In vitro measurements of ultrafiltration precision in hemofiltration and hemodialysis devices used in infants

Validation of a low-cost continuous renal replacement therapy dialysate fluid controller for experimental purposes

BACKGROUND

Continuous renal replacement therapy (CRRT) support is crucial for critically ill patients and it is underexplored in specific situations. Experimental CRRT offers a means to gain insights into these scenarios, but the prohibitive cost of CRRT machines limits their accessibility. This study aimed to develop and validate a low-cost and precise dialysate controller for experimental CRRT.

RESULTS

Our results demonstrate a commendable level of precision in affluent flow control, with a robust correlation (R2 = 0.99) for continuous flow and a strong correlation (R2 = 0.95) for intermittent flow. Additionally, we observed acceptable agreement with a bias = 3.4 mL (upper limit 95% = 43.9 mL and lower limit 95% = - 37 mL) for continuous flow and bias = - 20.9 mL (upper limit 95% = 54 mL and lower limit 95% = - 95.7 mL) for intermittent flow, in this way, offering a precise CRRT dose for the subjects. Furthermore, we achieved excellent precision in the cumulative ultrafiltration net (UFnet), with a bias = - 2.8 mL (upper limit 95% = 6.5 mL and lower limit 95% = - 12 mL). These results remained consistent even at low affluent flow rates of 8, 12, and 20 mL/min, which are compatible with CRRT doses of 25-30 mL/kg for medium-sized animals. Moreover, the acceptable precision of our findings persisted when the dialysate controller was subjected to high filter dialysate chamber pressure for an extended duration, up to 797 min.

CONCLUSIONS

The low-cost dialysate controller developed and tested in this study offers a precise means of regulating CRRT in experimental settings. Its affordability and accuracy render it a valuable instrument for studying CRRT support in unconventional clinical scenarios, particularly in middle-income countries' experimental ICU laboratories.

New perspectives in pediatric dialysis technologies: the case for neonates and infants with acute kidney injury

Advancements in pediatric dialysis generally rely on adaptation of technology originally developed for adults. However, in the last decade, particular attention has been paid to neonatal extracorporeal therapies for acute kidney care, an area in which technology has made giant strides in recent years. Peritoneal dialysis (PD) is the kidney replacement therapy (KRT) of choice in the youngest age group because of its simplicity and effectiveness. However, extracorporeal blood purification provides more rapid clearance of solutes and faster fluid removal. Hemodialysis (HD) and continuous KRT (CKRT) are thus the most used dialysis modalities for pediatric acute kidney injury (AKI) in developed countries. The utilization of extracorporeal dialysis for small children is associated with a series of clinical and technical challenges which have discouraged the use of CKRT in this population. The revolution in the management of AKI in newborns has started recently with the development of new CKRT machines for small infants. These new devices have a small extracorporeal volume that potentially prevents the use of blood to prime lines and dialyzer, allow a better volume control and the use of small-sized catheter without compromising the blood flow amount. Thanks to the development of new dedicated devices, we are currently dealing with a true "scientific revolution" in the management of neonates and infants who require an acute kidney support.

Daily practice evaluation of the paediatric set of a next-generation long-term haemodialysis machine

BACKGROUND

From 2006 to 2020, 24% of children starting haemodialysis in France weighed < 20 kg. Most new-generation long-term haemodialysis machines do not propose paediatric lines anymore but Fresenius has validated two devices for use in children above 10 kg. Our aim was to compare the daily use of these two devices in children < 20 kg.

METHODS

Retrospective single-center evaluation of daily practice with Fresenius 6008® machines, and low-volume paediatric sets (83 mL), as compared to 5008® machines with paediatric lines (108 mL). Each child was treated randomly with both generators.

RESULTS

A total of 102 online haemodiafiltration sessions were performed over 4 weeks in five children (median body weight 12.0 [range 11.5-17.0] kg). Arterial aspiration and venous pressures were maintained respectively over - 200 mmHg and under 200 mmHg. For all children, blood flow and volume treated per session were lower with 6008® vs. 5008® (p < 0.001), median difference between the two devices being 21%. In the four children treated in post-dilution mode, substituted volume was lower with 6008® (p < 0.001, median difference: 21%). Effective dialysis time was not different between the two generators; however, the difference between total duration of session and dialysis effective time was slightly higher (p < 0.05) with 6008® for three patients, due to treatment interruptions.

CONCLUSION

These results suggest that children between 11 and 17 kg should be treated with paediatric lines on 5008® if possible. They advocate for modification of the 6008 paediatric set to decrease resistance to blood flow. The possibility to use 6008® with paediatric lines in children below 10 kg deserves further studies.

