Constipation in critically ill adults

Table 1 Key definitions of constipation reported in the intensive care unit

Ref.	Definition of constipation used in the study	Setting	Remarks
Drossman et al[10], 2016	≥ 2 of 6 symptoms for ≥ 3 months, symptom onset ≥ 6 months prior (Rome IV criteria)	General population	Not validated in ICU patients; relies on patient self-report and chronic symptom history, which limits applicability in critical illness
Gacouin et al[11], 2010	Absence of bowel movement for ≥ 6 days after ICU admission	Medical ICU	Utilizes a longer bowel movement interval threshold compared to most ICU studies
Guardiola et al[12], 2016	Paralysis of the lower gastrointestinal tract	ICU	Proposes an alternative term to constipation in an ICU setting
Lewis and Heaton[13], 1997	Types 1-2 (hard, lumpy) suggest constipation (Bristol Stool Form Scale)	General population	Widely used to assess stool consistency; may serve as a complementary tool for assessing constipation in ICU patients
Mostafa et al[14], 2003	Failure for the bowel to open for 3 consecutive days	Surgical/medical ICU	Definition applied within a broader investigation of gastrointestinal dysfunction in ICU patients
Nassar et al[15], 2009	Need for treatment with laxatives or enemas	ICU	Defined by the need for pharmacological intervention
Patanwala et al[16], 2006	Absence of bowel movement within the first 4 days of ICU admission	Medical ICU	Adopts a 96-hour interval instead of the 72-hour period typical for ambulatory patients, accounting for the first 24 hours dedicated to patient stabilization, which can delay initiation of enteral nutrition or bowel regimen
van der Spoel et al[17], 2006	First defecation occurring after 6 days	Mixed ICU	One of the earliest studies proposing an ICU-specific operational definition of constipation

ICU: Intensive care unit.