Question

Nitroglycerin is administered by IV infusion in emergency situations. A typical infusion dose is 5 micrograms per minute. For a diluted nitroglycerin solution with a concentration of 100 micrograms per milliliter, what is the infusion rate in milliliters per hour?

Answer 1

3 mL/h

Explanation:

To understand these types of question, one has to be able to identify the variables, the unknown, have in mind the units, and also know what equation to use.

These are the variables the problem provides:

Dose = 5 ug/min

Concentration ⇒ C = 100 ug/mL

We have to figure out the infusion rate:

Infusion rate (velocity) ⇒ v = ? In [mL/h]

Note: the time units of the dose and the infusion rate are not equal (One is in minutes and the other one is in hour). Keep in mind the conversion.

The equation we have to use is the following (in [] are the units we were provided):

Dose [ug/min] = C [ug/mL] x v [mL/h]

Since the units of time are not equal, we have to remember to convert one correctly. Since we are solving for the infusion rate, minutes should be converted to hours:

Dose [ug/min x 60 min/h] = C [ug/mL] x v [mL/h]

Since we sorted out correctly our units, let’s solve for infusion rate:

v =
`(Dose)/(C)` ⇒ v =
`(5 ug/min * 60 min/h)/(100 ug/mL)` (ug and min cancels out, so final units are mL/h)

v = 3 mL/h

Conclusion: our infusion rate of nitroglycerin is equal to 3 mL/h