Prevalence of Delirium and Predictors of Longer Intensive Care Unit Stay

Introduction: The incidence of delirium varies in literature across the globe. Delirium is reported as one of the leading causes of increased length of hospital stay and mortality among intensive care unit (ICU) patients. This study aims to determine the prevalence and independent predictors of longer ICU stay among mechanically ventilated patients admitted into a medical ICU. Methods: In this prospective investigation, 207 consecutive patients admitted to the medical ICU beyond 72 h of mechanical ventilation at a tertiary care hospital between September 2020 and July 2021 were screened for delirium. ICU nurses assessed sedation and delirium status of patients after 72 h of mechanical ventilation using the Richmond Agitation Sedation Scale and Confusion Assessment Method for ICU. A multiple linear regression model was used to identify the predictors of more extended hospital stay, and the KaplanMeier curve was used to study time-to-event analysis. Results: Findings reveal that 161 (77.8%) patients develop delirium after 72 h of mechanical ventilation in the medical ICU. Patients who experienced delirium were advanced in age (mean ± standard deviation [SD]: 51.50 ± 14.97 vs. 37.39 ± 8.31 years, P ≤ 0.001), and more critically ill (mean ± SD: 15.84 ± 4.94 vs. 6.93 ± 2.07, P ≤ .001) and have multiple organs dysfunctions (mean ± SD: 12.56 ± 3.45 vs. 5.17 ± 1.83, P ≤ 0.001) at the time of admission compared to nondelirious patients. Patients who developed delirium significantly reported a higher oxygen flow (mean ± SD: 7.38 ± 1.08 vs. 6.30 ± 1.43 L/min, P = 0.001), a long duration of ICU stay (mean ± SD: 11.61 ± 1.71 vs. 9.24 ± 1.69 days, P ≤ 0.001), longer days on mechanical ventilation (mean ± SD: 8.44 ± 1.57 vs. 6.22 ± 1.46 days, P < 0.001) and shows higher in-hospital mortality ( P = 0.003). Acute Physiology and Chronic Health Evaluation-II (odds ratio [OR]: 0.068 95% CI: 0.027–0.019, P < 0.001) and SOFA (OR: 0.132, 95% CI: 0.075–0.189, P = 0.001) reported independent predictors of ICU stay after 72 h of ICU admission. Conclusions: Delirium was reported in more than two-thirds of patients after 72 h of mechanical ventilation. The severity of illness and multiple organ dysfunctions reported independent predictors for longer days of ICU stay.