QUESTION 1
What is the concentration of the syringe (in ng/ml) to be used for this child?
- 2 kg x 15 mcg/kg = 30 mcg
- 30 mcg in 50 ml = 30/50 = 0.6 mcg/ml
- 0.6 mcg x 1000 ng/mcg = 600 ng/ml
QUESTION 2
What is the flow rate (in ml/hour) that this child will need for this dose?
- For a dose of 5 ng/kg/minute
- 2 kg x 5 ng = 10 ng/minute
- 10 ng/minute x 60 minutes/hour = 600 ng/hour
- 600 ng/hour / 600 ng/ml = 1 ml/hour
QUESTION 3
What volume of the stock solution will need to be drawn up to add to the syringe to be used for this patient?
- 0.75 mg in 0.75 ml = 1 mg in 1 ml
- 1 mg/ml = 1000 mcg/ml
- The syringe requires 30 mcg to be diluted to 50 ml
- 30 mcg / 1000 mcg/ml = 0.03 ml
QUESTION 4
If the stock solution is diluted to a final ratio of 1:10, what volume of glucose 5% needs to be added to the stock vial?
- For a 1:10 dilution the final would be 1 ml of stock in 10 ml of final volume
- We start with 0.75 ml of stock so our final volume will be 10 x 0.75 ml = 7.5 ml
- Since 0.75 ml of the final solution will be the original stock solution the extra we need to add will be 7.5 ml – 0.75 ml = 6.75 ml
QUESTION 5
What volume of this diluted stock solution needs to be diluted to 50 ml to make the solution needed in Question 1?
- This diluted solution contains 0.75 mg (750 mcg) in 7.5 ml
- 750 mcg / 7.5 ml = 100 mcg/ml
- We need 30 mcg for our syringe, so 30 mcg / 100 mcg/ml = 0.3 ml
QUESTION 6
What rate will be needed for this patient if the dose is reduced to 3 ng/kg/min and the infusion concentration is halved to account for the reduced rates likely to be needed?
- To run the infusion at 3 ng/kg/min the dose required will be 3 ng/kg/min x 2 kg x 60 minutes = 360 ng / hour
- If the concentration is halved from Question 1, the solution will be 600 ng/ml x 0.5 = 300 ng/ml
- 360 ng/hour / 300 ng/ml = 1.2 ml/hour