Final answer:
To determine the safe number of 4% prilocaine cartridges for an ASA II, 180 lbs male patient, calculate the maximum dosage and divide by the dosage per cartridge, resulting in approximately 8.33 cartridges. After rounding up, 9 cartridges would be safe, but since 8 is the closest available answer choice, we select that option.
Step-by-step explanation:
The question asks how many cartridges of 4% prilocaine plain can be safely administered to an ASA II, 180 lbs, 40-year-old male patient. To calculate the maximum safe dose, we need to know that the maximum recommended dosage of prilocaine is 600 mg for a normal healthy adult, and each dental cartridge typically contains 1.8 mL.
Since the concentration of prilocaine is 4%, this means there are 40 mg of prilocaine per milliliter of solution (since 4% is 4 grams per 100 milliliters or 4000 mg per 100 milliliters; therefore, 40 mg per milliliter).
To find the total mg per cartridge, multiply the concentration (40 mg/mL) by the volume per cartridge (1.8 mL):
40 mg/mL x 1.8 mL/cartridge = 72 mg/cartridge.
To find out how many cartridges can be administered, divide the maximum safe dose by the mg per cartridge:
600 mg / 72 mg/cartridge ≈ 8.33 cartridges.
When rounding up, the patient can be safely given 9 cartridges. However, the closest answer option provided only goes up to 8 cartridges, so the correct choice would be:
c. 8