Intravenous (IV) drip chamber

Description 

Intravenous (IV) drip chamber refers to the elongated, sac-like, and transparent device attached and connected to the distal end of the intravenous line. In turn, this device is inserted into a designated site in the container—be it in the form of a collapsible plastic bag or bottle—of the IV fluid. When the IV fluid flows from its container into the IV line, the fluid is first collected in the drip chamber, wherein its essential functions occur. 

Functions

Allows admixed gas to bubble out 

In the chamber, gas admixed in the fluid is given a chance to bubble out and separate from the fluid. In this case, the fluid that continues to flow in the IV line is now free from admixed gas, which could cause air embolism and other patient complications. Because of its inherent function to allow the bubbling out of admixed gas, the drip chamber must not be filled up with IV fluid before and during the infusion. Ideally, it should only be half-filled to give space for the escaping gas from the fluid.

Allows medical or hospital staff to know fluid is flowing

One of the chamber’s basic functions is that it allows the medical or hospital staff to know and observe if the IV fluid is flowing or not. If there is an obstruction along the line—whether in the IV tubing or the catheter—fluid flow will not occur, and it is observable in the transparent chamber: no fluid drops! This observation can only take place if the chamber is half-filled with fluid.

Allows medical or hospital staff to regulate or control the flow rate 

Aside from allowing the bubbling out of gas from the fluid and giving a sign that fluid is flowing, the IV drip chamber, being made up of transparent plastic, allows the medical or hospital staff to observe and monitor the fluid’s flow rate. This is important because each patient has a different fluid requirement. One patient requires a faster rate; another one needs a slower rate. Still, another needs a moderate rate. It depends on the medical situation and condition of the patient. Thus, the flow rate must be regulated and controlled. This cannot be done without the transparent IV drip chamber, where the observer can count the number of fluid drops per minute. Again, to count the flow rate, the chamber must only be half-filled with fluid.

Basic Classifications

Based on the size of the dripping hole  

The drip chamber can be classified based on the size of the dripping hole. One type is called the macro-drip, wherein the dripping hole allows the fluid flow of about 10 to 20 gtt/ml. The other type is called micro-drip, which delivers a fluid flow of about 60 gtt/ml. The macro-drip is usually used among adult patients. In contrast, the micro-drip is generally used for pediatric patients, neonatal care, and when a potent medicine is admixed in the intravenous fluid that is being infused.

Based on the presence or absence of a filter

The IV drip chamber can also be classified according to whether it has a solution filter or not. One type of chamber is not equipped with a filter. While the other one has filtrating structure, which is called a filtered IV set. In the chamber with a filter, the upper reservoir is separated from the lower reservoir by a filtrating assembly, and the distance between the filtrating assembly and the bottom surface of the drip chamber determines whether the dislodged air bubbles from the filter assembly will be prevented drawn into the IV fluid that is being infused. The said distance is selected such that air bubbles will not admix with the IV fluid that is about to enter the patient’s circulatory system.

Based on the presence or absence of air vent  

If provided with an inlet of air, it is called a vented IV drip chamber. This air inlet is located immediately above the drip chamber, and it allows the entry of air into the container of the fluid being infused. This air that enters the fluid container will exert some pressure over the fluid, enhancing its entry into the IV tubing. This type of drip chamber is used when a bottled IV solution is being infused or used.

On the other hand, if the drip chamber is not provided with an air inlet, it is called a non-vented IV drip chamber, and it is used in the fluid being infused inside a collapsible bag.

Basic Operating Procedures

Installing the IV set with an emphasis on the IV drip chamber 

The IV set is wrapped in a sterile PE bag. Once it is opened, it has to be used immediately. If not, then there is no need to tear and open the wrapping immediately. Hold the IV tubing at the upper end of the IV drip chamber and then insert its spike into the IV fluid container. Immediately, fluid flows into the chamber. Ensure that the chamber is only half-filled with the fluid, approximately 1.5 cm in depth. When the roller clamp is released, the fluid enters the IV tubing and then into the patient’s vein.  

The drip chamber must be half-filled with fluid. 

The drip chamber must be half-filled with fluid before and during the infusion. If the chamber is filled up, then medical or hospital staff cannot observe if the fluid is flowing or not, and they cannot count the number of drops per minute. Also, no space will be left behind for the escaping gas to stay. On the other hand, if a minimal amount of fluid is available in the chamber, the possibility that gas will be drawn into the IV fluid being infused is very likely.

The procedure of reducing the amount of fluid in the chamber

If the chamber is filled up, reducing the fluid is in the following manner: Get hold of the fluid container, and then reverse it. While in a reversed position, press the chamber until the desired amount of fluid is returned into the IV fluid container, which could be in the form of a bottle or collapsible plastic bag.