Improving Medication Dosage Calculation Proficiency

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Correct medication delivery is a fundamental nursing task.

Correct delivery of medication is a fundamental task of the nursing profession. Given the potentially dire consequences of mistakes, from lengthened hospital stays and increased medical costs all the way up to the death of patients, medicine delivery is an aspect of the job that nurses must master.

An industry standard called the “five rights of medication administration” is often used to guide this process. Every time medication must be given, nurses should check to make sure they have the right patient, right drug, right dose, right route of administration, and right time of day. Some providers add further “rights” to this list. The Lippincott Nursing Center, for instance, also suggests that nurses verify the right documentation, reason/rationale for the medication, and patient response after taking the medication.

Of all the “rights,” dosage may be the trickiest. Nurses are often given basic medication information for a patient, then expected to make it happen correctly. Doing so may involve substantial mathematical juggling, which, given the hectic pace of many medical facilities, must be done on the fly. The process seems like a recipe for error — yet anything less than 100% accuracy is not acceptable. Improving nurses’ medication dosage calculation proficiency is therefore a critical and ongoing concern in the medical field.

How can nurses obtain the skill to execute precise dosing calculations? The groundwork is laid in academic coursework such as Ohio University’s online MSN program, which has a comprehensive MSN curriculum to prepare registered nurses (RNs) and other Bachelor of Science in Nursing (BSN) graduates for advanced nursing careers.

Do the Math

Basic mathematical proficiency lies at the heart of correct dosage calculation and is frequently required to administer medication correctly. One online quiz from the College of Licensed Practical Nurses of Alberta (CLPNA) gives a sample problem: “A suspension contains erythromycin 250 mg/5mL. How many grams of erythromycin are in 30mL of suspension?” The quiz does not go on to ask — but logically could — a question like, “If the patient has been prescribed a dosage of 750 mg, how many mL would you administer?” In a direct care setting, a nurse might expect to solve multiple problems of this type in a single day.

A calculation like this example is fairly simple, but others are much harder. The Lippincott Nursing Center explains that while fluid bolus and tablet dosages are straightforward to calculate, continuous IV infusions of high-risk medications can involve complex calculations. Lippincott also points out that misplaced decimals are a particular bugaboo of the nursing profession and can lead to devastating consequences. Accidentally shifting a decimal one space, for example, would transform a dosage of 0.02 mg to 0.2 mg — delivering a tenfold increase in the prescribed medication.

One easy way to improve mathematical accuracy, according to the Institute for Safe Medication Practices (ISMP), is to create “No Interruption Zones” for medication preparation. Nurses utilizing these areas for dosage calculation and preparation must not be spoken to or bothered in any way. They may also choose to wear special apparatus, such as vests or sashes, to signal that they should not be interrupted. Staff should be educated about these procedures to ensure compliance. Because studies show that the risk of medication error increases 12.7% with each interruption, reducing interruptions can be expected to have a substantial positive impact on dosage accuracy.

Automating the Process

Automated medication delivery takes some of the dosage burden off of nurses through technological advances such as smart infusion pumps, standard admixtures, and unit dosing. Barcode-assisted medication administration (BCMA), a technique in which nurses scan a patient’s wristband and medication codes before delivering medication, has proven to be particularly helpful, decreasing dosage errors by more than 90%. With such good results from technology, nurses may be tempted to skip the tiresome mathematical legwork required for complex care deliveries.

The website, however, explains that giving in to this temptation would be a mistake. The website uses an infusion pump as an example. “Unless the pump is malfunctioning, it will calculate the rate and dose of an infusion correctly, BASED ON USER INPUT. If the data programmed into the pump is incorrect, the pump will deliver incorrect medication doses and rates,” the site says.

What this means is that because nurses set up the machines and scan the barcodes, they are still ultimately in charge of dosage delivery. Calculating the medication dose, concentration, and infusion rate and ensuring that the machine agrees with a nurse’s math, says, is an essential double-check to ensure medication is administered properly.

Innovative Education

Nurses must demonstrate proficiency in dosage calculation before they graduate from nursing school. Many programs, in fact, require 100% proficiency on dosing examinations. Student nurses must retake tests as often as necessary to reach the “perfect” mark. The tests are generally traditional paper-and-pencil or electronic.

Although this type of dosage education is time-tested and standard, an article in the journal American Nurse suggests that it could be improved through the use of a simulation strategy. The study describes a test case in which students visited four stations that simulated real-world medical problems and presented corresponding medication delivery challenges. Students had 15 minutes at each station to determine the correct medication dosage. As with traditional pencil/paper tests, students were required to repeat tasks until they got the correct answers.

Results of the study were promising, with all students successfully accomplishing the tasks (although about half needed repeats). Post-study surveys revealed that 95% of participants felt that the exercise had increased their knowledge of medication safety and delivery, and 78% reported an increased appreciation for medication safety.

Such innovative teaching methods show great promise for the future of dosage calculation. Despite the increasing use of technological care delivery, human oversight remains essential — and finding the best ways to train nurses in medication administration are far from obsolete.

Ohio University’s Online Master of Science in Nursing (MSN) Program

The online MSN program at Ohio University is designed for practicing RNs who want to advance their expertise in the nursing field. Students can expect to leave the program with the skills they need to enter a variety of MSN nursing careers.

For more information about the online MSN program, MSN degree benefits, and additional concentrations for MSN nursing careers, visit Ohio University’s website.


Recommended Reading:

Patient Safety and Alarm Fatigue

How Nurse Educators Use Simulation as Teaching Tools

Master of Science in Nursing Curriculum


Importance of correct medication delivery – Lippincott Nursing Center

“Rights” of medication administration – Lippincott Nursing Center

Sample math question – College of Licensed Practical Nurses of Alberta

Straightforward vs. complex calculations – Lippincott Nursing Center

No interruption zones – Institute for Safe Medication Practices

Automating the process –

Innovative education – American Nurse