Association of oxygen saturation with delirium in hemorrhagic stroke: A retrospective cohort study using MIMIC-IV

Delirium is a common complication in patients with hemorrhagic stroke (HS) admitted to intensive care, but its association with peripheral oxygen saturation (SpO 2 ) remains uncertain. We analyzed 1935 adults with HS from the Medical Information Mart for Intensive Care IV (MIMIC-IV, v3.1). SpO 2 was recorded and categorized as low (<95%), moderate (95–98%), or high (>98%) after intensive care unit (ICU) admission. Delirium was identified using the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU). Associations were assessed with multivariable logistic regression, restricted cubic spline (RCS) modeling, subgroup analyses, and receiver operating characteristic (ROC) curves for SpO 2 , Glasgow Coma Scale (GCS), and their combination. Delirium occurred most frequently in the high SpO 2 group (29.6%), followed by the low (19.7%) and moderate groups (17.6%). Compared with the moderate group, high SpO 2 was consistently associated with increased delirium risk (adjusted odds ratio: 1.855–1.998; all P < .001), while low SpO 2 showed no independent association. RCS analysis demonstrated a U-shaped relationship with the lowest risk between 95% and 98%. Subgroup analyses confirmed consistency across patient characteristics. Combining SpO 2 with GCS improved prediction (AUC = 0.702) compared with either alone. High SpO 2 (>98%) was independently associated with increased delirium risk, while low SpO 2 (<95%) showed a nonlinear trend but was not statistically significant in fully adjusted categorical models. Maintaining SpO 2 around 95% to 98% and integrating SpO 2 with GCS may aid early risk stratification.