Shock Index and Postpartum Hemorrhage in Vaginal Deliveries: A Multicenter Retrospective Study

Unveiling the potential role of the shock index in maternal sepsis: reality or fantasy?

OBJECTIVE

Maternal sepsis continues to be a maternal health problem associated with 75,000 deaths per year worldwide, representing a greater burden in low- and middle-income countries (LMICs). Although the Shock Index (SI) has been widely studied in postpartum hemorrhage and in non-obstetric populations, it has not yet been widely studied in sepsis. We aimed to identify the relationship between Shock Index and suspected sepsis in pregnant and postpartum patients to explore the use of Shock index in the context of maternal sepsis and its relationship with sepsis-related outcomes.

METHODS

A single-center, retrospective, case-control study was conducted, including pregnant and postpartum patients attended between June 2015 and December 2020 in a high-complexity university hospital. This study was conducted in a High Obstetric Complexity Unit (UACO) in the southwest region of Colombia. Pregnant or postpartum women with infectious processes of obstetric or non-obstetric origins were included. Cases had sepsis diagnosis; controls showed infection process and systemic inflammatory response signs without confirmed sepsis. Those with unconfirmed infections and preterm conditions were excluded. A logistic regression model was conducted to examine the association between maternal factors and sepsis diagnosis, and significant variables were determined through univariate analysis and included in a multivariate model.

RESULTS

A total of 640 patients were included (343 cases and 297 controls), sepsis was significantly associated with a higher shock index at admission SI ≥ 0.9 (85.4% vs 75%, p = 0.001). No correlation was found between the Shock Index and C-reactive protein (CRP), leukocyte count, or ICU length of stay. The area under the receiver operating characteristic curve (AUROC) analysis identified a Shock Index of 1 as the optimal cutoff point, while the cutoff point of 0.9 demonstrated the highest sensitivity (85%). An SI ≥ 0.9 increased the risk of sepsis 1.94 times (95% CI 1.31-2.91, p = 0.001) and remained significant in the adjustment model (OR_adj 2.18, 95% CI 1.42-3,32, p < 0.001). Incidence of maternal sepsis, incidence of maternal complications, and perinatal outcomes were measured with a SI ≥ 0.9.

CONCLUSION

Our findings underscore the importance of using the Shock Index with a cutoff point of 0.9 as a predictive tool for sepsis in pregnant patients, emphasizing the need for timely intervention and continuous monitoring of patients.

The ability of shock index to predict refractory postpartum haemorrhage: A secondary analysis of the prospective and multicentre HELP MOM study

BACKGROUND

The predictability of severe and refractory postpartum haemorrhage (PPH) remains a challenge for clinicians and researchers.

OBJECTIVE

We aimed to evaluate the ability of the shock index to predict refractory PPH.

DESIGN

This study was a secondary analysis of a multicentre, prospective, observational study investigating the association between severe postpartum haemorrhage (PPH) and the subsequent development of mental disorders.

SETTING

Participants were patients who experienced severe PPH, characterised by blood loss of at least 1500 ml requiring the administration of sulprostone. The shock index, defined as the ratio of heart rate to SBP, was recorded at two time points: at the start of sulprostone infusion (T0) and at the time of the most severe symptoms after enrolment but before the occurrence of refractory PPH (T1). Refractory PPH was defined by the need for four or more blood products, interventional radiology, or laparotomy (excluding caesarean section).

THE MAIN OUTCOME

The predictive ability of the shock index was assessed using univariate and multivariate logistic regression and area under the receiver operating characteristic curve (AUROC).

RESULTS

From November 2014 to November 2016, 332 patients experienced severe PPH, of which 316 were included in the final analysis. The prevalence of refractory PPH was 35.4% (112/316). We found that high shock index levels at T0 were independently associated with the occurrence of refractory PPH: odds ratio (OR) 3.07 [95% confidence interval (CI), 1.22 to 7.89, P  = 0.017]. In addition, high shock index levels at T1 were also independently associated with the occurrence of refractory PPH: OR 5.28 (95% CI, 2.25 to 12.8), P  < 0.001. The AUROC of shock index levels measured at T0 and T1 were 0.614 (95% CI, 0.549 to 0.678) and 0.681 (95% CI, 0.616 to 0.746), respectively.

CONCLUSION

The shock index measured at the start of sulprostone infusion and at the worst time after enrolment, has poor discriminative power to predict this event.

Performance of Shock Index as a predictor of severe postpartum hemorrhage following cesarean section under spinal anesthesia: a retrospective cohort study

BACKGROUND

An early diagnosis of a postpartum hemorrhage (PPH) can be challenging. The Shock Index (SI), the ratio of heart rate to systolic blood pressure, appears to be a useful indicator for the early diagnosis of severe PPH after vaginal delivery. Our primary aim was to evaluate if the SI has a predictive value for severe PPH following cesarean section (C-section) under spinal anesthesia (SA) and its best predictive threshold.

