Intravascular devices

Superficial skin infections are treated without antibiotics. Local hygiene and disinfection with alcohol prevents spread of furunculosis. Local application of gentian violet in water (1%) is effective for impetigo. All pus collections must be drained by puncture or incision. Antibiotics are required only when systemic signs of infection are present or in patients with a high risk of complications (e.g. to prevent bacteraemia in a patient with prostheses or intravascular devices). 

In developed countries endocarditis is present in 1/1000 hospital admissions or 1-2 cases per million population. An increasing number of endocarditis cases are associated with intravascular device infections and the placement of prosthetic valves thus, endocarditis can be acquired during hospital stay. Men are afflicted more often than females, and most patients are >50 years of age. Pre-existing heart lesions predispose to bacterial endocarditis if they are accompanied by (thrombotic) alterations of the endocardial surface or blood flow such that bacteria... 

Switching from intravenous to oral antibiotics should be considered as soon as clinically appropriate. Prolonged intravenous therapy is associated with risk of intravascular device-related infection and delays discharge. Indicators for switch include resolution of fever, tachycardia, tachypnoea, hypotension and hypoxia and the patient should be clinically hydrated with good oral intake and no gastrointestinal absorption concerns. 

Karchmer AW. Infections of prosthetic valves and intravascular devices. In Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases, 5th ed. New York, Churchill Livingstone, 2000 903-917. 

DG Maki. Infections caused by intravascular devices used for infusion therapy pathogenesis, prevention and management. In AL Bisno, FA Waldvogel, eds. Infections Associated with Indwelling Medical Devices. Washington, DC ASM Press, 1994, pp. 155-212. 

Nosocomial bloodborne infections in hospitalized patients are associated with a two- to threefold increase in mortality. The origin of infection is usually either cannula-related or infusate-related. Cannula-related infections include those derived from percutaneous devices used for vascular access (e.g., needles, hubs, and plastic catheters). Maki reports that between 5 and 25% of intravascular devices are microbially colonized at the time of vascular withdrawal [25]. Large numbers of microorganisms are observed on the intravascular portion of the cannula or its tip (Fig. 1). 

Long-term implantation of intravascular devices is one of the major advances in modern medical and surgical practice. A common compUcation with these implanted foreign bodies is their susceptibility to pyogenic infections, especially due to Staphylococci (20). Establishment of such infections is due to either perioperative bacterial contamination or postoperative colonization of the... 

The current preferred treatment for PAVMs consists of embolization using coils or other intravascular devices [28]. Surgical resection used to be the only method of treatment before 1977 [8,28,54,65,66]. Vascular ligations, local resection, segmentectomy, lobectomy, or pneumonectomy were performed [20]. Properly performed in well-selected patients, surgery is associated with minimal morbidity and mortality but carries at least the same risks as any other... 

Thrombotic complications are common with catheter use. The development of a fibrin sheath is a near universal occurrence on intravascular devices such as central venous (Hoshal et al., 1971) and hemodialysis catheters, and can have a profound effect upon blood flow in the device (Trerotola, 2000). This sheath can be removed either by stripping (Rockall et al., 1997 Crain et al., 1996) or fibrinolytic medical therapy (Twardowski et al., 1998), or the catheter can be replaced to restore adequate flow performance. Recent randomized controlled clinical trials have revealed improved long-term outcomes with catheter exchange versus fibrin sheath stripping (Merport, 2000), while no outcome differences were realized in patients randomized to either fibrin sheath stripping or thrombolytic therapy (Gray, 2000). 

Pearson, M. L., Guideline for prevention of intravascular device-related infections. Part 1. Intravascular device-related infections An overview. Part II. Recommendations for the prevention of nosocomial intravascular device-related infections, Am. J. Infect. Control, 1996 24(4) 262-293. 

Device-related, intravascular devices, ventilators, d tube feeding infections... 

This chapter will be focused on antimicrobial PUs for intravascular applications. First, a classification of the types of PU intravascular devices and their impact in the medical held will be inhoduced. Then, a survey of infections associated with intravascular devices in terms of incidence, etiology, and pathogenesis will be presented. Next, management of device-related infections and the role of modified PUs in preventing intravascular device-related infections will be discussed. Finally, the future direction of novel antimicrobial polymers as biomaterials for the development of devices preventing biofilm-based infections will be described. 

A classification often used to distinguish the different typologies of intracorporeal medical devices is that considering their localization into the vascular system (intravascular devices) or not (extravascular devices). It is clear how these two classes of devices interact very differently with the host. Indeed, intravascular devices are destined to interact with the blood components while extravascular devices interact with the surrounding tissues or interstitial fluids. 

Intravascular devices are essential tools for the managanent of patients suffering from cardiovascular diseases, cancer, and other diseases. However, their implantation in the body exposes the patient to a substantial risk of infection. 

Microrganisms involved in intravascular device-related infections... 

In the following sections, antifouling and antimicrobial PUs will be presented in relation to their application for preventing intravascular device-related infections. 

The most experimented antimicrobial dmgs for intravascular devices are chlorhex-idine/silver sulfadiazine (CH/SS) and minocycline-rifampin (MR). From a historical point of view, CVCs coated with one of these two drugs are the first medicated catheters approved for clinical trials. 

In a more recent stndy rifampin was loaded into biodegradable polyester urethanes. The authors suggested the use of this antimicrobial-entrapped polyester urethane as a coating material for intravascular devices. Indeed, a sustained delivery of the antibiotic was obtained and related to a diffusion-dependent release mechanism. 

A crucial feature required for a successful application of PUs as biomaterials is their ability to prevent microbial colonization. Indeed, any implanted biomaterial is known to have the potential to put the patient at high risk of infection. In case of intravascular devices, the development of device-related infections may result in life-threatening consequences for the patient. 

Dmg-releasing PUs can be considered the first milestone in the prevention of intravascular device-related infections. Already, their clinical application has contributed to decreasing infection risk, mortality rate, and patient morbidity. However, the use of these drag-releasing polymers has elicited concerns in terms of durability and possible local emergence of resistant microorganisms. 

Device-related, intravascular devices, ventilators, and tube-feeding infections Surgical-site infections and HAIs in special care units Infections caused by organisms that are antibiotic resistant Tuberculosis and other communicable diseases Infections in the neonate population Geographic location of the facility Volume of patient or resident encounters Patient populations served Clinical focus of the facility Number of employees and staff... 

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