Hemodialysis access flow measurement: Comparison of ultrasound dilution and ultrafiltration method on NIKKISO DBB-EXA™ dialysis machine.

BACKGROUND: The methods of estimating vascular access (VA) flow rates are usually based on the indicator dilution theory by measuring recirculation during dialysis sessions. METHODS: This is an observational study comparing the VA flow rates measured by NIKKISO DBB-EXA™ and Transonic®. Sixty-five patients (38 M/27 F, mean age 72 ± 10 years) participated in the study. We measured the VA flow rates during dialysis twice with each method and repeated the procedure 7 days later. RESULTS: In 130 double measurements for each method on the same day, mean flow with Transonic® was 1413±715 ml/min and with DBB-EXA™ 1297 ± 664 ml/min. In Bland-Altman analysis, the mean difference between the two methods was 159 ± 211 ml/min (limits of agreement: -274 and 572 ml/min). Eighty-one out of the 130 DBB-EXA™ measurements were within 25% of the Transonic® measurements (62% accuracy). Regarding reproducibility of each method on different days, mean difference in the Bland-Altman analysis was 29 ± 620 ml/min (limits of agreement: -1186 and 1244 ml/min) for the Transonic® measurements and 132 ± 625 ml/min (limits of agreement: -1092 and 1356 ml/min) for the DBB-EXA™ measurements. The measurements on two different days were within 25% of each other for 52 of the 65 patients (80%) with the Transonic® method, and for 35 of the 65 patients (54%) with the DBB-EXA™ method. CONCLUSIONS: In conclusion, the DBB-EXA™ method underestimates VA flow rates compared to the Transonic® technique, resulting in a limited accuracy of 62%. There was poor reproducibility for both methods in different day measurements with better performance of the Transonic® technique. The DBB-EXA™ method could be used as a simple tool for a rough estimate of VA flow rates but cannot replace the Transonic® reference method.

Deleterious effects of intradialytic meals' suppression during the COVID pandemic.

BACKGROUND&AIMS: Patients with end-stage renal failure on chronic hemodialysis present an important risk of malnutrition, which is associated with a significant risk of morbidity and mortality. Meals during the dialysis session are important for maintaining the nutritional status of dialysis patients but represent a risk for intradialytic hypotension. During the COVID-19 pandemic, several dialysis centers stopped providing meals during the dialysis session as a protective measure. The aim of this retrospective, multicentric cross-over study was to study the evolution of the nutritional parameters of a cohort of hemodialysis patients for 12 months before, during and after the suspension of meals during dialysis due to the COVID-19 pandemics. METHODS: We registered the evolution of dry weight, C Reactive Protein (CRP), serum Potassium and Phosphate before the dialysis session, serum albumin and prealbumin levels as well as normalized Protein Catabolic Ratio (nPCR). RESULTS: We studied 168 hemodialysis patients (113M, 55F, mean age at inclusion:68.45 ± 0.45 years). The results ares shown as mean values (±SEM). The supression of the intradialytic meals led to significant reduction of the patients' dry weight (in Kg) from 78.66 ± 0.72 to 76.50 ± 0.49, p = 0.013, serum albumin (in g/l) (from 40.72 ± 0.16 to 39.25 ± 0.12, p < 0.001) and prealbumin levels (in g/l) (from 33.82 ± 0.31 to 32.73 ± 0.22, p = 0.004) as well as the nPCR values (from 1.08 ± 0.08 to 1.05 ± 0.11, p = 0.021). Serum CRP as well as predialytic Potassium and Phosphate levels did not change significantly. The reinstitution of the intradialytic meals led to a complete correction of the studied nutritional parameters with Body weight values evolving from 76.50 ± 0.49 to 78.28 ± 1.01, p = 0.025, serum albumin from 39.25 ± 0.12 to 40.53 ± 1.04, p < 0.001, serum prealbumin levels from 32.73 ± 0.22 to 33.95 ± 0.64, p = 0.001 an nPCR from 1.05 ± 0.11 to 1.08 ± 0.08, p = 0.021. CONCLUSION: In conclusion, the suppression of intradialytic meals during the COVID-19 pandemic had deleterious effects on the nutritional parameters of patients on chronic hemodialysis.

Fermentable carbohydrate supplementation alters nitrogen excretion in chronic renal failure.

BACKGROUND: Considerable attention has been given to the impact of nutrition on kidney disease. Most dietary attempts to treat chronic renal failure (CRF) and to decrease uremia use a protein restriction. An alternative dietetic approach based on fermentable carbohydrate (FC) supplementation of the diet could lead to the same urea-lowering effect by increasing urea nitrogen (N) excretion in stool, with a concomitant decrease of the total N quantity excreted in urine. METHODS: In the present prospective study, the impact of FC (40 g/d) on uremia and on N excretion routes was investigated during 5 weeks in nine CRF patients in the presence of a moderated restrictive protein diet (0.8 g/kg/d). Patients were their own controls and were treated by the cross-over method after randomization (5 weeks with FC versus 5 weeks without FC). RESULTS: Feeding FC significantly increased the quantity of N excreted in stool from 2.1 +/- 0.8 to 3.2 +/- 1.1 g/d (+51%) (P < .01) and decreased, in parallel, the urinary N excretion from 9.4 +/- 1.7 to 8.3 +/- 1.4 g/d (-12%) (P < .01). The total N quantities excreted by the two routes were unchanged by the FC, which shows that the FC was efficient to shift N excretion from the urinary route toward the digestive route. As a result of the increase of urea transfer into the colon, the plasma urea concentration was significantly decreased from 26.1 +/- 8.7 to 20.2 +/- 8.2 mmol/L (-23%) (P < .05). CONCLUSIONS: These results show the same beneficial effects in CRF as those obtained with a restrictive protein diet without its nutritional drawbacks. This should be confirmed by other prospective works over a longer duration and a larger number of patients to study the effects of FC on CRF progression and on CRF terminal stage tolerance.