METHODS

Retrospective single-center trial including women scheduled for C-section under SA with prevention of maternal hypotension by phenylephrine, and complicated by PPH between 2019 and 2021. Women were divided into two groups: non-severe PPH (blood loss <1000 mL) versus severe PPH (blood loss ≥1000 mL). SI was calculated and compared between the groups at four different time points: T0: prior to C-section; T1: at incision; T2: 15 minutes from start of PPH; T3: end of PPH management. Using receiver operating characteristic curve, we calculated the area under the curve (AUC) and the best diagnostic threshold (sensitivity and specificity) for predicting severe PPH.

RESULTS

Overall, 129 patients were included, 26 (20.2%) with severe PPH. Median SI was significantly higher at T2 in the severe PPH group (1.14 (1.10-1.25) versus 1.0 (0.85-1.10), P<0.001), but not at other times of management. An SI value of ≥1.17 was the best threshold with an AUC of 0.81 (95% CI 0.72 to 0.90), a sensitivity of 0.42 and a specificity of 0.88.

CONCLUSIONS

SI may be an early indicator of severe PPH during C-section under SA.

Shock index reference ranges in the first 48 h postpartum following elective cesarean delivery: A prospective cohort study

PURPOSE

To determine the reference values for the shock index (SI) in postpartum patients undergoing elective cesarean delivery with regional anesthesia.

METHODS

This prospective study was conducted at our tertiary center between August 1, 2023, and March 1, 2024. We calculated the reference values for the SI within the first 48 h postpartum for patients who underwent elective cesarean delivery after the 34th week of gestation. We excluded cases of vaginal delivery, post-term delivery (≥42 weeks of gestation), multiple pregnancies, stillbirths, fetal abnormalities, maternal cardiac disease, anemia, untreated hypo- or hyperthyroidism, and any hypertensive disorders diagnosed before or during pregnancy. Data collection, measurement of vital signs, and the administration of fluids pre-, intra-, and post-operatively, as well as the use and dosing of uterotonic agents for the prevention of postpartum hemorrhage (PPH), were standardized for all patients.

RESULTS

Our final analysis included 311 patients, with a mean SI value of approximately 0.7 (0.67-0.77) for all measurement performed within the first 48 h of the postpartum period. Further analyses revealed that the 90th and 95th percentiles of SI were around 0.9 throughout the study period. Additionally, SI reference values analyzed at different time points were consistent. Our analysis demonstrated that SI values were not influenced by the presence of a previous caesarean section, the administration of oxytocin or carbetocin, or parity in this particular cohort. Our analyses of vital signs also indicated that the 95th percentile of heart rate (HR) ranged from 96 to 100 bpm.

DISCUSSION

An SI value of 0.9 represents the 95th percentile of SI values throughout the first 48 h of the postpartum period. Any greater value should be evaluated carefully for potential adverse outcomes.

Tests for diagnosis of postpartum haemorrhage at vaginal birth

BACKGROUND

Postpartum haemorrhage (PPH) is the leading cause of maternal mortality worldwide. Accurate diagnosis of PPH can prevent adverse outcomes by enabling early treatment.

OBJECTIVES

What is the accuracy of methods (index tests) for diagnosing primary PPH (blood loss ≥ 500 mL in the first 24 hours after birth) and severe primary PPH (blood loss ≥ 1000 mL in the first 24 hours after birth) (target conditions) in women giving birth vaginally (participants) compared to weighed blood loss measurement or other objective measurements of blood loss (reference standards)?

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Web of Science Core Collection, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform to 24 May 2024.

SELECTION CRITERIA

We included women who gave birth vaginally in any setting. Study types included diagnostic cohort studies and cross-sectional studies that reported 2 x 2 data (number of true positive, false positive, false negative, and true negative results) or where the 2 x 2 data could be derived from test accuracy estimates. Eligible index tests included: visual estimation; calibrated blood collection devices; approach with calibrated drape and observations; blood loss estimation using the SAPHE (Signalling a Postpartum Hemorrhage Emergency) Mat; blood loss field image analysis and other technologies; uterine atony assessment; clinical variables (e.g. heart rate, blood pressure, shock index); early warning charts; haemoglobin levels; and predelivery fibrinogen levels. Eligible reference standards included objective methods such as: gravimetric blood loss measurement, which involves weighing collected blood, as well as weighing blood-soaked pads, gauze and sheets, and subtracting their dry weight; calibrated devices to measure blood volume (volumetric blood loss measurement); the alkaline-haematin method of blood loss estimation; and blood extracted using machine-extraction and measured spectrometrically as oxyhaemoglobin.

