Children's IV Medication Doses Prone to Errors
As any parent knows, when trying to give children liquid medicine, it can be difficult to get the dosage exactly right because of the small, sometimes transparent markings on the side of the syringe or dosage cup. Nurses in hospitals have similar problems with the medications they deliver, particularly those that are given intravenously, because of the relatively low doses that children require.
Children Require Very Small Doses Prepared from Large Commercial Stocks
According to Christopher S. Parshuram, MBChB DPhil of the University of Toronto, the currently available equipment is inadequate for accurate measurements of medications with volumes below 0.1 mL, yet in about 28.5% of children admitted to an intensive care unit, at least one dose of medicine was required to be in this very small volume.
Because this can lead to inaccurate doses, Parshuram and his team performed two studies. In the first, they looked at the requirements for small volumes based on the recommended use of 180 drugs for four hypothetical patients – a 3-kg neonate, a 5-kg six-month-old infant, a 10-kg one year old infant, and a 20-kg child three years of age.
Overall, the 180 drugs listed in the Canadian formulary could possibly be used for about 982 indications. For 8% of those indications, the recommended dose called for less than 0.1 mL of the stock solution.
In the second study, the team reviewed intravenous medications given to 1,531 patients admitted to a pediatric intensive care unit in 2006. A total of 71,218 doses were administered with about 7% of those being prepared from syringes containing a volume of less than 0.1 mL of solution. 17.5% of the medications were prepared from less than 0.2 mL.
The drugs most often prepared from less than 0.1 mL were lorazepam (a sedative), hydrocortisone (a steroid hormone), ranitidine (used to treat GERD), methylprednisolone (suppression of inflammation), fentanyl and morphine (both narcotics for pain).
"Our findings indicate a substantial source of dosing error that involved potent medications and affected more than a quarter of the children studied," the researchers observed. They concluded that most errors could be avoided if there were equipment available that could accurately measure the small volumes or if commercially available solutions were prediluted.
Uppal N, et al "Drug formulations that require potentially inaccurate volumes to prepare doses for infants and children" CMAJ 2011; DOI: 10.1503/cmaj.100467.