General description
The intravenous (IV) roller clamp is a part of the IV set. It serves as an integral part of the basic intravenous setup. It is placed and attached to the plastic tubing, which connects the drip chamber with the needle. Attached to the tubing provides a significant degree of flexibility in using it: it can be moved up and down the tubing line as needed, and it can still do its primary function.
Structures and parts
The IV roller clamp has two main parts: (1) the roller wheel and (2) the housing. The housing, in turn, has sidewalls, a bottom wall, and a top wall. The housing holds and supports the roller wheel and serves as the rolling platform of the roller wheel. The plastic IV tube is inserted between the roller wheel and the bottom wall of the housing. If the roller is rolled, the IV tubing is either pinched over or not. When squeezed, the IV tubing is compressed, and the IV flow stops.
Functions
The primary function of an IV roller clamp is to control the flow rate of the IV fluid. The roller has two directions: either it goes up or down. If it is rolled up, the flow rate increases, and when it is rolled down, the flow rate goes down. If the roller is fully rolled down its housing, then the flow rate completely stops. If the roller is fully rolled up its housing, then the flow rate is at its maximum.
For example, if the flow rate is currently observed to be at 40 drops per minute, but you want to decrease it to 20 drops per minute, then you roll down the roller. If you’re going to increase the flow rate to 60 drops per minute, then you roll up the roller.
Types
Marked or scaled roller clamp
In most designs of the IV roller clamp, the housing is not marked with anything. However, there is a trend to mark the roller clamp with a degree scale, indicating the fluid’s flow rate. For instance, if the medical staff intends to adjust the flow rate to 40 drops per minute, then all he has to do is to move the roller up or down and place the arrow of the roller on the preferred flow rate, as prescribed by the medical doctor in the order sheet. With this innovation, the medical staff does not have to count the number of drops per minute in the drip chamber. In effect, this will reduce the nurses’ and other medical staff’s workload and significantly ensure the patients’ safety.
Unmarked roller clamp
This is the usual type of roller clamp. In the absence of flow rate indicators in the roller clamp, then the nurse or assigned medical staff will have to count the required flow rate in the drip chamber and adjust the roller clamp as needed. To ensure that the roller will not move during infusion, we can wrap it with tape.
Materials
The IV roller clamps can be made up of ABS (acrylonitrile butadiene styrene). This compound provides the roller clamps with more appropriate mechanical properties, such as impact resistance, toughness, and rigidity, compared with other common polymers.
From the perspective of reducing the cost, we can make roller clamps of PE (polyethylene), which is now the most common use plastic.
Factors affecting IV flow rate
As mentioned in the preceding, the IV roller clamp is used to control and regulate the IV fluid’s flow rate. If IV fluid does not flow in infusion, it does not always mean that the IV roller clamp is the source of the problem. Other possible causes need to be searched for. The following could be among them:
Tube occlusion
This obstructing factor could happen if the IV tubing is kinked or bent. This occurs when the tubing is accidentally caught under the patient or equipment, such as beds and bed rails.
Vein spasms
It is a rule that if the fluid or medications to be infused are chilled, they must first be brought to room temperature before investing them. If this rule is not followed and infused without warming them first, then there will be vein spasms at or near the infusion site, which will obstruct the flow of the fluid.
Height of the fluid container
Since the fluid flow is affected by gravity, if the height of the drip chamber is less than 3 feet above the IV insertion site, then the flow rate will be drastically slowed down. The prescribed height is 3 feet above the IV insertion site.
Location or position of IV cannula
It is a basic rule that a needle should be inserted in a very stable and less movable part(s) of the patient’s extremities. If it is inserted in flexion and extension, when the patient moves his forearms or moves around, the flow rate may stop because the flow is obstructed. If this is the case, transfer the cannula to a more stable site.
Infiltration or extravasation
In the insertion of the needle, the hospital personnel who will do it should possess a high degree of expertise. If the vein is not punctured correctly, unnecessary bleeding under the skin and surrounding tissue and swelling will develop. If the site of insertion is swollen, the flow rate may stop.
Unnecessary touching or hitting the roller clamp or elevating the forearm
The patient should be instructed not to touch the roller clamp and avoid accidentally hitting or bumping it because it may cause the IV flow to stop. Advise the patient to keep his hand or arm, where the cannula is inserted, below the heart level. Unnecessary elevation of the arm or hand where the cannula is will slow or stop the IV flow.
Cannula gauge or diameter
The proper diameter or gauge of the needle must be used. The IV fluid flow rate will slow down if the diameter of the needle is too narrow. The wider the diameter of the needle is, the faster will be the flow rate.
