Question

Difficulty: MediumPharmacological and Parenteral Therapies

A client diagnosed with a pulmonary embolism has a documented admission weight of 187 lbs. The healthcare provider orders a continuous intravenous (IV) heparin infusion at a dose of 18 units/kg/hr. The pharmacy dispenses an IV bag containing 25,000 units of heparin in 250 mL of 5% dextrose in water. Calculate the required infusion pump rate in mL/hr. (Round the answer to the nearest tenth.)

Answer: 15.3 mL/hr

Answer

15.3
To safely administer a weight-based continuous intravenous infusion, the nurse must first establish the client's weight in kilograms (187 lbs÷2.2=85187 \text{ lbs} \div 2.2 = 85 kg). The weight is then multiplied by the ordered dose to find the hourly medication requirement (85 kg×18 units/kg/hr=1530 units/hr85 \text{ kg} \times 18 \text{ units/kg/hr} = 1530 \text{ units/hr}). Finally, the nurse determines the fluid volume needed to deliver this dose by dividing the hourly requirement by the concentration of the IV solution (25,000 units÷250 mL=100 units/mL25,000 \text{ units} \div 250 \text{ mL} = 100 \text{ units/mL}). Therefore, 1530 units/hr÷100 units/mL=15.3 mL/hr1530 \text{ units/hr} \div 100 \text{ units/mL} = 15.3 \text{ mL/hr}.

Step-by-Step Solution

1
Convert weight to kilograms.
85 kg
The prescribed dose is weight-based in kg, so the client's weight in lbs must be converted by dividing by 2.2.
2
Calculate the hourly heparin dose.
1530 units/hr
Multiplying the client's weight in kg by the prescribed hourly dose of 18 units/kg/hr provides the total required units per hour.
3
Calculate the volume rate of the infusion.
15.3 mL/hr
Dividing the required hourly dose (1530 units/hr) by the medication concentration (100 units/mL) yields the infusion pump rate in mL/hr.

Key Concept

Weight-Based Intravenous Medication Calculation

Alternative Method

Dimensional analysis can be used to set up the entire equation in one continuous step: 18 unitskg⋅hr×1 kg2.2 lbs×187 lbs×250 mL25,000 units=15.3 mL/hr\frac{18 \text{ units}}{\text{kg} \cdot \text{hr}} \times \frac{1 \text{ kg}}{2.2 \text{ lbs}} \times 187 \text{ lbs} \times \frac{250 \text{ mL}}{25,000 \text{ units}} = 15.3 \text{ mL/hr}.
Estimated Time:1m 30s
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