Posted by Sophie Lindgren, Senior Physician in Anesthesia & Intensive Care. Sahlgrenska University Hospital.
In Sweden more than 30000 central venous catheters are inserted each year. Catheterization of central veins has been described in scientific publications since the early 1900’s and catheter materials, insertion techniques and applications have evolved over the last century. In modern medical care, Central Venous Catheter/Central Venous Line (CVC/CVL) is used for safe administration of fluid, nutrition and blood vessel irritating drugs. The use is frequent in perioperative medicine and intensive care, but also in dialysis medicine, surgery, pediatric care and oncology, CVC use is widespread. It is broadly considered to be a safe method but it is associated with a range of technical and infectious complications.
There are various possibilities for establishing a central venue:
- Venous port (Porth-A-Cath): Intended for long-term use (> 3 weeks) and percutaneous insertion or through a minor detachment of the cervical vein or the jugular vein in local anesthesia or general anesthesia.
- Central Venous Catheter (CVC/CVL): Tunneled or non-tunneled. Mostly, ultrasonic placement and percutaneous insertion (via skin puncture without incision) are performed with local anesthesia in the cervical vein or the jugular vein. A tunneled CVC is intended for long-term use. A non-tunnelled CVC should preferably not last longer than 3 weeks.
- Peripherally-inserted central venous catheter (PICC line): Insert ultrasound and percutaneous via a small vein in the upper arm. These catheters are intended for both short and long term use.
Regardless of the placement technique or catheter type, the catheter tip should be placed in the upper hollow vein and / or in the transition to the right atrium in the heart. The tip position is checked by means of X-rays. The advantage of a central venous entry is that the patient will release the discomfort associated with recurrent sting and blood sampling. Also, it is not risk-free to administer antifungal drugs via a peripheral vein. The long-term need for a centrally located catheter is predominantly in the final stages of life (pain relief, nutrition), chronic dialysis treatment, intensive care and when chemotherapy is repeated for long periods of time.
When inserting central venous catheters, careful preparation can reduce the risk of complications. It is important to have good knowledge of local anatomy and anatomical variations, choose appropriate vessels, appropriate catheter type, maintain sterility, use a minimal invasive technique and call for help within a reasonable time when problems arise. Or you can make sure to have easy access to help and support, if you are inexperienced.
When inserting central venous catheters, one should apply something called “maximum sterile concept”. It is about creating the same conditions as for an operative procedure to reduce the risk of contamination of the catheter before and/or as it enters the bloodstream. See the pictures below.
When choosing a vessel, one should consider what the catheter should be used for, how long it should be, complication risk and how the patient’s anatomy at the instill sites looks. Is the patient bleeding discomfort? Does the patient have a pulmonary disease, is radiotherapy or have inoperative vascular grafts? Should the patient receive cytostatics or other vascular irritants or cardiotoxic substances? Is the catheter intended for dialysis? Is the patient immunosuppressed? What is most comfortable for the patient?
Internal jugular vein
In many clinics, CVK insertion is the first choice. The vessel is easy to visualize with ultrasound. The risk of lung damage is considered to be less. In case of injury or bleeding it is possible to compress the vessels on the throat. It can also be used for long-term access, but preferably via tunneling due to an increased infection risk compared with the vena subclavia.
This vessel is often used both for long-term and short-term access. It is somewhat harder to visualize with ultrasound than vena jugularis internal and external as it passes under the clavicle but with a lateral stick technique (stick as close to the axle joint as possible) it is possible to get a good insight. In most cases, the vessel is easy to identify via landmark technology. The risk of pneumothorax is for obvious reasons greater than for other vessel locations. In case of possible damage to the vessel with greater bleeding, it is not possible to compress this vessel because of its anatomical process. However, it has been shown in studies that sticking to the vein subclavia does not cause more serious vascular damage is sticking to the vessels on the throat. If you are inexperienced with CVK insertions or have had difficulty in inserting (more than three sticks) it is advisable to do a cardiothoracic (chest) X-ray control afterwards.
Axillary vein/basilic vein
These vessels extend on the forearm and can be easily visualized by ultrasound. They have a significantly smaller diameter than the central vascular and venous femoralis and are used for insertion of peripherally inserted central catheters (PICCs) and other types of longer catheters called “half-way” or “mid-way” catheters. A PICC reaches all the way to the vena cava superior. The advantage of using these vessel locations is that you can not cause postural complications such as pneumothorax or severe vascular injury. On the other hand, it has been shown in studies that the thrombosis risk is greater. A check of the catheter tightness by means of, for example, cardiovascular x-ray is appropriate.
Is a large vessel that is easy to visualize with ultrasound just below the skeletal ligaments. It is usually just medial about the artery femoralis but anatomical variations are common. This vessel location is not suitable for long-term access because the catheter will be close to the hip joint. The infection risk is also greater for catheters that are inserted here. Most commonly, this vessel is used in severe disease / trauma and major surgical procedures, especially when the patient is bleeding or when other vessel locations are not available for various reasons.
