Role of pulse plethysmograph in the prediction of hypotension in caesarean section patient under spinal anesthesia

Background: Spinal anesthesia is a commonly employed technique for anesthesia for caesarean section and is associated with hypotension which may cause maternal morbidity. Prediction of hypotension before the procedure can reduce complications. The study aimed to evaluate the role of pulse plethysmograph in the prediction of hypotension in caesarean section patients under spinal anesthesia. Methods: The observational study was conducted on 50 patients who were undergoing emergency or elective caesarean section. Spinal anesthesia was performed by anaesthesiologist using a 25 or 26-gauge spinal needle with bupivacaine at L3-4 interspinous space. Pre and post-anesthesia observations such as the width of pulse plethysmograph, non-invasive blood pressure in another arm, and heart rate were recorded. Paired T-test, Wilcoxon sign rank test, and chi-square test was used to analyse data using R Studio V 1.2.5001 software. Results: Post spinal anesthesia minor fall in systolic blood pressure (SBP) was observed in 11 patients, moderate fall in 21 patients, severe fall in 8 patients and a massive fall in 10 patients. A significant difference was observed between mean pre- and post-spinal anesthesia SBP (P<0.001). Width of pulse plethysmograph (PPG) was maintained in 14 patients whereas, narrowed and significantly narrowed PPGs were observed in 29 and 7 patients, respectively. Significant association was observed between grades of SBP and width of PPG (P<0.05). Receiver operating characteristic curve showed the width of PGG was good for prediction of hypotension in patient (AUC=0.828). Conclusion: Width of PPG can be used to predict SA induced maternal hypotension.