Final answer:
To calculate how many mg the patient will receive after 6 hours, first calculate the total amount of medication given in 6 hours (3 mL). Then, use the available concentration to determine the amount of medication in those 3 mL (90 mg).
Step-by-step explanation:
To calculate how many mg the patient will receive after 6 hours, we need to use the ordered amount and the available concentration of the medication.
First, let's calculate the total amount of medication that will be given in 6 hours. The ordered amount is 6 mL over 12 hours, so in 6 hours, the patient will receive half of that, which is 3 mL.
Next, we need to calculate how many mg are in 3 mL of the medication. The available concentration is 120 mg/4 mL, so for every 4 mL, there are 120 mg of the medication. Therefore, for 1 mL, there are 30 mg. Multiplying this by 3 mL, we find that the patient will receive 90 mg after 6 hours.