Prediction of Maternal Arterial Hypotension After Spinal Anesthesia by Passive Leg Raise Test.

Spinal anesthesia for cesarean section is associated with a high incidence of low blood pressure. However, the pathophysiology of this arterial hypotension is not unequivocal and could involve, in addition to drug vasoplegia, a mechanical cause linked to lower caval compression or even true or relative hypovolemia. Passive leg raise test has been proposed in an attempt to identify parturients who are more likely to develop low blood pressure after spinal anesthesia. Nevertheless, the data available on this volume expansion test to predict hemodynamic variations after performing spinal anesthesia are still limited and few objective criteria have been described to predict this arterial hypotension. The objective of the research is to study the hypothesis according to which the presence of hypovolaemia (true or relative) objectified by a positive passive leg raise test would cause hypotension more frequent and more marked in intensity. Patients will have a clinical hemodynamic and echocardiographic evaluation, before performing the spinal anesthesia, before and after the passive leg raise test. Then, the patients will benefit from a clinical hemodynamic evaluation during the preparation of the parturient in the operating room and finally after the completion of the spinal anesthesia and until the clamping of the umbilical cord.