P3B413: Nice Round Numbers: Development of an EHR Tool to Promote Liquid Medication Dose Rounding

Background: Home medication dosing errors are common and can cause patient harm. One source of potential error is improper measurement of the prescribed dose. The AAP’s Council on Quality Improvement and Patient Safety’s policy statement “Preventing Home Medication Administration Errors” calls for use of the electronic health record (EHR) to promote functionality such as automatic rounding to whole numbers for liquid medications. However, creating automatic system-wide rounding to whole mL doses may not be appropriate for every medication or patient. Additionally, allowing the use of “mL” units for order entry has the risk of order entry errors when multiple medication concentrations are available. Given these constraints, we developed a new EHR tool to aid providers in selecting patient-friendly whole mL doses when prescribing liquid medications and evaluated its effectiveness.

Methods: We developed a computer-generated dose rounding table that presents patient-specific, weight-based equivalents for whole mL doses when ordering liquid medications for home use. The table displays the appropriate mg and mg/kg dose for corresponding 1 mL increments to aid in decision-making (Figure 1). The table was inserted into the order entry form for liquid acetaminophen (160 mg/5 mL). Acetaminophen was chosen because it is a frequently prescribed outpatient medication in our patient population, has a single common dose range for all indications, and has a concentration (32 mg/mL) that is a barrier to calculating whole mL doses.

The proportion of whole mL outpatient liquid acetaminophen prescriptions with doses between 3 mL and 10 mL will be compared in the 4 months before and 4 months after implementation of the dosing table. Doses below 3mL are excluded as they may require an unacceptable degree of rounding and doses above 10 mL are automatically rounded to the nearest whole mL in our EHR. Statistical analysis will include a chi square test to evaluate differences in the proportion of whole mL doses.

Results: Prior to implementation of the dosing table, 35.7% (1366/3823) of acetaminophen prescriptions were rounded to the nearest mL (Figure 2). The rate of whole mL prescribing among attending physicians was 37.0% (831/2218) and for residents was 28.4% (149/525). In the urgent care setting, 40.0% (44/112) of acetaminophen prescriptions were written for a whole mL dose, compared to only 32.5% (359/1105) of prescriptions in the primary care setting. We anticipate improvements in the rates of whole mL dosing with the implementation of the dosing table, which has now been approved by our Medication Safety Committee.

Conclusion: This is the first study to evaluate the effectiveness of an intervention to promote whole mL dose rounding. EHR tools like this patient-specific dosing table may be preferable to automatic rounding to whole mL doses or the use of “mL” units for order entry.