Overview of Dose Calculation Desired Over Have Formula Method
There are generally three ways to figure out how much of a medication to give; these are called Dimensional Analysis, Ratio Proportion, and the Formula or Desired Over Have Method. For this explanation, we’ll concentrate on the Formula Method.
The Formula Method can be compared to a simple math puzzle we’re trying to solve. We use this method to find out an ‘unknown’ factor in a medical dosage, making it similar to the ratio method.
Calculating correct dosages often requires converting measurements – for instance, the weight measurements from pounds to kilograms or volume measurements from liters to milliliters. The beauty of the Formula Method lies in its simplicity, letting our healthcare professionals use a variety of measurement units and convert them to arrive at the correct answer. Basically, it acts as an extra safety measure to double or even triple-check the results obtained from other calculating methods.
Preparing for Dose Calculation Desired Over Have Formula Method
Knowing things like what different units of measurements convert to can help doctors make less errors when calculating. It’s very important that these are done correctly, no matter the specific method or formula they’re using.
Here are some common conversions:
* 1 kg (kilogram, a measure of weight) = 2.2 lb (pound, another measure of weight)
* 1 gallon (unit of liquid volume) = 4 quarts (another unit of liquid volume)
* 1 tsp (teaspoon, a measure of volume) = 5 mL (milliliters, another measure of volume)
* 1 inch (unit of length) = 2.54 cm (centimeters, another unit of length)
* 1 L (liter, a measure of volume) = 1,000 mL (milliliters, another measure of volume)
* 1 kg (kilogram, a measure of weight) = 1,000 g (grams, another measure of weight)
* 1 oz (ounce, a measure of weight) = 30 mL = 2 tbsp (tablespoons, a measure of volume)
* 1 g (gram, a measure of weight) = 1,000 mg (milligrams, smaller measure of weight)
* 1 mg (milligram, a small measure of weight) = 1,000 mcg (micrograms, even smaller measure of weight)
* 1 cm (centimeter, a measure of length) = 10 mm (millimeters, a smaller measure of length)
* 1 tbsp (tablespoon, a measure of volume) = 15 mL (milliliters, another measure of volume)
* 1 cup (unit of volume, often for liquids) = 8 fl oz (fluid ounces)
* 1 pint (another unit of volume) = 2 cups
* 12 inches = 1 foot (both are measures of length)
* 1 L (liter) = 1.057 qt (quarts, both are measures of volume)
* 1 lb (pound) = 16 oz (ounces, both are measures of weight)
* 1 tbsp (tablespoon) = 3 tsp (teaspoons, both are measures of volume)
* 60 minutes = 1 hour (units of time)
* 1 cc (cubic centimeter, a unit of volume) = 1 mL (milliliter, another unit of volume)
* 2 pints = 1 qt (quart, both are measures of volume)
* 8 oz = 240 mL = 1 glass (all are measures of volume)
* 1 tsp (teaspoon) = 60 gtt (drops from a dropper)
* 1 pt (pint) = 500 mL = 16 oz (all are measures of volume)
* 1 oz (ounce) = 30 mL (milliliters, both are measures of volume)
* 4 oz = 120 mL (both are measures of volume)
How is Dose Calculation Desired Over Have Formula Method performed
There are three main ways health professionals work out how much medicine to give a patient. These are: the ‘Desired Over Have’ method, ‘Dimensional Analysis’, and the ‘Ratio and Proportion’ method.
The ‘Desired Over Have’ method is like a simple math equation where we use a special formula to find out an unknown quantity – let’s call it ‘x’. As the name suggests, this method involves calculating the desired dose of the medication divided by what is on hand, and then multiplying it by the quantity.
For example, if a doctor orders a certain medicine called lorazepam for a patient, and he requests a dosage of 4 mg to be given. If the lorazepam available to the healthcare provider contains 2 mg in each milliliter (ml), they would work out how much to give with this method. This involves dividing the dose ordered (4 mg) by what they have (2 mg) and then multiplying it by how much is in each container (1 ml). The result will be 2 ml. This is the amount that should be given to the patient.
‘Dimensional Analysis’ is another method of working out dosages. An easy way to think about it involves creating fractions and canceling out units until we are left with the unit we want. In the case of the lorazepam medicine, the healthcare provider would create the fraction with milligrams over milligrams so they cancel out, leaving behind milliliters. This is useful because the result needs to be in milliliters. Going through the calculations, we again find that the dosage is 2 ml.
The ‘Ratio and Proportion’ system is an old way of working out dosages. Unlike the previous two methods, this uses only multiplication and division. Using the lorazepam example again, the healthcare provider would divide the amount they have on hand (2 mg for every 1 ml) by the desired amount (4 mg). The answer is ‘x’, which represents the amount of the drug the patient should be given. Following the calculations, we find that this is 2 ml.
All of these methods are useful for making sure a patient is given the right amount of medicine. It’s all calculated to ensure the patient’s safety and recovery.
Possible Complications of Dose Calculation Desired Over Have Formula Method
In 2016, a study looked at how being confident can affect a person’s ability to do math, especially when calculating medication doses. The people who took part in the study were in different types of educational programs and were of various ages, all aiming to become nurses. A key finding from the study was that about one-third of these students didn’t feel confident in their math skills, often because of negative experiences dating back to when they were in primary school.
The study concluded that feeling confident is important for being good at calculating medication doses and doing other types of math. Improving this confidence may be possible in a learning environment that encourages a deep understanding of the material.
What Else Should I Know About Dose Calculation Desired Over Have Formula Method?
Mistakes in taking medication can lead to severe problems and added costs for patients. Being able to do basic math and correctly calculate drug doses is very important to safely administer medications.
A recent study from 2016 found that 80% of nurses working in Intensive Care Units (places in hospitals where the sickest patients are treated) believe knowing how to calculate drug dosages correctly can effectively decrease cases of medication errors, especially while preparing medicines that are given intravenously (directly into a vein).
High-risk medications like heparin (a blood thinner) and insulin (used to treat diabetes) typically need a second look from another healthcare provider to ensure the dosage given is correct. It is necessary to follow the standard procedures and guidelines of your hospital or healthcare facility regarding double-check of dosage by another licensed provider.
A study from 2018 conducted by cancer nurses in three hospitals in Switzerland looked at the practice of double-checking medication and the challenges it faces, such as increased workload, time pressures, distracting working conditions, and lack of resources. Despite these challenges, the study concluded that cancer nurses strongly believe in the effectiveness of this double-checking practice, even though there are certain limitations in clinical practice.