Question

An IV Solution containing 20,000 Units of heparin in 500 ml of 0.45% NaCl is to be infused to provide 1000 Units of heparin per hour. How many drops per minute should be infused to deliver the desired dose of the IV set callibrates at 15 gtt/ml?

Answer 1

Total volume is 500 ml of 0.45% NaCl

Strength of drug(Injection Heparin) is 20,000 Units/500ml

$\large 20,000units\div 500ml=40units/ml$

I.e 40units of heparin is in one ml of 0.45% of NaCl and 1000units is in 25ml of NaCl

Desire dose of heparin is 1000 Units per hour.

That means the 25ml of NaCl needs to be transfused per hour.

$\large 500ml\div 25ml=20$

Total 20 hours needed to complete 500ml of NaCl

The drop factor is 15gtt/ml.

The formula of the drip factor is

$\large (Total volume\div total time in minutes)\times drop factor$

$\large (500ml\div 1200 minutes)\times 15$

$\large = 6.25 gtt/min$

6 to 7 drops per minute should be infused to deliver the desired dose of heparin.