Spinal Anesthesia Induced Hypotension During Cesarean Section

Many women experience low blood pressure after spinal anesthesia for Cesarean section. This low blood pressure may result in nausea, vomiting dizziness and impairment of uterine blood flow.The purpose of this study is to compare two methods for preventing low blood pressure associated with spinal anesthesia during Cesarean sections. In both methods, we will attempt to prevent low blood pressure using phenylephrine infusion that has been shown to be effective in recent research. In addition to receiving phenylephrine one group of patients will receive standard salt solution (Ringer's lactate solution), while the other group will receive a different, intravenous fluid called hydroxyethylstarch.

Inclusion criteria

• American Society of Anesthesiologists (ASA) physical status I and II
• Elective cesarean section
• Weight 50-120 kg, Height 150-180 cm
• Normal singleton pregnancy
• Beyond 36 weeks gestation
• No known fetal abnormalities
• Ages 18-35

Exclusion criteria

• Contraindications to spinal anesthesia
• Multiple gestation, placenta previa, accreta
• Pregnancy induced hypertension or preeclampsia
• Diabetes mellitus, cardiovascular diseases
• Coagulopathy
• Spinal cord abnormalities, spinal surgery, or preexisting neurological dysfunction
• Baseline HR <65
• Failed spinal anesthesia/inadequate sensory block for surgery
• History of abnormal bleeding
• History of adverse reactions to hydroxyethylstarch