Insertion technology and catheter material
There are different materials and techniques for inserting a catheter into the central bloodstream. Some techniques and materials are used in emergency situations, as it may be difficult to maintain full sterility. It is then important to extract or replace the catheter as soon as the patient is stabilized. For planned catheter deposits, always use a maximum sterile concept no matter what vessel, type of catheter material or puncture technique used.
Needle catheter (Seqalon T)
In acute situations, when you need quick access to the bloodstream, you can use a bit stiffer teflon catheters that sit directly over a slightly longer puncture needle. Then a leader is not needed to insert the catheter into the bloodstream. These catheters have a larger inner diameter and are slightly shorter than catheters that are inserted over the guide wire. It enables rapid fluid infusion and transfusion of blood products. These catheters are not intended for permanent use and should be removed as quickly as possible. The long needle increases the risk of vascular and thorax
Catheter over the guide wire (Seldinger technique)
Sven-Ivar Seldinger was an X-ray physician from Mora (Sweden) who invented the technique of percutaneously inserting catheters into the bloodstream over a guidewire inserted into the blood vessel via the needle. The technique also requires that you dilate the surrounding tissue and vessel wall before inserting the catheter (see figure below). The technology enabled the use of longer and a more soft silicone or polyurethane catheters without having to uncover the vessel first. This reduced the risk of both infectious and mechanical complications.
Catheter over guide wire via insertion instrument (modified Seldinger technology)
A variant of the Seldinger technique is used when inserting a venort, tunnelled CVK, PICC, Pulmonary artery catheter (PA) and also interventional X-ray catheters. The difference is that over the guide wire, insert an insertion instrument, removing the guide wire and via the lumen of the instrumentation then inserting its catheter.
Punction led by anatomical landmarks
Traditionally (before the ultrasound technique), identification of the vessel was to puncture only using anatomical landmarks and palpation of nearby arteries. Once the vessel was identified, X-ray contrast could be used to confirm the position. The most common approach was, however, using only the landmarks and palpation during the entire catheterization. When it’s straightforward, landmark-based insertion goes fast, but in anatomical variations and degenerative vascular changes, there is a greater risk of complicated multi-stick insertions, which increases the risk of pneumothorax and vascular injury. However, even with ultrasonic guided puncture it is a great help to be able to use the anatomical landmarks. When it is very urgent to get a central entrance, for example at prehospital healthcare, landmarking is still very useful.
Ultrasound guided puncture
Over the past ten years, the development of ultrasonic equipment has made it much easier to use the technology and ultrasonic puncture is now the first-hand option for central access. It has been shown in studies that ultrasound-guided punctures reduce the number of post-CVK complications. With the ultrasound probe longitudinally directed along the vessel to be punctured, the depth of the vessel and needle entry into the vessel can be followed throughout the procedure (so-called “Longitudinal Axis-In Plane” Procedure, LAX-IP). The use of ultrasound-proof needles is recommended as it is more difficult to assess the needle tip position using movements in the surrounding tissue. It reduces the risk of damage to the vessels, nerves, lungs and other surrounding tissues. Ultrasonic puncture does not take longer for a user but the technology requires a learning period.
Control of position of the catheter tip is recommended for any long-term insertion and when a catheter is used for administration of cytotoxic, vasoactive and vasodilatory drugs. The most common way of checking the tip position is by means of a chest X-ray or X-ray enlightment via a C-arch immediately after insertion. The catheter tip should lie in the distal superior caval vein or in the transition to the atrium.
A thorough documentation of CVC insertions is a necessity for the follow-up of possible complications. Monitoring of centralized entries is a prerequisite for maintaining patient safety and quality improvement in health care. We are legally obliged to document and continuously improve the quality of risky moments we expose patients to (SOSFS 2008: 1, 2011: 9, 2013: 6). There are international recommendations for what to be documented in connection with the insertion of central accesses. An absolute minimum is indication, type of catheter, number of lumens, choice of vessels, insertion technique (ultrasound or not), how many punctures (complicated or uncomplicated), level in the skin plane and whether x-ray control is necessary or not. An aid for maintaining patient safety upon insertion is to receive a checklist. Originally from the commercial aviation industry, the idea originated in a checklist for CVC insertion, created by Dr. “Checklist” Peter Pronovost, at John Hopkins Hospital, Maryland. The checklist was revised at Sahlgrenska University Hospital 2010 to Swedish conditions and has recently been updated. See picture below.
When the catheter is no longer needed or suspected of a CVC-related infection, the catheter should be discontinued as soon as possible. The extraction must be documented in the patient record. In case of infection, the catheter tip should be sent to the bacteriologist with a cultivation recommendation. If you suspect that the infection has spread to the bloodstream (catheter sepsis), peripheral blood cultures should also be taken and sent to the bacteriologist. It is important to sample peripheral venous blood for cultivation, as it is possible to compare the time to bacterial growth between the peripheral blood cultures and those withdrawn from the CVC. If the bacterial strains grow faster in the blood drawn from the CVC, it is a sign that the infection originates from the catheter. Antibiotic treatment should be initiated or supplemented in consultation with infectious physicians. A catheter that has lasted for a long time can get stuck in the vessel because of thrombosis and fibrin formation. If you know or suspect that catheter material is grown, vascular surgeons and radiological interventionists should be consulted for extraction.
