 Now let's look at a few more examples that are a little bit more involved and maybe a little bit more complicated. So our order here is insulin 3 units per hour. Our supply is insulin 200 units in 300 ml of normal saline. Again we want to know how many mL per hour we're going to give the patient. So I'll start by again what I'm looking for, milliliters per hour equals the milliliters I have given you are this 300 per 200 units. So I'll write the 300 mL on top per the 200 units. I need the hours on the bottom. So what I have here is three units per hour. So I'll write the units on the top, the hour on the bottom and I'll see where I can cross can. So units per hour. What I'm left with is milliliters per hour which is what I'm looking for. So now all I have to do is do my math and this comes out to 4.5 milliliters per hour. Next example, so now we have heparin 12 units per kilo per hour and the order, the supply is 25,000 units in 500 ml. Patience weight is 185 pounds and again I need to know how many milliliters per hour I'm going to administer for this patient. So what I'm looking for is milliliters per hour, excuse me. And so I have my milliliters right here so I'll write those on the top, 500 milliliters by 25,000 units. Again I'll write out the units. Then I'll have my units per kilo per hour. When there are something given with two times the per, then those whatever is beyond the slash goes on the bottom of the fraction. So in this case I'll write 12 units because that's where I need the units so I can cross-cancel them and then I'll write per kilo and then I'll just write slash. Now I can get rid of my units here, now I have the kilos in the hour so the hour is what I need, the mill is what I need, but I have the kilos now how do I get rid of those? I have the patient's weighting pounds given by knowing my ratio 2.2 pounds to 1 kilo. I'll start with getting rid of the kilos so I'll write 1 kilo per 2.2 pounds, kilo cancels out, kilo cancels out. I have milliliters per hour but I also have the pounds here on the bottom. So the patient's weight is 185 pounds which I can put over one. I can cancel out the pounds and now I'm looking all my units are gone. What I've left with is milliliters per hour which is what I'm looking for over here and now I do my math. And this ends up being 20.18 which typically but again refer to your rounding rules for your school 20.2 milliliters per hour. And then this is probably the most complicated example that you'll ever see. And if you go very methodically about it by applying this information that we've done in all these examples you will not have trouble solving this problem. So we have dopamine. Dopamine is 3 micrograms per kilo per minute. I also apply this dopamine 200 milligrams per 250 mL. Patient's weight is 190 pounds and I'm looking for mLs per hour. Now the first thing that I would advise you to pick up here is the difference in units. So we have micrograms and milligrams and in order to convert this we're going to refer back to our micrograms per milligrams right here. So we'll have to also convert minutes to hours and pounds to kilos. So let's look at this. So we're looking for milliliters per hour so I'll write that in the front here. My milliliters are my 250 so I'll write those on the top 250 milliliters by 200 milligrams. Now rather than starting to mess around with any of these other things not knowing what I should put in the numerator or denominator I'm going to go ahead and focus on getting rid of my milligram measure here because I sure don't need that in the front here. And I know that my conversion ratio is one milligrams to 1,000 micrograms, milligrams cancel. Now I have my micrograms here and I can use this fraction here to cross cancel. So micrograms, three micrograms per kilo per minute. Remember just like we had up here if there are two fractions they both go on the bottom. So I have the kilos and the minutes here on the bottom. So now I can cross cancel my micrograms. Now I have to left my kilos and my minutes. So the kilos let's focus on that first. I know that one kilo is 2.2 pounds so one kilo per 2.2 pounds kilo and kilo. And then I have my minutes here and I know that I have 60 minutes per hour. The minutes will have to go on the top and the hour on the bottom. So minutes cancel out again. So now the only unit that I have left here is my pounds. And in order to get rid of that I plug in the patient's weight which is 190 pounds. And I know that I can put that over one. So these cancel out. So now the most important thing is to go back and double check that everything that needs to be crossed out is crossed out. And really all the units that I'm left with here is only the milliliters per hour which is what I'm looking for. So my milligrams canceled out, my micrograms canceled out, my keto canceled out, my minutes canceled out, my pounds canceled out. I have left my hour and my milliliter. And now I do my math. And this one comes out to being 19.43 which will round down to 19.4 milliliters per hour. So looking back at this by the principle of cross-cancelling the numbers as well as units and memorizing our ratios here we can apply this to any math problem. Keep in mind always start with what you're looking for and then cross cancel the things that you're not looking for. Circle to make sure that what you're looking for is what you're left with. Especially in this example down here where we have several different dimensions here that everything needs to cancel itself out so that we're left with our units per hour, I'm sorry milliliters per hour that we're looking for here. Also look back and see if it makes sense. Again if dopamine came back to infusing at 0.032 or 743 milliliters per hour that just doesn't make any sense. Typically any kind of drips will be a one or two digit number so like in the singles or 10 digits or anything in the pediatric range will typically be there as well. Again if it's NICU medication it might be like 0.3 milliliters or something to that effect but for the most part it really needs to make sense. I encourage you to apply this principle to any kind of math problem no matter how simple or complicated and really if you follow this very methodical, this very methodical way you are really going to not have any trouble with any more dosage calculations. I hope this helped you in solving your math problems and dosage calculations. Please leave comments below. I'll be happy to review those and also any suggestions you have for me. Refer to my channel Nursing School Explained and I have more videos coming up there. You are also welcome to leave comments regarding topics you want me to review in the future and I'll be happy to address those. Thank you for watching Nursing School Explained and good luck on your math calculations and dosage quizzes.