Unraveling the Link: A Systematic Review and Meta analysis of Acute Respiratory Distress Syndrome and Delirium

Background Acute Respiratory Distress Syndrome (ARDS) is a critical condition characterized by severe hypoxemia and pulmonary edema, often resulting from pneumonia, sepsis, trauma, or aspiration. It affects 10-15% of ICU patients and is associated with high mortality rates (30-40%). Delirium, an acute cognitive impairment, is prevalent in critically ill patients, particularly in the ICU, and correlates with adverse outcomes. Objective This systematic review and meta-analysis aim to summarize the current evidence regarding the relationship between ARDS and delirium, focusing on the prevalence of delirium in ARDS patients, its impact on delirium development and mortality, potential correlations between the two conditions, and their clinical outcomes. Methods A systematic search was conducted across PubMed, Scopus, and Web of Science from inception until September 2024, leading to the identification of 838 records. Pooled risk ratios and prevalence were calculated using a random-effects model. The risk of bias was assessed using the revised Cochrane risk of bias tool for randomized trials (RoB2) and Risk of Bias in non-randomized studies of interventions (ROBINS-I) tool. Results Thirteen studies involving 10,052 patients with ARDS were included. The pooled prevalence of delirium among ARDS patients was 41% (95% CI: 23%–58%), with substantial heterogeneity. Meta-analysis showed a higher risk of delirium among ARDS patients compared with controls; however, this association was not statistically significant (RR 1.34, 95% CI: 0.63–2.83). No statistically significant associations were observed between delirium and comorbid depression or anxiety. Delirium in ARDS patients was consistently associated with prolonged ICU stay, longer mechanical ventilation, and adverse clinical outcomes. Conclusion Patients with ARDS frequently experience delirium, resulting in extended ICU admissions, prolonged mechanical ventilation, and cognitive impairment. Hypoxia, inflammation, sedation, and psychological factors contributes to delirium risk in ARDS patients. A multidisciplinary approach incorporating sedative minimization, early mobilization, and psychological support may mitigate delirium and improve patient outcomes. PROSPERO registration number (CRD42024564895): https://www.crd.york.ac.uk/PROSPERO/view/CRD42024564895