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

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.

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.

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.