| Popis: |
The major source of catheter-associated bacteremia is contamination of the catheter hub during connection-disconnection procedures. Between dialyses, the catheter lumens are commonly locked with heparin (H), which does not prevent bacterial growth. Prophylactic use of antibiotics mixed with H reduces bacteremic episodes, but risks the development of antibiotic-resistant strains of bacteria. A new method of catheter locking has been developed (U.S. Patent 6,423,050), wherein anticoagulant is injected first, followed by 0.1 ml air bubble, and a bactericidal solution. The anticoagulant is then located at the catheter tip, where clotting is a problem, and the bactericidal solution is located at the catheter hub, where bacterial contamination is common. The air bubble prevents mixing of the two solutions. A feasibility study has been conducted using H 5,000 units/ml as the anticoagulant, and acidified (pH = 2.0) concentrated (27%) NaCl (ACS) as the bactericidal solution (Twardowski ZJ and Moore HL. Bactericidal properties of acidified (pH 2.0), concentrated (27%) NaCl (ACS), a potentially useful agent for locking hemodialysis catheters. Hemodial Int. Abstracts, 2003; 7: this issue). Ten patients were randomized, either to H lock (5 patients, 62 treatments) or air-bubble method (5 patients, 56 treatments). In the control group the catheters were locked with H according to the capacity provided by the manufacturer with 0.1 ml overfill. In the experimental group, the catheters were locked with H (amount varied according to catheter fill volume), 0.1 ml air bubble, and 0.9 ml ACS. Altogether, the lumen was overfilled by 0.1 ml. According to calculations, an incidental, rapid injection of 0.1 ml air is harmless and rapid injection of up to 1.5 ml of ACS would not perceptibly affect blood pH and/or osmolality in the superior vena cava. The study was approved by the Institutional Review Board of the University of Missouri. There were no problems with locking of the catheters. There were no episodes of bacteremia in either group, except for one case associated with purulent drainage from the exit and same organism in both cultures. In three instances in each group, the locking solution could not be aspirated and was injected without any subjective symptoms or objective signs. We conclude that the air-bubble method of locking central-vein catheters is safe, and a full-scale prospective randomized study is feasible. |
Plný text