Fluid and vasopressor management for Cesarean delivery under spinal anesthesia: continuing professional development

Area of Science:

• Anesthesiology
• Obstetrics
• Pharmacology

Background:

• Spinal anesthesia commonly causes maternal hypotension in pregnant women.
• Understanding the physiological mechanisms and management strategies is crucial for patient safety.

Purpose of the Study:

• To review the physiology of maternal hypotension following spinal anesthesia.
• To evaluate the efficacy of fluids and vasopressors in managing this condition.

Main Methods:

• Review of physiological responses to spinal anesthesia.
• Analysis of fluid administration strategies (colloid/crystalloid preload/coload).
• Comparison of vasopressor agents (ephedrine vs. phenylephrine) and administration methods (bolus vs. infusion).

Main Results:

• Maternal hypotension is mainly due to peripheral vasodilation, not decreased cardiac output.
• Colloid preload, colloid coload, and crystalloid coload are effective fluid strategies; crystalloid preload is less effective.
• Phenylephrine is preferred over ephedrine due to risks of fetal acidosis; phenylephrine infusions are more effective than boluses.
• Pre-eclamptic patients experience less hypotension and tolerate moderate volume loading, but require cautious fluid management due to pulmonary edema risk.

Conclusions:

• Adopt fluid loading regimens other than crystalloid preload.
• Phenylephrine infusion during Cesarean delivery is safe and beneficial for mother and neonate.