CVAD adjuncts to IV administration sets

Section Recommendation statement Grading of recommendations
26. Needleless connectors that can be disinfected or decontaminated are to be placed on each lumen of a CVAD (1-7). Grade A
27. Multi-flow adaptors and three-way taps and connectors are to be changed when the administration set is changed (7). Consensus
28. Clamps should be engaged (when in situ) on the device’s lumen when disconnecting the administration set from the lumen. This is to prevent complications such as air embolus, bleeding or inadvertent drug or fluid bolus administration. Consensus
29. Avoid administration set disconnections. If an administration set is disconnected it must be discarded and a new set used. Consensus
The evidence review for these recommendations was current to December 2012. Clinicians are advised to check the literature as research may have been published that change these recommendations.


In the context of the limits set on this review, high level evidence relating to connectors was minimal or had a high risk of bias. There was support within the GDN for use of needle-free Luer devices to reduce the risk of needle stick injury and for the use of devices that prove easy to disinfect. The rationale for use of Luer connectors is to reduce risk of accidental disconnection, which may lead to bleeding or infective complications. The use of devices with specific antimicrobial parts and displacement valves was unresolved.

Injection and sampling ports are accessed numerous times during the day for patients with CVADs in intensive care. In addition, blood, fluids and/or other biological matter may collect via the CVAD . Frequent access and collection of matter creates opportunities for microorganisms to be introduced to the patient. The CDC and multiple guidelines recommend cleaning of these ports before accessing the system (8).

The use of multi-lumen CVADs is common in ICUs , however, there are occasions when a CVAD lumen or a section of a multi-flow adaptor may not be in use. This can create opportunities for problems such as:

  1. air embolism if disconnection occurs
  2. reflux of blood that can contribute to blockage of a lumen
  3. admixture or reflux of intravenous fluids.

Therefore, it is important that the clamps on unused CVAD lumens are engaged as appropriate. See Table 4.

Extension sets/add-on devices are considered part of the administration set as opposed to part of the CVAD and require changing when the administration set is changed.

Practice point 5: Needleless connectors

A 2012 review of needleless connectors (9) is available via CIAP in NSW . It is important to be aware of the functionality of the connector stocked in the facility. The basics include:
  • how it links into an intravascular system (usually Luer locking or split septum technology)
  • the complexity of the internal parts of the connector (how fluid moves through it)
  • when lumen clamping is required
  • how to ‘scrub the hub’.

Although product labelling does not always indicate the type of fluid displacement, connector devices can be distinguished by the way fluid moves through them.

A negative displacement needleless injection system will allow blood to reflux into the catheter lumen when the tubing or syringe is disconnected. A positive-pressure flushing technique is required when a negative-displacement device is used (see common needleless connectors table). A positive displacement needleless injection system will reserve a small amount of fluid to push toward the catheter tip at disconnection of the syringe or tubing, which prevents blood from remaining inside the lumen. A neutral displacement needle-free system will not allow fluid to move in either direction when tubing or a syringe is disconnected.

Negative and positive displacement devices are dependent upon flushing technique. A positive-pressure flushing technique is required with a negative-displacement device. The Infusion Nurses Society has defined positive pressure as a constant, even force within a catheter lumen preventing reflux of blood by clamping while injecting or by withdrawing from the catheter hub while injecting. However, positive-pressure flushing techniques prevent correct function of a positive-displacement system and should not be used with these devices.

Institutional policy often dictates the use of clamps on the catheter lumen to ensure closure when not in use. In facilities where positive-displacement devices are used clamping may also be used, but the tubing or syringe must be disconnected and sufficient time allowed for the positive fluid displacement prior to clamp activation.

Blood reflux into the catheter lumen results from syringe plunger rod compression and syringe or tubing disconnection. Although a positive-displacement system will displace the blood reflux caused by disconnection, there is no available research on its ability to overcome syringe compression reflux in addition to disconnection reflux.

The length of catheter lumen affected by blood reflux depends on the catheter lumen size. Catheters with a smaller lumen diameter will have more length filled with blood, whereas larger lumens will have a shorter length of reflux.

Table 4 Common needleless connectors

Type How it works Disconnection

Blunt cannula with split septum

Has simple split septum, which is opened by a blunt syringe to allow fluid down the pathway of the valve.

Flush, pulsatile, flush fluid into device using a positive pressure pulsatile flush technique, clamping catheter lumen while maintaining positive pressure and disconnect syringe.

Mechanical valve (with negative/neutral displacement)

Has an internal mechanism that, when compressed by the insertion of a syringe, opens a fluid pathway through the device.

Flush device using a positive pressure pulsatile flush technique, clamping catheter lumen while maintaining positive pressure and disconnect syringe.

Mechanical valve (with positive displacement)

Has an internal mechanism with the addition of a fluid reservoir that creates a positive displacement of fluid through the device when the syringe is disconnected and removed.

Flush device using a positive pressure pulsatile flush technique. Disconnect syringe and wait 2-3 seconds before clamping the catheter lumen closed. This allows time for the positive pressure feature of the valve to activate.

Grade of recommendation Description
A Body of evidence can be trusted to guide evidence
B Body of evidence can be trusted to guide practice in most situations
C Body of evidence provides some support for recommendation/s but care should be taken in its application
D Body of evidence is weak and recommendation must be applied with caution
Consensus Consensus was set as a median of ≥ 7
Grades A–D are based on NHMRC grades (50)


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