Relationship between visually estimated blood loss at delivery and postpartum change in haematocrit

Comparison of quantitative and calculated postpartum blood loss after vaginal delivery

BACKGROUND

Because there is no consensus on the method of assessing postpartum blood loss, the comparability and relevance of the postpartum hemorrhage-related literature are questionable. Quantitative blood loss assessment using a volumetric technique with a graduated collector bag has been proposed to overcome limitations of intervention-based outcomes but remains partly subjective and potentially biased by amniotic fluid or missed out-of-bag losses. Calculated blood loss based on laboratory parameters has been studied and used as an objective method expected to reflect total blood loss. However, few studies have compared quantitative with calculated blood loss.

OBJECTIVE

This study aimed to compare the distribution of postpartum blood loss after vaginal delivery assessed by 2 methods-quantitative and calculated blood loss-and the incidence of abnormal blood loss with each method.

STUDY DESIGN

Data were obtained from the merged database of 3 multicenter, randomized controlled trials, all testing different interventions to prevent postpartum blood loss in individuals with a singleton live fetus at ≥35 weeks of gestation, born vaginally. All 3 trials measured blood loss volume by using a graduated collector bag. Hematocrit was measured in the eighth or ninth month of gestation and on day 2 postpartum. The 2 primary outcomes were: quantitative blood loss, defined by the total volume of blood loss measured in a graduated collector bag, and calculated blood loss, mathematically defined from the peripartum hematocrit change (estimated blood volume × [(antepartum hematocrit-postpartum hematocrit)/antepartum hematocrit], where estimated blood volume [mL]=booking weight [kg] × 85). We modeled the association between positive quantitative blood loss and positive calculated blood loss with polynomial regression and calculated the Spearman correlation coefficient.

RESULTS

Among the 8341 individuals included in this analysis, the median quantitative blood loss (100 mL; interquartile range, 50-275) was significantly lower than the median calculated blood loss (260 mL; interquartile range, 0-630) (P<.05). The incidence of abnormal blood loss was lower with quantitative blood loss than calculated blood loss for all 3 thresholds: for ≥500 mL, it was 9.6% (799/8341) and 32.3% (2691/8341), respectively; for ≥1000 mL, 2.1% (176/8341) and 11.5% (959/8341); and for ≥2000 mL, 0.1% (10/8341) and 1.4% (117/8341) (P<.05). Quantitative blood loss and calculated blood loss were significantly but moderately correlated (Spearman coefficient=0.44; P<.05). The association between them was not linear, and their difference tended to increase with blood loss. Negative calculated blood loss values occurred in 23% (1958/8341) of individuals; among them, >99% (1939/1958) had quantitative blood loss ≤500 mL.

CONCLUSION

Quantitative and calculated blood loss were significantly but moderately correlated after vaginal delivery. However, clinicians should be aware that quantitative blood loss is lower than calculated blood loss, with a difference that tended to rise as blood loss increased.

Maternal body weight and estimated circulating blood volume: a non-linear approach

Postpartum haemorrhage continues to be a leading cause of morbidity and mortality in the obstetric population worldwide, especially in patients at extremes of body weight. Quantification of blood loss has been considered extensively in the literature. However, these volumes must be contextualised to appreciate the consequences of blood loss for individual parturients. Knowledge of a patient's peripartum circulating blood volume is essential to allow accurate interpretation of the significance of haemorrhage and appropriate resuscitation. Greater body weight in obesity can lead to overestimation of blood volume, resulting in inappropriately high thresholds for blood product transfusion and delays in treatment. The most recent Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries across the UK (MBRRACE-UK) surveillance report demonstrated the risk to this population, with more than half of all maternal mortality recorded in parturients who were either overweight or obese. Current linear calculations used to estimate circulating blood volumes based on patients' weights could be contributing to this phenomenon, as blood volume increases at a disproportional rate to body composition. In this review, we summarise the relevant physiology and explore the existing literature on the estimation of circulating blood volume, both during pregnancy and in obesity. Building on key works and principal findings, we present a practical, nonlinear approach to the adjustment of estimated blood volume with increasing body mass. This clinical tool aims to reduce the clinical bias influencing the management of obstetric haemorrhage in a population already at increased risk of morbidity and mortality. Discussion of the limitations of this approach and the call for further research within this field completes this review.

