Case-control study of shock index among women who did and did not receive blood transfusions due to postpartum hemorrhage

The golden hour for postpartum hemorrhage: Results from a prospective cohort study

OBJECTIVE

To evaluate the predictive capacity of vital signs for the diagnosis of postpartum hemorrhage (PPH).

METHODS

A prospective cohort study performed at the University of Campinas, Brazil, between February 2015 and March 2016 with women who delivered vaginally. Vital signs and postpartum bleeding were collected over 24 h. Exploratory data analysis was performed plus receiver operating characteristic curve analysis where the areas under the curve was used to determine the best cutoff points for sensitivity, specificity, likelihood ratio, and diagnostic odds ratio.

RESULTS

For the 270 women recruited, mean blood loss after 120 min was 427.49 ± 335.57 ml, while 84 (31.1%) and 22 (8.1%) women had blood loss ≥500 and ≥1000 ml, respectively. Heart rate cutoff point of 105 bpm measured between 21-40 min after birth identified blood loss ≥1000 ml with 90% specificity. A shock index (SI) of 0.965 at 41-60 min after birth identified blood loss ≥500 and ≥1000 ml within 2 h with approximately 95% specificity.

CONCLUSION

Shock index and heart rate measured after birth showed high specificity with low sensitivity to identify PPH. In clinical practice, "The rule of 1s" should receive special attention: SI ≥1, or heart rate >100 bpm, or estimated blood loss ≥1 L.

A prospective cohort study of shock index as a reliable marker to predict the patient's need for blood transfusion due to postpartum hemorrhage

Objective:

This study was aimed to compare the shock index (SI) values between patients who required blood transfusion due to postpartum hemorrhage (PPH) and patients who received no blood transfusion.

Methods:

We conducted this cross-sectional study at a tertiary center between January 2019 and June 2019. A total of 2534 patients who underwent vaginal delivery were included in this study. We measured SI values upon admission, 30 minutes, 1-hour, and 2-hours after delivery. We identified women who required blood transfusion as the study group. Control patients who delivered in the same period and received no blood transfusion were identified in the medical record system and randomly selected. Age, parity, BMI, and SI values at each one prepartum and three postpartum periods of the groups were analyzed.

Results:

A total of 2534 patients were included in the study. A varying amount of blood transfusion was performed in 54 patients (2.13%). When we compared with patients who did not receive blood transfusion after delivery, patients who received any amount of blood transfusion after vaginal delivery had significantly higher SI values 30 minutes after delivery (0.99±0.20, and 085±0.11, p=0.0001), at 1-hour (1.00±0.18, and 0.85±0.11, p=0.0001), and 2-hours (1.09±0.16, and 0.87±0.11, p=0.0001).

Conclusion:

SI value could be a reliable and consistent marker to predict the requirement for any amount of blood transfusion due to PPH.

A review of postpartum hemorrhage in low-income countries and implications for strengthening health systems

Postpartum hemorrhage (PPH) is the leading cause of maternal morbidity and mortality worldwide. Disparities in PPH-associated survival between high and low-/middle-income countries reflect an imperative for low-resource countries to improve strategies for rapid diagnosis and treatment. A review of current PPH diagnosis, prevention, treatment, and access to care in low-income countries has been used to understand, extract, and report the challenges that public health systems face in trying to solve the marked global disparity in PPH outcomes. Improvement in PPH survival begins with holistic strengthening of each step along the continuum of care in health systems and should include performance feedback measures and quality-of-care research.

Shock Index in the Prediction of Adverse Maternal Outcome

Introduction

WHO states that obstetric hemorrhage, hypertensive disorders of pregnancy and sepsis account for approximately 50% of maternal deaths worldwide. All these conditions are associated with changes in vital signs including blood pressure (BP) and heart rate (HR). Shock index (SI) is the ratio of HR to systolic BP.

Aims and Objectives

To evaluate role of shock index as an early indicator of adverse maternal outcomes and to determine the threshold points of SI for five adverse maternal outcomes.

Methodology

This was a prospective observational study on 1004 consecutively enrolled subjects presenting in labor. Vital signs and Shock Index were recorded. SI thresholds were analyzed with respect to obstetric complications and adverse outcomes. Parametric tests such as Chi-square, comparison of proportions, comparison of mean and ROC curve analysis were applied on the data.

Results

The mean SI value in the vaginal delivery group was 1.02 ± 0.26 and it was 0.95 ± 0.033 in the caesarean delivery group. The values of SI ((Mean and SD) for ICU admission were (1.23 (± 0.35)), for (MODS) it was (1.47 (± 0.84)), for blood transfusion > 4 units it was (1.15 (± 0.41)), for surgical intervention it was (1.58 (± 0.51)) and for maternal death (1.39 (± 0.85)). SI ≥ 1.4, had sensitivity 26.82% (21.09-33.19); specificity 100%(99.53-100), PPV was 100% and NPV was 82.96%(81.8-84.06)with an AUC of 0.8 (0.78-0.83) on ROC analysis. In subjects with PIH/eclampsia, SI was lower and in patients with severe anemia, SI was higher.

