Background and Goal of the Study
Spinal anesthesia is considered gold standard anesthetic technique for cesarean deliveries (CD) but is associated with a high rate of hypotension. The recent international consensus recommends continuous prophylactic phenylephrine infusion (PPI) administered throughout CD titrated to blood pressure measurements to prevent hypotension. However little information is available on hemodynamic profiles of women with twin pregnancies as compared to singleton pregnancies perioperatively. Therefore, in this study we aim to compare maternal hemodynamic changes both intraoperatively and postoperatively with the use of the NICAS bio impendence monitor in healthy singleton versus twin parturients undergoing CD deliveries with spinal anesthesia with PPI. 
Materials and Methods
After IRB approval and signed informed consent, healthy term women with either twin or singleton undergoing spinal anesthesia for uncomplicated CD were enrolled.   The following data were collected - cardiac output (CO), strove volume (SV), mean arterial pressure (MAP), and total peripheral resistance (TPR). Measurements were measured at 5 time points: 1) before arrival in OR , 2) after spinal anesthesia with PPI, 3) after beginning of oxytocin infusion 4) in post anesthesia care room 5)24 hours postoperatively and  6) 48 hours postoperatively. All parturients received standardized spinal solution consisting of 12 mg hyperbaric, 20 mcg fentanyl and 100 mcg preservative-free morphine. PPI was administered was titrated to preserve blood pressure to 20% of baseline blood pressure and stopped at the end of surgery. Oxytocin was administered as a continuous infusion (20 units/ 1000cc Ringer lactate) at a rate of 100cc/hr. 
Results
One hundred thirty seven women singletons  and 27 women twins competed the study. There were no significant differences between groups in age or BMI. . Intraoperatively there was no difference in any hemodynamic parameter. However postoperatively at all three times women with twin pregnancies had higher MAP, lower CO and higher TPR compared with parturients with singleton pregnancies
Conclusions
There were significant hemodynamic changes postoperatively but not intraoperatively in parturients with twin pregnancies compared to women with singleton pregnancies. These changes need to be studied further.


07 / The peripartum hemodynamic profile of singleton versus twin pregnacies in parturients delivering with spinal anesthesia and prophylactive phenylepherine drip measured by noninvasive cardiac output monitoring