[News on single needle dialysis: technique, indications, precautions and limits]

The technique of single needle dialysis (SN) was invented in the 1960s and enjoyed great success during the 1970s and '80s in northern Europe, particularly in Belgium. In recent years, the double needle mode has awakened new interest in this technique, as it may represent a good alternative to the use of a central venous catheter at the beginning of dialysis, while waiting for the growth of the arteriovenous fistula. For today's dialysis patients, mostly elderly with ever greater numbers of co-morbid conditions, in particular vascular disease, treatments have become ever more flexible and individually tailored. A single needle approach can be also used in the case of native fistula dislocation. The single needle technique requires careful control of dialysis dose, keeping recirculation into account. If the technique is used for long periods of time, there is the risk of inadequate dialysis dose and it is necessary to pay particular attention to the sampling of post dialysis urea for the KT/V calculation (always 20 minutes after the end of dialysis). Modern dialysis machines have greatly reduced the risk of hemolysis (which can be evaluated with the control of LDH pre and post dialysis) and of back-filtration which no longer represents a problem thanks to ultrapure dialysate. The probability of of blood circuit coagulation has also been greatly reduced thanks to citrate dialysis baths and membranes treated with heparin or vitamin E, and systems often do not require an increase of anticoagulants. The technique is, therefore, particularly reliable and easy to use thanks to its simplicity.