Central vein catheters

Side effects, such as headache and jaw pain, are observed, but the major drawbacks with epoprostenol therapy relate to its delivery. Epoprostenol has an extremely short half-life in the blood (2-3 min) and therefore must be administered by continuous intravenous infusion via a surgically implanted central vein catheter. This can lead to complications such as local infections, sepsis, or catheter-associated thrombosis. In addition, interruption of therapy due, for example, to pump failure can lead to a life-threatening rebound of symptoms. The compound itself is unstable at room temperature and must be stored in the refrigerator. Despite these severe drawbacks, i.v. epoprosenol remains a useful treatment for patients presenting with WHO class IV PAH. The problems with epoprostenol have led to the development of alternative agents. 

By means of an automatic infusor or a roll pump, 300-400 ml/ hour are reinfused through a filter system with a pore diameter of 22 pm via a central vein catheter. Reinfusion time should be... 

Via a central veiiau. i catheter. This route is used where long-term i.v. feeding is anticipated. Central vein catheters may remain patent tor years if cared for pro(K rly. 

Certain symptoms and side effects associated with cancer could be secondary to disease progression. For example, cancer metastases to the bones could cause chronic pain due to proliferation of cancer cells in the bones and the associated bone remodeling and destruction [89]. Also, tumors that compress veins, the use of central vein catheter [90], and relative immobility of the patient could lead to deep vein thrombosis with potential pulmonary embolism [91]. 

Verso M et al. Risk factors for upper limb deep vein thrombosis associated with the use of central vein catheter in cancer patients. Intern Emerg Med 2008 3 117-122. 

Timsit JF, Farkas JC, Boyer JM, et al. Central vein catheter-related thrombosis in intensive care patients incidence, risks factors, and relationship with catheter-related sepsis. Chest Inly 1998 114(1) 207-13. 

Twardowski ZJ The clotted central vein catheter for haemodialysis. Nephrol Dial Transplant 1998 13 2203-2206. 

Decisions regarding fistula adequacy and removal of a central vein catheter are made by the access team to ensure access patency by minimizing the risk of central vein complications, mainly infection or occlusion. 

For patients with central vein catheters, they should be educated in keeping the dressing sealed, clean and dry, especially when taking a shower. In case of bleeding or catheter withdrawal, the patient should press on the exit site and be admitted to the emergency room. In case of fever, pain or swelling, patients should immediately notify a member of the outreach health care team. 

TPN may be administered through a peripheral vein or through a central venous catheter. Peripheral TPN is used for patients requiring parenteral nutrition for relatively short periods of time (no more than 5-14 days) and when the central venous route is not possible or necessary. Peripheral TPN is used when the patient s caloric needs are minimal and can be partially met by normal... 

Invasive hemodynamic monitoring in patients with HF entails placement of a right heart or pulmonary artery catheter (PAC). The catheter is inserted percutaneously through a central vein and advanced through the right side of the heart to the... 

PN can be administered via a smaller peripheral vein (e.g., cephalic or basilic vein) or via a larger central vein (e.g., superior vena cava). Peripheral PN (PPN) is infused via a peripheral vein and generally is reserved for short-term administration (up to 7 days) when central venous access is not available. PN formulations are hypertonic, and infusion via a peripheral vein can cause thrombophlebitis. Factors that increase the risk of phlebitis include high solution osmolarity, extreme pH, rapid infusion rate, vein properties, catheter material, and infusion time via the same vein.20 The osmolarity of PPN admixtures should be limited to 900 mOsm/L or less to minimize the risk of phlebitis. The approximate osmolarity of a PN admixture can be calculated from the osmolarities of individual components ... 

Central PN refers to the administration of PN via a large central vein, and the catheter tip must be positioned in the vena cava. Central PN allows the infusion of a highly concentrated, hypertonic nutrient admixture. The typical osmolarity of a central PN admixture is about 1500 to 2000 mOsm/L. Central veins have much higher blood flow, and the PN admixture is diluted rapidly on infusion, so phlebitis is usually not a concern. Patients who require PN administration for longer periods of time (greater than 7 days) should receive central PN. One limitation of central PN is the need for placement of a central venous catheter and an x-ray to confirm placement of the catheter tip. Central venous catheter placement may be associated with complications, including pneumothorax, arterial injury, air embolus, venous thrombosis, infection, chylothorax, and brachial plexus injury.1,20... 

