Dmed’s NephroFlow device is as effective for ultrasound dilution (UD) for vascular access (VA) as existing devices such as the Transonic VA flow measurement technology, according to a Spanish study comparing the two led by Jose L Merino (Hospital University del Henares, Madrid, Spain) and published in the Journal of Vascular Access (JVA). NephroFlow meets the standard set by Transonic and demanded by current Spanish guidelines for UD-based assessment of the complication risks associated with arteriovenous fistula (AVF) for haemodialysis (HD).
The study was conducted with 44 patients with a mean age of 67 ± 12 years who had been on VA for at least three consecutive months. Patients were studied on the second day of their HD if they received three or more sessions, or the first day of the week if they received two. The sample size was calculated to be the smallest one required to offer the possibility of statistically significant results on the use of NephroFlow compared to Transonic. For NephroFlow, 80% of patients were measured at least twice while over half were measured at least twice for Transonic.
It was found that the mean flow for Transonic was 1222±805 ml/min while for NephroFlow it was 1252±975 ml/min. The authors described this as a representing a result “comparable to the accepted gold standard method” for VA flow surveillance. They claim that, upon review of other studies, “there is no method with better evidence than classic UD methods for VA surveillance.” Other methods such as duplex ultrasonography (DUS), they argue, take longer to achieve a measurement, as suggested for DUS in the study of Karava et al. The “speed for measurement could be a favourable aspect of the NephroFlow method,” they added.
Despite their conclusions broadly corroborating those of similar studies on UD methods for measuring VA, the authors were keen to note several limitations to their own. There were comparatively few patients involved in the study, and they were not all available for more than two measurements, limiting the authors’ ability to measure VA flow. Additionally, they noted that the study took place at one centre and, “although the conditions were intended to be as constant as possible these could influence the results.”
With all this considered, the authors maintained that “as far as we know, this is the first study comparing both methods [of UD assessment of VA].” They concluded by suggesting that the NephroFlow device “could be applied in the surveillance of VA in the detection of VA at risk, as recommended by the [Spanish] guidelines.”
Speaking exclusively to Renal Interventions, Merino supplemented this conclusion by saying that “we continue to use the device in our daily routine and its speed allows us to optimize nursing times. Although several guidelines question the benefit of routine surveillance, the GEMAV Guidelines and we believe low-cost and easily applicable devices can improve vascular access survival.”