DATA COLLECTION AND ANALYSIS

At least two review authors, working independently, undertook study screening, selection, data extraction, assessment of risk of bias, and assessment of the certainty of the evidence. We resolved any differences through consensus or with input from another author. We generated 2 x 2 tables of the true positives, true negatives, false positives, and false negatives to calculate the sensitivity, specificity, and 95% confidence intervals for each index test. We presented sensitivity and specificity estimates from studies in forest plots. Where possible, we conducted meta-analyses for each index test and reference standard combination for each target condition. We examined heterogeneity by visual inspection of the forest plots.

MAIN RESULTS

Our review included 18 studies with a total of 291,040 participants. Fourteen studies evaluated PPH and seven studies evaluated severe PPH. Most studies were conducted in a hospital setting (16 of 18). There were four studies at high risk of bias for the patient selection domain and 14 studies at low risk. For the index test domain, 10 studies were at low risk of bias, seven studies at high risk, and one study at uncertain risk. For the reference standard domain, one study was at high risk of bias and 17 studies at low risk. For the flow and timing domain, three studies were at high risk of bias and 15 studies at low risk. The applicability concerns were low for all studies across the domains. In the abstract, we have prioritised reporting results for common, important thresholds for index tests or where the certainty of the evidence for the sensitivity estimate was at least moderate. Full results are in the main body of the review. PPH (blood loss ≥ 500 mL) For PPH, visual estimation with gravimetric blood loss measurement as the reference standard had 48% sensitivity (95% confidence interval (CI) 44% to 53%; moderate certainty) and 97% specificity (95% CI 95% to 99%; high certainty) (4 studies, 196,305 participants). Visual estimation with volumetric blood loss measurement as the reference standard showed 22% sensitivity (95% CI 12% to 37%; moderate certainty) and 99% specificity (95% CI 97% to 100%; moderate certainty) (2 studies, 514 participants). The diagnostic approach with calibrated drape plus observations, with gravimetric blood loss measurement as the reference standard for PPH, showed 93% sensitivity (95% CI 92% to 94%; high certainty) and 95% specificity (95% CI 95% to 96%; high certainty) (2 studies, 53,762 participants). A haemoglobin level of less than 10 g/dL with gravimetric blood loss measurement as the reference standard showed 37% sensitivity (95% CI 30% to 44%; high certainty) and 79% specificity (95% CI 76% to 82%; high certainty) (1 study, 1058 participants). Severe PPH (blood loss ≥ 1000 mL) For severe PPH, visual estimation, with volumetric plus gravimetric blood loss measurement as the reference standard, showed 9% sensitivity (95% CI 0% to 41%; low certainty) and 100% specificity (95% CI 99% to 100%; moderate certainty) (1 study, 274 participants). A shock index level of 1.0 or higher (commonly used as a threshold for severe PPH) up to two hours after birth, with gravimetric blood loss measurement as the reference standard, showed 30% sensitivity (95% CI 27% to 33%; moderate certainty) and 93% specificity (95% CI 92% to 93%; moderate certainty) (1 study, 30,820 participants). A haemoglobin level of less than 10 g/dL, with gravimetric blood loss measurement as the reference standard, showed 71% sensitivity (95% CI 51% to 87%; moderate certainty) and 77% specificity (95% CI 75% to 80%; high certainty) (1 study, 1058 participants).

AUTHORS' CONCLUSIONS

Visual estimation of blood loss to diagnose PPH showed low sensitivity and is likely to miss the diagnosis in half of women giving birth vaginally. A diagnostic approach using a calibrated drape to objectively measure blood loss plus clinical observations showed high sensitivity and specificity for diagnosing PPH. Other index tests showed low to moderate sensitivities in diagnosing PPH and severe PPH. Future research should determine the accuracy of diagnostic tests in non-hospital settings and consider combining index tests to increase the sensitivity of PPH diagnosis.

FUNDING

Bill and Melinda Gates Foundation REGISTRATION: PROSPERO (CRD42024541874).

Emergency cesarean section in pregnant trauma patients presenting after motor vehicle collision

Background

Most pregnant trauma patients (PTPs) present after motor vehicle collision (MVC). The national rate and risk factors for emergency cesarean section (ECS) during the index hospitalization for pregnant trauma patients (PTPs) are unknown. We sought to investigate the national rate of ECS in PTPs presenting after MVC, hypothesizing a higher risk of ECS among those with severe injuries or elevated shock index (SI).

Methods

The 2020-2021 TQIP was queried for PTPs presenting after MVC. PTPs that underwent ECS were compared to patients that did not undergo ECS. Elevated SI was defined as ≥1. Severe injury was defined by abbreviated injury scale grade ≥3. Bivariate and multivariable logistic regression analyses were performed.

Results

From 1183 PTPs, 95 (8.0 %) underwent ECS. The median time to ECS was 115 min. The ECS group had higher rates of lung (27.4 % vs. 12.2 %, p < 0.001) injury, spleen (18.9 % vs. 5.5 %, p < 0.001) injury, and elevated SI (22.1 % vs. 9.8 %, p < 0.001). ECS patients had higher rates of complication (9.5 % vs. 2.1 %, p < 0.001) and death (4.2 % vs. 1.1 %, p = 0.012). Independently associated risk factors for ECS included severe head (OR 2.65, CI 1.14-6.17, p = 0.023) or abdominal (OR 2.07, CI 1.08-3.97, p = 0.028) injuries and elevated SI (OR 2.17 CI 1.25-3.79, p = 0.006).

