Prolonged hospitalization is a risk factor for delirium onset: one-day prevalence study in Slovenian INTENSIVE CARE UNITS

Delirium is a clinical syndrome often underestimated in the intensive care units (ICU). The aim of this study was to determine the prevalence and factors that influence the onset of delirium. A questionnaire was sent to intensivists in Slovenian ICUs, who estimated the prevalence of delirious patients. The questionnaire consisted of demographic data, type of ICU, diagnosis, reason for admission to the ICU, type of anesthesia and surgery, clinical condition, type of supportive therapy, presence of delirium, data on discharge, transfers between departments or patient outcome on day 30. Patient consciousness was assessed by the Richmond Agitation-Sedation Scale (RASS) and the presence of delirium by the validated delirium-screening Confusion Assessment Method for the ICU (CAM-ICU). Replies received from intensivists included data on 103 patients. According to RASS ≥-3, the prevalence of delirium was 9.5% (7 out of 74 patients). There was no difference in the prevalence of delirium between surgical and medical ICU patients (p=0.388). Delirious patients had longer hospital stay (p=0.002) and ICU stay (p=0.032) compared to patients without delirium. All delirious patients survived until day 30, whereas 19 patients without delirium died (p=0.092). Logistic regression analysis dismissed any association of delirium with patient mortality (p=0.998). Age, gender, anesthesia, mechanical ventilation, and type of surgical procedure could not be evaluated as risk factors for delirium. In Slovenian ICUs, a lower proportion of delirium was observed, as reported from similar studies. Risk factors such as gender, age, mechanical ventilation, sedation, anesthesia, or department could not predict delirium. However, prolonged hospitalization of ICU patients could predict the onset of delirium, but the presence of delirium did not increase patient mortality.