Pre-delivery hypotension after spinal anesthesia during cesarean section and its associated factors at Jigme Dorji Wangchuck National Referral Hospital, Bhutan

Introduction: The current choice of anesthesia for the cesarean section is spinal anesthesia. However, hypotension is the major complication. If promptly not recognized and treated, it increases the morbidity and mortality of the mother and fetus. This study was conducted to evaluate the rate of pre-delivery hypotension and risk factors following spinal anesthesia for cesarean section at the National Referral Hospital in Bhutan. Methods: A cohort study was conducted from 1st October 2018 to 30th June 2019 on 350 women undergoing cesarean section under spinal anesthesia. Pre-delivery hypotension was defined as systolic blood pressure < 100 mm Hg. The association of factors for hypotension was tested using multivariable binary logistic regression using a forward stepwise model. A p-value < 0.05 was considered significant. Results: The rate of pre-delivery hypotension was 74.6 % (n=261). History of hypertension during pregnancy (Adjusted OR 0.25, [0.11-0.60], p=0.013), prophylaxis use of ephedrine (Adjusted OR 0.45, [0.22-0.92], p= 0.024) and ondansetron (Adjusted OR 0.43, [0.22-0.82], p= 0.010),longer preoperative fasting duration (Adjusted OR 1.12, [1.01-1.21], p=0.024,), sensory block level <= T4 (Adjusted OR 3.4, [1.8-6.4], p=<0.001) and baseline systolic blood pressure less than or equal to 120 mmHg (Adjusted OR 2.8, [1.5-5.1], p=0.001) were significant risk factors. Conclusions: This study conduces that the rate of pre-delivery hypotension following spinal anesthesia in a cesarean section was high among women undergoing cesarean section. It is alarming as around two-third of women and fetus undergoing cesarean section under spinal anesthesia are at risk of consequences of hypotension. Most of the risk factors in the study are modifiable. The study suggests that if the anesthesia provider intervenes in managing the modifiable risk factors and treat hypotension promptly, it can help reduce the risk of women and fetus to spinal hypotension consequences.