A nurse is preparing to administer mannitol 0.2 g/kg IV bolus over 5 min as a test dose to a client who has severe oliguria

A nurse is preparing to administer mannitol 0.2 g/kg IV bolus over 5 min as a test dose to a client who has severe oliguria. The client weighs 198 lb. What is the amount in grams the nurse should administer? (Round the answer to the nearest whole number. Use a leading zero if it applies. Do not use a trailing zero.)

The Correct Answer and Explanation is:

To determine the amount of mannitol to administer, follow these steps:

1. Convert the client’s weight from pounds to kilograms:
   • The conversion factor is 1 lb=0.4536 kg1 \text{ lb} = 0.4536 \text{ kg}1 lb=0.4536 kg.
   • Weight in kg = 198 lb × 0.4536 kg/lb
   • Weight in kg = 89.8 kg (rounded to one decimal place)
2. Calculate the dose of mannitol based on the weight:
   • The prescribed dose is 0.2 g/kg.
   • Dose in grams = 0.2 g/kg × 89.8 kg
   • Dose in grams = 17.96 g
3. Round the result to the nearest whole number:
   • 17.96 g rounded to the nearest whole number is 18 g.

Therefore, the amount of mannitol to administer is 18 grams.

Explanation

1. Weight Conversion:

• The first step is to convert the client’s weight from pounds to kilograms because medical dosages are commonly calculated using metric units. This conversion is essential for accurate dosing and is done using the factor 0.4536 kg per pound.

2. Dose Calculation:

• The prescribed dose of mannitol is 0.2 grams per kilogram of body weight. To determine the total dose, multiply the weight in kilograms by this dose factor. This gives the amount of drug required based on the client’s weight.

3. Rounding:

• The final step is to round the calculated dose to the nearest whole number. This is standard practice in medication administration to avoid complications associated with fractional doses and to simplify preparation and administration.

In clinical practice, accurate dosing is crucial for the safety and effectiveness of the medication. Mannitol is used to treat oliguria by increasing urine output, so it’s essential that the dose is calculated precisely to avoid under-dosing or over-dosing, which could affect the client’s condition.