Preventive Intramuscular Phenylephrine in Elective Cesarean Section Under Spinal Anesthesia
Status:
Completed
Trial end date:
2018-08-31
Target enrollment:
Participant gender:
Summary
Spinal anesthesia is the preferred anesthesia method in cesarean section to provide
satisfactory analgesia and muscle relaxant with less impact on respiratory system. However,
hypotension often occurred due to the block of sympathetic nerve, causing maternal decline of
frontal lobe oxygenation, nausea vomit and the decrease of uteroplacental perfusion. Several
measures are used to prevent or treat hypotension caused by spinal anesthesia: prehydration,
limb compression, left lateral tilt of operation tables or usage of vasopressors. In the past
decade, the most recommended vasopressor to prevent or treat hypotension in spinal anesthesia
in cesarean section was phenylephrine, an α-adrenergic receptor, maintaining maternal blood
pressure and fetal acid-base state. In clinical work, there are two ways to use phenylephrine
: intravenous method with less onset time (several seconds and duration (several minutes) and
intramuscular method with longer onset time (10-15 minutes) and duration (1 hour). Many
trials demonstrated the protective effect of preventive intravenous phenylephrine on maternal
hemodynamics and neonatal acid-base status. However, few trials reported the effect of
preventive intramuscular phenylephrine on cesarean section under spinal anesthesia.