.7)/250 = x

x=mg/hr

multiply 1000 to get mcg and divide by 60 to get min

then round it to the nearest whole number

AN is fiddling with the spacing

8mg/250=x/3.7

3.7mL/1 hr X 8mg/250mL X 1 hr /60 min X 1000 mcg/ 1 mg = 2 mcg/min

Hope this helps!!!

It's often helpful to think these things through in words before ever embarking on any equations or formulas. Your instructor knows that, so she has given you a problem in a different format than you are used to, to see if you can figure it out. Rather than just launching into multiplication and division, think about what you're looking at hanging up on the IV pole. My goal here is not just to show you I know how to do the math but to show you how to think about how you're going to do the math. :)

So lessee here, what have we got?

8 mg = (how many) mcg? Right, 8000.

That number of mcg is in 250cc. So how many mcg are there in 1cc? That would be 8000 divided by 250 = 32 mcg in 1 cc.

If you have that number, how many mcg are in 3.7 cc? -- that gives you the mcg in an hour. That's 118.4 mcg per hour.

Divide by 60 to see how many mcg in a minute.(round to nearest whole number). That's 118.8 / 60 = 1.97, or 2 mcg/minute.

Does that make sense?

Solving for "x" is very simple and relies on a couple of basic concepts:

1) Don't fork (cuz AN gets mad at me when my sailor talk comes out) with the equal sign... Whatever is done on one side must be done exactly the same on the other side.

Think of it like a teeter-totter (if you're old enough to remember those...) or a lever on a fulcrum... in order to maintain stasis, a weight added, subtracted, or relocated on one side of the fulcrum must be offset by an equivalent action on the opposite side (remember when some jerk would jump off the teeter-totter and let you go crashing down?)

2) Multiplication is the inverse of division and subtraction is the opposite of addition.

3) Units can be canceled via multiplication/division just as can numbers.

4) Anything divided by itself equals one

You're trying to get 'x' all by itself (isolate it). Anywhere that 'x' is being multiplied (by either a number or a unit) calls for division by the same value (coefficient) on each side of the equal and anything being added to 'x' needs to be offset by an identical subtraction on each side of the equal.