What will be the flow rate, in drops per minute, to administer the dose ordered? You receive an order for 250mg of Aminophylline in normal saline (total volume 500mL). The patient weighs 110 lb. The Aminophylline is to be administered at a dose of 0.4 mg/kg/HR. Aminophylline Injection is supplied in 10mL vials with 25 mg/mL. The IV set to be used delivers 60gtts/ml.
A. 40 gtts/min B. 42 gtts/min C. 38 gtts/min D. 41 gtts/min
Y. Dawne, Content Blogger, Diploma in Journalism, Amsterdam, Netherlands
Answered Feb 07, 2019
The correct answer to this question is A.
To administer 250 mg of Aminophylline, you would need one 10ml vial. (Each 10ml vial is 25mg/ml. 250mg = 10ml.) This means, that for the toal volume of 500ml, you need 490ml of saline and 10ml of Aminophylline. The patient weighs 110lbs (50kg).
To achieve the rate of 0.4mg/kg/hr, the patient needs to receive 20mg of Aminophylline per hour. 250mg of Aminophylline divided by 20mg/hr gives the infusion a total run time of 12.5 hours. 500ml of total volume divided by the 12.5 hour infusion time lets us know that the patient should receive 40ml/hr, or 0.6667ml per minute. Knowing that the IV delivers 60gtts/min, we multiply the ml/min x gtts/min (0.6667 x 60). This gives us the flow rate of 40gtts/min.