Amiodarone IV concentrations greater than 3 mg/mL in D5Whave been associated with a high incidence of peripheral vein phlebitis however, concentrations of 2.5 mg/mL or less appear to be less irritating. Therefore, for infusions more than 1 hour, amiodarone IV concentrations should not exceed 2 mg/mL unless a central venous catheter is used. Use an in-line filter during administration. 

Hydration to establish diuresis both prior to and during administration is recommended to minimize renal toxicity the standard 24 mg/ml sol may be used undiluted via a central venous catheter, dilute to 12 mg/ml with D5W or NS when a peripheral vein catheter is used... 

FIGURE 17-2 Schematic representation of an implantable vascular access port that can be used with PCA. The port can be connected to a PCA pump via a percutaneous needle, and a catheter leads from the port to a large central vein. [From Knox LS. Crit Care Nurse. 1987 7 71 with permission.]... 

For short-term feeding (less than 14 days) NICE (2006) recommends parenteral feeding via a peripheral venous catheter for those patients who do not need central access. A GTN patch can be applied above the peripheral venous catheter site to promote vasodilatation of the vein for those patients who have narrow veins. Some TPN is unsuitable for peripheral administration due to the nitrogen and glucose concentration these must go through a central venous catheter. 

After rapid intravenous administration hypotension, shock, and atrioventricular block can occur and can be fatal (2). The rate of infusion should not exceed 5 mg/minute. Qther adverse effects reported during intravenous infusion include sinus bradycardia (236), facial flushing, and thrombophlebitis (236-239). The risk of this last complication can be reduced by infusing the drug into as large a vein as possible and preferably via a central venous catheter, or perhaps by using a very dilute solution of the drug (240). 

Fracture of a central venous catheter due to compression between the clavicle and the adjacent first rib has been reported (5). A pinched-off sign on X-ray indicates the need to remove the catheter, because of a significant risk of subsequent fracture, which has an incidence of 0.9%. Catheters lying anterior to the subclavian vein between the clavicle and the first rib are hable to be compressed and to fracture subsequently. This is a potentially life-threatening complication that can be averted by correct placing of the central venous catheter and by immediate chest radiography to search for evidence of catheter kinking or compression. 

Lung transplant patients appear to be at increased risk of air embolism from catheters perhaps because of the considerable negative intrathoracic pressure that can develop when the diseased lung is replaced with a normal lung. Lung transplant patients are often also emaciated and have little subcutaneous tissue, allowing for a short tract from the central venous line insertion site to the opening of the central vein. 

With double-lumen intravenous catheters for acute hemodialysis, hemperfusion, and plasma exchange, the most common complications are bleeding, hematomas, catheter failure, risk of infection, central vein thrombosis and stenoses, and rarely, air embohsm. Femoral placement is the site associated with the fewest non-in-fectious comphcations [16]. Comphcations of treatment will be discussed below. 

Hemodialysis (HD) is the method of extracorporeal drug removal most commonly used in the treatment of poisoning [1]. The apparatus consists of a blood circuit, an electronic and mechanical device (with pumps and pressure monitors), a dialyzer cartridge (containing hollow permeable fibers), and a dialysate circuit (of purified water with added electrolytes). In practice, a double-lumen catheter is first placed in a central vein. 

When blood is collected from a central venous catheter or arterial line, it is necessary to ensure that the composition of the specimen is not affected by the fluid that is infused into the patient. The fluid is shut off using the stopcock on the catheter, and lOmL of blood is aspirated through the stopcock and discarded before the specimen for analysis is withdrawn. Blood properly collected from a central venous catheter and compared with blood drawn from a peripheral vein at the same time shows notable differences in composition. A comparison of arterial blood with central and peripheral venous blood is illustrated in Table 2-5. 

