Evaluation of perfusion index to predict hypotension in lower segment caesarean section under spinal anaesthesia

Background: Spinal Anaesthesia is the most popular choice for elective caesarean section. Both general anaesthesia and regional anaesthesia are acceptable techniques for anaesthesia for elective and emergency caesarean sections. Objectives: The study aimed to investigate the role of the perfusion index in predicting the incidence of hypotension following spinal anaesthesia in parturients undergoing elective lower segment caesarean sections. Methods: A prospective, observational study was carried out among sixty parturients posted for elective caesarean section. The study was conducted in the operation theatres of Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi. About 60 participants were interviewed for the study. Data were entered and analysed with the help of the Statistical Package for Social Science (SPSS) version.16.                                                                              Results: Sixty eligible ASAI (American society of anaesthesiologist’s physical status classification) parturients scheduled for elective caesarean section were divided into two groups pre-operatively after determining their baseline Perfusion Index (PI) as those with PI ≤ 3.5 and those with PI > 3.5 using a Masimo® pulse oximeter probe. When comparing the heart rate at time intervals among the two groups, it became increasingly clear that those with baseline PI > 3.5 had generally higher heart rate especially immediately after the block and at 2nd, 4th, 6th,8th, 10th, 12th, 14th and 20th minutes. Conclusion: The study concludes that a Perfusion Index > 3.5 is associated with a higher incidence of hypotension in lower segment caesarean section under spinal anaesthesia. The hemodynamic parameters such as increased heart rate and significantly lower systolic, diastolic and mean arterial pressures in parturients with baseline PI > 3.5 suggest that these patients have lower baseline SVR and depleted autonomic resilience to hypotension compared to those with baseline PI ≤ 3.5. High BMI seems to be significantly associated with high baseline PI.