Conclusion

The national rate of ECS among PTPs presenting after MVC is 8 % with most occurring within the first 2 hours of arrival. Severe head and abdominal injuries as well as elevated SI are risk factors for ECS.

Quantitative blood loss measurement methods for early detection of primary postpartum haemorrhage following vaginal birth: A scoping review

AIM

To map the commonly used quantitative blood loss measurement methods in clinical practice and provide a solid foundation for future studies.

DESIGN AND METHOD

This study adhered to the JBI methodology for scoping reviews and preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews. We conducted a literature search using five databases to retrieve articles published between January 2012 and September 2022. The search was repeated on 29 February 2024. Data extraction and verification were carried out by two independent researchers using a self-designed data extraction form.

RESULTS

Ultimately, 26 studies published between 2012 and 2024 were considered eligible for inclusion. Six categories of methods were identified from the 26 articles. Among the included studies, only two involved randomized controlled trials, with the majority being observational studies. The World Health Organization (2012) version of the postpartum haemorrhage diagnostic criteria was predominantly used in most studies. Gravimetric and volumetric methods emerged as the most commonly used methods for quantifying postpartum haemorrhages. The timing of blood collection was inconsistent among the included studies. Only 12 studies mentioned measures for the management of amniotic fluid.

CONCLUSIONS

This scoping review supports the replacement of the visual estimation of blood loss with quantitative assessment methods. Supporting a specific assessment approach is not feasible due to the variability of the study. Future research should focus on establishing the best practices for specific quantitative methods to standardize the management of postpartum haemorrhage and reduce the incidence of postpartum haemorrhage-related adverse outcomes.

RELEVANCE TO CLINICAL PRACTICE

Healthcare professionals need to acknowledge the low accuracy of visual estimation methods and implement quantitative methods to assess postpartum blood loss. Given the limitations inherent in each assessment method, quantification of blood loss should be combined with assessment of maternal vital signs, physiologic indicators and other factors.

Fluid resuscitation strategy in patients with placenta previa accreta: a retrospective study

Objectives

Obstetric hemorrhage is the leading cause of maternal death worldwide. Placenta previa accreta is one of the major direct causes of postpartum hemorrhage, accounting for two-thirds of obstetric hemorrhage cases. Fluid resuscitation is a life-saving procedure for patients suffering from massive hemorrhage. This study aims at evaluating the risk factors of massive hemorrhage and appropriate fluid resuscitation strategy in patients with placenta previa accreta.

Methods

This study retrospectively analyzed the risk factors for massive hemorrhage, clinical characteristics, and perinatal outcomes of patients with placenta previa accreta. Maternal noninvasively evaluated hemodynamic indicators, including maternal heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and shock index, were collected and analyzed at nine time points, from the administration of anesthesia until the end of procedures, in patients diagnosed with placenta previa accreta and receiving different fluid supply volumes.

Results

Complicated with placenta increta/percreta and gestational age of delivery later than 37 weeks are two independent risk factors of massive hemorrhage in patients with placenta previa accreta. A total of 62.27% (170/273) patients diagnosed with placenta increta/percreta had massive hemorrhage, significantly higher than those diagnosed with placenta previa accreta (5.88%, 6/102). Patients delivered after 37 weeks of gestation had significantly higher ratios (86.84%, 99/114) of massive hemorrhage compared with those delivered between 36 and 36+6 weeks of gestation (35.39%, 63/178). Maternal SBP, DBP, and MAP started to decrease immediately after the baby was delivered and reached a relatively stable trough state at 15-30 min after delivery. No statistical differences were found in hemodynamic indicators, the occurrence of hypotension, or in-hospital days after the procedure among the transfusion volumes < 30 ml/kg, 30-80 ml/kg, and ≥ 80 ml/kg groups.

Conclusion

Patients with a suspected diagnosis of placenta previa accreta should plan to deliver before 37 weeks of gestation. The ability to identify concurrent placenta increta/percreta should be improved to schedule a reasonably rapid perioperative plan. Restrictive fluid resuscitation could achieve good effects in maintaining hemodynamic stability in patients with placenta previa accreta. A time period of 15-30 min after delivery is the critical stage for fluid resuscitation.

Use of Shock Index, Modified Shock Index, and Age-Adjusted Shock Index for Detection of Postpartum Hemorrhage

PURPOSE

The aim of this study is to evaluate the role of shock index (SI), modified shock index (MSI), and delta shock index (ΔSI) in predicting postpartum hemorrhage (PPH) and adverse maternal outcomes.

