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Updated:
8 October, 2024
Peripheral venous catheters (PVCs) are fundamental for vascular access, providing a means to administer fluids and medications rapidly and safely. Typically, PVCs are placed in a superficial subcutaneous vein on the dorsum of the hand or in the antecubital fossa. They are also used for blood transfusions and continuous infusion of vasoactive drugs, nutritional solutions, and intravenous anesthetics. PVCs are commonly referred to as "Venflon."
Peripheral Venous Catheter (PVC)
A PVC consists of a plastic cannula with a stylet inside. The stylet is a sharp metal needle inside the cannula that is withdrawn immediately after positioning the plastic cannula in the vein. Some PVCs have a protective cover that occludes and protects against needle sticks after the metal stylet is removed (needle stick protection). Some PVCs (such as Venflon) have a valve housing (“chimney”) on the base of the cannula for venous injections, while others allow injections only through the proximal end of the cannula.
Today, PVCs are always sterile, single-use plastic cannulas with a metal stylet. For awake patients with stable vital signs, a peripheral venous catheter of 0.8-1.2 mm in diameter (blue-pink-green) is usually sufficient. The color and dimensions may vary depending on the manufacturer. A PVC should not remain in the same vein for more than a few days and should be checked daily for cleanliness, leakage, or infections. For critically ill patients, at least two PVCs should be inserted, and for patients with trauma or significant bleeding, at least three PVCs should be inserted, with at least two being large-bore.
Typically, a PVC is inserted without anesthesia in sizes ranging from 0.8 to 1.4 mm. Children and sensitive patients may be offered “topical” anesthesia with skin-numbing patches. In sizes of 1.7-2.0 mm, local anesthesia should be administered if the patient is fully awake, not sedated, severely drowsy, or in a coma or under general anesthesia. If three attempts to insert the needle fail, it may be necessary to reassess the indication, take a break, or have another person insert the needle. Difficult-to-cannulate patients should receive help from experienced personnel, preferably an anesthesia nurse. The first attempt is usually the best chance of success. Hypovolemic patients, patients in shock, “over-cannulated patients,” and obese or overweight patients can present very challenging conditions for successful PVC insertion. Ultrasound-guided puncture can be a helpful tool in such cases.
The insertion itself is performed in two consecutive steps:
- A) Penetration through the skin but not the vessel wall
- B) Penetration through the vessel wall once the needle is under the skin.
If the patient has well-filled and visible veins, steps A and B can often be performed in one motion. However, for difficult-to-cannulate patients or those with small or barely visible veins, it is better to perform the insertion in two steps: A followed by B.
The needle’s angle against the skin at step A is steeper than at step B, which should be nearly flat. A common mistake is to have too steep an angle when penetrating the vessel wall, causing the needle tip to go underneath the vessel instead of into it. When penetrating the vessel wall, it’s important not to withdraw the stylet too early. The cannula should be advanced at least one centimeter before retracting the stylet but should not be advanced too far, as there’s a risk of passing entirely through the vessel. The cannula is secured with a specific adhesive dressing (e.g., Tegaderm), which allows inspection of the insertion site.
Veins in the arm become more filled through stasis or by lowering the arm “declining stasis.” Venous stasis can be achieved with a tourniquet or a blood pressure cuff. Heat and light tapping on the vein can also help a little.
If a PVC is needed for more than two days, it can be replaced with a midline catheter, which is inserted under sterile conditions using ultrasound into the veins of the upper arm.
PVK storlekar och indikation
| Färg | Storlek (G) | Storlek (mm) | Indikation |
|---|---|---|---|
| Blå | 22G | 0.8 | Till äldre och patienter med svåra vener. |
| Rosa | 20G | 1.0/1.1 | Vanlig storlek till normal i.v. medicinering. |
| Grön | 18G | 1.2 | För i.v. medicinering och blodtransfusioner. |
| Vit/Gul | 1.4 | För blodtransfusioner och snabba infusioner. | |
| Grå | 16G | 1.7 | Större blodtransfusioner. |
| Brun | 14G | 2 | Sällan i bruk. Till traumafall. |
Midline
This catheter is 20 or 25 cm long. A midline catheter is inserted percutaneously under ultrasound guidance through a vein in the upper arm, typically the basilic vein. These catheters are designed for both short- and medium-term use, 1-3 weeks. They can often replace a central venous catheter (CVC) for venous access. A small dose of local anesthetic, Xylocaine 1%, can be applied first. Under sterile conditions, the basilic vein is punctured using a tourniquet and ultrasound. The tourniquet is then released, and a guidewire is inserted into the vessel. Dilation follows with a dilator, and a small skin incision with a sharp scalpel may be required. The midline catheter is inserted approximately 20 cm over the guidewire, which is then removed. The catheter is secured with a special bracket that clamps it at the skin surface. Both the clamp and the catheter are taped in place with a special dressing.
A midline catheter provides vascular access via the upper arm – with a maximum length of 25 cm. The catheter tip is located in a peripheral vein before reaching the chest. A midline catheter is an alternative to a CVC and can remain in place longer than a conventional PVC (recommended for treatments lasting 5-28 days). However, it is generally reserved for patients who cannot receive a conventional PICC line or whose treatment requires IV access for more than five days. When irritating drugs like certain antibiotics and chemotherapy agents are given, a PICC line is preferred, as the central location of the catheter tip allows the drug to diffuse into the high blood flow near the catheter tip.
Rapid Infusion Catheter (RIC Line)
A large, short catheter designed for rapid transfusions with an internal diameter of 7.5 or 8 French. After identifying the vessel with a puncture needle and guidewire, the skin is lightly incised with a sharp scalpel. A 20-gauge catheter is inserted into a peripheral vein, and a guidewire is advanced. A moderate skin incision is made with a scalpel blade, and the dilator (blue catheter) is inserted into the vein before the catheter is placed over the guidewire. This allows for large, rapid transfusions of blood products.
Regardless of insertion technique or catheter type, the catheter tip should be placed in the superior vena cava and/or the transition to the right atrium in the heart. The tip location is confirmed with an X-ray. The advantage of a central venous line is that the patient avoids the discomfort associated with repeated needle sticks and blood draws. It is also not without risk to administer irritating drugs via a peripheral vein. Long-term need for a centrally located catheter primarily occurs in end-of-life care (pain relief, nutrition), chronic dialysis treatment, intensive care, and when chemotherapy is administered repeatedly over long periods.
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