Ordered Dopamine IV at 4 mcgkgmin Available 200 mg in 250 ml

Ordered: Dopamine IV at 4 mcg/kg/min. Available: 200 mg in 250 ml NS. The patient weighs 165 pounds. At what rate in ml/hr will the nurse set the IV pump? Ordered: Dopamine IV at 4 mcg/kg/min. Available: 200 mg in 250 ml NS. The patient weighs 165 pounds. At what rate in ml/hr will the nurse set the IV pump?

Solution

Solution

First we need to focus on what units of measure would we want in the answer. In this problem we are kindly given \"mL/hr.\" We are also given that there are 200 mg dopamine in 250 mL (or 200 mg/250 mL). We can also say that in 250 mL there are 200 mg dopamine (or 250 mL/ 200 mg).

The other important bit to realize is that 4 mcg/kg/min can also be written as 4 mcg/(kg x min).

4mcg/kg/min means for 1kg of weigt , 4mcg/min needs to be adminstered.

Now Patient weight is 165 lb (pounds).

Also we know that 1 lb=0.45 kg

Thus, 165 lb=0.45*165kg =74.25kg .....i

4mcg/kg/min means for 1kg of patient weight, 4mcg/min needs to be adminstered.

Thus for 74.25kg of patient weight ,the total drug to be adminstered =4*74.25 mcg/min =297 mcg/min ---ii

It means that for a patient of 74.25kg, 297 mcg is needed to be given in a minute .

or converting it to hours we can say that in 1/60 hours, 297 mcg has to be provided.

Thus in 1 hours total mcg needed to be provided =297*60 mcg =17820 mcg .....iii

Now we know that 1microgram (mcg) is equal to 1 mg .

=> 17820 mcg =17820 mcg * 1mg/1000 mcg

=17.820 mg ...iv

Now , 200 mg is available in 250 ml NS

thus 1 mg will available in 250ml/200 =1.25 ml

or 17.820 mg will be avaialbe in 1.25*17.820 ml

=22.275 ml

This is the fluid requirement per hour (refer equation ---iii and iv)

This is the flow rate that the nurse must set in ( =22.275ml/hr)