Venous access devices are the group devices ranging from peripheral iv cannula to central catheter used to access the venous circulation. Vascular access devices are inserted into veins via peripheral or central vessels for the purpose of diagnosis making or therapeutic reasons.
- Blood sampling
- Central venous pressure measurement
- Administration of medication and/or fluids
- Total parenteral nutrition
- Blood transfusions
The choice of venous access devices should be based on the requirement of use and the duration for which it is intended.
Venous access devices could be single lumen or multiple lumens. Multiple-lumen devices have been increasingly linked to a higher infection risk.
It goes without saying that venous access devices are inserted under aseptic techniques.
There are two major types of devices
- Peripheral venous devices
- Central venous devices
There are different subtypes of each type which we would discuss.
Types of Venous Access Devices
- Peripherally Inserted Central Catheter (PICC)
- Central – Venous Catheter
- Percutaneous Non-Tunneled Catheter
- Tunneled Central Venous Catheter
- Implanted Port
Peripheral Venous Access Devices
Peripheral Short or Cannulae
Peripheral vascular devices are less than 3 inches (7.5 cm)in length; over-the-needle catheter [cannula] is most common.
Peripheral cannulae are the most commonly used type of venous access devices and are suitable for short-term infusions of fluids, blood products, and medication.
A cannula is a flexible tube containing a needle that can be inserted into a vein. The most commonly used veins are
In dire needs, veins of lower extremities can be considered but are best avoided due to It increased the risk of thrombophlebitis.
Inflammation, fibrosis, thrombosis or recent previous punctures are contraindications of iv cannulations.
Polyurethane-based cannulae are preferable due to the flexibility of the material and thus further reducing the risk of phlebitis.
They are suitable for iso-osmotic or near iso-osmotic and whose pH value is between 5 – 9. [Central access is recommended for vesicant drugs.]
The blockage is a known issue and repeated venipunctures may be needed to maintain IV access.
Peripheral veins are prone to phlebitis and subcutaneous perivenous infiltration, and the catheter should not stay in one site longer than 48 – 72 hours.
A midline catheter or PICC be is used when the duration of therapy will likely exceed 6 days.
These devices are between 3 – 8 inches (7.5 – 20 cm) long and are inserted within 1.5 inches (3.75 cm) above or below the antecubital fossa. Catheter tip ends in the peripheral vasculature below the axilla.
These could be considered for use in patients with peripheral veins or where the central venous catheter cannot be inserted for one reason or other especially when the duration of therapy is not prolonged
The vein of choice for insertion is the basilic, as it is large and straight.
Midlines maintain intravenous access without repeated venipunctures.
Midline catheters should be considered for IV therapy when infusions which are iso-osmotic or near iso-osmotic and whose pH value is between 5 – 9. [Central access is recommended for vesicant drugs.]
Midline catheter [or PICC] when the duration of IV therapy is likely to exceed 6 day
Central Venous Access Devices
It is a single or double lumen central venous catheter inserted via a peripheral vein – the tip terminates in the superior vena cava.
It is inserted into an antecubital fossa vein – the basilic or cephalic and advanced into the superior vena cava. The tip position is usually confirmed radiologically.
PICC is indicated when there is lack of peripheral access or for infusion consists of vesicant and irritant drugs/fluids, parenteral nutrition and hyperosmolar solutions. They are also used when long-term access is required. However, If anticipated therapy exceeds more than one year, a tunneled catheter or implanted port should be considered.
PICC carries lesser risk than central lines. They are available as single and double-lumen catheters.
PICC placement is contraindicated in
- Axillary node dissection/irradiation
- Lymphoedema of the arm, axillary node disease
- Skin infection at the insertion site.
Central Venous Catheters
These devices are inserted directly into the central veins. Internal jugular, subclavian and femoral veins are most common veins used for access and the tip goes to superior vena cava.
These are used to
- Monitor central venous pressure
- Large amounts of fluid or blood products especially vesicants or irritants
- Repeated specimen collection and TPN.
These devices further could be of following types
- Implantable ports.
The choice of which device to use will depend on how ill the patient is, the reason for insertion and patient preference.
CVCs may have single or multiple lumens. Multiple lumens allow numerous drugs to be administered simultaneously and are used in acutely ill patients and intensive care units.
Central venous catheters may be inserted at the bedside or in radiology under fluoroscopy. Radiographic confirmation of tip location is required prior to use.
Duration of IV therapy will likely exceed 6 days, often several weeks or months.
These central venous catheters are used most commonly. Common sites for insertion are the subclavian, jugular, or femoral vein.
Recommended for short-term access to the central circulation in critical situations, or when peripheral access is inadequate or inappropriate.
Not generally recommended for home care, but client circumstances and care requirements should be considered on an individual basis.
Non-tunneled CVCs are used in patients who have acute illnesses. Jugular sites are more prone to infection due to the difficulty of securing the catheter to the patient’s neck securely.
These are similar to the non-tunneled except that the outer exposed part is surgically tunneled through subcutaneous tissue to an exit site generally on the chest or abdominal wall. A cuff that lies in the subcutaneous tunnel, around which fibrous tissue grows, helps to secure the device. This tunneling procedure requires surgical placement.
These are indicated in patients in whom long-term vascular access is expected.
Tunneled lines are easy to care for, so patients are often educated to care for their line.
These are not as widely used now as in past because of better central access devices.
These devices after insertion need their outer part to be implanted surgically under the subcutaneous skin. they offer better cosmesis as they are hidden.
Being unexposed, they are associated with fewer risks and are easily accessed using a non-coring needle, which can remain in situ for up to seven days.
Patency is maintained by regular flushing with heparin-based solutions. They require minimal care and manipulation.
They require a minor surgical procedure for placement and removal. When not in use, requires less maintenance
Subcutaneous Infusions (Hypodermoclysis)
Subcutaneous infusion, or hypodermoclysis, is a technique whereby fluids are infused into the subcutaneous space via small-gauge needles that are typically inserted into the thighs, abdomen, back, or arms.
These can be used for continuous or intermittent infusions of isotonic fluids and selected medications. these are used only for a small duration