The factors of maternal hypotension undergoing elective cesarean section with combined spinal epidural anesthesia and the prevention method

Abstract

Objective To analyze the factors of maternal hypotension undergoing elective cesarean section with combined spinal epidural anesthesia (CSEA), and to investigate the prevention method. Methods A retrospective study was conducted in 240 pregnant women undergoing ASA Ⅰ-Ⅱ elective cesarean section with CSEA, who were admitted to The Third Affiliated Hospital of Guangzhou Medical University from June 2010 to May 2010. The dependent variable was the person-time of hypotension, and the 18 independent variables were capacity control, usage of phenylephrine, the variety of anesthetics, intervals of blood pressure measuring, maternal age, height, body weight, body mass index, the dosage of hemabate, the continuous dose and total dosage of phenylephrine, intraoperative dosage of venous transfusion, the amount of liquid input before anesthesia, the total liquid amount, intraoperative blood loss volume, operative time, tactile sensation block level and pressure sensitivity block level. The data were analyzed by multiple linear regression models. According to the usage of phenylephrine, we regrouped the patients into 3 groups: without preventive treatment group, preventive treatment group, preventive treatment plus persistent treatment group. The pH value, base excess (BE) of newborn′s umbilical venous blood and the 1 minute Apgar score after birth of the 3 groups were analyzed by the one-way analysis of variance. Results The multiple linear regression equation for predicting hypotension: the person-time of hypotension=0.218-34.206 the continuous dose of phenylephrine + 1.096 the total dosage of phenylephrine -0.214 the variety of anesthetics. The person-time of hypotension of the 3 groups were 3.53±2.02, 2.76±1.81 and 0.88±1.17, respectively. The person-time of hypotension of preventive treatment plus persistent treatment group were obviously less than the other two groups (P 0.05). The results showed that a dose of phenylephrine (1 μg/kg) plus a maintenance dose [0.25-0.35 μg/(kg·min)] through an intravenous injection during CSEA was an effective method to prevent hypotension. Conclusions The maintenance dose of phenylephrine is the main factor for maternal hypotension undergoing elective cesarean section with CSEA. Key words: Cesarean section; Anesthesia, obstetrical; Anesthetics, combined; Hypotension; Prevention