Baseline Perfusion Index as a Predictor of Post-spinal Hypotension in Elective Caesarean Section: A Prospective Observational Study.

Introduction Spinal anaesthesia is the preferred technique for cesarean delivery, but it is frequently associated with hypotension, leading to adverse maternal and fetal outcomes. Early prediction remains a clinical challenge. Perfusion index (PI), a non-invasive marker of peripheral perfusion, has emerged as a potential predictor. Methodology This prospective observational study included 100 parturients undergoing elective lower segment caesarean section under spinal anaesthesia. Baseline PI was recorded preoperatively, and patients were categorized into two groups: PI ≤3.5 and PI >3.5. Hypotension was defined as a mean arterial pressure of <65 mmHg. Hemodynamic parameters, vasopressor requirement, and fluid administration were recorded. Regression and ROC curve analysis were performed. Results The incidence of hypotension was significantly higher in the PI >3.5 group (84%) as compared to the PI ≤3.5 group (12%) (p < 0.001). Baseline PI was a strong predictor of hypotension (OR 4.69, p < 0.001). The model demonstrated good discriminative ability (AUC = 0.895), with sensitivity of 75% and specificity of 88.5%. Higher PI was also associated with increased vasopressor and fluid requirements. Conclusion Baseline PI is a reliable, non-invasive predictor of post-spinal hypotension in parturients. Its incorporation into routine preoperative assessment may enable early risk stratification and targeted haemodynamic management.