Perfusion Index and its Relation to Hypotension of Parturients Undergoing Cesarean Section Under Spinal Anesthesia: An Observational Study

Background and Objective: Spinal anesthesia is preferred for cesarean deliveries; however, it causes hypotension in parturients. Clinicians prefer several methods to predict hypotension in parturients after spinal anesthesia. Generally, a non-invasive oscillometric method for the measurement of blood pressure is recommended for parturients; however, this method is unable to detect hypotensive episodes promptly. The objectives of this study were to establish a correlation between the intra-operative perfusion index and intra-operative hypotension in parturients undergoing cesarean section under spinal anesthesia. Materials and Methods: Total of 185 parturients who underwent cesarean section under spinal anesthesia (epidural ropivacaine) were included in the analysis. A drop of >= 20% in mean arterial blood pressure from baseline or <65 mmHg a diastolic blood pressure was considered hypotension. A total of 10 mg bolus of ephedrine was administered intravenously for hypotension. Results: After administration of spinal anesthesia to parturients, diastolic blood and mean arterial blood pressures (p<0.0001 for both) decreased and perfusion index (p = 0.0004) increased compared to their pre-operative conditions. A total of 120 (65%) parturients had an intra-operative perfusion index >= 3 and 65 (35%) parturients had an intra-operative perfusion index <3. Unlike parturients with an intra-operative perfusion index <3, parturients who had an intra-operative perfusion index >= 3 required administration of bolus ephedrine injection during cesarean section procedures (p<0.0001). Mean arterial blood pressure of parturients before cesarean section, intra-operative diastolic blood pressure, mean arterial blood pressure before administration of bolus ephedrine injection and changes in diastolic blood and mean arterial blood pressures of parturients after administration of spinal anesthesia were negatively correlated with perfusion index (p<0.0001 for all). Conclusion: The perfusion index is a useful tool for predicting intra-operative hypotension and its episodes in parturients undergoing cesarean section under spinal anesthesia.