Invasive hemodynamic monitoring usually is performed with a flow-directed pulmonary artery (PA) or Swan-Ganz catheter placed percutaneously through a central vein and advanced through the right side of the heart and into the PA. Inflation of a balloon proximal to the end port allows the catheter to wedge, yielding the PAOP, which estimates the pulmonary venous (left atrial) pressure and, in the absence of intracardiac shunt or mitral valve or pulmonary disease, left ventricular diastolic pressure. Additionally, cardiac output may be measured and systemic vascular resistance (SVR) calculated. Normal values for hemodynamic parameters are listed in Table 14—12. 

Central venous catheters vary in composition, lumen size, number of injection ports, and other special features that affect ease or convenience of care and maintenance. They may be placed for shorter long-term access. Frequently, short-term central venous access is obtained in critically ill neonates via a catheter placed in the umbilical vein. ° Other sites for central venous access in infants and older children are similar to those in adults. When therapy is expected to last longer than 4 weeks, the catheter usually is tunneled subcutaneously before entering the central vessel, secured initially with retaining sutures, and anchored in place with a felt cuff that promotes the growth of subcutaneous flbrotic tissue around the catheter. The injection port may remain external or be concealed entirely beneath the skin. Implanted central venous catheters have a larger port or reservoir that is surgically placed beneath the skin surface and anchored in the muscle of the chest wall. 

The intravenous route is used to deliver larger volumes (e.g. replacement and hyperalimentation solutions). Positioning catheters in a central vein s blood flow avoids multiple injections in seriously ill patients. Rapid dilution occurs compared to injection in peripheral veins. In the latter, infiltration, phlebitis due to osmolarity, pH and the characteristic of the drug and excipients can damage the vessels and lead to the loss of veins for therapy. Other common risks encountered with intravenous administration include activity restriction, impact of normal fluctuations in feeding, activity and sleeping patterns, the pulling out of intravenous lines by the patient, infection and extravasion. 

In 1991 it was estimated that more than 150 million intravascular catheters were being procured in the United States each year (Maki and Mermel, 1998). Of this number, more than 5 million were central venous catheters (Maki and Mermel, 1998). Catheters have a critical role in modem health care and are used in increasing numbers for central access of the major arteries and veins, as well as for an ever-expanding array of invasive procedures (Crump and Collignon, 2000). 

The anatomic location for temporary central venous catheter (CVC) insertion and placement can be dictated by certain patient or disease restrictions, but the most common sites are the internal jugular vein (neck), the femoral vein (groin), and the subclavian position (upper chest). The internal jugular approach is the first choice for placement of a hemodialysis CVC, while femoral placement is favored when rapid insertion is essential (Canaud et al., 2000). Subclavian vein access has fallen from favor because of a higher incidence of thrombosis and stenosis associated with this site, which can ultimately prevent use of the veins in the downstream vascular tree for high-flow applications such as dialysis (Cimochowski et al., 1990 Schillinger et al., 1991). 

Twardowski, Z. J. High-dose intradialytic urokinase to restore the patency of permanent central vein hemodialysis catheters, Am. J. Kidney Dis., 1998 31(5) 841-847. 

Nimodipine is poorly soluble in water <0.1 mg/mL. The licensed pharmaceutical product Nimotop infusion solution contains 0.2 mg/mL nimodipine and 170 mg/mL macrogol 400. This high concentration of macrogol is needed to dissolve the active substance but causes phlebitis when Nimotop is administered via a peripheral vein. Therefore in the product information it is recommended to administer Nimotop via a central venous catheter. 

According to some recommendations [36] if osmolarity of the infusion is higher than 500 mOsmol/1, administration should occur via a central venous catheter that is inserted in a vessel with high blood flow such as the vena subclavia, proximal axillary vein or superior vena cava. 

Osmolarity of the nutrient admixtures and thereby the infusion route is determined by the type and amount of the components mixed. In general the admixtures are hyperosmolar and to be administered via a central venous catheter in a big vein (vena cava superior or vena subclavia). Only admixtures with a maximum osmolarity of900 mOsm/ L can be administered via a peripheral vein and only for a limited period of time [69]. Lmig term parenteral nutrition can be also administered via a port (see Sect. 13.10.3) especially when patients are treated at home. Because of the high probability of incompatibilities nutrition admixtures should always be administered via a separate line and Y-site infusion should be avoided. 

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