Delirium in the cardiac intensive care unit: Determinants and prognosis

Older and critically ill patients are at risk of delirium in hospital.

To explore the factors associated with and the prognostic value of delirium in older patients in a cardiac intensive care unit (CICU).

All consecutive patients aged>75years admitted to a CICU from January 2018 to December 2018 were included.

The study included 451 consecutive patients (47% male), with a median age of 83 (80-88)years and a median modified Charlson Comorbidity Index score of 1 (1-3). The median left ventricular ejection fraction was 55% (40-60%). The prevalence of delirium at admission was 6.8% (31 patients), and the frequency during the CICU stay was 11.9% (50 patients). Patients with delirium were older (P=0.044), with a history of cognitive disorders (P<0.001), stroke/transient ischaemic attack (P=0.046) and zopiclone use (P=0.001). Sepsis (odds ratio 22.8, 95% confidence interval [CI] 9-65; P<0.001) and cardiogenic shock (odds ratio 3.9, 95% CI 1.29-11.48; P=0.007) were pathological conditions present in patients with delirium. Geriatric factors associated with delirium were faecaloma (P=0.008), acute urinary retention (P=0.010), urinary catheter instauration (P<0.001) and opioid use (P=0.002). Patients with delirium had a longer CICU length of stay (3 (2-5) versus 2 (1-3) days; P<0.001) and a longer in-hospital length of stay (11 (5-21) versus 7 (3-12) days; P<0.001). In the multivariable analysis, delirium was associated with a higher risk of in-hospital death (hazard ratio 3.79, 95% CI 1.55-9.31: P=0.005), adjusted for N-terminal prohormone of B-type natriuretic peptide concentration.

The onset of delirium in older patients affects prognosis in the CICU. Physicians must search for geriatric factors, sepsis and cardiogenic shock in the context of delirium.