Question

Calculate the units as indicated by the problem. Use labels where provided to calculate dosages. Order: $500\mathrm{mL}$ of $0.9\mathrm{\%}\mathrm{NS}$ with 10,000 units of heparin at $120\mathrm{mL}/\mathrm{hr}$. Calculate the hourly heparin dosage (units/hr).

Short answer

The hourly heparin dosage is 2400 units/hr.

Step-by-step solution

Identify the Total Dosage of Heparin

The order specifies a total of 10,000 units of heparin mixed in the 500 mL of 0.9% NS solution. This is the total dosage that will be infused.

Determine the Infusion Rate in mL/hr

The solution is to be infused at a rate of 120 mL per hour. This is the rate at which the solution is administered into the body.

Calculate the Concentration of Heparin per mL

Calculate the concentration of heparin per mL by dividing the total heparin units by the total solution volume: $$\text{Concentration of Heparin (units/mL)}=\frac{10,000\text{ units}}{500\text{ mL}}$$This comes out to 20 units/mL.

Calculate the Hourly Dosage in Units

To find the hourly dosage, multiply the concentration (units/mL) by the infusion rate (mL/hr): $$\text{Hourly Dosage (units/hr)}=20\text{ units/mL}\times 120\text{ mL/hr}=2400\text{ units/hr}$$

Key concepts

Heparin Dosage

Heparin is a critical anticoagulant medication that helps prevent the formation of harmful blood clots. Calculating the correct dosage of heparin is essential to ensure patient safety and the effectiveness of the treatment.
The dose is generally measured in units. In our scenario, you have an order for 10,000 units of heparin which are mixed into a solution. Understanding how these units are distributed within the solution and delivered per time unit is crucial.
To find out how much heparin is administered per hour, we look at the concentration of heparin in the solution and the rate at which this solution is infused into the body. This helps address the needs of the specific patient's treatment plan efficiently.

Infusion Rate

The infusion rate is simply how quickly a fluid or medication is delivered into the patient's system, often measured in milliliters per hour (mL/hr).
It's essential to know the infusion rate as it determines how fast the body receives the medication or fluid.

• In the exercise, the infusion rate is given as 120 mL per hour.
• This rate ensures the medication is delivered consistently over time.

To calculate the amount of a drug, like heparin, delivered each hour, knowing the infusion rate helps set a baseline for calculations before factoring in the medication concentration.

Concentration Calculation

Concentration is key when determining the potency of a medication within a solution. It tells you how much of the active drug is present in each milliliter of fluid.
In the example, we determine concentration by dividing the total units of heparin by the total volume of the solution:
$$\text{Concentration (units/mL)}=\frac{10,000\text{ units}}{500\text{ mL}}=20\text{ units/mL}$$
This calculated value signifies that each mL of the solution contains 20 units of heparin.
Such calculations are critical for ensuring the patient receives the precise dosage of medication necessary for their treatment plan. Understanding concentration is a fundamental step in medication dosage calculations, ensuring both safety and efficacy.