Final answer:
The nurse should administer 12.5 mL of the Brethine solution to provide the prescribed 250 mcg loading dose of terbutaline for a client in preterm labor.
Step-by-step explanation:
To calculate the volume of the Brethine solution that the nurse should administer, we need to use the following formula:
Volume to be administered = (Desired dose x Total volume) / Concentration of stock solution.
The desired dose is the loading dose of terbutaline prescribed, which is 250 mcg. The concentration of the Brethine (terbutaline) solution in the IV bag is given by the amount of drug added to the total volume of diluent, so we have 20 mg in 1000 mL of D5W. We need to ensure that the units are consistent by converting the 20 mg (which is 20,000 mcg) into mcg because the prescribed dose is in mcg.
Therefore, we calculate the volume as follows: 250 mcg x 1000 mL) / 20,000 mcg = 12.5 mL.
The nurse should administer 12.5 mL of the Brethine solution to deliver a 250 mcg dose of terbutaline.