MATERIAL AND METHODS

In this cross-sectional cohort study, a study group consisting of 416 pregnant women who delivered at our hospital and had postpartum hemorrhage was compared with 467 control patients with normal follow-up. SI (pulse/systolic blood pressure), MSI (pulse/mean arterial pressure), ΔSI (input SI - 2nd- or 6th-hour SI) values were calculated.

RESULTS

A total of 883 postpartum women were included in the study. The study group had higher peripartum, 2nd-hour, and 6th-hour SI values (p=0.011, p=0.001, p<0.001, respectively). Peripartum MSI values (p=0.004), 2nd-hour MSI values (p<0.001), and 6th-hour MSI values (p<0.001) were significantly lower in the control group than in the PPH group. When the groups were evaluated, the cut-off value of the 2nd-hour SI parameter was>0.8909 (sensitivity 30%, specificity 84%), and the 6th-hour SI parameter was>0.8909 (sensitivity 40%, specificity 80%) for predicting postpartum hemorrhage requiring blood transfusion and surgical intervention. The cut-off value of the 2nd-hour MSI parameter was>1.2 (sensitivity 34%, specificity 82%), and the cut-off value of the 6th-hour MSI parameter was>1.2652 (sensitivity 32%, specificity 90%).

CONCLUSION

The 2nd- and 6th-hour SI and 2nd- and 6th-hour MSI values were significantly higher in patients with postpartum hemorrhage. Values greater than 0.89 for SI and 1.2 for MSI were considered significant for predicting postpartum hemorrhage with maternal impairment.

Predictive performance of Shock Index for postpartum hemorrhage during cesarean delivery

BACKGROUND

The Shock Index (SI), defined as heart rate divided by systolic blood pressure, is reportedly an early surrogate indicator for postpartum hemorrhage (PPH). However, most previous studies have used clinical data of women who delivered vaginally. Therefore, we aimed to evaluate the SI pattern during cesarean delivery and determine its usefulness in detecting PPH.

METHODS

This was a single-center retrospective study using the clinical data of women (n = 331) who underwent cesarean delivery under spinal anesthesia at term between 2018 and 2021. We assessed the SI pattern stratified by total blood loss and evaluated the predictive performance of each vital sign in detecting PPH (total blood loss ≥1000 mL) based on the area under the receiver operating characteristic curve (AUROC).

RESULTS

At 10-15 min after delivery, the mean SI peaked between 0.84 and 0.90 and then decreased to a level between 0.72 and 0.77, which was similar to that upon entering the operating room. Among 331 women, 91 (27.5%) were diagnosed with PPH. There was no correlation between SI and total blood loss (rs = 0.02). The SI had low ability to detect PPH (AUROC 0.54, 95% confidence interval 0.47 to 0.61), which was similar to other vital signs (AUROCs 0.53-0.56).

CONCLUSION

We determined the pattern of SI during cesarean delivery. We found no correlation between SI and total blood loss. Unlike in vaginal delivery, the prognostic accuracy of SI for PPH detection in cesarean delivery was low.

Shock index as a predictor of postpartum haemorrhage after vaginal delivery: Secondary analysis of a multicentre randomised controlled trial

OBJECTIVE

To describe the shock index (SI) distribution during the first 2 hours after delivery and to evaluate its performance when measured 15 and 30 minutes after delivery for predicting postpartum haemorrhage (PPH) occurrence in the general population of parturients after vaginal delivery.

DESIGN

Secondary analysis of a multicentre randomised controlled trial testing prophylactic administration of tranexamic acid versus placebo in addition to prophylactic oxytocin to prevent PPH.

SETTING

15 French maternity units in 2015-2016.

SAMPLE

3891 women with a singleton live fetus ≥35 weeks, born vaginally.

METHODS

For each PPH-related predicted outcome, we calculated the area under the receiver operating characteristic curve (AUROC) values of the SI at 15 and 30 minutes after delivery and its predictive performance for SI cut-off values of 0.7, 0.9 and 1.1.

MAIN OUTCOME MEASURES

Quantitative blood loss ≥1000 ml (QBL ≥1000 ml) measured in a graduated collector bag and provider-assessed clinically significant PPH (cPPH).

RESULTS

Prevalence of QBL ≥1000 ml and cPPH was respectively 2.7% (104/3839) and 9.1% (354/3891). The distributions of the SI at 15 and 30 minutes after delivery were similar with a median value of 0.73 and 97th percentile of 1.11 for both. The AUROC values of the 15-minute SI for discriminating QBL ≥1000 ml and cPPH were respectively 0.66 (lower limit of the 95% confidence interval [LCI] 0.60) and 0.56 (LCI 0.52); and for the 30-minute SI 0.68 (LCI 0.61) and 0.49 (LCI 0.43).

CONCLUSIONS

The shock index at 15 and 30 minutes after delivery did not satisfactorily predict either QBL ≥1000 ml or clinical PPH.

