Overview of Central Venous Catheter
A central venous catheter, or CVC, is a small tube that’s placed into a large vein in your body. This vein is usually located in your neck, upper chest, or groin. The tube is then pushed further until it ends up in the large vein that carries blood back to your heart. When people say “central line” or “central venous access”, they’re talking about this tube and the process used to put it in place. This technique has been around since 1929 and has become a key part of research on how the heart works and treatment methods for various diseases.
There are all sorts of reasons why a central venous catheter might be used. For example, it can be used to provide nutrition straight into your bloodstream if you’re unable to eat, for dialysis treatments (which clean your blood when your kidneys can’t), to help add or remove plasma from your blood (plasmapheresis), to deliver medications directly into your bloodstream, and to monitor your heart. They can also be used to help with more advanced procedures, like placing a pacemaker (a device that helps control your heartbeat) through your veins.
Since the 1960s, the process used to place a central venous catheter hasn’t changed very much, apart from one recent addition. Now, ultrasound images are often used when the catheter is being inserted into the vein in your neck. This is because the images help to reduce the risks of complications and increase the chances of getting it right first time.
There are still debates about the best place to insert the catheter and the chances of complications depending where it’s placed. However, what is clear is that knowing how to put in and look after a central venous catheter is an extremely important skill for medical professionals. They are especially useful in the care of very ill patients. The main goal of this article is to go over why a CVC may be used, when it shouldn’t be used, how it’s done, potential complications and how to manage a central venous catheter once it’s in place.
Anatomy and Physiology of Central Venous Catheter
Central venous catheters, which are tubes placed into a large vein in your neck, upper chest, or groin to give medications, fluids, nutrients or treatments directly into the blood stream, have three main sites for insertion. These are the internal jugular vein found in the neck, the common femoral vein in the groin, and the subclavian veins under the collarbone. These sites are chosen when the catheter is needed for a short period of time, ranging from days to weeks.
The basilic and brachial veins, found in the upper arm, are often used for catheter placement when it’s needed for a longer term. The plan for where to place the catheter depends on the patient’s medical condition and the comfort and experience of the doctor placing the catheter.
The internal jugular vein, situated in the neck, is a popular choice for catheter placement because it’s easy to access, has low risk of complications, and can be visualized using ultrasound during the procedure. Some doctors may prefer the right side due to more direct path and its larger size making it easier to place the catheter.
The subclavian vein, located just under the collarbone, is another option. It has the benefit of low infection and clotting rate. However, it has a higher risk of causing a collapsed lung, demands more skill to use ultrasound for placement, and its location behind the collarbone makes compression to stop bleeding more difficult.
The third option is the common femoral vein which is found in the groin. This location can be favored in critical situations as it doesn’t interfere with other resuscitation equipment. It also allows the patient to move their arms and legs more freely. However, catheters in this location are more likely to cause blood clots and possibly infections, even though it’s not a concern for a collapsed lung with this site.
It’s important to note that unlike the internal jugular or subclavian lines, catheters in the femoral vein don’t allow accurate measurement of the pressure within the vein system, which could be important for some specific medical conditions.
Why do People Need Central Venous Catheter
There are several different reasons why a doctor might need to create a central venous access, or a route into a person’s major veins, often for the delivery of medicines or monitoring of the body. Here are a few of these reasons:
* When a patient needs multiple types of drugs administered at the same time. Some medicines, like vasopressors (which increase blood pressure), nutrition given straight into the veins, chemotherapy, and other strong, acidic medications, can’t be administered using a normal, peripheral intravenous (IV) line placed in the arm or hand.
* When a patient needs immediate medical attention and finding a vein for an IV line is tough.
* For the commencement of external therapies that filter or clean the blood, such as dialysis (cleaning the blood when kidneys are not functioning), plasmapheresis (removal, treatment, and return of blood plasma), and continuous renal replacement therapy (another method to treat kidney failure).
* For keeping a check on hemodynamics, or the forces that influence blood flow. This includes central venous pressures or the pressure within the large veins near the heart.
* For carrying out different vein-related procedures, which may include inferior vena cava filter placement (a device to prevent blood clots from being carried into the lungs), thrombolytic therapy (breakdown of blood clots), transvenous cardiac pacing (regulating heart beat), and intra-venous stenting (placing a small mesh tube within a vein to improve blood flow).
When a Person Should Avoid Central Venous Catheter
Sometimes, it might not be safe for a patient to have a central venous catheter put in. This is a tube that goes into one of the big veins in your body. Whether or not this can happen depends on a few things, like where they want to put the tube in, how urgently you need it, and other health conditions you might have.
There are times when putting in a catheter is absolutely not safe:
* If there’s an active skin or soft tissue infection at the place they want to put the catheter in.
* If the spot is distorted because of things like implanted devices (for example, catheters for dialysis or pacemakers).
* If there’s vascular (blood vessel) damage above or below the spot where they want to put the catheter in, which can happen due to injury.
There are also times when it might be more risky but still possible. This is called a “relative contraindication.” It needs to be thought through carefully.
