Intravenous (IV) extension sets are forms of tubing. One end is provided with a capped Luer lock connector, and the other end is equipped with a capped Luer slip connector. The tubing is made up of PVC (flexible).
As the name implies, it is used to add length to an existing infusion tubing. Although extending the length of the current line reduces the flow rate, medical staff still use IV extension sets because of added benefits to the patients and the healthcare staff. The only restriction to its use is when a faster infusion rate is required, as in a medical emergency, such as severe bleeding and hypovolemic episodes.
The bore type and the tubing length determine the flow rate. If the bore has a greater diameter, the faster flow rate will be. If the tubing is longer, then the flow rate is slower.
Hence, there are three types available for use in terms of the bore: microbore, standard bore, and macrobore. In terms of length, there are several options available, too. In addition, some IV extension sets have an injection port or a pre-pierced Y-site injection port where additional medications could be infused.
- Extension sets are connected to IV catheters to allow a longer distance between the patient and the fluid being administered. This is often resorted to when necessary equipment in and around the infusion site crowd the area.
- While still inside the patient’s peripheral vein, there are times that the peripheral cannula is temporarily not in use because the infusion is stopped for some reason. To keep and maintain the opening of the needle, medical staff connect an IV extension set to it and flush it with standard saline solution, followed by a positive pressure cap. When a normal saline solution is used to maintain the opening of the needle, then the cannula is said to be saline-locked. Suppose the cannula is not flushed with standard saline solution. In that case, the needle that is still inserted in the patient’s peripheral vein will eventually be blocked by a blood clot if no infusion is done for some time.
- When a peripheral cannula is used for a long time and intermittent medication, an IV extension set should be attached to it to prevent micro-movements of the cannula, preventing its unintended removal and thereby prolonging its use.
- When it is expected that a continuous infusion will be stopped from time to time, the use of an IV extension set attached to the peripheral catheter will be resorted to because it is easier to stop the infusion for some time and convert it into a saline-locked catheter.
- The IV extension set is a small and short tube that is added to an existing line. As such, it is easily managed, and it can be saline-locked when needed, preventing the IV from falling out or preventing the catheter needle from pricking the side of the vein at the site of insertion when changing lines or administering intermittent IV medications.
- Since the IV extension set reduces the frequency of changing catheter needles, the hospital staff and patients are less likely to experience needlesticks, promoting their safety.
- Needleless extension sets are provided with backflow valves that prevent blood from leaking out when changing lines.
- They improve line safety and durability at the expense of flow rate.
- They help reduce micro-movements at the IV insertion sites and protect healthcare staff and patients from blood and body fluid exposure when changing the IV tubing.
- The extension set has a clamp that can immediately prevent the backflow of blood, reducing the exposure of nurses and other healthcare staff.
When an existing line is lengthened by adding a tube, such as an IV extension set, the flow rate in the said tube is reduced. Hence, in a medical emergency wherein a faster rate of infusion is needed and required, such as in severe bleeding, an IV extension set must not be added to the existing IV line.
Care and precautions
Concerning peripheral cannula
- IV extension sets need to be changed when the access device, such as the peripheral cannula, is changed.
- Upon suspicion that there is bacterial contamination or breakage in integrity, replace the IV extension set.
- IV extension sets need to be primed and attached to the cannula at the time of IV insertion using and observing an aseptic non-touch technique.
- When exiting from the flushing of the IV extension set, a positive pressure clamping technique must be used.
- When not in use, IV extension sets must be clamped.
Back-tracking is one of the more severe complications in using an IV extension set, especially if the said set has several ports. With several lines connected to a single access point, back-tracking of fluids can occur if one of the lines has no flow or slower flow, and the more substantial flow will take the route of lesser resistance. Back-tracking is said to occur when the fluid flow does not take the ordinary or intended course; instead, it takes a reverse or different flow.
Two possible events will occur if there is back-tracking of IV fluid:
(1) under-infusion or
(2) bolus delivery of IV drugs
Whichever takes place is not suitable for the patient. In under-infusion, the patient received less fluid—including the drug that it contains—than what was needed; in bolus delivery, the patient received more than what was required, and toxicity may occur. Specifically, bolus delivery happens when the flow rate in one line—previously slower or not flowing—is suddenly increased after flushing or when the occlusion is suddenly dislodged.
Following are the precautions about the use of an IV extension set with multiple ports:
- If not necessary, avoid using IV extension sets with multiple ports because back-tracking of fluid is highly possible in this design.
- To avoid back-tracking, consider using IV lines with one-way valves.
- Apply clamps to all lines that are not in use.