Changing trends in the management of hypotension following spinal anesthesia in cesarean section.

Hypotension during cesarean section under spinal anesthesia remains a frequent scenario in obstetric practice. A number of factors play a role in altering the incidence and severity of hypotension. Counteracting aortocaval compression does not significantly prevent hypotension in most singleton pregnancies. Intravenous crystalloid pre-hydration is not very efficient. Thus, the focus has changed toward co-hydration and use of colloids. Among vasopressors, phenylephrine is now established as a first line drug, although there is limited data in high-risk patients. Though ephedrine crosses the placenta more than phenylephrine and can possibly cause alterations in the fetal physiology, it has not been shown to affect the fetal Apgar or neurobehavioral scores.