Is the shock index correlated with blood loss? An experimental study on a controlled hemorrhagic shock model in piglets

INTRODUCTION

The quantification of blood loss in a severe trauma patient allows prognostic quantification and the engagement of adapted therapeutic means. The Advanced Trauma Life Support classification of hemorrhagic shock, based in part on hemodynamic parameters, could be improved. The search for reproducible and non-invasive parameters closely correlated with blood depletion is a necessity. An experimental model of controlled hemorrhagic shock allowed us to obtain hemodynamic and echocardiographic measurements during controlled blood spoliation. The primary aim was to demonstrate the correlation between the Shock Index (SI) and blood depletion volume (BDV) during the hemorrhagic phase of an experimental model of controlled hemorrhagic shock in piglets. The secondary aim was to study the correlations between blood pressure (BP) values and BDV, SI and cardiac output (CO), and pulse pressure (PP) and stroke volume during the same phase.

METHODS

We analyzed data from 66 anesthetized and ventilated piglets that underwent blood spoliation at 2 mL.kg-1.min-1 until a mean arterial pressure (MAP) of 40 mmHg was achieved. During this bleeding phase, hemodynamic and echocardiographic measurements were performed regularly.

RESULTS

The correlation coefficient between the SI and BDV was 0.70 (CI 95%, [0.64; 0.75]; p < 0.01), whereas between MAP and BDV, the correlation coefficient was -0.47 (CI 95%, [-0.55; -0.38]; p < 0.01). Correlation coefficient between SI and CO and between PP and stroke volume were - 0.45 (CI 95%, [-0.53; -0.37], p < 0.01) and 0.62 (CI 95%, [0.56; 0.67]; p < 0.01), respectively.

CONCLUSIONS

In a controlled hemorrhagic shock model in piglets, the correlation between SI and BDV seemed strong.

Incidence of postpartum hemorrhage based on the improved combined method in evaluating blood loss: A retrospective cohort study

OBJECTIVE

In view of the current clinical inaccuracies and underestimations of postpartum hemorrhage amount, this study aims to investigate the incidence, etiology, clinical characteristics of postpartum hemorrhage in different modes of delivery based on the combination of volumetric method, gravimetric method and area method in evaluating blood loss.

DESIGN

This retrospective cohort study was conducted in Hangzhou Women's Hospital from January 2020 to June 2021, including 725 cases of postpartum hemorrhage among 18,977 parturients. Based on different modes of delivery, the participants were divided into three groups: vaginal delivery, forceps delivery, and cesarean section, for comparison.

METHODS

Using an improved combined assessment method for blood loss, we retrospectively analyzed a cohort of parturients with postpartum hemorrhage who underwent vaginal delivery, forceps delivery, or cesarean section and were hospitalized in Hangzhou Women's Hospital from January 2020 to June 2021.

RESULTS

(1) Among the 18,977 parturients, 725 cases of postpartum hemorrhage occurred, with an incidence rate of 3.8%, and severe postpartum hemorrhage accounted for 0.4% of the cases. (2) The incidence of postpartum hemorrhage was significantly higher in the forceps delivery group than in the vaginal delivery group (χ2 = 19.27, P<0.001), while the incidence of severe postpartum hemorrhage was significantly higher in the cesarean section group than in the vaginal delivery group (χ2 = 8.71, P = 0.003). (3) The causes of postpartum hemorrhage were statistically different among the different delivery modes, with varying underlying factors (P<0.001). (4) Patients with postpartum hemorrhage in different delivery modes showed statistically significant differences in age, body mass index (BMI), birth weight, gestational age, gravidity, parity, the decline of postpartum peripheral blood hemoglobin concentration, and estimated blood loss (P<0.05). (5) The proportion of blood transfusion was significantly higher in the cesarean section group than in the vaginal delivery and forceps delivery groups (χ2 = 231.03, P<0.001).

LIMITATIONS

This study is a single-center retrospective study, which may have led to selection bias in case selection. Additionally, the implementation of the combined three blood loss assessment methods may not have been strictly followed in all cases. Moreover, due to the mixing of bleeding with amniotic and irrigation fluids, the accuracy of evaluation may have been affected, leading to the possibility of inaccuracy of blood loss.

CONCLUSIONS

Forceps delivery and cesarean section increase the risk of postpartum hemorrhage, but forceps delivery does not significantly increase the incidence of severe postpartum hemorrhage. Uterine atony remains the leading cause of postpartum hemorrhage, while birth canal laceration and placental factors are the second most common causes of postpartum hemorrhage in forceps delivery and cesarean section, respectively. In this study, the volumetric method, gravimetric method and area method were combined to quantitatively assess postpartum hemorrhage amount. The combined method has strong clinical practicability and is less affected by subjective factors, although it also has limitations. In the future, we still need to focus on the early prediction and identification of postpartum hemorrhage, and further improve the quantitative assessment of postpartum blood loss.