Expanding the Spectrum of Extracorporeal Strategies in Small Infants with Hyperammonemia

Hyperammonemia is a life-threatening condition mainly due to the neurotoxicity of ammonia. Ammonia scavengers may be insufficient, and extracorporeal treatment may be required. Continuous treatments are preferred, and a high-dose continuous renal replacement therapy (CRRT) must be prescribed to ensure a fast ammonia depletion. Many of the children with hyperammonemia are newborns, with lower blood volume than older children. The majority of the CRRT systems are adult-based, with large extracorporeal priming volumes and inadequate UF control. Recent strides have been made in the development of CRRT systems more suitable for young children with smaller sets to use in adult machines and dedicated monitors for neonates and infants. The main advantage of the machines for adults is the higher dialysis fluid flows, however with greater hemodynamic risks. Pediatric monitors have been designed to reduce the extracorporeal volume and to increase the precision of the treatment. However, they have substantial limitation in clearance performances. In this review, we discuss on current strategies to provide CRRT in newborns and small infants with hyperammonemia. We also presented our experience with the use of CARPEDIEM™ implemented in a CVVHDF modality, boosting the diffusive clearance with a post-replacement convective mechanism.

Real-life effects, complications, and outcomes in 39 critically ill neonates receiving continuous kidney replacement therapy

BACKGROUND

Continuous kidney replacement therapy (CKRT) has been expanded from simple kidney replacement therapy to the field of critical illness in children. However, CKRT is rarely used in critically ill neonates in the neonatal intensive care unit (NICU). This study aimed to describe patients' clinical characteristics at admission and CKRT initiation, CKRT effects, short-term outcomes, and predictors of death in critically ill neonates.

METHODS

A 7-year single-center retrospective study in a tertiary NICU.

RESULTS

Thirty-nine critically ill neonates received CKRT between May 2015 and April 2022 with a mortality rate of 35.9%. The most common primary diagnosis was neonatal sepsis in 15 cases (38.5%). Continuous veno-venous hemodiafiltration and continuous veno-venous hemofiltration were applied in 43.6% and 56.4% of neonates, respectively. The duration of CKRT was 44 (18, 72) h. Thirty-one patients (79.5%) had complications due to CKRT-related adverse events, and the most common complication was thrombocytopenia. Approximately 12 h after the CKRT initiation, urine volume, mean arterial pressure, and pH were increased, and serum creatinine, blood urea nitrogen, and blood lactate were decreased. In the multivariate logistic regression analysis, neonatal critical illness score [odds ratio 0.886 (0.786 ~ 0.998), P = 0.046] was an independent risk factor for death in critically ill neonates who received CKRT.

CONCLUSIONS

CKRT can be an effective and feasible technique in critically ill neonates, but the overall mortality and CKRT-related complications are relatively high. Furthermore, the probability of death is greater among neonates with greater severity of illness at CKRT initiation. A higher resolution version of the Graphical abstract is available as Supplementary information.

The Infant KIdney Dialysis and Utrafiltration (I-KID) Study: A Stepped-Wedge Cluster-Randomized Study in Infants, Comparing Peritoneal Dialysis, Continuous Venovenous Hemofiltration, and Newcastle Infant Dialysis Ultrafiltration System, a Novel Infant Hemodialysis Device

OBJECTIVES

Renal replacement therapy (RRT) options are limited for small babies because of lack of available technology. We investigated the precision of ultrafiltration, biochemical clearances, clinical efficacy, outcomes, and safety profile for a novel non-Conformité Européenne-marked hemodialysis device for babies under 8 kg, the Newcastle Infant Dialysis Ultrafiltration System (NIDUS), compared with the current options of peritoneal dialysis (PD) or continuous venovenous hemofiltration (CVVH).

DESIGN

Nonblinded cluster-randomized cross-sectional stepped-wedge design with four periods, three sequences, and two clusters per sequence.

SETTING

Clusters were six U.K. PICUs.

PATIENTS

Babies less than 8 kg requiring RRT for fluid overload or biochemical disturbance.

INTERVENTIONS

In controls, RRT was delivered by PD or CVVH, and in interventions, NIDUS was used. The primary outcome was precision of ultrafiltration compared with prescription; secondary outcomes included biochemical clearances.

MEASUREMENTS AND MAIN RESULTS

At closure, 97 participants were recruited from the six PICUs (62 control and 35 intervention). The primary outcome, obtained from 62 control and 21 intervention patients, showed that ultrafiltration with NIDUS was closer to that prescribed than with control: sd controls, 18.75, intervention, 2.95 (mL/hr); adjusted ratio, 0.13; 95% CI, 0.03-0.71; p = 0.018. Creatinine clearance was smallest and least variable for PD (mean, sd ) = (0.08, 0.03) mL/min/kg, larger for NIDUS (0.46, 0.30), and largest for CVVH (1.20, 0.72). Adverse events were reported in all groups. In this critically ill population with multiple organ failure, mortality was lowest for PD and highest for CVVH, with NIDUS in between.

CONCLUSIONS

NIDUS delivers accurate, controllable fluid removal and adequate clearances, indicating that it has important potential alongside other modalities for infant RRT.