EXAMPLE 1

Calculate the dose of Morphine 

in a 4 kg baby at 25 microgram/kg/hour.
1 ampoule contains 1 ml solution 
having 1 mg of Morphine. 
How much Normal Saline need to be added to run at a 
rate of 1 ml per hour for 24 hour?

Calculation: 
Dose of Morphine= 25 microgram/kg/hr 
Weight of baby= 4 kg 
Amount of morphine required = 25X4 =100 microgram/hr 
So, in 24 hours total amount of Morphine required= 100X24 =2400 microgram 
In the ampoule, 
1 ml= 1 mg or, 1000 microgram Morphine 
Now, 1000 microgram Morphine is present in 1 ml 
So, 1 microgram Morphine is present in 1/1000 ml 
So, 2400 microgram Morphine is present in 1X2400/1000 ml= 2.4 ml 
Now, Morphine solution is to be run at a rate of 1 ml per hour for 24 hour. 
So, total amount required to be given in 24 hours = 1X24= 24 ml 
Hence, amount of Normal saline to be added= 24-2.4 ml= 21.6 ml 

Ans. Amount of Normal saline to be added is 21.6 ml.