* If a patient has coagulopathy, which means their blood doesn’t clot normally. This can make it harder to stop bleeding, but the chance of heavy bleeding from a catheter placement is less than 1%.
* If a person has low platelets (thrombocytopenia), which help blood clot, the chances of something going wrong are higher.
* If a patient isn’t able to stay still during the procedure.
* If it’s hard to see where to put the tube because of birth defects or injuries.
* If a patient is very overweight, which may make placing the catheter harder.
Patients with a blood clotting issue, particularly measured by a test called an international normalized ratio (INR) of more than 3.0 or platelets of less than 20 x 10^9/L have a higher risk of bleeding. Sometimes, these patients might need blood products like fresh frozen plasma, which contains clotting factors, or extra platelets before or after the catheter is put in.
Where they put the catheter in depends on the person’s situation. For example, the spot just above your collarbone might not be safe if you have a clotting issue, because there are a lot of big blood vessels in that area. Also, they might not want to put a catheter in the side of your neck if you’re wearing a cervical collar or if they’ll need to use this spot for another procedure during your hospital stay. They might also avoid the femoral site (in your groin) if it will be needed for another procedure like a heart cath. Each patient’s situation needs to be judged on its own.
Equipment used for Central Venous Catheter
There are different brands that produce central venous catheter insertion kits and a variety of catheter types available. In general terms, you will need a machine that uses high-frequency sound waves (ultrasound) with a linear probe that sends out the sound waves, a set of sterilized products, a protective cap and mask for your head, the introduction set with the central venous catheter, lidocaine (a type of painkiller), several sterilized syringes, sterilized solutions for flushing in 10 cc syringes, a sterilized dressing that is air and water tight, and a ‘bio-patch’, if you have one.
Items that don’t need to be sterile can include:
- A head cap (a bouffant or surgeon’s cap)
- A mask with eye protection
But the products that must be sterilized could be:
- Personal protective gear like gloves and a surgical gown
- A sheet that is used to cover you (a drape)
- A piece of sterilized cloth (4×4 gauze)
- Disinfectant swabs or something comparable (like chlorohexidine swabs)
- A sterilized cover for ultrasound probe with sterilized gel used with ultrasound
- ‘Bio-patch’
- Catheter caps for each tube of the catheter, also known as ‘Luer locks’
Generally, a Central venous catheter kit contains:
- The central venous catheter that has triple-tubes, double-tubes, or a single tube with a larger bore
- An 18 gauge needle that introduces the catheter, with a syringe
- An #11 blade scalpel (a small knife to make an incision)
- A guidewire which helps to position the catheter
- A vasodilator that helps to widen your blood vessels
- A suture material usually 3-0 silk suture attached to a needle or a needle holder used to stitch wounds
- A saline lock (the number can vary based on the device) for flushing the catheter with a sterile fluid
- 1% lidocaine, a tiny needle (25 or 27 gauge), a syringe
- An ultrasound machine paired with a high-frequency linear transducer
Who is needed to perform Central Venous Catheter?
Inserting a CVC, which is a tube placed into a large vein in your body, should be done by a healthcare professional who has been well-trained in this procedure. This professional, often called a proceduralist, is skilled at inserting these tubes correctly and safely. In addition, a nurse is needed to help the proceduralist during the procedure.
Preparing for Central Venous Catheter
Before a central venous catheter insertion procedure (a procedure where a long, thin tube is placed into a large vein in the body to administer medication or fluids), the doctor needs to get your approval. First, the doctor talks to you about the process, its advantages, potential risks, and complications. After you give your consent, the medical team prepares for the procedure by gathering the necessary tools and ensuring the room is clean and free of non-essential staff and visitors for maximum cleanliness.
Using an ultrasound machine, the doctor chooses the best spot to insert the tube. This could be in the internal jugular vein in your neck, the subclavian vein under your collarbone, or the femoral vein in your groin. The doctor will consider the layout of your veins, nearby body structures, and which spot will make the process easiest. You will then be put in a position that aids in the procedure.
If the procedure involves the internal jugular vein or subclavian, you’ll be placed in a position called Trendelenburg, which involves lying flat on your back with your feet elevated higher than your head. This position helps enlarge the vein and increases the chances of a successful procedure on the first attempt. If the femoral vein is involved, you will lie flat on your back.
Your bed’s height will be adjusted, and your clothing and jewelry will be removed to create a clean working area. You’ll also be connected to a heart monitor that will continually check your vital signs every 5 minutes.
After scanning your anatomy using an ultrasound, preparations for the procedure will begin, involving cleaning the chosen site, setting sterilized equipment, and ensuring all the necessary equipment is within reach. When everything is set and you are ready, the doctor puts on protective gear to maintain a sterile environment. The doctor then inserts the catheter in the chosen vein. Before starting the procedure, the doctor and the nurse will pause and cross-check everything once again. This cross-check is known as a “time out”.
How is Central Venous Catheter performed
Depending on your body shape and the type of vein the doctor is aiming to access, you might be placed in a “Trendelenburg” position — this simply means that your feet are higher than your head. It might be necessary to put a cushion under your back to make it easier to insert the needle and widen the vein.
