Article of the Month - Oct 2021

Survival of infants treated with CKRT: comparing adapted adult platforms with the Carpediem

Ped Nephrol. 2021 Aug 20;1-9. doi: 10.1007/s00467-021-05180-y. Online ahead of print.

SL Goldstein, E Vidal, Z Ricci et al.

Reviewed by Ayesa Mian


Provision of continuous kidney replacement therapy (CKRT) in the neonatal intensive care unit has traditionally required the adaptation of machines designed for adults as well as use of a blood prime in order to minimize the risks of hypotension and anemia.  Blood priming places infants at risk for hyperkalemia, hypocalcemia, coagulopathy and HLA exposure, the last of which can impact future renal transplantation if needed.   The accuracy of the blood pump at low blood flow rates as well as the accuracy of the scales create additional challenges for the safe delivery of care to small infants.   The development of CARPEDIEMTM (Cardio-Renal Pediatric Dialysis Emergency Machine), a dialysis machine specifically designed to provide CKRT for newborns and small infants (2.5-9.9 kg), has the potential to improve outcomes because of its small circuit volumes, accurate low blood pump and replacement fluid/ dialysate pump rates.

Purpose of this study:

The purpose of this study was to compare patient outcomes for neonates/ small infants < 5 kg treated with CARPEDIEM with a weight-matched cohort from the ppCRRT registry.  The primary outcome was subject survival to CKRT discontinuation.    The secondary outcome was survival to ICU discharge. 

Study design and methods:

This is a retrospective cohort analysis of all infants and children who weighed < 5 kg at ICU admission and were supported with CARPEDIEM as part of their clinical care from June 2013 – May 2018 in 6 Italian centers.  Treatment modality, timing and criteria for treatment initiation and termination, as well as prescription were based on local institutional practice.   The ppCRRT registry includes patients enrolled from 13 US centers from Jan 2001-June 2005.

Data collected from CARPEDIEM and ppCRRT registries included subject demographics, vascular access, CKRT treatment parameters, PRISM II scores and fluid overload.


Aggregate demographic and CKRT treatment data were described by medians (IQR).

Potential differences in demographic, CKRT treatment, and patient outcome data between the 2 registries were compared with the Kruskal-Wallis test or chi-square analysis with Fisher’s exact test for categorical variables. Sensitivity analyses were also performed.


(N=39 in registry)
(N= 344 in registry)
Eligible Subjects (<10 kg) 38 84
Subjects enrolled (wt < 5 kg at ICU admission) 34 48
(43 treated with PrismaTM
5 with Baxter BM-25)

Demographics:  No differences noted between the 2 registries with respect to PRISM II scores at ICU admission, age, weight, serum creatinine, eGFR, % fluid overload or urine output at CKRT initiation.  More patients in the ppCRRT group received vasopressors at CKRT initiation.  Children in the CARPEDIEM registry had longer ICU stays prior to CKRT initiation.

Indications for CKRT in children < 5 kg in both registries included cardiac, inborn error of metabolism (IEM), pulmonary, renal, and sepsis.  Indications in the ppCRRT registry also included hepatic and oncologic.   Approximately 25% of pts in each registry required CKRT for renal or sepsis indications.   In the CARPEDIEMTM registry, the single most common indication for CKRT was cardiac (38% of cases) whereas in the ppCRRT registry it was IEM (28%) followed by cardiac (26%).

Survival to CKRT termination was higher in the CARPEDIEMTM registry but survival to ICU discharge did not differ between the 2 registries.

(N= 48)
p- value
Survival to CKRT termination 33 (97%) 21 (44%) 0.0001
Survival to ICU discharge 17 (50%) 21 (44%) 0.58

In the CARPEDIEMTM cohort, subjects who did not survive to ICU discharge had a higher severity of illness compared to survivors (median [IQR] 23[29,30] vs 16.5 [9,23], p=0.01).  15 of 18 patients who did not survive from CKRT discontinuation to ICU discharge received >2 CKRT procedures; 13 of these died at least 2 days after CKRT discontinuation.


Infants receiving CKRT with the CARPEDIEMTM tolerate CKRT well with excellent survival to CKRT discontinuation.   The authors acknowledge the data should be interpreted cautiously given the study is a retrospective comparison of practice in 2 different countries across two eras more than a decade apart.

Why is this important?

This is the first study comparing outcomes of small infants (< 5kg) receiving CKRT with a novel device, CARPEDIEMTM, designed specifically to address their unique needs with similar size infants dialyzed using adult machines adapted to try and accommodate their needs.   CARPEDIEMTM has recently been FDA approved in the US but we have limited experience using it whereas the Europeans have been using it for a few years.   By sharing our experiences and patient outcomes both domestically and internationally, we can learn from one another and further advance the field of neonatal kidney support therapy more expeditiously.