Long-term vascular access in the rat: importance of asepsis.

Chronic indwelling vascular catheters have been used in the rat for many types of experimental studies. Most experiments have been of short duration with little attention to aseptic technique during catheter placement. In this study, rats subjected to a sterile superior vena cava (SVC) catheterization technique, a convential clean but nonsterile SVC catheterization technique, or sham operation were compared. Male Fischer 344 rats (wt 175-200 g) were catheterized or sham operated and then received food and water ad libitum for 25 days. At time of spontaneous death or being killed the SVC was examined grossly and microscopically for infection. Three of six nonsterile conventionally catheterized animals died, and five of these six animals had infected catheters. All sterilely catheterized and sham-operated rats lived 25 days, and none had catheter infection. Sterilely catheterized rats gained weight (1.9 g/day), were in positive nitrogen balance, and had organ weight and blood studies similar to sham-operated noncatheterized controls. Nonsterile catheterization resulted in catheter infection such that normal physiological studies would be uninterpretable.