Relationship between Delirium, Acute Respiratory Distress Syndrome (ARDS), and In-hospital mortality to the patients in Intensive Care Unit (ICU).

Abstract

Objective: To risk of acute respiratory distress syndrome (ARDS) mortality in intensive care unit (ICU) and know the extent to which delirium and persistent coma influence the association between ARDS and in-hospital mortality issues of critical care infrastructure. Study Design: Prospective Observational Cohort study. Setting: Bakhtawar Amin Memorial Trust Teaching Hospital, Multan. Period: December 2025 to February 2026. Methods: Adult patients (≥18 years) admitted in ICU were enrolled. Daily delirium screening was performed using the Confusion Assessment Method for the ICU (CAM-ICU) combined with the Richmond Agitation–Sedation Scale (RASS). ARDS was diagnosed according to the 2012 Berlin Definition. Multivariable logistic regression was used to evaluate associations, adjusting for age, APACHE II score, duration of mechanical ventilation, sedative exposure, and comorbidities. Results: Of 612 enrolled patients, 57 (9.3%) were diagnosed with ARDS. Delirium occurred in 68% of intubated ARDS patients, compared to 49% in intubated non-ARDS patients and 19% in non-intubated patients (P < 0.001). After multivariable adjustment, ARDS was independently associated with a 5.8-fold increased odds of delirium relative to non-intubated patients (adjusted odds ratio [aOR] = 5.82; 95% CI: 1.42–23.85; P = 0.014), whereas mechanical ventilation without ARDS conferred a more modest increase (aOR = 2.04; 95% CI: 1.18–3.51; P = 0.011). In unadjusted analysis, ARDS was linked to a 9.7 fold higher odds of in-hospital mortality (OR = 9.71; 95% CI: 2.94–32.08). However, this association weakened considerably after adjusting for delirium and persistent coma (aOR = 4.96; 95% CI: 1.38–17.82), suggesting partial mediation by neurological complications. Conclusion: In ICU setting, ARDS is a significant independent risk factor for ICU delirium beyond the effects of mechanical ventilation alone. Moreover, delirium and coma appear to mediate a substantial portion of the mortality risk associated with ARDS. These findings emphasize the critical need for structured delirium prevention protocols including conservative sedation, early mobilization, and routine cognitive screening in ARDS management within Pakistan’s resource-limited critical care environments.