A wide range of complications can affect patients who receive a central catheter. The complications are usually divided into the categories “technical and infectious complications”. The first category includes vessel/thoracic damage, catheter failure, catheter dysfunction and loss of guide wire and/or catheter material into the bloodstream. The second category includes local skin and soft tissue infection at the site as well as catheter-induced blood borne sepsis. Although these complications are unusual in relation to the large number of days in which these catheters lie inside the patients, they cause major suffering, deaths and significantly increase the cost of medical care. Insertion of catheters via central vasculature on the throat and thorax can cause life-threatening bleeding and puncture of the lung and pericardium. PICC is not affected by this type of serious insertion complications as these catheters are introduced via a small vein in the upper arm. The longer a catheter is, the greater the risk of colonization of microbes and infections spread to the bloodstream. There is uncertainty regarding the risk of infection and thrombosis at the various types of centrally located catheters. The larger and longer the catheter is, the greater the risk of thrombosis in the vessel where the catheter is located. There are data indicating that PICC and coarse dialysis catheters may cause more thrombosis than other catheter types. For infectious complications, venues and tunneled CVCs seem to be the best option as they go under the skin, minimizing the risk of bacterial contamination during use, care and care.
The serious complications are unusual in relation to the large number of days the catheters use, ranging from 5-80 events per 10,000 “catheter days” in published studies, but the consequences for the patients affected are high. Wrong positioning of the catheter tip, catheter dysfunction, catheter material / bloodstream guide wire, pulmonary embolism thrombophlebitis, pneumothorax, vascular injury and arrhythmias are examples of mechanical complications described in scientific literature. It is important to be aware that serious complications may occur in connection with CVC submission and to quickly process and treat them. This may involve rapid contact with the surgeon, radiologist or thoracic surgeon. Prevention and optimization of CVC insertion conditions can be avoided to reduce the risk of mechanical complications. Access to ultrasound and through communication is to recommend, as well as operations-like conditions as possible. Using a checklist for CVC insertion is also preventive (see image above).
Invasive blood borne infections vary in different patient materials between 0 and 30 per 1000 catheter days. Infectious complications cause prolonged care time, increased healthcare costs, healthcare and deaths. Central venous catheter-related infection (CVC-related infection, CRI) is a major cause of iatrogenic morbidity and mortality. In all patient categories, the incidence varies between 0 to 30 per 1,000 catheter day and night, depending on the type of care unit. Intensive care units (ICU) generate relatively more CRIs. Mortality varies in different studies from no increase up to 35 percent. Care time can be extended 10-20 days and 12 percent of all intensive care infections are related to a central venous infarct. However, several studies show that with simple measures, the incidence can be significantly reduced. In case of suspected infection, the catheter tip should be sent to the bacteriologist with a cultivation recommendation. If you suspect that the infection has spread to the bloodstream (catheter related sepsis), peripheral blood cultures should also be taken and sent to the bacteriologist. It is important to apply for the referral period for blood crops, as it is possible to compare the time to bacterial growth between the peripheral blood cultures and those withdrawn from the CVC. If the bacterial strains grow faster in the blood drawn from the CVC, it is a sign that the infection originates from the catheter. Antibiotic treatment should be initiated or supplemented in consultation with infectious physicians.
There is very strong evidence that follow-up of CVC complications is important in preventing complications from occurring. There is a wide range of evidence-based measures that healthcare professionals must follow in order to reduce the complication risk when inserting and using core infections. Continuous follow-up of CVC complications and feedback to the activities is a prerequisite for motivating healthcare professionals to follow these evidence-based measures. Organized training in CVC insertion and management is also important to minimize all types of complications. Ultrasonic puncture reduces the risk of mechanical complications upon insertion. X-ray control after complicated insertions or for catheter tip position control, allows for earlier detection of mechanical complications.
The formation of local vascular access centers is considered to be of great importance to quality of care and patient safety at CVC deployment and care. This is because the focus on vascular access to a few individuals is concentrated and can optimize local and technical conditions. It also facilitates local follow-up of the inserted central venous infections at a clinic or hospital.
- Frykholm et al. Clinical guidelines on central venous catheterisation (2014) ACTA Anaesth Scand
- Lindgren et al. Survey of central venous catheterisation practice in Sweden (2013) ACTA Anaesth Scand
- Pikwer et al. Complications associated with peripheral or central routes for central venous cannulation (2011) Anaesthesia
- Silberzweig et al. Reporting standards for central venous access (2003) J Vasc Interv Radiol