Table 1. Descriptions and examples of acute gastrointestinal injury grade.

Grade	Description	Examples
I	increased risk of developing GI dysfunction or failure (a self-limiting condition)	Postoperative nausea and/or vomiting during the first days after abdominal surgery, postoperative absence of bowel sounds, diminished bowel motility in the early phase of shock
II	GI dysfunction (a condition that requires interventions)	Gastroparesis with high gastric residuals or reflux, paralysis of the lower GI tract, diarrhoea, IAH grade I (IAP 12–15 mmHg), visible blood in gastric content or stool. Feeding intolerance is present if at least 20 kcal/kg BW/day via enteral route cannot be reached within 72 h of feeding attempt
III	GI failure (GI function cannot be restored with interventions)	Despite treatment, feeding intolerance is persisting—high gastric residuals, persisting GI paralysis, occurrence or worsening of bowel dilatation, progression of IAH to grade II (IAP 15–20 mmHg), low APP (below 60 mmHg). Feeding intolerance is present and possibly associated with persistence or worsening of MODS
IV	Dramatically manifesting GI failure (a condition that is immediately life-threatening)	Bowel ischaemia with necrosis, GI bleeding leading to haemorrhagic shock, Ogilvie’s syndrome, ACS requiring decompression

GI, gastrointestinal; ACS, abdominal compartment syndrome; APP, abdominal perfusion pressure; MODS, multiple organ dysfunction syndrome; IAH, intra-abdominal hypertension; IAP, intra-abdominal pressure; BW, body weight.