Prolonged Hospitalization Is a Risk Factor for Delirium Onset: One-Day Prevalence Study in Slovenian Intensive Care Units

Abstract

SUMMARYDelirium 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.

Predisposing and Precipitating Factors Associated With Delirium

“…Reasons for exclusion were no diagnosis by physician or research personnel (428 studies), no characterization of predisposing or precipitating factors (338 studies), retrospective study design (86 studies), not diagnosed by reference standard (108 studies), no multivariable model (43 studies), delirium assessment not conducted in person (25 studies), not cohort or case-control design (20 studies), sample included less than 50 patients (12 studies), abstract only (18 studies), cohort previously reported (3 studies), and pediatric population (1 studies). Ultimately, 315 studies…”

“…A list of included studies with number of participants and NOS score is included in eTable in Supplement 1). There were 138 studies (43.8%) that excluded participants due to a language barrier (participants were excluded if they did not speak the same language that delirium assessors used).…”

“…A total of 33 predisposing factors were identified. Advanced age and cognitive impairment or dementia were identified in the most studies and participants; 112 studies with 50 418 participants (among whom 9147 patients had delirium) identified age and 130 studies with 42 124 participants (among whom 9617 patients had delirium) identified cognitive impairment or dementia as factors. The following predisposing factors were variably defined across studies: functional impairment, cardiovascular disease, central nervous system disorders, and psychiatric disorders.…”

“…We conducted a systematic review of the literature to identify predisposing and precipitating factors associated with delirium. Across 315 included studies…”

Is It Time to Redefine Cognitive Dysfunction after Cardiac Surgery? The Importance of Methodological Consistency

“…On the other hand, early postoperative assessment should be at the earliest seven days following surgery to reduce the effect of surgical pain, pharmacological interventions and sleep deprivation on test findings 12 . Furthermore, as early postoperative period may be complicated by development of delirium, to avoid misleading diagnosis, and bearing in mind that delirium is a well-recognized predictor of POCD occurrence, neuropsychological testing must be accompanied with delirium assessment, and its appearance must be documented 8,16 . In addition, later postoperative cognitive evaluation most likely should be performed at three months after cardiac surgery, when full physical, neurophysiological, and emotional recovery from exhausting surgical procedure is expect-ed 5 .…”