Impact of Intravenous Fluids and Enteral Nutrition on the Severity of Gastrointestinal Dysfunction: A Systematic Review and Meta-analysis

INTRODUCTION: Gastrointestinal dysfunction (GDF) is one of the primary causes of morbidity and mortality in critically ill patients. Intensive care interventions, such as intravenous fluids and enteral feeding, can exacerbate GDF. There exists a paucity of high-quality literature on the interaction between these two modalities (intravenous fluids and enteral feeding) as a combined therapy on its impact on GDF. AIM: To review the impact of intravenous fluids and enteral nutrition individually on determinants of gut function and implications in clinical practice. METHODS: Randomized controlled trials on intravenous fluids and enteral feeding on GDF were identified by a comprehensive database search of MEDLINE and EMBASE. Extraction of data was conducted for study characteristics, provision of fluids or feeding in both groups and quality of studies was assessed using the Cochrane criteria. A random-effects model was applied to estimate the impact of these interventions across the spectrum of GDF severity. RESULTS: Restricted/ goal-directed intravenous fluid therapy is likely to reduce ‘mild’ GDF such as vomiting (p = 0.03) compared to a standard/ liberal intravenous fluid regime. Enterally fed patients experienced increased episodes of vomiting (p = <0.01) but were less likely to develop an anastomotic leak (p = 0.03) and peritonitis (p = 0.03) compared to parenterally fed patients. Vomiting (p = <0.01) and anastomotic leak (p = 0.04) were significantly lower in the early enteral feeding group. CONCLUSIONS: There is less emphasis on the combined approach of intravenous fluid resuscitation and enteral feeding in critically ill patients. Conservative fluid resuscitation and aggressive enteral feeding are presumably key factors contributing to severe life-threatening GDF. Future trials should evaluate the impact of cross-interaction between conservative and aggressive modes of these two interventions on the severity of GDF.