RESUMO
PURPOSE: Tunneled catheters play an important role in the delivery of hemodialysis, for both temporary and long-term vascular access. Proper catheter tip positioning is critical for optimal blood flow and performance. The modular Cannon Catheter II Chronic Hemodialysis Catheter is placed tip first, then tunneled back to the exit site, in a simple technique (retrograde tunneling) that provides precise tip placement within the right atrium. This retrospective study evaluated 6-month efficacy and safety of the Cannon catheter in 38 patients. METHODS: Monthly mean flow, pressure, Kt/V, and URR were determined. Safety parameters included early and late device-related complications, device removals, and device survival. RESULTS: 87% of subjects had history of vascular access failure. Cannon catheters were inserted via an internal jugular vein with retrograde tunneling in all patients without insertional complication. Mean flow ranged from 369.0 to 404.8 ml/min, with a trend for increasing flow over time. High flow allowed delivery of correspondingly high clearance. Mean URR remained > or = 71%; mean weekly Kt/V ranged between 1.55 and 1.60, above current K/DOQI adequacy guidelines. There were no device-related hospitalizations or deaths. Catheter-related bacteremia occurred in 3 patients over the 6 months (0.62 bacteremias/1,000 patient-days), resolving through out-patient treatment. The Cannon catheter provided extended high flow vascular access (> or = 6 months or until hemodialysis catheter-based access was no longer needed) in 95% of patients. CONCLUSION: Retrograde tunneling of the Cannon Catheter II Chronic Hemodialysis Catheter allowed optimal tip placement and high flow rates, as well as safe, reliable, extended use.
RESUMO
A chronic hemodialysis patient presented with elevated serum ammonia concentration (189 micromol/l) and acutely altered mental status. He had been adequately dialyzed over the prior months and had no evidence of liver dysfunction, despite serological evidence for hepatitis C virus infection. His mental status deteriorated to coma despite vitamin replenishment, intensive hemodialysis, lactulose treatment, and blood pressure control over a 3-day period. Blood free L-carnitine concentration was depressed, and total carnitine concentrations was normal. Three hours after a single 2 g dose of L-carnitine was administered intravenously, the mental status reverted to normal. Hyperammonemia resolved over a 5-week period. We suspect that subclinical liver dysfunction and dialysis status in tandem contributed to the carnitine deficiency, hyperammonemia, and confusion and that the L-carnitine administration reversed these biochemical and clinical abnormalities.