Question

Calculate the units as indicated by the problem. Use labels where provided to calculate dosages. Order: 1 L D5W with 35,000 units of heparin at \(20 \mathrm{~mL} / \mathrm{hr}\). Calculate the hourly heparin dosage (units/hr).

Short answer

The hourly heparin dosage is 700 units/hour.

Step-by-step solution

Understand the Order

We are given an order for 1 liter (1000 mL) of D5W with 35,000 units of heparin. The infusion rate is 20 mL per hour.

Determine Concentration of Heparin

First, calculate the concentration of heparin in the IV fluid. Since there are 35,000 units of heparin in 1000 mL of D5W, the concentration is \( \frac{35000 \text{ units}}{1000 \text{ mL}} = 35 \text{ units/mL} \).

Calculate Hourly Heparin Dosage

The infusion rate is 20 mL/hour. Multiply the concentration of heparin by the infusion rate to get the hourly dosage: \( 35 \text{ units/mL} \times 20 \text{ mL}/ \text{hr} = 700 \text{ units/hr} \).

Key concepts

Heparin Dosage

Heparin is a medication often used to prevent blood clots in patients. When calculating heparin dosages, it's crucial to start by understanding the order completely. In this example, we are instructed to administer a specific volume of fluid containing a predefined amount of heparin over a set period. The primary objective is to figure out how much heparin is delivered per hour. Knowing the total units of heparin available in the entire solution helps in setting the stage for further calculations. Here, the bag contains 35,000 units of heparin dissolved in 1 liter of D5W. This information is critical as the dosage impacts patient safety and treatment efficacy. Understanding the precise dosage and how this impacts the patient's therapy will ensure correct and effective use of heparin in treatment plans.

IV Infusion Rate

The IV infusion rate provides insight into how quickly a solution is delivered to the patient. It's usually described in milliliters per hour (mL/hr). For this problem, the infusion rate is 20 mL/hr, meaning every hour, 20 milliliters of the solution are infused into the patient's bloodstream. This information is essential not only for ensuring proper medication dosing, but also for managing fluid balance, especially in patients sensitive to volume shifts. By carefully setting and monitoring the infusion rate, healthcare providers customize the treatment to fit the specific needs of each patient, balancing both the therapeutic and safety requirements.

Unit Conversion

In medical calculations, unit conversion is frequently necessary to ensure that all units are consistent and compatible. This exercise requires understanding how to convert units to obtain the necessary dosage per hour. The original concentration was given as units per liter, which needed to be calculated in units per milliliter for further calculations. Converting from 35,000 units per liter to 35 units per milliliter makes it straightforward to pair this with the infusion rate, which is also in milliliters. Keeping consistent units throughout helps ensure accuracy and prevents potentially dangerous dosing errors. Always double-check conversions and match units before proceeding with further calculations.

Concentration Calculation

Concentration calculation is the step that links the total drug amount in a solution with the volume of that solution. This tells you how much of the drug is in each milliliter, a necessary step for dosing calculations. Here, the concentration of the heparin was calculated by dividing the total units of heparin, 35,000, by the total volume, 1 liter (or 1000 mL). The resultant concentration is 35 units/mL. This value is crucial as it directly influences how much of the drug is administered during a typical infusion period. Understanding concentration allows for quick adjustments based on the patient's specific health needs, such as necessary increases or reductions in drug dosing. Therefore, it's one of the most fundamental skills in medical dosage calculations.