Delirium in the ICU: how much do we know? A narrative review

Abstract

Delirium in critical ill patients is a complex and common neurological syndrome in the intensive care unit (ICU) that is caused by a range of structural or functional abnormalities. ICU Delirium is associated with reduced compliance, prolonged hospital stays, greater use or delayed withdrawal of sedatives, higher rates and durations of mechanical ventilation, and higher rates of mortality. The aetiology and pathogenesis of ICU delirium are unclear, and the lack of better prediction, prevention, and treatment measures leads to a non-standardized control of delirium. By searching the relevant literature, we aim in this narrative review to describe progress in the pathogenesis, predictive biomarkers, diagnosis, and treatment of ICU delirium.

Keywords: Delirium; biomarkers; diagnosis; intensive care unit; treatment.

Figure 1.

Potential pathophysiology of delirium. IL-1β, interleukin 1β; IL-2, interleukin 2; IL-6, interleukin 6; CRP, C-reactive protein; TNF-α, tumour necrosis factor α; CCL-2, C-C chemokine ligand 2; CXCL-1, chemokine C-X-C motif ligand 1; HARs, human accelerated regions; MTNR1B, melatonin receptor 1B gene; Apo-E, apolipoprotein E; SAA, serum anticholinergic activity; CSF AA, cerebrospinal fluid anticholinergic activity; 5-HT, serotonin; 6-SMT, 6-hydroxymelatonin sulfate; S-100β, S100 calbindin B; NSE, neuron-specific enolase. Drawn with Figdraw.

Figure 2.

Classification of pharmaceutical interventions for delirium.