Carbohydrates induce liver test disturbances in case of treatment of critically ill patients with triple chamber parenteral nutrition bags, even with disturbed liver test at start. Lipids and proteins do not.

Rationale
Parenteral Nutrition Associated Liver Disease (PNALD) is often reported in an ICU setting.(1) Mechanisms and magnitude of impact remain largely unknown. (2) We aimed to investigate which parameters contribute to liver disturbances (LD).

Methods
Adult patients admitted to a tertiary intensive care department for at least 3 days (Jan 2017-Dec 2019) and treated with PN (three components) ≥3 days were included in a retrospective single centre cohort study. Patients were divided in two groups: with or without LD, defined as 2 out of 3 liver parameters (AST, ALT or AP) elevated (≥ 1.5x Upper Limit of Normal) at day 1 of PN. To assess contributions of proteins, lipids and carbohydrates (CH) on AST, ALT, AP, GGT, TB and INR (set as dependent variables) a linear mixed-effect model using SPSS version 28, was used.

Results
Out of 224 patients, 62 (28%) patients had LD and 162 (72%) did not at start of PN treatment. Mean age was 60 ± 17 years with and 65 ± 16 years without LD. Female 38%/37%. Carbohydrates contribute significantly to an increase of gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) both in patients with and without LD. No significant evidence was found for lipids and proteins in both models.

Conclusions
In critically ill patients treated with PN for at least 3 days with triple chamber bags, only the volume of CH is a contributing factor to an increase of GGT, ALT and AST. For proteins and lipids, no significant evidence was found that they would cause a further deterioration of liver values. This challenges common knowledge and requires further research.