Association between Early Postoperative Systemic Inflammation Response Index and Prolonged Intensive Care Unit Stay After Elective Brain Tumor Surgery

Objective: The systemic inflammation response index (SIRI) is a novel inflammatory marker. This study aims to evaluate the association between early postoperative SIRI and a prolonged intensive care unit (ICU) stay exceeding 24 hours after brain tumor (BT) surgery. Methods: Patients aged 18 years or older who were admitted to the ICU following elective BT surgery between January 2023 and December 2024 were analyzed. Preoperative and postoperative variables were compared between patients with a short ICU stay (<24 hours) and those with a prolonged ICU stay. Logistic regression analyses were performed to evaluate the association between perioperative variables, including early postoperative SIRI, and prolonged ICU stay. Receiver operating characteristic (ROC) curve analysis, along with area under the curve (AUC) and Youden index, was conducted to assess the discriminatory performance of early postoperative SIRI. Results: A total of 206 patients who were admitted to the intensive care unit following elective BT surgery were included in the study. 109 patients were classified as having an ICU length of stay less than 24 hours, whereas 97 patients were classified as having an ICU length of stay exceeding 24 hours. In multivariable logistic regression analyses, hypertension (odds ratio [OR] = 4.365, 95% confidence interval (CI): 1.903-10.010, p = 0.001), postoperative SIRI level (OR = 1.090, 95% CI: 1.041-1.142, p < 0.001), hemorrhage (OR = 14.348, 95% CI: 1.663-123.812, p = 0.015), cerebral edema (OR = 5.972, 95% CI: 1.076-33.148, p = 0.041) and neurological deficit (OR = 2.582, 95% CI: 1.072-12.149, p = 0.032) were independently associated with prolonged ICU stay following BT surgery. Using prolonged ICU stay as the endpoint, ROC analysis identified an optimal SIRI cutoff value of 10.94, with a sensitivity of 56.7%, specificity of 81.7%, and an AUC of 0.728. Conclusion: Given the clinical importance of optimizing ICU resource utilization, early postoperative SIRI may provide adjunctive information reflecting postoperative inflammatory response associated with prolonged ICU stay, particularly when interpreted with other clinical parameters.