Prevention of Hypotension following Spinal Anaesthesia for Caesarean Section: Comparison of Pretreatment with Crystalloid and Ephedrine Infusion

Abstract

BACKGROUND Regional anaesthesia has become the preferred technique for caesarean section because of higher incidence of maternal mortality and morbidity associated with general anaesthesia. Spinal hypotension occurs as a result of sympathetic blockade and decreased venous return due to decreased systemic vascular resistance and venous pooling. Such episodes of hypotension have been shown to cause decreased Apgar scores and foetal acidosis. Preloading with intravenous fluids, left uterine displacement and prophylactic/ therapeutic vasopressors have all been used in the prevention and management of hypotension traditionally. However no single method has been proved satisfactory. In terms of neonatal and maternal outcomes, prevention of hypotension is considered superior to treatment of established hypotension. In this study, we compare the efficacy of preloading of crystalloids with Ephedrine infusion in prevention of hypotension following spinal block in caesarean patients. Objectives- Primary objective is to determine the incidence of hypotension following spinal anaesthesia in patients receiving preloading with crystalloids and preloading with Ephedrine. Secondary objective is to compare intraoperative maternal and foetal adverse effects of pre-treatment with crystalloids and Ephedrine. METHODS An observational study was conducted in 90 patients belonging to ASA I and II categories undergoing elective LSCS. One category received 10ml/kg Ringer Lactate and other category 10mg Ephedrine in 10ml/kg Ringer Lactate 15-30 minutes prior to spinal block. All patients received SAB with 22.2ml 0.5% Bupivacaine heavy at L3-L4 space. HR and BP were monitored periodically and fall in MAP of ≥20% was noted and managed with rescue Ephedrine. Maternal adverse events, foetal APGAR scores and umbilical blood gas analysis noted. RESULTS Incidence of hypotension was significantly less in Ephedrine category as compared to crystalloid category. Incidence of maternal adverse events as well as foetal parameters was not significantly different. CONCLUSIONS Preloading with Ephedrine decreases the incidence of maternal hypotension when compared to crystalloids alone. KEY WORDS Caesarean Section, Crystalloids; Ephedrine, Foetal Acidosis, Mean Arterial BP, Preloading, Spinal Hypotension.