Evaluation During Postpartum Hemorrhage

Postpartum hemorrhage is an obstetric emergency that is the leading and the most preventable cause of maternal death that occurs on the day of birth. The treatment of postpartum hemorrhage in a timely fashion is crucial to prevent morbidity and mortality. The accurate assessment of blood loss during delivery and the postpartum period remains a major challenge. Hence, it is imperative to have a standardized evaluation strategy for accurate assessment of blood loss, adequate classification of hemorrhage, and timely initiated interventions. The multidisciplinary evaluation strategy should be in place regardless of the delivery route.

Management of severe peri-operative bleeding: Guidelines from the European Society of Anaesthesiology and Intensive Care: Second update 2022

BACKGROUND

Management of peri-operative bleeding is complex and involves multiple assessment tools and strategies to ensure optimal patient care with the goal of reducing morbidity and mortality. These updated guidelines from the European Society of Anaesthesiology and Intensive Care (ESAIC) aim to provide an evidence-based set of recommendations for healthcare professionals to help ensure improved clinical management.

DESIGN

A systematic literature search from 2015 to 2021 of several electronic databases was performed without language restrictions. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to assess the methodological quality of the included studies and to formulate recommendations. A Delphi methodology was used to prepare a clinical practice guideline.

RESULTS

These searches identified 137 999 articles. All articles were assessed, and the existing 2017 guidelines were revised to incorporate new evidence. Sixteen recommendations derived from the systematic literature search, and four clinical guidances retained from previous ESAIC guidelines were formulated. Using the Delphi process on 253 sentences of guidance, strong consensus (>90% agreement) was achieved in 97% and consensus (75 to 90% agreement) in 3%.

DISCUSSION

Peri-operative bleeding management encompasses the patient's journey from the pre-operative state through the postoperative period. Along this journey, many features of the patient's pre-operative coagulation status, underlying comorbidities, general health and the procedures that they are undergoing need to be taken into account. Due to the many important aspects in peri-operative nontrauma bleeding management, guidance as to how best approach and treat each individual patient are key. Understanding which therapeutic approaches are most valuable at each timepoint can only enhance patient care, ensuring the best outcomes by reducing blood loss and, therefore, overall morbidity and mortality.

CONCLUSION

All healthcare professionals involved in the management of patients at risk for surgical bleeding should be aware of the current therapeutic options and approaches that are available to them. These guidelines aim to provide specific guidance for bleeding management in a variety of clinical situations.

Management of Hemorrhagic Shock: Physiology Approach, Timing and Strategies

Hemorrhagic shock (HS) management is based on a timely, rapid, definitive source control of bleeding/s and on blood loss replacement. Stopping the hemorrhage from progressing from any named and visible vessel is the main stem fundamental praxis of efficacy and effectiveness and an essential, obligatory, life-saving step. Blood loss replacement serves the purpose of preventing ischemia/reperfusion toxemia and optimizing tissue oxygenation and microcirculation dynamics. The "physiological classification of HS" dictates the timely management and suits the 'titrated hypotensive resuscitation' tactics and the 'damage control surgery' strategy. In any hypotensive but not yet critical shock, the body's response to a fluid load test determines the cut-off point between compensation and progression between the time for adopting conservative treatment and preparing for surgery or rushing to the theater for rapid bleeding source control. Up to 20% of the total blood volume is given to refill the unstressed venous return volume. In any critical level of shock where, ab initio, the patient manifests signs indicating critical physiology and impending cardiac arrest or cardiovascular accident, the balance between the life-saving reflexes stretched to the maximum and the insufficient distal perfusion (blood, oxygen, and substrates) remains in a liable and delicate equilibrium, susceptible to any minimal change or interfering variable. In a cardiac arrest by exsanguination, the core of the physiological issue remains the rapid restoration of a sufficient venous return, allowing the heart to pump it back into systemic circulation either by open massage via sternotomy or anterolateral thoracotomy or spontaneously after aorta clamping in the chest or in the abdomen at the epigastrium under extracorporeal resuscitation and induced hypothermia. This is the only way to prevent ischemic damage to the brain and the heart. This is accomplishable rapidly and efficiently only by a direct approach, which is a crush laparotomy if the bleeding is coming from an abdominal +/- lower limb site or rapid sternotomy/anterolateral thoracotomy if the bleeding is coming from a chest +/- upper limbs site. Without first stopping the bleeding and refilling the heart, any further exercise is doomed to failure. Direct source control via laparotomy/thoracotomy, with the concomitant or soon following venous refilling, are the two essential, initial life-saving steps.

Predictive accuracy of the shock index for severe postpartum hemorrhage in high-income countries: A systematic review and meta-analysis

AIM

The shock index has been suggested as a screening tool for predicting postpartum hemorrhage (PPH); however, there is little comprehensive evidence regarding its predictive accuracy. This systematic review and meta-analysis aim to investigate the predictive accuracy of the shock index for severe PPH in high-income countries.

