To investigate the effect of acute hypervolumic hemodilution (AHHD) in cesarean section for pernicious placenta previa via arterial pressure-based cardiac output (APCO) .

Seventeen singleton pregnant women with pernicious placenta previa, who underwent selective cesarean section with general anesthesia in our hospital between August 2016 and February 2017, were included in the study. All patients were monitored for APCO, and the blood was diluted by 20 to 30 ml/kg after anesthesia induction. The fluid infusion rate was adjusted according to the stroke volume variation (SVV) and stroke volume index (SVI) , and the expansion time was controlled within 60 min. The hemodynamic parameters, such as heart rate, mean arterial pressure (MAP) , central venous pressure (CVP) , SVV, SVI, cardiac index (CI) , systemic vascular resistance (SVR) at each time points, including after the induction of general anesthesia (before blood dilution, T0) , before the fetal delivery (after blood dilution, T1) , when separating the placenta (when bleeding, T2) , when beginning blood transfusion (when the blood loss was large, T3) , and when closing the abdominal cavity (the blood transfusion was completed, T4) , were recorded. The blood gas analysis was performed at each time points also.

The CVP at T1 increased compared with that at T0, whereas increased compared with that at T2-T4 (all P<0.05) . The CI increased at T1-T3 compared with that at T0, and the SVI increased at T1-T4 compared with that at T0 (all P<0.05) . There were no significant changes in the CI and SVI between T2-T4 and T1 (all P>0.05) . The SVV at T1 was lower than that at T0, and the SVV at T3 was higher than that at T1 (both P<0.05) . The SVR at T1 and T2 decreased compared with that at T0 (both P<0.05) . The haematocrit (Hct) and hemoglobin (Hb) at T1-T4 decreased compared with those at T0 (all P<0.05) , whereas there were no statistically significant differences in the Hct and Hb between T2-T4 and T1 (all P>0.05) . The blood gas analysis showed that there were no statistically significant differences in the blood Na⁺, K⁺, Ca²⁺ and blood glucose between T1 and T0 (all P>0.05) . The blood pH and base excess at T1-T4 decreased compared with those at T0 (all P<0.05) . All patients received transfusion of blood products.

AHHD can effectively maintain the stability of intraoperative hemodynamics and internal environment under the guide of APCO.

Hemodilution; Arterial pressure-based cardiac output; Pernicious placenta previa; Cesarean section; Hemodynamics