Conclusion

SI performed well as a screening tool in the prediction of adverse maternal outcomes. SI ≥ 0.9 was significantly associated with maternal adverse outcomes: ICU admission, MODS, surgical intervention, blood transfusion and death. The study proposes an SI cut-off of 0.9 for referral and a cut-off of 1.1 for intervention in a tertiary care hospital. Patients with PIH/eclampsia tend to have lower mean SI values as compared to the rest of the study population, suggesting that SI may not be a reliable indicator in patients with PIH/eclampsia.

Ability of shock index and heart rate to predict the percentage of body blood volume lost after vaginal delivery as an indicator of severity: results from a prospective cohort study

Background

Postpartum hemorrhage (PPH) is the leading cause of maternal mortality worldwide, but it mainly affects women from low- and middle-income countries. Despite being a treatable condition, the high number of maternal deaths resulting from PPH is outstanding for at least 25 years. Late diagnosis and difficulties in identifying women who will develop severe postpartum bleeding can, in part, explain the high incidence of PPH. Over the past few years, researchers have focused on identifying a simple, accessible and low-cost diagnostic tool that could be applied to avoid maternal deaths. In particular, it has been suggested that vital signs and shock index (SI) could be useful. The objective of this study was to evaluate whether vital signs are correlated with the percentage of body blood volume (BBVp) lost after vaginal delivery.

Methods

A prospective cohort study was performed at the Women’s Hospital of UNICAMP, Brazil. The inclusion criteria were women delivering vaginally who did not suffer from hypertension, hyper- or hypothyroidism, cardiac disease, infections or coagulopathy. Blood loss was measured over 24 hours using a calibrated drape and by weighing compresses, gauzes and pads. Vital signs were measured up to 24 hours after delivery. We evaluated the BBVp lost, and generated a Receiver operating characteristics (ROC) curve with area under the curve (AUC) analysis to determine the cut-off values for vital signs to determine the likelihood of postpartum bleeding above the 90^th percentile within 24 hours of delivery.

Results

A total of 270 women were included. The mean blood loss within 24 hours of vaginal delivery was 570.66 ± 360.04 mL. In the first 40 minutes, 73% of the total blood loss over the 24-hour period had occurred, and within 2 hours, 91% of women had bled 90% of the total blood loss. Changes in SI and heart rate (HR) were statistically significant in predicting postpartum bleeding (P ≤ 0.05). Higher values for likelihood ratio (LR) to identify BBVp loss above the 90^th percentile within 2 hours were a SI above 1.04 at 41-60 minutes after birth (LR = +11.84) and a HR above 105.2 bpm at 21-40 minutes after birth (LR = +4.96). Both measures showed high specificity but low sensitivity.

Conclusion

Values of SI and HR are statistically significant in predicting postpartum bleeding with high specificity but low sensitivity. The cut-off points were 1.04 for SI and 105 bpm for HR.

Shock index and heart rate standard reference values in the immediate postpartum period: A cohort study

Objective

To determine Shock Index (SI) reference values in the first two hours of the postpartum period after objectively measuring postpartum bleeding.

Materials and methods

A complementary analysis using data from a prospective cohort study at Women’s Hospital of the University of Campinas, Brazil, between 1 February 2015 and 31 March 2016. It included women giving birth vaginally unless they had one of these conditions: gestational age below 34 weeks, hypertension, hypo- or hyperthyroidism without treatment, any cardiac disease, infections with fever or sepsis, history of coagulopathy or delivery by C-section. Blood loss was measured by adding the blood volume collected in the drape placed under the women’s buttocks and the weight of gauzes and compresses used (excluding the dry weight). Vital signs were measured every 5–15 min after delivery. Exploratory data analysis was performed to assess the mean, standard deviation, median, and percentiles (5^th, 10^th, 25^th, 50^th, 75^th, 90^th, 95^th). To identify variation among the periods after delivery, the mean SI and heart rate (HR) values observed for the following intervals were used in the analysis: 0–20 min, 21–40 min, 41–60 min, 61–90 min and 91–120 min.

Results

One hundred eighty-six women were included. The mean age ± SD was 24.9 ± 6.1 years and the mean gestational age at birth was 39.2 ± 1.8 weeks. At the puerperal period, the mean SI values ranged from 0.68 ± 0.14 to 0.74 ± 0.15. The percentile distribution ranged from 0.46 (5^th percentile) to 1.05 (95^th percentile). The mean HR values ranged from 80.8 ± 12.7 bpm to 92.3 ± 14.4 bpm. The percentile distribution ranged from 62.0 bpm (5^th percentile) to 117 bpm (95^th percentile).

Conclusion

Reference ranges were established for SI and HR values which showed small variations throughout the postpartum period.