METHODS

A comprehensive search was conducted on MEDLINE, Cochrane Central Register of Controlled Trials, and Web of Science (from inception to June 2021). Studies assessing the predictive performance of the shock index for PPH in high-income countries were included. Two or more reviewers independently extracted the data and assessed the risk of bias and applicability concerns using the modified Quality Assessment of Diagnostic Accuracy Studies 2 tool. PPH requiring higher-level care, such as blood transfusions, were considered as primary analyses. We described the hierarchical summary receiver-operating characteristic curve for data synthesis.

RESULTS

Nine studies were included after the eligibility assessment. All studies were considered to either have a high risk of bias or high applicability concerns. The sensitivity of the four studies that defined severe PPH as PPH requiring blood transfusion ranged from 0.51 to 0.80, whereas their specificity ranged from 0.33 to 0.92.

CONCLUSIONS

This review shows that the predictive performance of the shock index for severe PPH is inconsistent. Therefore, the evidence for using the shock index alone as a screening tool for PPH in high-income countries is insufficient.

STUDY REGISTRATION

This review was prospectively registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000044230).

Postpartum haemorrhage in anaemic women: assessing outcome measures for clinical trials

Background

Postpartum haemorrhage (PPH) is a leading cause of maternal mortality worldwide. Maternal anaemia greatly increases the risk of PPH, and over a third of all pregnant women are anaemic. Because anaemia reduces the oxygen-carrying capacity of the blood, anaemic women cannot tolerate the same volume of blood loss as healthy women. Yet the same blood loss threshold is used to define PPH in all women. The lack of an established PPH definition in anaemic women means the most appropriate outcome measures for use in clinical trials are open to question. We used data from the WOMAN-2 trial to examine different definitions of PPH in anaemic women and consider their appropriateness as clinical trial outcome measures.

Main body

The WOMAN-2 trial is assessing tranexamic acid (TXA) for PPH prevention in women with moderate or severe anaemia at baseline. To obtain an accurate, precise estimate of the treatment effect, outcome measures should be highly specific and reasonably sensitive. Some outcome misclassification is inevitable. Low sensitivity reduces precision, but low specificity biases the effect estimate towards the null. Outcomes should also be related to how patients feel, function, or survive. The primary outcome in the WOMAN-2 trial, a ‘clinical diagnosis of PPH’, is defined as estimated blood loss > 500 ml or any blood loss within 24 h sufficient to compromise haemodynamic stability. To explore the utility of several PPH outcome measures, we analysed blinded data from 4521 participants. For each outcome, we assessed its: (1) frequency, (2) specificity for significant bleeding defined as shock index ≥1.0 and (3) association with fatigue (modified fatigue symptom inventory [MFSI]), physical endurance (six-minute walk test) and breathlessness. A clinical diagnosis of PPH was sufficiently frequent (7%), highly specific for clinical signs of early shock (95% specificity for shock index ≥1) and associated with worse maternal functioning after childbirth.

Conclusion

Outcome measures in clinical trials of interventions for PPH prevention should facilitate valid and precise estimation of the treatment effect and be important to women. A clinical diagnosis of PPH appears to meet these criteria, making it an appropriate primary outcome for the WOMAN-2 trial.

Trial registration

ClinicalTrials.gov NCT03475342, registered on 23 March 2018; ISRCTN62396133, registered on 7 December 2017; Pan African Clinical Trial Registry PACTR201909735842379, registered on 18 September 2019.

Mortality of hospital walk‐in trauma patients: a multicenter retrospective cohort study

Aim

To investigate the characteristics of patients who visited the emergency department by themselves after experiencing trauma and subsequently died, and to identify the prognostic factors of mortality in such patients.

Methods

Adult patients with trauma visiting the emergency department by themselves between 2004 and 2019 in Japan were identified using a nationwide trauma registry (the Japan Trauma Data Bank). The characteristics of patients who died were compared with those who survived, and multivariable logistic regression analysis was used to determine the independent association of each preselected variable with in‐hospital mortality (end‐point).

Results

Of the 9753 patients eligible for analysis, 4369 (44.8%) were men, and the median age was 75 years. Of these patients, 130 (1.3%) died in the hospital. The following factors had a significant association with in‐hospital mortality: age, male sex, Charlson Comorbidity Index (CCI) 3–4 and ≥5 with CCI = 0 as a reference, circumstances of injury (free fall and fall at ground level), Glasgow Coma Scale score, Shock Index ≥ 0.9, severe injuries of the head, abdomen and lower extremities, and Injury Severity Score ≥ 15.

Conclusions

Several risk factors, including older age, male sex, higher CCI, circumstances of injury (free fall and fall at ground level), lower Glasgow Coma Scale score, higher Shock Index, and severe injuries of the head, abdomen, and lower extremities, were identified as being associated with the death of trauma patients visiting the emergency department by themselves. Early identification of patients with these risk factors and appropriate treatment may reduce mortality posttrauma.