OBJECTIVES: To assess the delirium severity (DS), its risk factors and association with adverse patient outcomes in chronically critically ill (CCI) patients.

DESIGN: A prospective cohort study.

SETTING: A tertiary care hospital with postacute intensive care units (ICUs) in Germany.

PARTICIPANTS: N=267 CCI patients with critical illness polyneuropathy and/or critical illness myopathy, aged 18-75 years, who had undergone elective tracheotomy for weaning failure.

INTERVENTIONS: None.

MEASURES: Primary outcomes: DS was assessed using the Confusion Assessment Method for the Intensive Care Unit-7 delirium severity score, within 4 weeks (t1) after the transfer to a tertiary care hospital. In post hoc analyses, univariate linear regressions were employed, examining the relationship of DS with clinical, sociodemographic and psychological variables. Secondary outcomes: additionally, correlations of DS with fatigue (using the Multidimensional Fatigue Inventory-20), quality of life (using the Euro-Quality of Life) and institutionalisation/mortality at 3 (t2) and 6 (t3) months follow-up were computed.

RESULTS: Of the N=267 patients analysed, 9.4% showed severe or most severe delirium symptoms. 4.1% had a full-syndromal delirium. DS was significantly associated with the severity of illness (p=0.016, 95% CI -0.1 to -0.3), number of medical comorbidities (p<0.001, 95% CI .1 to .3) and sepsis (p<0.001, 95% CI .3 to 1.0). Patients with a higher DS at postacute ICU (t1), showed a higher mental fatigue at t2 (p=0.008, 95% CI .13 to .37) and an increased risk for institutionalisation/mortality (p=0.043, 95% CI 1.1 to 28.9/p=0.015, 95% CI 1.5 to 43.2).

CONCLUSIONS: Illness severity is positively associated with DS during postacute care in CCI patients. An adequate management of delirium is essential in order to mitigate functional and cognitive long-term sequelae following ICU.

TRIAL REGISTRATION NUMBER: DRKS00003386.