Weighing Inconsistencies Contribute Heavily to Pediatric Medication-Dosing Errors

October 19, 2020
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Medications are intended to effectively treat patients, but they can be harmful and even deadly in the wrong doses.

Weight-based medication-dosing errors can have drastic and lasting results and can be more common than you may think. In fact, one study estimated a 73% probability of an error occurring in a single instance of administrating intravenous medication. And the U.S. Food and Drug Administration reports that dosing errors make up more than 40% of fatal medication errors.

These errors can be especially significant in a pediatric environment, as pediatric medication-dosing errors can have devastating effects. According to an analysis of the U.S. Pharmacopeia’s MEDMARX database, “one-third of pediatric medication errors were the result of ‘improper dose/quantity’ due to weight-dosing errors (a significantly higher fraction than in adults), and 2.5% of those pediatric dosing errors led to patient harm.”

Common Causes of Weight Inaccuracies

Up to 18% of serious, yet preventable medication errors are due to a lack of crucial information such as the patient’s weight, which plays a pivotal role in determining the correct dosage of a medication—and understanding the threshold for toxicity. Common causes of weight inaccuracies include the following:

  • Medications are prescribed BEFORE a pediatric patient is weighed
    Children can be especially difficult to weigh accurately, especially if the proper equipment isn’t readily available, as noted in one study where only 6% of U.S. Emergency Departments had appropriate pediatric equipment on hand. Subsequently, staff may incorrectly estimate the patient’s weight or have parents hold a child on an adult scale and calculate the weight.
  • Parents inaccurately report their child’s weight
    Anecdotal data from a parent or using a prior documented weight that is no longer accurate puts children at a higher risk of a dosing error as their actual weight is not used when a medication is prescribed. Prescribing the wrong medication dose for a child could result in an overdose or an insufficient dose for proper treatment.
  • Weight is measured in pounds but recorded in kilograms
    If the unit of measure is not indicated or input incorrectly into an Electronic Medical Record (EMR) or the EMR has a default unit of measurement in kilograms and weight is recorded in pounds, it is easy to end up with an inaccurate weight in the chart. This can also occur if the scale has settings in both pounds and kilograms, which can be inadvertently changed. These errors can easily slip through the cracks as there is no “typical” or “normal” range of weight for pediatric patients, as is more common for adults.

Weight inaccuracies can have catastrophic results. For example, one reported case involved a pediatric patient whose mother was a patient safety analyst with extensive medical knowledge. She noticed that, while her toddler had been weighed in pounds, his weight had been input into the practice’s EMR system in kilograms, resulting in a drastic dosage miscalculation. Given her knowledge, she recognized that the dosage prescribed was incorrect.

“We only gave him half [of his prescribed medication],” the mother said. “Luckily we did, because the next day the physician called and said there had been a mix-up.” The medication dose prescribed was double what was indicated.

Moving to a Standardized Kilogram-Based Weighing Process

Patients often have their weight measured in pounds. However, medication dosing is typically calculated using the metric system. This discrepancy in measurement systems opens the door for miscalculations. Add to this the need to convert weight to kilograms to determine correct medication dosage, and the room for human error is significant. A study by Pediatric Emergency Care found that “a large proportion of weight errors led to subsequent medication-dosing errors (34% on average). … Common weight errors included the weight in pounds being substituted for the weight in kilograms and decimal placement errors.”

Recommendations to ensure accurate patient weight measurement and recording include:

  1. All providers that care for pediatric patients should have access to infant and pediatric scales that weigh in kilograms.
  2. Standards should be set to measure, record, and display weight in kilograms only in the medical record or EMR.
  3. As adoption of EMR software continues, pediatric providers should consider implementing decision-support prompts that pop up key data points such as weight, i.e., a pop up appears if an entry is outside of established parameters such as a typical weight range for an established age group.
  4. EMR-integrated digital scales should be employed wherever possible to eliminate the potential for patient weight–entry errors.

Many pediatric facilities are slowly converting to the metric system or implementing protocols to measure in kilograms only. However, a sizeable number of facilities have not made the conversion for a variety of reasons, including: the often-prohibitive cost of purchasing new scales, an inability to track possible dosage errors, and cultural resistance in the U.S.—only Burma, Liberia, and the U.S. continue to use the traditional English system as their primary system of weights and measurements. And the U.S. is the only industrialized nation that does not principally use the metric system in its commercial and standards activities. However, according to the CIA, there is increasing acceptance in science, medicine, government, and many sectors of industry.

Starting the Process of Implementing Kilogram-Standardization Protocols

With those obstacles, implementing a unified measuring system in the medical industry is a slow process that requires significant planning. But in the absence of unification, it’s still possible to reduce weight-based medication dosing errors by adopting the use of standardized weighing scales—a critical first step in bridging the gap and mitigating errors.

AliMed offers a variety of  KG Only and KG Locking Patient Scales to aid practices and hospitals incorrectly weighing and dosing pediatric patients. KG Only models only measure weight in kilograms while KG Locking models leverage Everlock® technology to allow staff to set and lock weight measurements in kilograms. Also, many models offer EMR-connectivity to transmit accurate weight measurements directly into EMR systems, reducing the risk of human error.

These solutions are ideal for facilities looking to make a change but are not yet prepared to make a holistic move toward 100% metric standardization. They allow for protocols that ensure kilogram weighing only while retaining the functionality of weighing in pounds and kilograms.


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