IV set stands for Intravenous Infusion set. It is a set of tubing that is used for the infusion of drugs and nutrients from the infusion bag/bottle to the vein of the patient. Since the medication is directly infused into the circulatory system, it is the fastest mode of drug delivery.
IV Set Parts and Uses
The parts may slightly differ from one manufacturer to another.
- Spike:- Spike allows the flow of fluid from the reservoir bag/ bottle to the drip chamber.
- Solution Filter:- FIlters out particles from the IV fluid.
- Drip Chamber (Fluid Chamber):- Inside the drip chamber, we can see the fluid, drip down into the IV tube. So, it helps to measure the manual IV setup. By counting the number of drops per minute, the rate of flow can be measured.
- Tubing:- Allows the fluid to travel from the reservoir bag to the patient.
- Roller Clamp (Regulator):- By rolling the clamp along the IV tube, the rate of flow of fluid can be controlled.
- Injection Site:- Allows for the IV injection into the cannula when the IV set is in use.
- Luer Connector:- This connects to the IV cannula
- Needle:- Allows for injection into the cannula.
Working Principle of the IV Set
The IV set operates on the action of gravity.
When the IV bottle/bag is fixed at a higher position in comparison to that of the patient level, the gravitational force pulls down the fluid. Thus the fluid flows into the veins of the patients.
The rate of flow of fluids is controlled with the help of the roller clamp. Generally, when the clamp is moved upward, the tube will open. Similarly, by rolling the clamp downward, the internal diameter of the tubing can be narrowed. Thus, by rolling the clamp to a suitable position, the rate of flow of fluid can be controlled.
Types of IV Set
( IV Set Size )
Based on the sizes of the liquid drop, the infusion sets are of two types.
- Macro drip IV set:- As the name suggests, the macro drip consists of wider tubing. Due to this reason, it produces drops of bigger diameter. Macro drips are mainly of 3 types. They are 10 gtt/ml, 15 gtt/ml, and 20 gtt/ml. (Note:- 10 gtt/ml means that 10 drops of liquid= 1ml). Greater is the value of gtt/ml, smaller is the size of the tube, and vice versa.
The macro drip tube is suitable for normal applications where precision is not of higher concern. For example, it is used in routine IV administration such as infusion of IV fluids without any medication.
- Micro drip IV set:- As the name suggests, the micro drip consists of narrower tubing. Due to this reason, it produces drops of smaller diameter. Micro drip (mini drop), generally comes in a single size which is 60 gtt/ml. This implies that 60 drops of liquid make a total volume of 1 ml.
The micro drip is suitable for applications where precision is of higher concern. It is used in infants and children. Also, the medication that needs higher precision is used via a micro drip.
The values such as 60 gtt/ml, 10 gtt/ml, 15 gtt/ml, and 20 gtt/ml stated in the above paragraphs are the drop factors of the IV set. In other words, the IV set drop factor refers to the number of drops that are equal to 1 ml of the same liquid. The drop factor depends upon numerous factors such as the diameter of the tubing, viscosity of the fluid, etc. You can find the drop factor in the packaging of the IV set.
Manual IV Set Up
First of all, go through the specifications of the IV set and the IV bag/bottle. Look for the composition, expiry date, etc. Once you have ensured that everything is normal about the products, go through the following steps.
- Close the roller clamp or the flow regulator.
- Then, hold the reservoir bag/bottle in an upright position and prick at the top part with the help of the spike of the IV set. Make sure that, you do not hold the spike. Else the spike may be contaminated.
- Hang the IV bag/ bottle in an upside-down position in an IV stand.
- Let the fluid accumulate in the drip chamber. Do not fill up the drip chamber. Else, you will not be able to set the drip-rate. Similarly, the chamber should not be empty.
- Once the fluid chamber is half-filled, open the roller clamp.
- Allow the fluid to flow through the tubing. This will allow getting rid of all the air present within the tubing.
- Once the tubing is free of any bubbles within, turn off the roller clamp.
- Now open the needle and connect the IV set to the patient.
- Finally, adjust the drip rate with the help of a roller clamp.
The above steps are used when you are simply hanging the IV bag/bottle in the IV stand. But, if you are using an instrument such as an IV infusion pump, the procedure can be slightly different. You can allow the machine to take care of the drip rate, volume rate, etc. You can also allow the infusion pump to get rid of bubbles from the tube. I have explained these things in the topic of the IV infusion pump system.
Drawbacks of Manual IV Set Up
The only method of infusion in the manual system is via the drip method. This method depends upon the rate of flow of liquid drops in the drip chamber. Since the drip rate can depend upon various factors, the accuracy of infusion rate is lower in comparison to infusion via the pump.
The main problem is due to the variation in the liquid pressure. We know that the pressure exerted by the fluid is given by the formula ‘ P= dgh’, where
d = density of the fluid
g = acceleration due to gravity
h= height of the fluid
For a given fluid, the value of ‘g’ and ‘d’ remains constant. But ‘h’ can vary. It varies upon the factors such as
- The position of IV cannula
- The displacement of the reservoir bag in an IV stand, to the level of the heart of the patient.
- The level of fluid in the reservoir bag, etc.
The main problem here is that during the process of infusion, the level of fluid in the reservoir bag will decrease. Due to this reason, the pressure exerted by the fluid will also decrease. So, the drip rate will also decrease. Thus, the drip rate should be checked from time to time.
IV set is useful for intravenous therapy. Due to this reason, it has got a number of advantages.
- It is the fastest way to deliver the medication and fluid replacement.
- The mode of infusion therapy can be bolus, drip, or extended infusion.
- It allows the infusion of additional medications through the injection site of the IV set. In other words, multiple medications are possible.
- It is suitable for the patient who can not take the medications and nutrients from the mouth.
- The piercing action for infusion is a painful task.
- There can be chances of inflammation and infection.
- There can be the chances of extravasation or infiltration. Extravasation is an unintentional condition in which, the therapy is administered outside a vein.