Dimensional Analysis for Drug Calculations

Hi, this is Sarah with RegisteredNurseRN.com and I'm going to talk to you about dimensional analysis. Dimensional analysis is used to solve drug and dosage calculation problems that you may encounter in nursing school. Before you start working dimensional analysis problems, you must first learn the metric table. So, let's get started. In my previous video, I talked about the metric table and went over it with you. If you need a copy of the metric table, you can go to our website, RegisteredNurseRN.com backslash metric table, and you can print it out. It's in Microsoft.exe format, and you can have that as a reference. And behind me is a metric table, and I'm going to show you how to use the metric table and to solve conversion problems. But first, let me talk about dimensional analysis. Dental analysis is a problem-solving tool. technique where you can solve for any numbers or values and multiply them by one and not change the value. So I'm going to show you just using a basic problem how you would set one up and how it works. Once you get the hang of it solving drug and dosage calculations is really easy. Also we are doing a video series of how to solve different types of drug and dosage calculations problems that you may encounter in nursing school. So, be sure to check those out. We'll have them listed on our website and on this YouTube channel. So, let's start working some problems. The first problem I have is 8 grams equals how many milligrams? This is just a basic conversion problem that you may be asked to solve. Above here, we have the metric table. It's a very good idea you memorize this metric table before you start working the problems. That way, you can just work the problem and not have to go back and forth. and look at the table but since we're beginning we're gonna go we need the table in front of us and so we're going to learn how to do it by looking at the table I've already worked the problem out here because I felt like having it worked out you could see what I was talking about and then I'll go back and work another problem by hand okay how I like to set my problems up is I like to first set the problem up you have the top and the bottom these are not fractions a lot of people think that these are fractions it's not fractions so get out of the mindset of thinking it's a fraction. I put 8 grams equals how many milligrams. Some people like to put one but I like to put how many milligrams. The key is you are trying to get from grams to milligrams because the problem is asking for milligrams. So what we're going to do is in dimensional analysis you work the problems diagonally like this and you want to cancel out whatever is going here. is grams. So we wanted to cancel that out. So we put eight grams equals how many milligrams. So we're going to write grams. And if we look at our metric table, we will see that one gram equals a thousand milligrams. So we're going to put one gram equals a thousand milligrams. And the problem was asking us for milligrams. So we're done. All we have to do now is multiply and divide. We're going to multiply eight times. a thousand which equals 8,000 multiply everything on the bottom the only thing on the bottom is one so you'll put 8,000 divided by one which equals 8,000 milligrams there's 8,000 milligrams and 8 grams so that was a basic problem now let's take it a little step further Okay, let's see. 8 grams equals how many micrograms? Before, we were doing milligrams, but let's do micrograms. Again, I'm going to set up the problem like this. 8 grams equals how many micrograms? So we're going to move grams over here because remember you work dimensional analysis diagonally. So we're going to move our grams and we're going to go up to our metric table and we're going to see how many grams are in a microgram. So as you look at your metric table. You don't really see that one gram equals so many micrograms. So we're going to go two milligrams. You see, according to the table, one gram equals a thousand milligrams. So we'll do that. Our goal is to get to micrograms. These dimensional analysis problems can be several steps. So one gram equals a thousand milligrams. Okay, we have canceled out our grams, so we're going to mark our grams out. Now, write milligrams over here because, again, we work diagonally. And we're going to go up to our table. And we're trying to get to micrograms. So let's see if we can find on the table if something will equal to micrograms. We do. We see. one milligram equals a thousand micrograms. So we're going to write one and it equals a thousand micrograms and write a thousand micrograms and we're going to cancel out our milligrams. Okay and what was the problem asking us for? It was asking us for micrograms. So we are done. We can multiply and divide now. So, you're going to take 8 times 1000 times 1000, which equals 8 million, and you're going to multiply on the bottom, 1 times 1 equals 1, and then you're going to divide. 8 million divided by 1 equals 8 million. So there are 8 million micrograms in 8 grams. Okay, let's do one more problem just to make sure you get the hang of it. This problem is 100 milliliters equals how many ounces? Again, we're going to set up our problem with what it's asking for. 100 milliliters equals how many ounces? With dimensional analysis, again, we work diagonally. So we're going to move milliliters over here. And we're going to go and refer to our metric table. How can we get from milliliters to ounces? So we see up here, there's really not one milliliter equals so many ounces. So this is probably going to be a multiple step problem. So it says that 15 milliliters. equals 1 tablespoon and then what 2 tablespoons equals 1 ounce so what we'll do is we'll start out with milliliters so we'll write 15 milliliters equals 1 tablespoon milliliters cancels out And now we're going to move tablespoons down here at the bottom and we're going to refer to our table and our key is to get to ounces. So we see that two tablespoons equals one ounce. So we're going to put two tablespoons equals one ounce. equals one ounce. And tablespoons cancels out. Now we're done because we've got to ounces is what we were supposed to solve for. So we are going to multiply everything at the top and bottom and then divide. A hundred times one times one is a hundred. And fifteen times two is thirty. 100 divided by 30 is 3. So your answer is there are 3 ounces in 100 milliliters. So that is the basic conversions on how to use dimensional analysis. I hope that helped explain it. I remember whenever I was in nursing school, whenever I actually figured out how to use dimensional analysis, I thought it was the best thing ever. Please go to our website, RegisteredNurseRN.com. We have a lot of practice quizzes that you can work and see how well you did on the quiz for free. It's RegisteredNurseRN.com and we have a slider on the page. Just click quizzes and it will take you there. Be sure to also check out our video tutorials because we're going to be solving more complex conversion problems that you'll see in nursing school like IV boluses, dosage and calculations based on a patient's weight and it gets a little bit more in depth. So I hope this helped clarify some things and thank you so much for watching and be sure to check out our website, RegisteredNurseRN.com.