Understanding How Health Providers Identify Women with Postpartum Hemorrhage: A Qualitative Study

OBJECTIVE

 To identify how health providers recognize postpartum hemorrhage early and the difficulties involved in it.

METHODS

 An exploratory, descriptive study using a qualitative approach through a semi-structured interview technique. In total, 27 health professionals (nursing technicians, nurses, medical residents in Gynecology and Obstetrics, hired medical doctors, and medicine professors) working in a tertiary-level hospital of reference in women's health care in the State of São Paulo, Brazil, participated in the study through an invitation. After they accepted the invitation, they signed the free and informed consent form. All interviews were recorded and transcribed, and a thematic analysis was conducted. We found three analysis categories: a) perception of the severity: "there is something wrong with the women"; b) difficulties in the early diagnosis of postpartum hemorrhage; and c) the process to improve obstetrical care.

RESULTS

 Caregivers believe teamwork and communication should be improved. Besides the visual estimation of blood loss, the nursing team is attentive to behavioral symptoms like irritability, while the medical staff follow protocols and look for objective signs, such as altered vital signs.

CONCLUSION

 Besides the objective evaluations, the subjective perceptions of the providers are involved in the clinical judgement regarding the diagnosis of postpartum hemorrhage, and this should be included in a broader diagnosis strategy.

Can measuring blood loss at delivery reduce hemorrhage-related morbidity?

Quantitation of blood loss after vaginal and cesarean delivery has been advocated for the timely detection of postpartum hemorrhage and activation of protocols for resuscitation. Morbidity and mortality from postpartum hemorrhage is considered to be largely preventable and is attributed to delayed recognition with under-resuscitation or inappropriate resuscitation. Optimizing detection of postpartum hemorrhage through refining how blood loss is measured is therefore clinically relevant. In this review on quantitative blood loss for postpartum hemorrhage, recent advances in the methods used to quantitate blood loss will be reviewed, with a comparison of utility and precision for blood loss measurement after vaginal and cesarean delivery. Considerations for the implementation of a quantitative blood loss system on the labor and delivery unit, including its benefits and challenges, will be discussed. The existing evidence for impact of blood loss quantitation in obstetrics on hemorrhage-related morbidity will be delineated, along with knowledge gaps and future research priorities.

Introduction of standardized, cumulative quantitative measurement of blood loss into routine maternity care

Introduction: Postpartum hemorrhage (PPH) is the leading cause of maternal morbidity in the UK. Visual estimation of blood loss is unreliable yet remains common practice. As part of a national quality improvement project to improve care during PPH, standardized, quantitative measurement of blood loss (QBL) for all deliveries was introduced into a tertiary obstetric unit in Cardiff, Wales.Methods: Retrospective analysis of 875 consecutive maternities between December 2017 and February 2018 was undertaken. Of these, 372 mothers had both pre- and post-partum hemoglobin (Hb) were recorded. Regression analyses were performed to investigate the relationship between change in Hb adjusted for red cell transfusion and QBL.Results: The correlation coefficient between QBL and adjusted change in Hb for all deliveries (n = 372) was 0.57. This corresponded to an estimated fall of adjusted change in Hb of 15.3 g/L (95% CI: 13.1, 17.6) per 1000 mL blood loss.Discussion: QBL has been shown to be reliable across all maternity settings, with reproducible results in theater and delivery rooms (on the obstetric unit and alongside midwifery-led unit). QBL is moderately correlated with adjusted change in Hb for all volumes of bleeding and gives clinicians more accurate knowledge of blood loss than visual estimation. This low-cost, low-fidelity intervention can influence the timely escalation of clinical care and therefore patient outcome.

Postpartum hemorrhage: new insights for definition and diagnosis

The current definition of is inadequate for early recognition of this important cause of maternal death that is responsible for >80,000 deaths worldwide in 2015. A stronger definition of postpartum hemorrhage should include both blood loss and clinical signs of cardiovascular changes after delivery, which would help providers to identify postpartum hemorrhage more promptly and accurately. Along with the amount of blood loss, clinical signs, and specifically the shock index (heart rate divided by systolic blood pressure) appear to aid in more accurate diagnosis of postpartum hemorrhage.

