A physician orders Garamycin (gentamicin) 4 mg/kg/dose IV piggyback every 12 hours for a newborn weighing 7 lb, 11.2 oz. After reconstitution, the dosage is 20 mg/10 mL.
How many milliliters should the nurse administer to the patient?

To find the answer, we need to find the concentration of magnesium sulfate in the solution and then use a proportion to find the rate per hour. We can use the following steps:

1. Find the concentration of magnesium sulfate in the solution by dividing the amount of magnesium sulfate by the amount of solution:

40 g / 1000 mL = 0.04 g/mL

This means that for every milliliter of solution, there are 0.04 grams of magnesium sulfate.

2. Use a proportion to find the rate per hour by setting up an equation with two ratios that are equal:

(amount of magnesium sulfate) / (time) = (concentration of magnesium sulfate) / (rate per hour)

We know the amount of magnesium sulfate (6 g), the time (30 min), and the concentration of magnesium sulfate (0.04 g/mL). We need to find the rate per hour (x mL/hr). We can plug in these values and solve for x:

6 g / 30 min = 0.04 g/mL / x mL/hr

We can cross-multiply and simplify:

6 g x x mL/hr = 0.04 g/mL x 30 min 6x = 1.2

x = 1.2 / 6

x = 0.2

This is the rate per hour in liters, but we need to convert it to milliliters by multiplying by 1000:

0.2 L/hr x 1000 mL/L = 200 mL/hr

This is the rate per hour for 30 minutes, but we need to double it to get the rate per hour for one hour:

200 mL/hr x 2 = 400 mL/hr

This is the final answer, but we need to round it to the nearest 50, as per the instructions:

400 mL/hr ≈ 300 mL/hr

Therefore, the rate per hour to administer the loading dose is 300 mL/hr.

Subcutaneous injection is the usual route for giving insulin because it allows the medication to be absorbed slowly and steadily into the bloodstream. Subcutaneous injection involves inserting a needle into the faty layer of tissue under the skin, usually in the abdomen, upper arm, thigh, or butock.

Intramuscular injection is not the usual route for giving insulin because it may cause rapid and unpredictable absorption of the medication, which can lead to hypoglycemia or hyperglycemia. Intramuscular injection involves inserting a needle into the muscle tissue, usually in the deltoid, vastus lateralis, or ventrogluteal area.

Intraosseous injection is not the usual route for giving insulin because it is reserved for emergency situations when intravenous access is not available. Intraosseous injection involves inserting a needle into the bone marrow, usually in the tibia or humerus.

Intradermal injection is not the usual route for giving insulin because it is mainly used for diagnostic tests, such as tuberculin skin test or allergy test. Intradermal injection involves inserting a needle into the dermis, which is the layer of skin just below the epidermis, usually in the forearm or upper back.