Intravenous literature: Kam, K.Y.R., Mari, J.M. and Wigmore, T.J. (2011) Adjacent central venous catheters can result in immediate aspiration of infused drugs during renal replacement therapy. Anaesthesia. 8th Nov [epub ahead of print].
Dual-lumen haemodiafiltration catheters enable continuous renal replacement therapy in the critically ill and are often co-located with central venous catheters used to infuse drugs. The extent to which infusions are immediately aspirated by an adjacent haemodiafiltration catheter remains unknown. A bench model was constructed to evaluate this effect. A central venous catheter and a haemodiafiltration catheter were inserted into a simulated central vein and flow generated using centrifugal pumps within the simulated vein and haemodiafiltration circuit. Ink was used as a visual tracer and creatinine solution as a quantifiable tracer. Tracers were completely aspirated by the haemodiafiltration catheter unless the infusion was at least 1 cm downstream to the arterial port. No tracer was aspirated from catheters infusing at least 2 cm downstream. Orientation of side ports did not affect tracer elimination. Co-location of central venous and haemodiafiltration catheters may lead to complete aspiration of infusions into the haemodiafilter with resultant drug under-dosing.