Hypotension is a common problem during spinal anesthesia for cesarean delivery. Intravenous fluid loading is used to correct preoperative dehydration and reduce the incidence and severity of hypotension. Different fluid regimens have been studied but colloid preload and crystalloid co-load have not been compared.
In this randomized double-blind study, 210 patients scheduled for elective cesarean section under spinal anesthesia were randomly allocated to receive either 6% hydroxyethyl starch 130/0.4 500 mL before spinal anesthesia (colloid preload) or Ringer's acetate solution 1000 mL administered rapidly starting with intrathecal injection (crystalloid co-load). Maternal hypotension (systolic blood pressure <80% of baseline or <90 mmHg) and severe hypotension (systolic blood pressure <80 mmHg) were treated with 5 and 10mg ephedrine boluses, respectively. The primary outcome was the incidence of hypotension. Secondary outcomes included the incidence of severe hypotension, total ephedrine dose, nausea and vomiting and neonatal outcome assessed by Apgar scores and umbilical artery blood gas analysis.
Data analysis was performed on 205 patients; 103 in the colloid preload group and 102 in the crystalloid co-load group. There were no significant differences in the incidence of hypotension (52.4% vs. 42.2%; P=0.18) or severe hypotension (15.5% vs. 9.8%; P=0.31) between colloid preload and crystalloid co-load groups, respectively. The median [range] ephedrine dose was 5 [0-45]mg in the colloid preload group and 0 [0-35]mg in the crystalloid co-load group (P=0.065). There were no significant differences in maternal nausea or vomiting or neonatal outcomes between groups.
The use of 1000 mL crystalloid co-load has similar effect to 500 mL colloid preload in reducing the incidence of hypotension after spinal anesthesia for elective cesarean delivery. Neither technique can totally prevent hypotension and should be combined with vasopressor use.