See what you can expect from our sample questions and explanations, and try one from our Clinical Med Math QBank. Once you submit your answer, two calculation methods will be displayed.
The nurse is administering 2.8 mL of hydromorphone to a pediatric client who weighs 61 lb and reports pain. How many milligrams per kilogram per dose (mg/kg/dose) is the nurse administering? Record your answer using one decimal place.
Correct Answer: 0.1 mg/kg/dose
Using dimensional analysis, perform the following steps to calculate the prepared dose of hydromorphone (HM) in milligrams per kilogram:
Identify the prepared volume, available medication, client’s weight, and required units
Volume: 2.8 mL HM / dose Available: 1 mg HM / mL Weight: 61 lb / Required: mg HM / kg | dose
Convert the administration volume to the prepared dose of HM in milligrams per kilogram
Volume × available medication ÷ weight = mg HM / kg | dose
OR
( mL HM / dose ) ( mg HM / mL ) ( lb / kg ) ( / lb ) = mg HM / kg | dose
OR
( 2.8 mL HM / dose ) ( 1 mg HM / mL ) ( 2.2 lb / kg ) ( / 61 lb ) = 0.1009… mg HM / kg | dose
Round to one decimal place
0.1009… mg HM / kg | dose ≈ 0.1 mg HM / kg | dose
Educational objective:
To calculate the prepared dose of hydromorphone, the nurse should first identify the administration volume (eg, 2.8 mL/dose),available medication (eg, 1 mg/mL), and client′s weight (61 lb) and then convert to the dose (eg, 0.1 mg/kg/dose).
The formula method is an alternate way to calculate medication dosages. However, this method may increase the occurrence of miscalculation and medication errors. If you choose to use this method, do not round any calculations until the final step.
Using the formula method, perform the following steps to calculate the prepared dose of hydromorphone (HM) in milligrams per kilogram:
Convert the weight to kilograms
( kg / 2.2 lb ) ( 61 lb / ) = 27.7272 kg
Convert the administration volume of HM to the prepared dose in milligrams
Administration volume / available volume x available dose = mg HM / dose
OR
2.8 mL HM / mL HM x 1 mg = 2.8 mg HM / dose
Convert the prepared dose to the weight-based dose of HM
( 2.8 mg HM / dose ) ( / 27.7272 kg ) = 0.1009… mg HM / kg | dose
Round to one decimal place
0.1009… mg HM / kg | dose ≈ 0.1 mg HM / kg | dose
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