Novel dialysis cannulas: are they worth the higher price tag?

Accessory hemodialysis equipment, including dialysis cannulas, usually lack controlled and independent testing before being introduced onto the market. The aim of this study is a prospective comparison of a newly designed curved-tip dialysis cannula with a standard dialysis cannula of the same size from the same manufacturer. Fifteen chronic dialysis patients were enrolled onto a prospective 4-month crossover study. All patients had arteriovenous fistulas, except for two patients with polytetrafluoroethylene grafts. The routinely used standard cannulas were replaced by either a curved-tip 15G cannula or a new standard 15G cannula from the same manufacturer. The two cannulas were compared with respect to puncture-related pain and/or problems and bleeding complications, as well as blood-flow dynamics. Venous and arterial access pressures were recorded at blood-flow rates of 100 to 400 mL/min. Linear regression analyses of arterial and venous pressure profiles showed the same regression lines for the standard and curved-tip cannulas. Plasma haptoglobulin levels and occlusion times necessary to stop bleeding after removal of the cannulas did not differ between the two cannulas. Both patients and nurses independently reported equal puncture-related pain and/or problems for both cannulas on visual analogue scales. No correlation was found between puncture problems reported by nurses and puncture pain reported by patients. The curved-tip cannula does not offer an advantage compared with the less expensive standard cannula. Controlled testing of advertised advantages by manufacturers of accessory equipment should be a prerequisite before introduction into routine clinical treatment.