Fecal Lactate and Resuscitation Outcomes in Critical Illness

This study evaluates the prognostic value of fecal lactate and the fecal-to-serum lactate gradient as early biomarkers of tissue hypoperfusion in critically ill patients. While serum lactate is widely used, it may not accurately reflect splanchnic perfusion. This prospective observational study aims to determine whether fecal lactate levels obtained within the first 12-24 hours can predict poor response to resuscitation at 24 hours. The primary outcome is a composite of increased vasopressor requirements, persistent hyperlactatemia, worsening organ dysfunction, or death.

Inclusion Criteria: * Adult patients ≥18 years admitted to the intensive care unit (ICU) * Evidence of tissue hypoperfusion defined by at least ONE of the following: Arterial serum lactate ≥2.0 mmol/L or Hypotension requiring vasopressors to maintain mean arterial pressure (MAP) ≥65 mmHg * Clinical signs of hypoperfusion (capillary refill time \>3 seconds or mottling score ≥2) * Availability of fecal sample within the first 24 hours of ICU admission Exclusion Criteria: * Active gastrointestinal bleeding * Recent abdominal surgery (\