Infusion is a method that allows healthcare professionals to inject a product such as a drug or a solution into the body on a regular basis. It allows large amounts to be continuously administered directly into the bloodstream for rapid action.

Intravenous means that the product is injected directly into a vein and therefore into the bloodstream. There are two types of intravenous administration. First, direct intravenous administration, fast or slow, using a needle. The other type of administration is the one we are talking about here. This is the infusion, using a catheter placed in a vein (or in an artery, in the case of certain chemotherapy drugs).

Infusion is a means of delivering a therapeutic product continuously, slowly and for a long time to the body. There are two routes of infusion:

• the peripheral venous route (the catheter is placed in a vein in the upper limb);
• the central venous line (the catheter is implanted in a large vein, such as the subclavian or internal jugular).

The product passes through the vein under the action of gravity or by means of a pump. Depending on the duration of the treatment, it is also possible to install, under local anesthesia, an implantable chamber in place of the catheter. This method makes it possible to preserve the veins in the event of the need for a regular infusion.

Intravenous infusion allows the administration of injectable solutions in liquid form. It can be drug therapy, plasma, saline, nutrient solution. It is also possible to inject several types of medication (painkillers and antibiotics, for example) at the same time, by connecting several lines to be infused with the catheter.

We also talk about parenteral treatment, as opposed to enteral treatment that goes through the digestive tract. Here, the product arriving directly in the bloodstream, it does not pass through the digestive system. Its action will therefore be much faster than that of an oral medication, for example.

Placing a peripheral venous catheter is a very frequent care procedure (the annual number of peripheral venous catheters is estimated at 25 million in France).

An intravenous infusion can be for therapeutic or diagnostic purposes. It is performed when healthcare professionals need to inject a product continuously and often in large quantities (drugs, fluids, etc.). The infusion allows the product to be injected at a regular rate, spread over time. It also helps to preserve the veins by installing a catheter or an implantable chamber. It thus avoids repetitive venipuncture.

Making an infusion is used to provide water and electrolytes (salt, potassium, etc.) in precise quantities or to administer medication quickly and continuously. This method allows a rapid action because directly in the bloodstream. It is also used during repeated administration, spread over time, such as intravenous feeding or chemotherapy.

To set up an infusion, the healthcare professional needs:

• A catheter (a very thin, flexible plastic tube with a very fine needle that is used to place it in the vein);
• An infusion bag containing the solution for injection;
• An infuser or tubing (small tube connecting the bag to the catheter).

A few hours before the infusion is placed, it is possible to put numbing cream on the skin where the infusion will be placed.

The infusion is performed under severe aseptic conditions in order to decrease the risk of infection. As with a blood test, the healthcare professional will place a tourniquet on the arm to bring out the vein before disinfecting the skin. Once the skin is pricked, the catheter is put in place. As it is a flexible and thin tube, it is much less unpleasant than the needle.

The tourniquet is then removed and the catheter connected to the bag by the tubing. The healthcare professional checks the proper functioning and flow of the infusion. He will then come to monitor that everything is going correctly and regularly. The duration of the infusion depends on the doctor’s prescription. It can last from an hour to a few days depending on the reason and the product injected.

After the infusion, the body received what it needed:

• Water in case of dehydration;
• Nutrients in case of parenteral nutrition;
• Treatment in case of illness.

The main risk of intravenous infusion is the risk of infection. The infection can be local (at the site of the catheter) or systemic (ie throughout the body) and potentially severe. It concerns 1% of catheter placements.

To reduce the risk of infection, healthcare professionals respect important hygiene measures and ask patients to respect them as well.

Another possible side effect, but rare, is the Venturi effect. This results from a bad installation of the infusion can be the cause of serious accidents by disconnection or passage of air.