The central role of the gut in intensive care

Abstract

Critically ill patients undergo early impairment of their gut microbiota (GM) due to routine antibiotic therapies and other environmental factors leading to intestinal dysbiosis. The GM establishes connections with the rest of the human body along several axes representing critical inter-organ crosstalks that, once disrupted, play a major role in the pathophysiology of numerous diseases and their complications. Key players in this communication are GM metabolites such as short-chain fatty acids and bile acids, neurotransmitters, hormones, interleukins, and toxins. Intensivists juggle at the crossroad of multiple connections between the intestine and the rest of the body. Harnessing the GM in ICU could improve the management of several challenges, such as infections, traumatic brain injury, heart failure, kidney injury, and liver dysfunction. The study of molecular pathways affected by the GM in different clinical conditions is still at an early stage, and evidence in critically ill patients is lacking. This review aims to describe dysbiosis in critical illness and provide intensivists with a perspective on the potential as adjuvant strategies (e.g., nutrition, probiotics, prebiotics and synbiotics supplementation, adsorbent charcoal, beta-lactamase, and fecal microbiota transplantation) to modulate the GM in ICU patients and attempt to restore eubiosis.

Gastrointestinal function in critically ill patients

“…However, the precise role and underlying mechanisms are incompletely understood. The interactions between the gut and other organ systems, with a focus on the microbiome, were recently summarized [21].…”

“…Potential interactions and mechanisms between gastrointestinal dysfunction and multiple organ dysfunction during critical illness are visualized in Fig. 1 [3,[21][22][23][24][25][26][27][28][29].…”

Altered intestinal microbiome and metabolome correspond to the clinical outcome of sepsis

“…In some cases, sepsis progresses to multiple-organ dysfunction syndrome, which worsens outcomes. Accumulating evidence has established strong interactions between gut microbiota dysbiosis and the pathogenesis of multiple diseases, including sepsis [ 1 – 3 ]. During critical illness, gastrointestinal transit changes, as well as unique medication and nutrition patterns, can drive dramatic changes in the gut microbiota [ 1 ].…”

High Prevalence of Small Intestinal Bacterial Overgrowth Syndrome in ICU Patients: An Observational Study

“…18 On the other hand, gut dysbiosis in critically ill patients and its subsequent effect on the brain-gut, lung-gut, and heart-gut axis, among others, is a growing field of interest, but evidence concerning pathophysiology and underlying mechanisms is still scarce. 19…”

“…18 On the other hand, gut dysbiosis in critically ill patients and its subsequent effect on the brain-gut, lung-gut, and heart-gut axis, among others, is a growing field of interest, but evidence concerning pathophysiology and underlying mechanisms is still scarce. 19 The primary goal of our study was to assess the prevalence of SIBO in mechanically ventilated, critically ill patients. Secondary objectives included investigation of the effect of SIBO on intensive care unit (ICU) length of stay (LOS), ventilator-associated pneumonia (VAP), and all-cause in-hospital mortality rate in critically ill patients.…”