Question

Round the weight to the nearest tenth. A client weighs \(200 \mathrm{lb}\). Order: Administer a bolus of heparin sodium IV at 80 units/kg. How many units will you administer?

Short answer

7272 units

Step-by-step solution

Convert Pounds to Kilograms

Since 1 kilogram is approximately 2.2 pounds, we need to convert the patient's weight from pounds to kilograms. The conversion is done using the formula: \( \text{Weight in kg} = \frac{\text{Weight in lb}}{2.2} \). Substitute the given value: \( \text{Weight in kg} = \frac{200}{2.2} \approx 90.91 \text{ kg} \).

Round the Weight to the Nearest Tenth

To round 90.91 kg to the nearest tenth, we look at the hundredths place which is 1. Since 1 is less than 5, we round down. Therefore, the weight becomes 90.9 kg.

Calculate the Dose in Units

To find out how many units of heparin to administer, use the formula: \( \text{Dose in units} = \text{Weight in kg} \times 80 \text{ units/kg} \). Substitute the rounded weight: \( \text{Dose in units} = 90.9 \times 80 = 7272 \text{ units} \).

Conclusion

You need to administer 7272 units of heparin sodium.

Key concepts

Metric Conversion

When calculating medical dosages, it is often necessary to convert between different measurement systems. A commonly required conversion in the healthcare setting is between pounds and kilograms, especially since most medical formulations are dosed based on weight in kilograms.
It helps to remember that 1 kilogram is approximately equal to 2.2 pounds. This conversion factor is crucial when dealing with weight-based dosing. To convert weight from pounds to kilograms, you use the formula:

• Weight in kg = Weight in lb / 2.2

For instance, if a patient weighs 200 lb, the conversion would be:

• Weight in kg = 200 / 2.2 ≈ 90.91 kg

This ensures that the medication is dosed correctly according to the patient's actual weight in kilograms, which is the standard weight measurement used in medical calculations.

Rounding Numbers

Rounding numbers is an important step in medical dosage calculations. It ensures that the medication dose is both accurate and safe for the patient. When tasked with rounding a number to the nearest tenth, it’s essential to pay attention to the digit in the hundredths place.
To illustrate, let’s look at the number 90.91:

• The tenth place is occupied by the digit 9.
• Look at the hundredths place, which is occupied by the digit 1.
• Since 1 is less than 5, you round down, keeping the tenth place as 9.

Hence, 90.91 rounded to the nearest tenth is 90.9. This slight adjustment is standard practice to keep dosages within safe and effective ranges. Rounding correctly is an essential skill in healthcare to prevent dosing errors.

Weight Conversion

Weight conversion and its precision in measurements are critical in healthcare, particularly when determining proper dosages. Tying in with metric conversion, accurate weight measurements need precision and correct conversion methodologies.
In clinical practice, weight conversion is often performed from pounds to kilograms. After conversion, rounding is typically executed to maintain precision without over-complicating the dosing instructions.
For example, having converted a weight from 200 pounds to approximately 90.91 kilograms, the importance of precision arises. After rounding to the nearest tenth, the weight is 90.9 kg. This conversion and rounding ensure medication calculations like heparin doses are precise. Precision prevents errors in medication administration, which is why this step is integral to medical dosing calculations.