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 calculate the amount of mannitol to administer based on the client’s weight and the prescribed dosage, we start with the client’s weight in pounds and convert it to kilograms.
- Convert Weight to Kilograms:
The conversion factor from pounds to kilograms is 1 kg = 2.20462 lb.
[
\text{Weight in kg} = \frac{198 \text{ lb}}{2.20462} \approx 89.81 \text{ kg}
] - Calculate the Dose:
The prescribed dose is 0.2 g/kg.
[
\text{Dose in grams} = 0.2 \text{ g/kg} \times 89.81 \text{ kg} \approx 17.96 \text{ g}
] - Round to the Nearest Whole Number:
When rounding 17.96 to the nearest whole number, we get 18 g.
Thus, the nurse should administer 18 grams of mannitol as a test dose.
Explanation
Mannitol is an osmotic diuretic used in medical settings to manage conditions like severe oliguria, where urine output is critically low. This medication works by increasing osmolarity in the renal tubules, which helps draw water out of the tissues into the urine, thereby increasing urine production.
When calculating the dosage for medication, it’s crucial to accurately convert the patient’s weight into the required units, as many medications are dosed based on body weight. In this case, the dose of 0.2 g/kg means that for every kilogram of body weight, the patient receives 0.2 grams of the medication. This ensures that the administration is tailored to the patient’s specific needs, minimizing the risk of underdosing or overdosing.
The calculation also highlights the importance of rounding to comply with medication administration protocols. Rounding is necessary to ensure practical dosing, as medications are often supplied in standard concentrations and formulations.
In conclusion, the administration of 18 grams of mannitol is based on careful calculations derived from the patient’s weight, ensuring safe and effective treatment for oliguria.