The association between the time from oxytocin cessation during labour to Cesarean delivery and postpartum blood loss: a retrospective cohort study

PURPOSE

Prolonged exposure to oxytocin during augmentation of labour is associated with uterine atony and an increased risk of postpartum hemorrhage (PPH) due to oxytocin receptor desensitization. Cessation of oxytocin infusion during labour may facilitate recovery of oxytocin receptor function, which then helps to restore myometrial contractility and decrease postpartum blood loss. We examined the association between oxytocin recovery interval, i.e., the time from discontinuing oxytocin to Cesarean delivery (CD) for labour arrest, and blood loss.

METHODS

This retrospective cohort study included women who underwent CD for labour arrest following oxytocin-augmented labour from July 1, 2013 to July 19, 2015 at our institution. Data were collected on patient demographics, labour and delivery characteristics, oxytocin induction and augmentation, recovery interval, and PPH risk factors. The primary outcome was estimated blood loss (EBL), calculated using the hematocrit variation method.

RESULTS

Data on 490 women were analyzed. The mean (standard deviation) EBL was 1,341 (577) mL; the amount of oxytocin administered during labour was 6,447 (6,868) mU, and the oxytocin recovery interval was 99 (65) min. Every ten-minute increase in the recovery interval was associated with a 10-mL decrease in EBL (95% confidence interval [CI], -18 to -3; P = 0.009). Morbidly obese women had a significantly higher EBL than those with a body mass index < 40 kg·m^-2 (mean difference, 572 mL; 95% CI, 382 to 762; P < 0.001). The amount and duration of oxytocin administered during labour, but not the oxytocin recovery interval, was associated with the use of additional interventions to control PPH (P = 0.005).

CONCLUSION

Our study shows that an increase in the oxytocin recovery interval is associated with a decrease in blood loss at CD in women with oxytocin augmented labour. These data support discontinuing the oxytocin infusion as soon as the decision is made to proceed with CD for labour arrest, particularly in morbidly obese women.

Effect of on-site training on the accuracy of blood loss estimation in a simulated obstetrics environment

OBJECTIVE

To determine the effect of on-site training on the accuracy of blood loss estimation in a simulated obstetrics environment.

METHODS

In a tertiary hospital in Nigeria, clinical scenarios were created in April 2013 using known blood volumes in an objective structured clinical examination fashion. Doctors and nurses who worked in the obstetrics unit observed and recorded the blood volume at different clinical stations (first study stage). Subsequently, the actual amount of blood was revealed, followed by on-site training on the volume capacities of the study instruments. Three weeks later, the second stage of the study was performed like the first stage but using different amounts of blood for all stations. The differences in the mean errors of blood loss estimation between the two stages were determined.

RESULTS

The analysis included 144 healthcare providers who completed both stages of the study. There were significant differences in the mean error of blood loss estimation before and after the training session for the following stations: delivery bed (P<0.001), sanitary pad 1 (P=0.001), sanitary pad 2 (P=0.001), delivery pad (P=0.001), floor (P<0.001), and laparotomy pad (P=0.001).

CONCLUSION

Periodic education by simulation using clinical scenarios could improve the accuracy of visual blood loss estimation.

Blood loss predictive factors and transfusion practice during percutaneous nephrolithotomy of kidney stones: a prospective study

Objectives

Bleeding is the most common complication of percutaneous nephrolithotomy (PCNL). Injudicious transfusion is frequently performed in current practice, even though it is not always needed. This study aimed to identify the predictive factors of blood loss in the PCNL procedure and evaluate the perioperative transfusion practice.

Methods

A prospective study of PCNL was randomly performed by two consultants of endo-urology at our institution. The inclusion criteria were adults with kidney pelvic stones >20 mm or stone in inferior calyx >10 mm or staghorn stone. Those with coagulopathy, under anti-coagulant treatment or open conversion were excluded. A full blood count was taken at baseline and during 12, 24, 36, 72-hours post-operatively. Factors such as stone burden, sex, body surface area, shifting of hematocrit level and amount of blood transfused were analyzed statistically using line regression to identify the predictive factors of total blood loss (TBL).