Here’s what happens during the procedure:
1. Using an ultrasound for guidance, the doctor will identify the vein they’re aiming to access. They’ll use a local anesthetic to numb the area if you’re awake.
2. Still using the ultrasound as a guide, the doctor will insert a special needle into the vein. The angle of the needle should be somewhere between 45 and 90 degrees, and the doctor will hold a syringe attached to the needle.
3. Once the doctor sees dark blood in the syringe — a sign they’ve successfully accessed the vein — they’ll stabilize the needle and detach the syringe. They’ll then adjust a small, flexible, wire-like tube called a guidewire into the needle. The guidewire should enter easily; if it doesn’t, that might mean there’s a problem, like a blocked vein.
4. The needle will then be safely removed, and the doctor will use the ultrasound again to get a good look at the vein where the guidewire is inserted. If there’s any uncertainty about whether the guidewire is properly positioned inside the vein, the doctor won’t proceed to the next step as any misplacement could lead to complications.
5. The doctor will then make a small skin incision using a scalpel. This incision is for inserting something called a “dilator”. This dilator is designed to enlarge the site of insertion which helps to minimize blood loss and makes insertion easier.
6. Working gradually, the dilator is lightly pressured into the incision. This helps to widen the soft tissue to allow the insertion of a central venous catheter (CVC). The CVC is a thin tube placed into your vein to administer medications or fluids directly into your bloodstream.
7. Following that, the guidewire is gently removed and the CVC is inserted over the guidewire into the vein. During this, it’s vital no one loses contact with the guidewire as it guides the CVC into the vein.
8. Before the doctor secures the line with sutures (stitches), he/she ensures the central venous catheter is set correctly within the central vein. Various checks might be done, including blood tests, X-Rays or by monitoring your blood pressure. This is to confirm the line is correctly positioned and working as expected, as well as to ensure there were no complications during the procedure. For instance, an X-Ray would show if the catheter’s end is in the right position within the heart’s large veins, either the superior vena cava or the inferior vena cava.
This procedure is vital in many treatments as it ensures the rapid and effective delivery of medication or fluids directly into your bloodstream.
Possible Complications of Central Venous Catheter
There are several potential problems or complications that can happen during the process of inserting a central venous catheter (a tube placed into a large vein in your neck, chest, or groin to give medications or fluids). There can also be complications due to the tube staying inside you for some time.
Problems that can occur during the procedure include:
* Irregular heartbeats – usually caused by irritation of the atria or ventricles (the upper and lower chambers of your heart) from the guide wire used in the procedure.
* Piercing or puncturing an artery.
* Puncturing the lung, which could potentially cause a pneumothorax (a collapsed lung).
* Bleeding – this can cause a hematoma (a solid swelling of clotted blood) which can block the airway.
* Damage to the trachea (windpipe).
* The creation of air bubbles in the blood vessels (air emboli) during the process of inserting or removing the catheter.
Problems that can occur after the procedure include:
* Catheter-related bloodstream infections – these can be bacterial or fungal.
* Narrowing of the central vein (central vein stenosis).
* Formation of blood clots (thrombosis).
* Delayed bleeding, especially if multiple attempts are needed in a patient with a bleeding disorder (coagulopathic patient).
What Else Should I Know About Central Venous Catheter?
A central venous catheter is a tube that doctors put into a large vein in your neck, chest, or groin to give medication or fluids or to collect blood for medical tests. When done correctly, this can be a safe and effective procedure that can even save lives. However, there are some important safety measures that the doctor must remember when doing this procedure.
Before starting, the doctor will make sure everything is set up correctly. This includes having all the right people and tools ready to go. If something does go wrong, being prepared can help avoid making it worse.
The doctor will also check to make sure that all the equipment is clean and not damaged. Keeping things sterile is very important because an infection from a central line can be very serious. Central line infections are severe and can be life-threatening.
If the doctor is inserting the catheter into a vein in your neck or upper chest, they’ll usually take a quick X-ray right after to make sure everything is in place correctly. This reduces the risk of a lung collapse and ensures that the line ends up in the right place, which is the superior vena cava, a large vein that carries blood into the heart.
If they tried to put the catheter into a vein in your neck but couldn’t, the doctor might decide to try a vein in your shoulder area next. This is because trying the other side of your neck might increase the risk of causing both lungs to collapse. To check if the catheter is in the vein, they might use a method called manometry. But it’s important to note that this method can be tricky to interpret if you’re critically ill, such as in shock.
Doctors prefer to use ultrasound guidance when placing these catheters in the neck, shoulder, or groin vein because it makes the procedure safer and more successful. One critical safety measure is that the doctor must always keep hold of the guide wire while it’s inside you. If they lose it, it could migrate into other parts of the body, requiring additional procedures to get it back.
After placing the catheter, they will check to ensure it’s correctly placed. This can involve different methods, such as an X-ray, checking the pressure in the catheter, or analyzing a blood sample. The doctor will also make sure not to use excessive force at any time during the procedure to prevent any damage to your body.
