Introduction The utilisation of chyme reinfusion therapy (CRT) by returning the output from the proximal limb into the distal limb of double enterostomies is a safe and effective method to improve nutritional uptake and maintain intestinal integrity in adult populations. This technique is also particularly suitable for neonatal patients with life-threatening conditions such as congenital bowel abnormalities and necrotising enterocolitis (NEC). Despite its promise, it has only had irregular uptake in neonatal patients. We aimed to identify the frequency, methodology and adverse events associated with CRT in the appropriate neonatal population.

Methods A ten-year retrospective cohort study was conducted using database searches at two major paediatric hospitals in New Zealand. All patients with suitable anatomy were identified, and data on CRT methodology and outcomes were recorded.

Results Of the 49 neonates identified with double enterostomy 23 (47%) underwent CRT for high stoma output, risk of short gut syndrome or as a routine protocol before re-anastomosis. A nasogastric feeding tube was inserted into the distal limb and collected chyme was reinfused via manual bolus or automated syringe driver. The median (IQR) weight gain increased from 13.9 (3.50 - 22.89) to 24.37 (19.68 - 29.99) g/day during CRT (p = 0.04). 18 infections requiring medical intervention but unrelated to CRT occurred in 13 patients (56%). The rate of non-infectious adverse events was 24, with 7% remaining free from any adverse events.

Conclusion Chyme reinfusion is an underutilised method of improving nutrition in neonates with intestinal failure. Premature neonates requiring double enterostomy formation are at high risk of infectious and non-infectious complications, but few of these are related to CRT. Standardised protocols providing clear eligibility criteria and detailed methodology for CRT are required to promote uniform utilisation of this practice.

TH, EL, IB, and CK work for, or are shareholders in the University of Auckland spin-out company The Insides Company. The remaining authors have no relevant conflicts to declare.

This project was supported by The Insides Company who received a R&D Experience grant from Callaghan Innovation to fund this study

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This was a retrospective cohort study from two tertiary centres in New Zealand; Starship Children's Hospital (Auckland) and Wellington Hospital. Ethical approval was granted by the Health and Disability Ethics Committee (HDEC) EXP14061, with locality approval at both sites (2023 LOCAL 14061 and 2023-CCHV-61).

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Data Availability: Data used for analysis will be made available upon reasonable request, conditional on ethical approvals

Grants: This project was supported by The Insides Company who received a R&D Experience grant from Callaghan Innovation to fund this study

Disclosures: TH, EL, IB, and CK work for, or are shareholders in the University of Auckland spin-out company The Insides Company. The remaining authors have no relevant conflicts to declare.