Hi guys. Welcome back to nursing tips with Tammy and today we are focusing on
medication administration, specifically oral tablets. Now what do you do when the
doctor orders a dose that you don't have on the floor. In the short answer - math -
but don't let that scare you. Today I'm going to show you three methods to
successfully calculate the right dose for the right patient. The first method we
are going to look at is ratios, second after that is we're going like a
proportions, and then the last one is dimensional analysis. Before we get
started though, there are two free quizzes in the description area of this
video, so please download version number one and meet me at the board. Great so
now we're back with our first quiz question. A patient who has ramipril 25
milligrams ordered and we have 50 milligram tablets available. In a ratio
we set up two sides of a value statement. On the one side I'm putting what I know,
one tab is 50 milligrams, I use a colon to separate them, and I'm going to put
down how many in 25. I do a visual look at 50 - 25 what did I do
I divided by two to get to that answer. So I will do the same for the tablets.
One tablet divided by two is one-half tablets and that's my answer for my
dosing. With proportions we're setting up two
fractions or two mathematical equations that are equal to each other. So in this
case one tablet over is 50 milligrams is equal to a question mark over 25
milligrams. This is known as our cross multiply, we want to get rid of the
denominators. So I'm going to take 25 milligrams multiply that by one tablet
and that will equal to my unknown x by 50 milligrams. Now to get rid of that 50
milligrams on the right side and isolate that question mark, I need to divide both
sides by 50. So on the left hand side of the equation you can see 50 milligrams
is crossed out leaving just the question mark, on the right hand side I'm going to
cross off milligrams and solve. So 25 tablets divided by 50 is equal to my
mystery dose; 0.5 tablets is equal to my dose which is the same as the ratios.
With dimensional analysis, this is another problem-solving method that
states you can multiply any factor or number by a 1 as it does not change the
outcome. So for example I'm going to start out with what I want to know- how
many tablets, and then I'm going to put in what do I know already. Now I could
write 50 milligrams over one tab or one tab over 50 milligrams.
I want tabs in the numerator so I choose this method. Dimensional analysis has us
working in diagonals. So the other piece of information I have is I'm looking for
a 25 milligram dose and I want to cross off milligrams. Now I'm left with tablets
so I can solve. One tablet times by 25 divided by 50 and I'm going to show you
all the steps here - is equal to 25 tab divided by 50, which equals one half
tablet. I end up with the exact same answer as my other two methods. So there
you go it's pretty easy right? But wait what if the doctor orders a dose that
doesn't match the units that I have on the floor. I'm gonna have to do a
conversion so lets look at question number five if you need to brush up on
the metric system watch my video and come back and join us and we're going to
look at how to work through a question that
fires conversions . So this question is asking me how many cefalexin 500
milligram tablets I will be giving to my patient who has an order for 0.5 grams.
So we need to put these into the same units so we are going to do a conversion.
Now because my tablets are available in milligrams I'm going to convert 0.5
grams into milligrams and then I can use my ratios and proportions. So 0.5 grams
times 1000 is equal to 500 milligrams. I now know that the dose required is the
same as the dose available. So I'm going to give one tablet. Now for proportions
because we already have the correct dose available,
I'm just including the math for you to see how you would work that out. So with
dimensional analysis I'm still going to start out with what am I looking for and
that is how many tablets. So I'm going to start with that. I know that I have one
tablet is 500 milligrams on the floor and I want to get rid of milligrams but
I don't have anything else in my question. So I go to my conversion table
and I see 1000 milligrams is equal to one gram. I can then cross off the
milligrams. I'm left with grams still to get rid of. Back to my question I see I
have a 0.5 gram dose so I'm going to put that into my formula next, so multiply by
0.5 grams. The grams cross off and I'm left with tabs and I can go ahead and
solve.
Hey-ya did it and I knew you could. Three ways to solve those pesky math problems.
Now do me a favor, comment below let me know which is your favorite method and
subscribe, then you'll be first in line for the next video which is weight-based
calculations. Until we're together again, make it a great day )