the safe delivery of nutritional therapies to malnourished patients includes enteral ... chloride (PVC) plastic catheters for the infusion of PN admixtures into the SVC of ... Despite these benefits, when compared to standard CVCs, a meta-analysis of .... Nutrition: central venous catheters (access, care, diagnosis and therapy.
The Red Section
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Choosing the Right Central Venous Catheter for Parenteral Nutrition Dejan Micic, MD1, Carol Semrad, MD1 and Vineet Chopra, MD, MSc2 Am J Gastroenterol https://doi.org/10.1038/s41395-018-0203-8
Introduction
The practice of safe and effective enteral nutrition (EN) and parenteral nutrition (PN) support is an important aspect in the abilities of a clinical gastroenterologist. Unfortunately, formal education programs for nutrition training in the course of a gastroenterology fellowship are often lacking. This leaves clinical gastroenterologists with the responsibility to safely deliver nutritional support to patients with little formal training. A critical step in the safe delivery of nutritional therapies to malnourished patients includes enteral access for EN and adequate venous access for PN. Here we provide the practicing physician useful guidance on the choice of venous access for PN support. The use of PN has come a long way from the first intravenous (IV) solutions composed of glucose, plasma and lipids in the early 1900s to the inception of modern formulas by Dudrick and colleagues at the University of Pennsylvania in 1968 [1]. A main limitation to the use of PN early on was the lack of indwelling plastic catheters for safe administration of concentrated formulas. The administration of PN requires the use of a central venous catheter (CVC) with the tip at junction of the superior vena cava (SVC)/right atrium due to the hypertonic and acidic properties of the solution. Studies on the reactivity of plastic polymer-based catheters in tunneled subcutaneous tissue of dogs, led to the use of polyvinyl chloride (PVC) plastic catheters for the infusion of PN admixtures into the SVC of beagles [1]. Subsequent advances in tunneled IV catheters and sterile placement of catheters resulted in reductions in complications of PN delivery. Parenteral nutrition is now the mainstay of shorter-term therapy (3 mo) of use
Safe insertion site in the proximal arm
Highest risk of catheterrelated thrombosis
Can be removed by home nursing or in the outpatient clinic Implanted port
Often readily available in patients with a history of cancer
Higher risk of catheterrelated bloodstream infection Generally requires removal in the setting of infection
In those requiring longer-term or life-long PN, single-lumen silicone tunneled catheters are favored over PICCs and implantable ports for reasons to include a decreased risk of thrombosis, infection, and the ability to use ethanol locks to prevent infectious complications. Due to the lack of data in the use of polyurethane catheters with ethanol lock solutions (with respect to catheter integrity), tunneled silicone catheters are preferred, particularly when ethanol lock solutions are used to limit recurrent bloodstream infections [9].
Insertion Site
The goal of CVC placement for PN is to ensure that the catheter tip is at the SVC/right atrial junction; the site associated with a decreased incidence of venous thrombosis [10]. Central access into the SVC is associated with decreased infectious complications when compared to femoral access into the inferior vena cava (IVC) [10]. In the absence of accessible proximal vessels into the SVC, translumbar, transhepatic, and tunneled femoral techniques have been described [11] for PN support. The creation of a subcutaneous tunnel between the skin and venous access sites decreases infection and dislodgement risk and allows for a skin site that does not interfere with undergarments (upper chest wall or anterior abdominal wall) and permits self-care of catheters [12].
Complications
Complications of CVCs include placement-related (pneumothorax, bleeding, vascular injury), mechanical (catheter occlusion, www.nature.com/ajg
breakage), infectious (tunnel and bloodstream infections), and venous thrombosis/SVC syndrome. Risk factors for thrombotic catheter complications include: underlying thrombophilia, active malignancy, catheter site (femoral site > internal jugular or subclavian), and prior venous thromboembolism [10]. PICC size and lumen number are also associated with an increased risk of thrombosis development [10]. Catheter-related bloodstream infections are used as a quality marker and serve as a surrogate marker of catheter care and maintenance. Clinical risk factors associated with the development of CRBSI include prior bloodstream infections, use of PN, multilumen catheters, and active malignancy [13]. Catheter-related infections occur as a result of microbial contamination of the external or internal surface of the catheter or associated infusates, microbial adherence, biofilm formation, and dissemination into the bloodstream [14]. The skin is the most common source of external contamination resulting in adherence of bacteria to the catheter immediately upon entry. Combination 2% chlorhexidine gluconate (CHG)/70% alcohol (Chloraprep ) solutions are recommended for skin cleansing prior to catheter placement and with dressing changes [14]. Dressings should remain clean, dry and should adequately cover the catheter site. The type of external dressing includes the use of traditional sterile gauze with overlying tape or transparent polyurethane film dressings (TegadermTM, OpsiteTM, BioclusiveTM), which allow for visualization of the catheter exit site and monitoring for collection of moisture or debris. While a Cochrane metaanalysis failed to identify differences in infectious outcomes with respect to dressing type, conclusions were limited by individual small sample sizes [14]. Additional means of decreasing the risk of external contamination of the catheter surface include the use of CHG-impregnated polyurethane foam disks (BiopatchTM) and securement devices resulting in a decreased incidence of CRBSI (RR: 0.42–0.79) and catheter colonization (RR: 0.39–0.67) [15]. Contamination of the internal lumen of the catheter can be prevented through the adequate use of hand hygiene, access-site disinfection with 70% ethanol and use of saline lock solutions when the catheter is not in use [14].
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IV solutions or additives are associated with decreased risks of catheter-related complications. Application of evidence-based principles has the potential to improve both safety and quality of PN delivery. Understanding and implementing the above principles, although often lacking in clinical gastroenterology curricula, is required in order to improve the quality of PN care. Acknowledgements We thank Dr. Edwin McDonald for his assistance in figure preparation. CONFLICTS OF INTEREST
Guarantor of the article: Dejan Micic, MD. Specific author contributions: All authors contributed equally to mansucript creation. Financial support: None. Potential competing interests: None. References 1. 2. 3.
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Conclusion
The use of PN requires meticulous attention to the length of anticipated therapy, patient history of bloodstream infection and thrombosis, type of central catheter and catheter tip location prior to PN initiation to limit complications. When possible, a single-lumen catheter should be placed. In hospitalized patients without a history of thrombosis and for shorter-term use (