 

Results

Eighty-five patients were enrolled in this study. Mean TBL was 560.92 ± 428.43 mL for both endo-urology surgeons. Stone burden was the most influential factor for TBL (p=0.037). Our results revealed that TBL (mL) = -153.379 + 0.229 × stone burden (mm2) + 0.203 x baseline serum hematocrit (%); thus considerably predicted the need for blood transfusion. A total of 87.1% patients did not receive perioperative transfusion, 3.5% received intra-operative transfusion, 7.1% received post-operative transfusion, 23% had both intra and post-operative transfusion, resulting in a cross-matched transfusion ratio of 7.72. Mean perioperative blood transfused was 356.00 ± 145.88 mL.

Evaluation of measured postpartum blood loss after vaginal delivery using a collector bag in relation to postpartum hemorrhage management strategies: a prospective observational study

AIM

To evaluate the incidence of postpartum hemorrhage (PPH) and severe PPH via routine use of a pelvic drape to objectively measure blood loss after vaginal delivery in connection with PPH management.

METHODS

This prospective observational study was undertaken at the obstetrical department of the Charité University Hospital from December 2011 to May 2013 and evaluated an unselected cohort of planned vaginal deliveries (n=1019 live singletons at term). A calibrated collecting drape was used to meassure blood loss in the third stage of labor. PPH and severe PPH were defined as blood loss ≥500 mL and ≥1000 mL, respectively. Maternal hemoglobin content was evaluated at admission to delivery and at the first day after childbirth.

RESULTS

During the study period, 809 vaginal deliveries were analysed. Direct measurement revealed a median blood loss of 250 mL. The incidences of PPH and severe PPH were 15% and 3%, respectively. Mean maternal hemoglobin content at admission was 11.9±1.1 g/dL, with a mean decrease of 1.0±1.1 g/dL. Blood loss measured after vaginal delivery correlated significantly with maternal hemoglobin decrease.

CONCLUSIONS

This study suggests that PPH incidence may be higher than indicated by population-based data. Underbuttocks drapes are simple, objective bedside tools to diagnose PPH. Blood loss should be quantified systematically if PPH is suspected.

Is accurate and reliable blood loss estimation the 'crucial step' in early detection of postpartum haemorrhage: an integrative review of the literature

BACKGROUND

Postpartum haemorrhage (PPH) is the leading cause of maternal mortality in low-income countries and severe maternal morbidity in many high-income countries. Poor outcomes following PPH are often attributed to delays in the recognition and treatment of PPH. Experts have suggested that improving the accuracy and reliability of blood loss estimation is the crucial step in preventing death and morbidity from PPH. However, there is little guidance on how this can be achieved. The aim of this integrative review was to evaluate the various methods of assessing maternal blood loss during childbirth.

METHODS

A systematic, integrative review of published research studies was conducted. All types of studies were included if they developed, tested, or aimed to improve methods and skills in quantifying blood loss during childbirth, or explored experiences of those involved in the process.

RESULTS

Thirty-six studies were included that evaluated the accuracy of visual estimation; tested methods to improve skills in measurement; examined their effect on PPH diagnosis and treatment, and / or explored additional factors associated with blood loss evaluation. The review found that health professionals were highly inaccurate at estimating blood loss as a volume. Training resulted in short term improvements in skills but these were not retained and did not improve clinical outcomes. Multi-faceted interventions changed some clinical practices but did not reduce the incidence of severe PPH or the timing of responses to excessive bleeding. Blood collection bags improved the accuracy of estimation but did not prevent delays or progression to severe PPH. Practitioners commonly used the nature and speed of blood flow, and the condition of the woman to indicate that the blood loss was abnormal.

CONCLUSIONS

Early diagnosis of PPH should improve maternal outcomes, but there is little evidence that this can be achieved through improving the accuracy of blood loss volume measurements. The diagnosis may rely on factors other than volume, such as speed of blood flow and nature of loss. A change in direction of future research is required to explore these in more detail.

Assessment of sublingual misoprostol as first-line treatment for primary post-partum hemorrhage: results of a multicenter trial

AIM

The study investigated the effectiveness of sublingual misoprostol when used as primary treatment of primary post-partum hemorrhage (PPH) in a low-income country.

