Overview of Dose Calculation Ratio and Proportion Method
Medications have to be carefully calculated to ensure safe and effective dosages. There are three main ways to do this: dimensional analysis, ratio proportion, and the formula method. Today, we’ll focus on the ratio-proportion method.
This method lets us compare numbers, measurements or values. To use it, first we need to make a ratio and a proportion. A ratio is a way to show the relationship between two things. It’s often expressed as a fraction. For example, if you’re comparing the number of cats to dogs in a house, and there are 3 cats and 5 dogs, your ratio would be 3/5. A proportion, on the other hand, is two equal ratios.
These calculations are easier to do when expressed as fractions, and when we cross multiply or divide to cancel out similar units or volumes. Here’s how it’s done: first, you look at the fraction. The number on the top is called the numerator and the number on the bottom is the denominator.
Then, you multiply and divide the numerator and the denominator, after canceling out the same units. Sometimes, we use a colon (:) or slash (/) to show division in these kinds of calculations. To make things easier, the numerator (top number of a fraction), goes to the left of the colon or slash. The denominator (bottom number), gets put to the right of it.
If there’s an amount that we don’t know in the equation, we use an (x) to represent this unknown quantity. We put (x) on the left of the equation, so it’s easier to do the cross multiplication and division. Just remember that the same units of measurement and numbers on the top and bottom of a fraction can be cancelled out!
Equipment used for Dose Calculation Ratio and Proportion Method
Healthcare professionals often use calculators to figure out the correct dosages of medication. Calculators can be helpful in reducing mistakes related to math errors. However, they aren’t as useful when it comes to spotting conceptual misunderstandings (Savage, 2015).
A research study by Boyle and Eastwood discovered that without the use of calculators, in a group of twenty paramedics who filled out a written drug calculation questionnaire, they found 40% conceptual mistakes, 60% arithmetic errors, and 25% computational errors (Boyle & Eastwood, 2018).
The findings of this study reveal the importance of continued learning in order to enhance basic math skills, such as using formulas correctly, creating a math equation, and doing long division without a calculator. This is especially significant since calculators might not always be accessible in situations before reaching the hospital, and mobile applications might not be reliable due to limited phone coverage. The researchers concluded that basic training in performing manual drug calculations should be included in education programs (Boyle & Eastwood, 2018).
Using one of the three mentioned methods to calculate drug dosages – Ratio and Proportion, Desired Over Have or Formula, and Dimensional Analysis – can simplify the process of manual drug calculation. No matter which method healthcare workers choose to use, it’s beneficial to employ a second method as a backup to the first one in order to further reduce the likelihood of medication errors due to incorrect dosage calculation.
How is Dose Calculation Ratio and Proportion Method performed
Understanding how to do calculations for medication dosage can be tricky. Here are three ways: the Ratio and Proportion Method, the Desired Over Have or Formula Method, and the Dimensional Analysis Method. Let’s break each one down, using an example where a doctor orders 4 mg of a drug called lorazepam to be given to a patient via intravenous injection.
Ratio and Proportion Method
This method involves setting up fractions or ratios, representing the quantity of the drug you have and the quantity you need to give to the patient. For our lorazepam example, let’s say you have vials with a concentration of 2 mg per mL. To calculate how many milliliters you need to give to reach the ordered 4 mg dose, you can set up a fraction like this: 2 mg (what you have)/1 mL (the corresponding volume) = 4 mg (what the doctor ordered)/x mL (the volume you need to give), and solve for ‘x’. In this case, ‘x’ equals 2 mL.
Desired Over Have or Formula Method
This method uses an equation in which you divide the ordered dose (the desired amount) by the concentration of the drug you have and then multiply by the volume. In the case of our example, you would use the formula (4 mg dose ordered * 1 mL)/2 mg (drug concentration) = 2 mL (volume needed).
It’s important to remember that the units of measurement have to match up. If not, you’d need to convert them to like units. But in this case, both the ordered dose and the concentration are measured in milligrams, which cancel out, leaving only milliliters (the volume needed), so no conversion is required.
Dimensional Analysis Method
In this method, you essentially create a chain of conversions until you end up with the unit of measurement you want (in this case, milliliters). For the lorazepam example, you’d set up your conversions like this: (4 mg ordered/1) x (1 mL/2 mg), and continue multiplying and dividing until you get your answer, which is 2 mL.
All three methods should lead to the same result. Being familiar with more than one method provides you with a way to cross-check your calculations and ensure accuracy when administering medications.
What Else Should I Know About Dose Calculation Ratio and Proportion Method?
Mistakes when it comes to medication can be dangerous and costly for patients. This is mainly due to the fact that taking the wrong dosage of a medication, or not following the instructions correctly, can either make the medication ineffective or harmful. Understanding the correct dosage of medication is especially important in pediatrics because it involves calculating doses based on several factors such as a child’s height, weight, body surface area, and level of growth and development. The more complicated these calculations get, the greater the risk of making mistakes.
A study in 2016 looked at intensive care unit (ICU) nurses and found that 80% of them believe that having good knowledge of how to calculate drug dosages is crucial to reducing mistakes when preparing intravenous drugs. These are drugs that are given through a drip that is inserted into a patient’s vein.
Another study in 2018, done by a team of cancer ward nurses in 3 Swiss hospitals, dealt with the process of double-checking the dosage and limitations of doing so in real-world healthcare settings. Factors such as the heavy workload and time constraints faced by nurses, environments that easily lend themselves to distractions, and lack of resources, were all identified as problems. Despite these challenges, the study reported that cancer ward nurses still believe strongly in the effectiveness of double-checking medication, even though it sometimes presents issues during actual clinical practice.