Use Of Perfusion Index As A Non-Invasive Predictor Of Post-Spinal Hypotension In Parturients Undergoing Elective Caesarean Section: A Prospective Observational Study

Abstract

Background: Post-spinal hypotension (PSH) is a common and potentially serious complication of spinal anaesthesia in obstetric practice. Early identification of patients at risk allows for timely preventive measures. The perfusion index (PI), a non-invasive measurement derived from pulse oximetry, may help predict PSH.

Methods: This prospective observational study was conducted on 92 healthy parturients scheduled for elective lower segment caesarean section (LSCS) under spinal anaesthesia. Preoperative PI was recorded using a Masimo pulse oximeter. Patients were monitored for 30 minutes post spinal block for the development of hypotension, defined as a fall in systolic blood pressure ≥25% from baseline or <90 mmHg. Receiver Operating Characteristic (ROC) curve analysis was used to determine the PI cut-off for predicting PSH.

Results: PSH occurred in 66 (71.74%) parturients. The mean baseline PI was significantly higher in the hypotension group (4.15 ± 1.19) than in the normotensive group (2.94 ± 0.96) (p < 0.0001). A PI value ≥3.5 predicted PSH with a sensitivity of 83.3% and specificity of 70.8%. The area under the ROC curve (AUC) was 0.845, indicating good diagnostic accuracy.

Conclusion: A baseline PI value ≥3.5 is a reliable predictor of PSH in parturients undergoing elective LSCS. Incorporating PI into preoperative assessment could help reduce maternal and fetal complications associated with PSH.