METHODS

Maternity care providers in three Nigerian hospitals administrated 800 μm sublingual misoprostol to women experiencing PPH. The outcome variables were estimated blood loss and the need for additional uterotonic drugs after initial treatment with misoprostol. Entry criteria included women in term spontaneous labor, while exclusion criteria were women with operative delivery and those experiencing PPH not due to atonic uterus.

RESULTS

One hundred and thirty-one women with PPH were treated over 6 months. Estimated blood loss ranged 500-2500 mL. Twenty women (15.3%) required additional uterotonic drugs to control continuing blood loss. There were no maternal deaths, while seven perinatal deaths were recorded.

CONCLUSION

We conclude that although sublingual misoprostol is effective in reducing blood loss due to PPH, it does not effectively treat all forms of PPH. Additional uterotonics and other ancillary treatments would be required.

The risk of postpartum hemorrhage in women using high dose of low-molecular-weight heparins during pregnancy

BACKGROUND

Low-molecular-weight heparins (LMWH) are the most commonly used anticoagulant during pregnancy for prevention or treatment of VTE. However, the size of the associated risk of postpartum haemorrhage (PPH) is unknown.

OBJECTIVE

To assess the bleeding risk of high dose LMWH, also in relation to time between last dose LMWH and delivery.

MATERIAL AND METHODS

From 1999 to 2009, we followed 88 pregnant women who were started on therapeutic anticoagulation. Controls were pregnant women without LMWH, matched 1:4 for parity, mode of delivery, age, gestational age and delivery date. PPH was defined as >500 ml blood loss for vaginal delivery (severe PPH in vaginal delivery as >1000 ml) and >1000 ml for cesarean section (CS). Women were divided into subgroups by the interval between last dose of anticoagulation and delivery (<12, 12-24 hrs, >24 hrs).

RESULTS

Risk of PPH after vaginal delivery was 30% and 18% for LMWH-users and non-users, respectively (OR 1.9, 95%CI 1.1-3.5). Risk of severe PPH after vaginal delivery was not different (5.6 vs 5.0%; OR 1.1; 0.4-3.6). Risk of PPH after CS was 12% in LMWH-users and 4% in non-users (OR 2.9; 0.5-19.4). Both events of LMWH-users occurred after emergency CS. The risk of PPH associated with delivery within 24 hours after last dose of LMWH was 1.2 fold higher (95%CI 0.4-3.6) compared to a larger interval.

CONCLUSION

High dose LMWH carries an increased risk of more than 500 mL blood loss after vaginal delivery. However, this results not in more clinical relevant severe PPHs. The interval between last dose of LMWH and delivery does not influence the risk of PPH.

Blood loss during laparoscopic radical prostatectomy - is it significant or not?

Introduction

The traditional assessment of blood loss during laparoscopic radical prostatectomy (LRP) is based on the blood volume collected intraoperatively in the suction device bottles. While this method is not perfect, analysis of changes in blood cell count (BCC) resulting from LRP is advisable.

Material and methods

71 men were submitted to LRP due to prostate cancer in our institution over an 18-month time period. From this group, we isolated 60 men with clinically minimal intraoperative blood loss (<200 ml) and included them into the study. Mean age of the cohort was 62.8 years. We performed standard BCC on the day before and 6 hours after the surgery. At the same time points, we measured creatinine serum concentration and calculated eGFR to avoid the data misinterpretation resulting from impaired renal function in the postoperative period.

Results

Statistically and clinically significant differences regarding all BCC parameters measured pre- and postoperatively were observed. The number of red blood cells, hemoglobin concentration, and hematocrit diminished by 17.5% (4.68T/l vs. 3.86T/l, p <0.02), 17.0% (8.93 mmol/l vs. 7.41 mmol/l, p < 0.02), and 17.9% (0.429 vs. 0.352, p <0.02), respectively. Simultaneously, renal function was stable with no significant change in eGFR (82.9 ml/min/1.73 m^2 vs. 79.09 ml/min/1.73 m^2, p = 0.28).

Conclusions

Standard LRP brings on a significant blood loss. While clinically insignificant, this blood loss seems to be as high as approx. 600 ml based on laboratory findings. BCC seems to be a more accurate method of intraoperative blood loss estimation compared to measurement of blood volume collected intraoperatively in the suction device bottles.