Question

The doctor orders a continuous infusion (IV) of morphine for a post-operative teenager of 200 mcg/kg q 3 hr. The teenager weighs 105 lbs. You have 2 mg/mL solution of morphine available for IV injection. STATE THE ANSWER IN SCIENTIFIC NOTATION AND CORRECT NUMBER OF SIGNIFICANT FIGURES

a. What rate of infusion (mL/hr) should you set for the IV drip?

b. The continuous infusion device can only hold a total of 25 mL of morphine solution. How long will it be before you have to replace the morphine solution? Express your answer in hours with the remainder converted to minutes. (i.e. your answer should be something like “in 3 hours and 14 minutes”).

Answer 1

Answer (a):

Weight of teenager = 105 lbs = 47.627 kg

the total amount of medicine required for teenager = 47.627 x 200 mcg for 3 hour = 9525.4 mcg for 3 hour = 9.5254 mg for 3 hour

Therefore,

amount of medicine required for teenager per hour = 9.5254/3 mg = 3.1751 mg

Now,

since 2 mg of medicine is present in = 1 ml of the solution

therefore, 3.1751 mg f medicine will be present in = 3.1751/2 ml = 1.58755 ml = 1.59 ml

Hence, the rate of infusion (mL/hr) = 1.59 ml/hr

Answer (b):

the rate of infusion (mL/hr) = 1.59 ml/hr

Therefore,

the time required in diffusing 25 ml of medicine solution = 25.00/1.59 hr = 15.72 hr = 15 hour and 43 minutes