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 (SpO2) remains uncertain. We analyzed 1935 adults with HS from the Medical Information Mart for Intensive Care IV (MIMIC-IV, v3.1). SpO2 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 SpO2, Glasgow Coma Scale (GCS), and their combination. Delirium occurred most frequently in the high SpO2 group (29.6%), followed by the low (19.7%) and moderate groups (17.6%). Compared with the moderate group, high SpO2 was consistently associated with increased delirium risk (adjusted odds ratio: 1.855-1.998; all P < .001), while low SpO2 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 SpO2 with GCS improved prediction (AUC = 0.702) compared with either alone. High SpO2 (>98%) was independently associated with increased delirium risk, while low SpO2 (<95%) showed a nonlinear trend but was not statistically significant in fully adjusted categorical models. Maintaining SpO2 around 95% to 98% and integrating SpO2 with GCS may aid early risk stratification.