Effect of Tourniquet Binding of Cervical on the Blood Volume of Amniotic Fluid in Cesarean Section

Amniotic fluid embolism (AFE) is a rare complication specially to obstetrics.When amniotic fluid enters the maternal circulation , a sudden onset of a series of pathophysiologic changes such as pulmonary hypertension, hypoxemia, circulatory failure, disseminated intravascular coagulation, and multiorgan failure may occur. Routinely, the typical AFE triad is uneasy to discover, and nonspecific adverse reactions such as irritability, chills, chest tightness and shortness of breath, transient drop in blood pressure, and nausea and vomiting are often seen during delivery of the fetus and placenta. All of the above symptoms may suggest that the amniotic fluid has entered into the bloodstream. In clinical anesthesia, investigators observed that women with placenta praevia and placenta implantation were less likely to suffer these nonspecific symptoms after delivery of the fetus compared with women with normal pregnancies.The investigators speculated it might be related to the fact that obstetricians used tourniquets to reduce intraoperative hemorrhage in the former, blocking venous return to the lower uterine segments to reduce the inflow of amniotic fluid into the uterus. Therefore, this study was conducted to investigate whether the use of tourniquet after delivery of the fetus could reduce the amount of amniotic fluid entering the bloodstream and thus reduce the incidence of intraoperative adverse events.