SUMMARY. We need central venous catheters (CVCs) in management of critically ill patients with severe burns, either for the administration of fluids or monitoring hemodyname status. Central venous catheterization may cause different early or late complications, which depend on the physician's erudition, the quality of the catheters and quality of Intensive Care Unit (ICU) nursing care for insertion. 272 CVCs were inserted in 114 both adult and pediatric patients from 2004 to 2006 in the ICU of the Burn Centre in Ostrava. The average insertion length of the catheter was 10.2 days, and the average total length of catheterization was 24 days. The total number of catheterdays was 2768. All catheter tips removed were routinely cultured. The most frequent infecting pathogens were coagulase-negative Staphylococci. Peripheral blood cultures were examined in case of fever. Bacterial findings from wounds, sputa and urine were monitored in all patients. No exogenous catheter sepsis according to Maki's criteria occurred in our study group. Endogenous catheter colonization with positive peripheral blood culture and bacteraemia occurred in 4 cases, which means an incidence density of 1.44 endogenous colonizations per 1000 catheter-days. The quality of used catheters and particularly the technique of placement and maintenance of catheters are considered crucial for good results in the ICU of Burn centre in Ostrava..
Key words: central venous catheterization, central venous catheters-related infections, central venous catheters-related bloodstream infections, endogenous bacterial findings
While we are aware of risks related to central venous catheterization, we cannot avoid using CVCs (central venous catheters) in critically ill patients with severe burns. CVCs are commonly used for the administration of fluids, medications, blood products and parenteral nutrition and to monitor hemodynamic status, and also to facilitate patient positioning. Central venous catheterization may cause different early or late complications, which depend on the physician's erudition, the quality of the catheters and quality of ICU nursing care for insertion sites (6, 8, 10, 11).
Catheter-related sepsis (endogenous sepsis or catheter colonization during bacteraemia from other known infection source) is dangerous for immunodeficient burn patients (5- 7). We can consider the incidence of exogenous catheter sepsis as the hygiene criterion of ICU.
Catheter-related sepsis was defined according to Maki's criteria (7) catheter tip colonization was the significant growth of a micro organism (>15 colony-forming units) from the catheter tip. l Ox more than in blood culture obtained from a peripheral vein, no apparent source of bactcraemia except the catheter, and signs of systemic infection which end after catheter removal. The placement of catheters was performed in operating rooms or ICU boxes with laminar air-conditioning after dressing removal, skin disinfection and use of sterile drapes around the insertion site. The catheters were inserted by experienced physicians using sterile-barrier precautions: surgical antiseptic hand wash, sterile gown, gloves, mask and cap. The percutaneous entry sites were attended 3 times per day by the ICU nurse. First, insertion sites were disinfected with povidoneiodine, and then topical antimicrobial ointment (neomycin plv. ads.) was applied. The connecting lines were disinfected and coated by occlusive dressing to prevent infection from dressings covering burned areas.
During the study period, 362 burn patients were admitted- of whom 114 had central venous catheter inserted (Fig. 1).
<% immagine "Fig. 1","gr0000026.jpg","Patientes with CVCs in Burn Centre of Faculty Hospital in Ostrava ",230 %>
CVCs were inserted in 114 patients (mostly adults) out of 272. The number of CVCs/days of catheterizution duration were for adult burn patients 2.8/ 10, for pediatric burn patients I .75/9.25. The average length of catheterization was 24.2 days. The average insertion length of the catheter was 10.2 days (Fig. 2).
<% immagine "Fig. 2","gr0000027.jpg","Clinical characteristics of burned patients with CVCs ",230 %>Near equal frequency of subclavian and femoral catheter insertion in this study group relates to a localization of burns and preferred short-term femoral insertions of dialysis catheters for lower risk of technical complications (Fig. 3).
<% immagine "Fig. 3","gr0000028.jpg","CVC's insertions sites ",230 %>All catheter tips removed were routinely cultured. Eight out of 272 catheters were massively colonized and 37 were only contaminated. The rest of them (227) were sterile (Fig. 4).
<% immagine "Fig. 4","gr0000029.jpg"," Rates of catheters with bacterial colonization and contamination",230 %>The most frequent infecting pathogens were coagulasenegative Staphylococci; less frequent was an Enterobacteriaceae species, while the other microorganisms occurred sporadically (Fig. 5).
