Comparison of Hydroxyethyl Starch and Crystalloid Coload Combined With Norepinephrine Infusion for Hypotension

Comparison of 6% Hydroxyethyl Starch (130/0.4) and Crystalloid Coload Combined With Prophylactic Norepinephrine Infusion for Postspinal Anesthesia Hypotension in Patients Undergoing Caesarean Section

The purpose of this study is to investigate the ED50 and ED90 for an effective 6% Hydroxyethyl starch (130/0.4) or crystalloid coload combined with prophylactic norepinephrine infusion dose for postspinal anesthesia hypotension in patients undergoing cesarean section.

Post-spinal anesthesia hypotension is a frequent complication during spinal anesthesia for cesarean section. The incidence of post-spinal anesthesia hypotension is as high as 62.1-89.7% if prophylactic measures are not taken. Colloid fluid coload has been highly demonstrated for prevention and/or treatment of post-spinal anesthesia hypotension. In addition, there's some evidence that prophylactic infusion of norepinephrine could effectively reduce the incidence of post-spinal anesthesia hypotension in parturients undergoing cesarean section. However, the ED50 and ED90 for an effective 6% Hydroxyethyl starch (130/0.4) or crystalloid coload combined with prophylactic norepinephrine infusion dose for postspinal anesthesia hypotension is still unknown. The purpose of this study is to investigate the ED50 and ED90 for an effective 6% Hydroxyethyl starch (130/0.4) or crystalloid coload combined with prophylactic norepinephrine infusion dose for postspinal anesthesia hypotension in patients undergoing cesarean section.

Inclusion Criteria:

• 18-40 years
• Primipara or multipara
• Singleton pregnancy ≥ 37 weeks
• American Society of Anesthesiologists physical status classification I to II
• Scheduled for elective cesarean section under spinal anesthesia

Exclusion Criteria:

• Body height < 150 cm
• Body weight > 100 kg or body mass index (BMI) ≥ 40 kg/m2
• Eclampsia or chronic hypertension or baseline blood pressure ≥ 160mmHg
• Hemoglobin < 7g/dl
• Coagulation or renal function disorders
• Known allergy to hydroxyethyl starch
• Fetal distress, or known fetal developmental anomaly