In my previous video, I talked about the metric table and went over it with you. If you need a copy of the metric table, you can go to our website, RegisteredNurseRN.com backslash metric table, and you can print it out. It's in Microsoft.exe format, and you can have that as a reference.

And behind me is a metric table, and I'm going to show you how to use the metric table and to solve conversion problems. But first, let me talk about dimensional analysis. Dental analysis is a problem-solving tool.

technique where you can solve for any numbers or values and multiply them by one and not change the value. So I'm going to show you just using a basic problem how you would set one up and how it works. Once you get the hang of it solving drug and dosage calculations is really easy. Also we are doing a video series of how to solve different types of drug and dosage calculations problems that you may encounter in nursing school.

So, be sure to check those out. We'll have them listed on our website and on this YouTube channel. So, let's start working some problems.

The first problem I have is 8 grams equals how many milligrams? This is just a basic conversion problem that you may be asked to solve. Above here, we have the metric table.

It's a very good idea you memorize this metric table before you start working the problems. That way, you can just work the problem and not have to go back and forth. and look at the table but since we're beginning we're gonna go we need the table in front of us and so we're going to learn how to do it by looking at the table I've already worked the problem out here because I felt like having it worked out you could see what I was talking about and then I'll go back and work another problem by hand okay how I like to set my problems up is I like to first set the problem up you have the top and the bottom these are not fractions a lot of people think that these are fractions it's not fractions so get out of the mindset of thinking it's a fraction. I put 8 grams equals how many milligrams.

Some people like to put one but I like to put how many milligrams. The key is you are trying to get from grams to milligrams because the problem is asking for milligrams. So what we're going to do is in dimensional analysis you work the problems diagonally like this and you want to cancel out whatever is going here. is grams. So we wanted to cancel that out.

So we put eight grams equals how many milligrams. So we're going to write grams. And if we look at our metric table, we will see that one gram equals a thousand milligrams.

So we're going to put one gram equals a thousand milligrams. And the problem was asking us for milligrams. So we're done.

All we have to do now is multiply and divide. We're going to multiply eight times. a thousand which equals 8,000 multiply everything on the bottom the only thing on the bottom is one so you'll put 8,000 divided by one which equals 8,000 milligrams there's 8,000 milligrams and 8 grams so that was a basic problem now let's take it a little step further Okay, let's see.

8 grams equals how many micrograms? Before, we were doing milligrams, but let's do micrograms. Again, I'm going to set up the problem like this. 8 grams equals how many micrograms?

So we're going to move grams over here because remember you work dimensional analysis diagonally. So we're going to move our grams and we're going to go up to our metric table and we're going to see how many grams are in a microgram. So as you look at your metric table. You don't really see that one gram equals so many micrograms. So we're going to go two milligrams.

You see, according to the table, one gram equals a thousand milligrams. So we'll do that. Our goal is to get to micrograms.

These dimensional analysis problems can be several steps. So one gram equals a thousand milligrams. Okay, we have canceled out our grams, so we're going to mark our grams out. Now, write milligrams over here because, again, we work diagonally. And we're going to go up to our table.

And we're trying to get to micrograms. So let's see if we can find on the table if something will equal to micrograms. We do. We see. one milligram equals a thousand micrograms.

So we're going to write one and it equals a thousand micrograms and write a thousand micrograms and we're going to cancel out our milligrams. Okay and what was the problem asking us for? It was asking us for micrograms.

So we are done. We can multiply and divide now. So, you're going to take 8 times 1000 times 1000, which equals 8 million, and you're going to multiply on the bottom, 1 times 1 equals 1, and then you're going to divide. 8 million divided by 1 equals 8 million.

So there are 8 million micrograms in 8 grams. Okay, let's do one more problem just to make sure you get the hang of it. This problem is 100 milliliters equals how many ounces? Again, we're going to set up our problem with what it's asking for. 100 milliliters equals how many ounces?

With dimensional analysis, again, we work diagonally. So we're going to move milliliters over here. And we're going to go and refer to our metric table. How can we get from milliliters to ounces? So we see up here, there's really not one milliliter equals so many ounces.

So this is probably going to be a multiple step problem. So it says that 15 milliliters. equals 1 tablespoon and then what 2 tablespoons equals 1 ounce so what we'll do is we'll start out with milliliters so we'll write 15 milliliters equals 1 tablespoon milliliters cancels out And now we're going to move tablespoons down here at the bottom and we're going to refer to our table and our key is to get to ounces.

So we see that two tablespoons equals one ounce. So we're going to put two tablespoons equals one ounce. equals one ounce.

And tablespoons cancels out. Now we're done because we've got to ounces is what we were supposed to solve for. So we are going to multiply everything at the top and bottom and then divide.

A hundred times one times one is a hundred. And fifteen times two is thirty. 100 divided by 30 is 3. So your answer is there are 3 ounces in 100 milliliters.

So that is the basic conversions on how to use dimensional analysis. I hope that helped explain it. I remember whenever I was in nursing school, whenever I actually figured out how to use dimensional analysis, I thought it was the best thing ever. Please go to our website, RegisteredNurseRN.com. We have a lot of practice quizzes that you can work and see how well you did on the quiz for free.

It's RegisteredNurseRN.com and we have a slider on the page. Just click quizzes and it will take you there. Be sure to also check out our video tutorials because we're going to be solving more complex conversion problems that you'll see in nursing school like IV boluses, dosage and calculations based on a patient's weight and it gets a little bit more in depth. So I hope this helped clarify some things and thank you so much for watching and be sure to check out our website, RegisteredNurseRN.com.

Transcript for:Dimensional Analysis for Drug Calculations

Transcript for:
Dimensional Analysis for Drug Calculations