Vascular access devices

Impla.nta.ble Ports. The safest method of accessing the vascular system is by means of a vascular access device (VAD) or port. Older VAD designs protmded through the skin. The totally implanted ports are designed for convenience, near absence of infection, and ease of implantation. Ports allow dmgs and fluids to be deUvered directiy into the bloodstream without repeated insertion of needles into a vein. The primary recipients of totally implanted ports are patients receiving chemotherapy, bolus infusions of vesicants, parenteral nutrition, antibiotics, analgesics, and acquired immune disease syndrome (AIDS) medications. 

Two sets of blood cultures should be obtained, because two sets of cultures are required to rule out contamination. At least one should be drawn percutaneously and one drawn through each vascular access device, unless the device was recently (less than 48 hours) inserted. 

More expensive and costly to produce Potential for infection at site of injection Potential for sepsis Potential for thrombophlebitis Potential for fluid overload Potential for air embolism Potential for extravasation Psychological distress by the patient Require specialized equipment, devices, and techniques to prepare and administer drugs Potential for pain upon injection Potential for tissue damage upon injection Risk of needlestick injuries and exposure to blood-borne pathogens by health care worker Increased morbidity associated with long-term vascular access devices Disposal of needles, syringes, and other infusion devices requires special consideration... 

Proper care of the vascular access device and site (if applicable). 

Surgical incision Penetrating trauma Vascular access devices Impaired mucociliary function of the lungs Smoking... 

Skin Venipuncture, bone marrow aspiration, urinary catheterization, vascular access devices, radiation, biopsies Bacteria S. aureus, S. epidermidis. Bacillus spp., Corynebacterium jeikeium Fungi Candida... 

Blood cultures (two or more sets, including vascular access devices) for bacteria and fungi cultures of other suspected infection sites (infection can be documented microbiologically in only about 30% of cases, about one-half of which are due to bacteremia). 

Design considerations for vascular access devices include ease of handling, insertion, and use minimal thrombotic and other biocompatibility-related complications stmctural and operational reliability over time and optimization for application-specific performance issues (Canaud et al., 2000). Three different catheter tips are shown in Fig. 20.10 to illustrate these variations in design and structure. Because of the distinct characteristics of the different treatments and agents deployed through catheters, it is not practical to provide specific values for flow rates, pressure drops, viscosities, and other important transport properties. 

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. 

VAD Vascular Access Device, Venous Access Device... 

Catheter-related bacteraemia (CRB) and catheter dysfxmction are major sources of morbidity and mortality when central venous catheters (CVCs) are used as long-term vascular access devices in haemodialysis patients. Attempts have been made to minimise these complications by the prophylactic use of catheter locking solutions. The current study aims to describe the recent advances in the field of lock solutions and discusses the benefits and risks associated with the routine use of antimicrobial and/or antithrombotic lock solutions [ll J. These solutions may improve patency and CRB, but at the same time, these may be cost-prohibitive. 

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