Determination of Shock Index Reference Values for Prepartum and Early Postpartum Period in Vaginal Delivery: A Prospective, Cross-sectional Study

Abstract

Background: The study aims to determine the variation of shock index (SI) before and after vaginal delivery and establish standard reference values in mothers who have not postpartum hemorrhage.Materials and Methods: A total of 2534 women who delivered vaginally were enrolled in the study. This prospective cross-sectional study was completed between November 2018 and September 2019 in our referral hospital. The exclusion criteria were anemia, cesarean delivery, maternal heart diseases, maternal thyroid disease, gestational hypertensive disorders, patients received epidural anesthesia, and less than a 34 week 0 day gestation, patients who had postpartum hemorrhage (PPH). We defined PPH as blood loss > 1000 ml at the time of delivery. All patients’ SI (heart rate/systolic blood pressure) were measured prepartum and at the 30th minutes, 1st and 2nd-hour postpartum period. Shock index reference ranges were measured separately according to BMI, age, and parity groups. Results: 10136 SI values were assessed. The mean age ± SD was 27.28±5.95 years. The mean BMI ± SD was 24.89±4.87 kg/m2. The prepartum and postpartum 30th minutes, 1st hour, and 2nd hour mean shock index values were 0.76±0.07; 0.85±0.12; 0.84±0.12 and 0.81±0.12 respectively. The variation in SI values was significant by the Tukey test (P < 0.05).Conclusions: For SI to be a diagnostic character in the issue of PPH, reference values must be known, so in this study shock index reference percentile ranges and mean ± standard deviation of SI values were established.Key Words: Pregnancy, Shock index, Vaginal delivery