The Incidence and Prognosis of ICU Delirium: A Retrospective Study from a Single Center

Purpose Delirium is a frequent occurrence amongst Intensive Care Unit (ICU) patients, but studies on its causes are sparse and its risk factors vary from disease to disease. Here, in this study, an attempt was made to investigate the factors associated with the prognosis of delirium in the ICU. Methods An observed study was performed of consecutive patients from September 2016 to November 2016 who were admitted to the ICU. The patients were screened for delirium by using the diagnostic tools of the Richmond Agitation Sedation Scale score and the Confusion Assessment Method ICU. Patients were divided into subgroups according to heart/vascular, cerebral, pulmonary, maxillofacial/limbs, obstetric, urinary and spinal disease. Results A total of 406 patients of which 186 developed delirium (45.8%). The main causes of delirium were different. The only independent factor for delirium in heart and vascular subgroups was the quality of sleep (Odds Ratio (OR) = 0.236, p < 0.001 [0.111–0.500]). For those with intestinal disease, the risk factors included age (OR = 2.514, p = 0.002 [1.397–4.524]), use of vasoactive therapies (OR = 13.799, p = 0.002 [2.669–71.361]) and the quality of sleep (OR = 0.114, p < 0.001 [0.036–0.366]). Older age (OR = 1.100, p = 0.022 [1.014–1.194]), higher acute physiology, age and chronic health evaluation II scales (OR = 1.255, p < 0.001 [1.112–1.417]) and the quality of sleep (OR = 0.090, p = 0.034 [0.010–0.829]) were noted as risk factors for septic shock patients. Delirium led to extended ICU-stays ( p < 0.001), and only the subgroups of septic shock patients showed a difference in 28-day mortality rates ( p = 0.006). Conclusion The incidence of delirium and its associated risk factors varied according to disease type. In the study cohort, the highest 28-day mortality was recorded for the patients admitted for septic shock who had developed delirium.