Management of Gastrointestinal Failure in ICU

Abstract

Althoughgastrointestinal dysfunction seemingly arises frequently in intensive care unit patients,it is usually underdiagnosed or underestimated, because the pathophysiology involved isincompletely understood and its exact clinical relevance still remains controversial with anunknown yet probably adverse impact on the patients’ outcome. The gut is considered to play a significant role in the processes of systemic inflammation, sepsis and multiple organdysfunction syndrome following hemorrhagic shock,trauma, burns, pancreatitis, major abdominal operations, andin critically ill patients in general.The concept of bacterial translocation and gut-origin sepsis as causes of systemic infectiouscomplications and multiple organ dysfunction syndrome in surgical and critically ill patientshas been a recurring issue over the last decades attracting the scientific interest. Gastrointestinal failure in ICU patients is often suspected by the lack of normal bowel sounds, regurgitation, vomiting, high gastric drainage volumes (>500 mL/day), diarrhea, abdominal distension or GI bleeding .Because clinical evaluation of the intestinal function is difficult, radiological signs are nonspecific, subtle or absent and there is lack of universally accepted criteria for gut failure in ICU patients, gut dysfunction often goes unrecognized, leading to poor outcomes. Intestinal obstruction belongs to highly severe conditions, requiring a quick and correct diagnosis as well as immediate, rational and effective therapy.Cardinal features of intestinal obstruction are Pain abdomen, Vomiting,Distension of abdomen,Constipation and Dehydration. Absence of passage of flatus and/or feces and abdominal distension are the most common symptoms and physical finding of patients with acute mechanical bowel obstruction, respectively. Although A wide spectrum of causes of intestinal obstruction but they mainly require rapid effective fluid and electrolytes resuscitation with close monitoring tostabilize the patient until proper management in done. Conservative treatment may be effective enough in some causes according the pathological mechanism (eg: paralytic ileus). Short bowel syndrome is defined as a group of problems related to poor absorption of nutrients causing disability.Short bowel syndrome is one of the most common forms of intestinal failure. Patients with Short bowel syndrome typically experience severe diarrhea, steatorrhea, nutrient deficiencies, electrolyte disturbances, dehydration, malnutrition, and weight loss. Common conditions resulting in Short bowel syndrome include surgical resection due to Crohn’s disease, ulcerative colitis, malignancy, mesenteric vascular disease, trauma, adhesions, or small bowel volvulus. Some patients also experience malabsorption due to irradiation and mucosal disease. According to the remaining segment the supportive nutrition is recommended. So fluid and nutritional support vary from patient to another somehow. Although the cause is mainly surgical removal of intestine the trials of intestinal implantation is carried out to increase the length of functioning intestine. The treatment of acute pancreatitis is purely symptomatic and supportive because there is no effective therapy to prevent the activation of inflammatory and proteolytic cascades. This vicious cycle of cell signaling is believed to be triggered by bacterial infection, predominately Gram-negative strains.The most likely hypothetical source of the bacterial infection is the gastrointestinal tract. Bacterial translocation is caused by increased permeability in the gut and a consequent migration of macromolecules such as bacteria, endotoxins and antigens from the gastrointestinal tract to the portal system, mesenteric lymph nodes, liver, spleen and pancreas. This process leads to the stimulation of macrophages, circulatory neutrophils and granulocytes, and then the release of pro-inflammatory cytokine causes an inflammatory response. If the inflammatory response, which is initially part of the defense mechanisms of the host, is over-activated, it may turn into a self-destructive process. The unbalanced production of inflammatory mediators might lead to the development of systemic inflammatory response syndrome (SIRS), infectious pancreatic necrosis and ultimately multi-organ failure (MOF). It is well known that several situations develop into acute pancreatitis, but the mechanisms and how those mechanisms develop the disease remain uncertain. Why do some individuals develop edematous pancreatitis and others develop a more severe necrotic pancreatitis, Knowledge regarding pancreatitis pathogenesis may have important implications in prevention and treatment of the disorder. If the early events that generate the inflammatory process are understood and if pro-and anti-inflammatory factors that modulate the severity of the disease are known treatment can be implemented so the process will not happen or possible associated complications will be minimized. The different scores aim to assess and predict the severity of the illness.