NursingSprint

Step 1: Convert the client's weight from pounds to kilograms

Formula:

kg = lb ÷ 2.2

Calculation:

kg = 154 ÷ 2.2 = 70 kg

Step 2: Calculate the total dose required in mg

Formula:

Dose (mg) = Weight (kg) × Dose per kg

Calculation:

Dose = 70 × 1 = 70 mg

Step 3: Use the concentration to calculate the volume to administer

Formula:

Volume (mL) = Dose (mg) ÷ Concentration (mg/mL)

Calculation:

Volume = 70 ÷ 40 = 1.75 mL

Step 4: Round the final answer to the nearest tenth

Rounded Volume:

1.8 mL

Final Answer:

1.8 mL

Educational Insight

Gentamicin is an aminoglycoside antibiotic with a narrow therapeutic index, making accurate, weight-based dosing essential to prevent toxicity, especially nephrotoxicity and ototoxicity. This calculation demonstrates a stepwise approach: converting weight, calculating the appropriate dose, and adjusting based on the supplied concentration. Rounding to the nearest tenth is critical in IM administration to maintain both accuracy and safety.