<% immagine "Fig. 5","gr0000030.jpg"," Bacterial findings from catheter tips (45x)",230 %>In massively colonized catheters we found positive endogenous bacterial colonization and in 4 cases positive peripheral blood culture (Fig. 6).
<% immagine "Fig. 6","gr0000031.jpg","Bacterial findings in burn patients with catheter colonization ",230 %>In contaminated catheters we found only positive endogenous bacterial colonization (Fig. 7).
<% immagine "Fig. 7","gr0000032.jpg","Bacterial findings in burn patients with catheter contaminations ",230 %>There was no exogenous catheter sepsis according to Maki's criteria in our study group (Fig. 8).
<% immagine "Fig. 8","gr0000033.jpg","Results ",230 %>Endogenous catheter colonization with positive periphera] blood culture and bacteraemia occurred in 4 cases, which means an incidence density of 1.44 infections/ 1000 catheterdays.
The other endogenous colonized or contaminated catheters were not associated with positive peripheral blood culture or with typical clinical manifestation.
In burn patients it is necessary to consider general criteria of insertion-site choice (to prefer vena cava superior to inferior because of lower risk of thromboembolism and infection (4).jugular vein to subclavian in patients with tracheostomy; to consider clavicular fracture in anantnesis) but also to avoid the burn areas if possible (5). It is necessary for a physician to know more central venous access sites to avoid the catheter insertion in burn areas. It is recommended to change the insertion site every 3 days if the burned area is nearby. The insertion site for the new catheter was changed immediately in patients suspected of having a catheter related infection (5). A number of materials have been used in catheter production since Aubaniac, who was the first to perform central venous catheterization in 1952. Catheters made from silicone, acrylate and polyurethane, antimicrobialcoated with chlorhexidine or sulphadiazine are used nowadays. Anti microbial-coated catheters usage is evidently cheaper than treatment of sepsis, despite the fact that acquisition costs of these catheters are high (8). Triple-lumen catheters percutaneously inserted using the Seldinger technique are preferred in burn patients because they can be simultaneously used either for fluids and drug administration and hemodynamic monitoring. Catheter-related sepsis has been associated with high mortality rate, up to 2890 (9). Regarding prevention of both infectious and occlusive complications, full sterile barrier precautions during CVC insertion and maintenance are recommended (10, 11). Also the use of multiple-lumen impregnated catheter avoiding the burn areas and CVCs replacement within the first signs of infection is needed. C VCs should be removed as soon as possible when they are no longer needed. Elective CVC replacement on a routine basis is not recommended because of high risk of technical complications and minimal impact on catheter-related sepsis incidence (4). It is important to choose suitable diameter of catheter compared with the vessel size. Flushing of the CVC w ith an anticoagulant and not using it for blood sampling is also recommended (I ). There is evidence of double risk of technical complications and early catheter-related sepsis if the physician performing the insertion procedure is not sufficiently experienced (10). A relatively large diameter of the inserted catheter, infected insertion site (13), no sterile maintenance (6, 10, I l) and relatively long indwelling time (2) were associated with higher incidence of catheter-related infection. The catheter-relatcd local infection (CRLI) incidence was higher for femoral than for subclavian accesses. The incidence of arterial catheter-related infection is the lowest (3). In some studies there is no difference in catheter infection incidence between the catheters located in the upper or lower vena cava in burn patients (13). The incidence number of catheter-related sepsis was 1 .55 per 1000 catheterdays in the ICUs in the EU countries and 0.33 per 1000 catheter-days in countries outside the EU. This discrepancy may- be due to variable level of surveillance in different countries (12).
To prevent infectious complications connected with central venous catheterization in burn patients it is important that catheter insertion should be performed in operating rooms or ICU sterile boxes by experienced physicians using sterilebarrier precautions: surgical antiseptic hand wash, sterile gown, gloves, mask and cap. We recommend the use of triple-lumen catheters impregnated with chlorhexidine or silversulphadiazine. It is of great importance to attend to the percutancous entry sites 3 times per day by using povidone-iodine and topical antitnicrobial ointment (neomycin ptv.ads.) and to have the connecting lines disinfected and covered by occlusive dressing.
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