Venous access devices

Into an intermittent venous access device called a heparin lock (a small IV catheter in the patient s vein connected to a small fluid reservoir with a rubber cap through which the needle is inserted to administer the drug)... 

K.I. Akinwande, and D.M. Keehn, Dissolution of phenytoin precipitate with sodium bicarbonate in an occluded central venous access device. Ann. Pharmacother. 29 707-709, 1995. 

Restoration of function of central venous access devices as assessed by the ability to draw blood... 

There is some disagreement as to whether infectious complications differ with the use of different types of chronic central venous access devices in patients with cancer. In one study there was no significant difference in the risk of infection between subcutaneous ports and external catheters (26). However, this has been disputed by other workers, who found that in children with cancer there was a lower infection rate when subcutaneous ports were used compared with external catheters (27). The differences between the studies and the conclusions reached may be the result of their size and design, rather than real differences. 

Infective endocarditis is a serious complication of centrally placed venous access devices. The successful treatment in situ of a large thrombus associated with the tip of the catheter has been described (29). The antibiotic regimen was gentamicin and vancomycin, both delivered via the venous access device vancomycin was allowed to remain in situ between each 8-hourly dosing. This regimen successfully eradicated the thrombus within 3 weeks, without removal of the hue. 

Keung YK, Watkins K, Chen SC, Groshen S, Silberman H, Douer D. Comparative study of infectious complications of different types of chronic central venous access devices. Cancer 1994 73(ll) 2832-7. 

Venugopalan P, Louon A, Akinbami FO, Elnour IB. Endocarditis with a large thrombus complicating a central venous access device. Ann Trop Paediatr 1999 19(l) 101-3. 

Dependent on system used for compounding solution transfer sets, bags, syringes, technician time, pharmacist time Administration sets, solution filter, pump, nursing time Venous access device... 

Alteplase Tissue plasminogen activatra Restoration of function to central venous access devices Bleeding, infection... 

Vascular access devices are classified in peripheral and central venous access devices. Central veins are located in the trunk and neck and are larger in the diameter than peripheral veins. Figure 13.5 shows the diameter of different large vessels. 

A tube or line is necessary for the transport of the infusion solution from the container to the venous access device. The administration can be done by gravity or pump-infusion or by syringes and syringe pumps. 

Central venous access device Non-tunelled CVC Tunelled CVC PICC Apheresis/ haemodialysis catheter Implantable Port Peripheral venous access device Cannula Midline catheter... 

Fig. 13.12 Decision models for the selection of adequate venous access devices. Therapy related factors, such as duration cind frequency of administration upper part of the decision model) and characteristics of the infusion solutions lower part of the decision model) determine the selection of proper venous access devices [76] (Copyright C.R. Bard Inc)...

VAD Vascular Access Device, Venous Access Device... 

The first step in establishing a venous access service is selecting the appropriate central venous access device (VAD). Knowledge of the available devices and the current indication for insertion are needed for an informed decision. Modern day devices are available in a wide array of forms, sizes, and configurations. Despite these differences, the end result is placement of a catheter tip within the central circulation, the vena cava or right atrium. 

Long-term central venous access devices used for chemotherapy can be categorized into peripherally inserted central catheters (PlCCs), chest wall external catheters (tunneled and non-tunneled), and subcutaneous ports (chest wall and extremity). 

Several factors influence the choice of a specific venous access device length and frequency of therapy patient comfort or activity ability to care for the device personal preference (physician, nurse, home health care and patient). Devices suitable for intermediate lengths of treatment (weeks to months) include PICCs, non-tunneled, and tunneled chest wall catheters. Longer therapies (months to years) favor tunneled external chest wall catheters and subcutaneous ports. Daily access would favor an external... 

Brant-Zawadzki M, Anthony M, Mercer EC (1993) Implantation of P.A.S. Port venous access device in the forearm under fluoroscopic guidance. AJR Am J Roentgenol 160 1127-1128... 

Hinke DH, Zandt-Stastny DA, Goodman LR, Quebbeman EJ, KrzywdaEA, Andris DA (1990) Pinch-off syndrome a complication of implantable subclavian venous access devices. Radiology 177 353-356... 

Many different types of venous-access devices are available. Peripherally inserted central venous catheters (PICCs), which can be made of PU or silicone, are inserted into a vein in the arm rather than in the neck or chest. Nontunneled CVCs are shortterm catheters, made of PU or silicone as well, inserted into the internal jugular, subclavian, or femoral vein. Tunneled CVCs are long-term catheters implanted surgically under the skin. One end of the catheter remains outside the skin and the exit site is typically located in the chest. Passing the catheter under the skin helps to reduce the infection risk and provides stability. Implantable ports are similar to tunneled catheters but are left completely under the skin. They consist in small devices, made of plastic or titanium, inserted beneath the skin and connected to a catheter allowing vascular access. Under the skin, the port has a septum through which drugs can be injected and blood samples can be withdrawn. 

In patients with CKD, preservation of the integrity of peripheral and central veins is of vital importance for future hemodialysis access. Avoid i.v. infusion or vein puncture in the forearm and upper arm veins at both arms whenever possible. Insertion of venous access devices carries the risk to injure the veins and thereby incite phlebitis, sclerosis, stenosis or thrombosis and has to be avoided. Whenever a central venous catheter is needed, catheterization of the internal jugular or femoral vein is always preferred. Use of subclavian vein should be... 

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