Background and Goal of Study:The incidences of delirium in the intensive care unit among studies  vary  from 10% to 70% according to patient settings and tools for diagnosis of delirium.1 Delirium in the intensive care unit (ICU) increases the risk of prolonged mechanical ventilation, prolonged hospitalization, and mortality.2The purpose of the study was to determine if delirium in the surgical  intensive care units (SICU) was an independent risk factor of clinical outcomes during hospitalization.

Materials and Methods: A muti-center, prospective cohort study was conducted between April 2011 and January 2012. All patients who were admitted into nine university-based  SICU were enrolled. Delirium was diagosed by using Delirium Screening Checklists. The short term clinical outcomes of the study included ICU mortality and 28-day hospital mortality.  Cox proportional hazard multivariable regression analyses  were used to assess the effects of delirium on its clincal outcomes and presented with hazard ratio (HR) and 95% confidence interval (CI).Time to event was assessed using Kaplan Meier curve and compared using log-rank test. 

Results and Discussion: A total of 4,652 patients were included. One hundred and sixty three patients were dignosed delirium at some points during the ICU stays (3.5%, 163 out of 4,652). Patients who experienced delirium were significantly older (65.0± 15.8 years versus 61.6 ± 17.3 years, p = 0.013), and had higher ASA PS (24.3% versus 12.2, p < 0.001), higher Acute Physiology and Chronic Health Evaulation II score (APACHE II score) [16 (12-22) versus 10 (7-15), p < 0.001], and higher Sequential Organ Failure Assessment (SOFA) [5 (2-8) versus 2 (1-5), p < 0.001] compared to non delirium. Delirious patients also required longer ventilator days [7 (4-17) versus  2(1-4) days, p< 0.001], longer length of hospital stay [22 (14-34) versus 15 (9-26) days, p < 0.001], higher ICU mortality (24% versus 9.1%, p < 0.001) , and higher 28-day mortality (28.2% versus 13.3%, p < 0.001) (Table 1). Delieirous patients were associated with increased ICU mortality (adjusted HR = 3.46; 95% CI: 1.19-10.04, p = 0.022) and increased 28 –day mortality (adjusted HR = 2.93; 95% CI : 1.35-6.33, p = 0.006) (Table 2). Figure 1 shows Kaplan Meier curve of survival upto 28 days after admission into hospital of  both groups. The finding of this study was consistent with previous studies. 2-3

Conclusion
Delirium in ICU was a major predictor of  ICU mortality and 28 day hospital mortality . Early detection of delirium in the intensive care unit and treat the modifiable risk factors may improve chance of survival.

The impact of delirium on clinical outcomes in multi-center Thai surgical intensive care units: a prospective cohort study