Central Venous Catheters - Research Paper Example

Central Venous Catheter A central venous catheter, also known as vascular access device "is a long, thin, flexible tube used to give medicines, fluids, nutrients, or blood products over a long period of time, usually several weeks or more" (Fahy, 2007).Central venous catheters or CVCs are used widely in intensive care patients all over the world. They are important tools, not only in the critical care units, but also in the operating rooms. According to the European Prevalence of Infection in Intensive Care study (cited in (Akmal et al, 2007), CVCs are inserted in about 78 percent of the patients for some indication or the other. CVCs serve several roles in a critically ill patient. They facilitate monitoring of the hemodynamic system, provide access for administration of various materials like blood products, fluids, medications and total parental nutrition (Parks, 2009). Other indications of CVCs include need for prolonged intravenous line, administration of chemotherapeutic agents that are sclerosing, monitoring of central venous pressure and inability to secure intravenous access (Putigna and Solenberger, 2009). CVC was first used by Forssmann in 1929, but medical use began in 1950s (Putigna and Solenberger, 2009). CVCs are available in different brands and sizes. Physicians can chose the type and size based on the requirement of the patient. Sites for insertion of CVS include femoral vein, internal jugular vein and subclavian vein (Putigna and Solenberger, 2009). The most preferred route is the subclavian vein because it allows mobility of the patient. For those receiving cardiopulmonary resuscitation, femoral vein is preferred. In some patients like new borns for parenteral nutrition and in children requiring intravenous access for intermediate term for prolonged therapies either at home or in hospital, central catheters are inserted through peripheral veins like the saphenous vein or the brachial vein (Putigna and Solenberger, 2009). Many types of catheter are available. Tunneled catheter is one that is inserted into a central vein from a particular location and then tunneled under the skin to another exit site. The dacron cuff holds in place at the exit site, just under the skin. Implanted ports are similar to tunneled catheters, but are present under the skin. Medications are injected into the catheter through the skin. Peripherally inserted central catheter is inserted through a peripheral vein than directly into a central vein. CVCs can have one, two or three lumens (Putigna and Solenberger, 2009). While inserting a CVC, the patient must be properly sedated and secured to minimize movement. The skin must be cleaned with an appropriate antiseptic like povidone-iodine solution and then draped with towels which are sterile. It is better to use a local anesthetic like 1percent lignocaine. Specific positioning is essential and is dependent on the site of insertion. For inferior jugular vein catheter insertion, the head of the patient is rotated towards the side opposite to the area of insertion. there are actually 3 approaches to internal jugular vein: central, anterior and posterior. For subclavian vein insertion, the patient is turned in 15-20° Trendelenburg position so that venous dilation is maintained and air embolus is prevented.. A roll of towel must be placed between the shoulder blades. For femoral vein insertion, frog-leg positioning is done with the help of soft restraints. The size of the catheter must be selected based on the age and weight of the patient and also the location of the catheter. After sedating, cleaning, draping and positioning, insertion of the CVC is done. Insertion is different for different veins (refer to figures). The CVC is held in place by either a suture, or a staple or occlusive dressing. the line tends to get thrombosed and hence must be regularly flushed with saline or heparinised saline. Some CVCs may need to be impregnanted with antibiotics. Catheters for long term use have clamps to make sure that the valves are closed (Putigna and Solenberger, 2009). After the insertion of the catheter, it is important to perform a plain radiography to note the position of the tip of the catheter. It also rules out pneumothorax (Putigna and Solenberger, 2009). The incidence of pneumothorax is highest in subclavian catheterisation. Though CVCs have many advantages, they too, like any other medical tools are associated with complications. The complications can be widely categorized into mechanical and non-mechanical or infections (Akmal et al, 2007). CVCs are associated with increased risk of infections, the most common ones being gran-positive cocci, especially coagulase negative staphylococci. But, 28 percent of the infections are due to gram negative organisms. These infections lead to catheter-related blood stream infections, which contribute to significant morbidity and mortality to already critically ill patients (McGee, 2006). In a study by Akmal et al (2007), systemic infections related to CVCs were detected in 15 percent of femoral catheters. In subclavian catheters, 10 percent were infected. 4.3 percent of internal jugular catheters were infected. The main source of microorganisms for infection is the skin wound from which the catheter was inserted. From here the microorganisms travel through the catheters lumen and cause bacteremia and thereafter septicaemia. The incidence of infection is more than 3 times in multi-lumen CVCs when compared to single-lumen CVS. Blood stream infection is mainly caused due to colonization of the distal tip that is present intravascularly (McGee, 2006). Contamination of the hub occurs mostly in long term CVS because of increased manipulations and interceptions. the contamination occurs from the hands of the inserter (Alkamal, 2007). One of the important strategies to prevent infection is stringent cleaning of the site of insertion (Fahy, 2007). Detection of signs of infection in a patient with inserted CVC warrants evaluation of infection by doing blood cultures both from the catheter and from else where. If the catheter blood sample gross culture before the outside sample, the CVC is the source of infection. Most CVC-related infections settle down with use of antibiotics based on culture and sensitivity. In some cases, the catheter may need to be removed. It is a good and recommended practice to culture all tips of CVCs after removal (Alkamal, 2007). The most common mechanical complications are incompressible artery puncture and barotrauma. These complications can be fatal. The incidence of these complications depends on the expertise and can range between 0-12 percent. Other mechanical complications include pneumothorax, hematoma in the mediastinum, arterial puncture, hemothorax and adjacent nerve injury. The risk of mechanical complications can be reduced using J guide wires for insertion and flexible catheters (Alkamal, 2007). Complications can also be reduced by localising the vein through ultrasound and awareness of insertion depths that are safe (McGee, 2006). However, such an application is extremely costly. Malpositioning into the right atrium is rarely associated with complication, but perforation of the atrium is fatal. Hence it is recommended to maintain catheter tips above superior vena cava. Infact, it is better to place the tip in internal jugular vein as it eliminates any chances of slipping into the right atrium (Alkamal, 2007). CVCs are contraindicated in the presence of burns or infection over the desired site of insertion, venous thrombosis of the vessel chosen for insertion, coagulopathy that is uncorrected, presence of a mass or a tumor that is obstructing the vein, anomaly or abnormality of the vessel, lack of consent when there is no emergency and ability to achieve similar needs through a peripheral line. Presence of bacterial septicemia is a relative contraindication. Coagulation studies must definitely be done prior to insertion of catheter to minimize risk of bleeding. Increased prothrombin time, increased partial thromboplastin time and platelet count of less than 10,000 per cmm are contraindications for CVC insertion (Putigna and Solenberger, 2009). Thus, CVC insertion must be individualized and based on the advantages and disadvantages of the tool and the procedure. References Akmal, A.H., Hasan, M., Mariam, A. (2007). The incidence of complications of central venous catheters at an intensive care unit. Ann Thorac Med., 2, 61-3. Fahy, B. (2007). Central Venous Catheter. Am J Respir Crit Care Med ., 176, P3-P4. McGee, W.T. (2006). Central Venous Catheterization: Better and Worse. Journal of Intensive Care Medicine, 21, 51-53. Parks, R. (2009). Central venous Catheters. WebMD. Retrieved on 19th November, 2010 from http://www.webmd.com/a-to-z-guides/central-venous-catheters-credits Putigna, F., and Solenberger, R. (2009). Central Venous Access. Emedicine from WebMD. Retrieved on 19th November, 2010 from http://emedicine.medscape.com/article/940865-overview Read More