Category: Nutrition

Enteral feeding, even when the gut does not feel very good?

Purpose of review

To summarize knowledge on the gut function in relation to enteral nutrition.

Recent findings

The gut is certainly suffering during critical illness but our understanding of the exact mechanisms involved is limited. Physicians at bedside are lacking tools to identify how well or bad the gut is doing and whether the gut is responding adequately to critical illness. Sensing nutrition as a signal is important for the gut and microbiome. Enteral nutrition has beneficial effects for the gut perfusion and function. However, early full enteral nutrition in patients with shock was associated with an increased number of rare but serious complications.

Summary

Whenever synthesizing knowledge in physiology and available evidence in critically ill, we suggest that enteral nutrition has beneficial effects but may turn harmful if provided too aggressively. Contraindications to enteral nutrition are listed in recent guidelines. For patients with gastrointestinal dysfunction but without these contraindications, we suggest considering early enteral nutrition as a signal to the gut and to the body rather than an energy and protein provision. With this rationale, we think that low dose of enteral nutrition could and probably should be provided also when the gut does not feel very good. Understanding the feedback from the gut in response to enteral nutrition would be important, however, monitoring tools are currently limited to clinical assessment only.

Correspondence to Annika Reintam Blaser, Department of Anaesthesiology and Intensive Care, University of Tartu, Puusepa 8, Tartu 50406, Estonia. E-mail: annika.reintam.blaser@ut.ee

Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.

Nutrition, defecation, and the lower gastrointestinal tract during critical illness

Purpose of review

The goal of this report is to delineate the correlation between constipation as a manifestation of impaired gastrointestinal transit with adverse clinical outcomes, to identify risk factors, which predispose to this condition, and outline a management scheme for prophylactic treatment.

Recent findings

Constipation is common in the ICU, affecting upwards of 60–85% of critically ill patients. As suggested by case series and observational studies, constipation may be an independent prognostic factor identifying patients with greater disease severity, higher likelihood of organ dysfunction, longer duration of mechanical ventilation, prolonged hospital length of stay, and possibly reduced survival. Treating constipation is a low priority for intensivists often relegated to the nursing service, and few ICUs have well designed protocols in place for a bowel regimen. Small randomized controlled trials show improvement in certain outcome parameters in response to a daily lactulose therapy; hospital length of stay, sequential organ failure assessment scores, and duration of mechanical ventilation. However, aggregating the data from these studies in two separate meta-analyses showed that the effect of a bowel regimen on these three endpoints were not statistically different.

Summary

No causal relationship can be determined between constipation and adverse outcomes. Nonetheless, a clinical correlation seems to exist. Whether constipation is an epiphenomenon or simply a reflection of greater severity of critical illness, at some point it may contribute to worsening morbidity in the ICU. A graded prophylactic bowel regimen should help reverse impairment of the gastrointestinal transit and aid in reducing its deleterious impact on the hospital course of the critically ill patient.

Correspondence to Stephen A. McClave, MD, Professor of Medicine, Director of Clinical Nutrition, Division of Gastroenterology, Hepatology, and Nutrition, University of Louisville School of Medicine, Louisville, KY 40205, USA. Tel: +1 502 262 8677; fax: +1 502 562 3967; e-mail: samcclave@louisville.edu

Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.

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