Intravenous therapy is the infusion of fluid directly into the venous circulation of a patient, usually via a cannula. There are various indications for the administration of fluid, such as replacement of electrolytes, restoration of blood volume or maintenance in the surgery-staved patient.
Intravenous (IV) therapy can also be used in the administration of drugs (such as in chemotherapy); it has a fast action, compared to enteral routes, as the medication is delivered straight into the circulation.
In this article, we shall look at the principles behind setting up an intravenous fluid infusion.
Fluid Bag Information
Before setting up an intravenous fluid infusion, it is important to check the fluid bag. Although there are different types of fluid, the bags all have a similar structure and labelling.
- Type of fluid
- Expiry date of fluid
- Port for injection
- Port for insertion of giving spike
Introduce yourself to the patient, check the patient details, and check the prescription chart. Note the type of fluid, volume, and time to be given over. Ensure to check for any allergies
Explain the procedure to the patient and gain their consent. Check the fluid bag for any cloudiness or particulate matter present; do not use the bag if any such impurities are present. Remove the outer packing of the bag and hang it up on a drip stand.
Open the giving set and close the flow control using the roller-ball clamp on the line. Remove the cover from the port on the bag by twisting and breaking it off. Insert the spike into the port, without touching the end.
Half fill the filling chamber by squeezing it then release the roller ball clamp to allow the fluid to run through the giving set. Ensure no bubbles are in the line and clamp off the roller ball.
Decontaminate your hands and don apron and gloves. Clean the hub of the bionector with a chlorhexidine wipe, then flush the cannula with saline. Attach the giving set to the bionector. Set the infusion rate by adjusting the roller ball.
Calculating the Drip Rate
The drip rate refers to the number of drops of fluid that enter the filling chamber each minute. The drip rate is set manually, and determines the speed at which the fluid is infused into the patient. It is calculated as follows:
First calculate the ml/hr required:
- E.g. 1 litre bag of normal saline to be given over 8 hours = 1000ml/8hrs = 125ml/hr
Then calculate the ml/min required:
- E.g. 125ml/hr = 125ml/60mins = 2ml/min
For a standard giving set, 20 drops in 1ml. Therefore, you can calculate the number of drops per minute:
- E.g. 2mls/min = 40 drops/min
- Intravenous therapy is the infusion of fluid directly into the venous circulation of a patient
- Ensure to maintain a sterile procedure when setting up any fluid infusion
- The drip rate can be calculated through estimating that around 20 drops are in 1ml of crystalloid fluid