OB Hemorrhage - EBL Measurement Resources

OBJECTIVES: Following the results of the Confidential Enquiries into Maternal Deaths report, which claims two maternal deaths annually in the UK from postpartum haemorrhage, our aim was to assess the accuracy of 'visual estimation of blood loss' and produce suitable pictorial and written algorithms to aid in the recognition and management of massive obstetric haemorrhage.
DESIGN: Observational study to determine discrepancy between actual blood loss (ABL) and estimated blood loss (EBL).
SETTING: Teaching hospital.
POPULATION: Hundred and three obstetricians, anaesthetists, midwives, nurses and healthcare assistants.
METHODS: Clinical scenarios were reproduced in the form of 12 Objective Structured Clinical Examination (OSCE) style stations augmented with known volumes of whole blood. Individual staff estimated the blood loss visually and recorded their results. Digital photographs were used to produce a pictorial 'algorithm' suitable for use as a teaching tool in labour ward.
MAIN OUTCOME MEASURES: Areas of greatest discrepancy between EBL and ABL.
RESULTS: Significant underestimation of the ABL occurred in 5 of the 12 OSCE stations: 500-ml (50-cm diameter) floor spill, 1000-ml (75-cm diameter) floor spill, 1500-ml (100-cm diameter) floor spill, 350-ml capacity of soaked 45- x 45-cm large swab and the 2-l vaginal postpartum haemorrhage on bed/floor.
CONCLUSIONS: Accurate visual estimation of blood loss is known to facilitate timely resuscitation, minimising the risk of disseminated intravascular coagulation and reducing the severity of haemorrhagic shock. Participation in clinical reconstructions may encourage early diagnosis and prompt treatment of postpartum haemorrhage. Written and pictorial guidelines may help all staff working in labour wards.

AIM: To determine the accuracy of the estimation of blood loss using simulated clinical examples.
SETTING: Over 100 attendees came together at a seminar about postpartum haemorrhage in June 2006. Five blood loss assessment stations were constructed, each containing a simulated clinical example. Each station was numbered and was made up of a variety of equipment used in birthing suites. Over 5L of 'artificial' blood was made. The artificial blood was similar to the colour and consistency of real blood.
SAMPLE: A convenience sample of 88 participants was given a response sheet and asked to estimate blood loss at each station. Participants included midwives, student midwives and an obstetrician.
RESULTS: Blood in a container (bedpan, kidney dish) was more accurately estimated than blood on sanitary pads, sheets or clothing. Lower volumes of blood were also estimated correctly by more participants than the higher volumes.
DISCUSSION: Improvements are still needed in visual estimation of blood loss following childbirth. Education programs may increase the level of accuracy.
CONCLUSION: We encourage other clinicians and educators to embark upon a similar exercise to assist midwives and others to improve their visual estimation of blood loss after birth. Accurate estimations can ensure that women who experience significant blood loss can receive appropriate care and the published rates of postpartum haemorrhage are correct.

OBJECTIVE: Visually estimated blood loss has long been known to be imprecise, inaccurate, and often underestimated, which may lead to delayed diagnosis and treatment. Our purpose is to determine whether a brief didactic course can improve visually estimated blood loss and whether prior clinical experience influences estimation of blood loss.
METHODS: Reconstituted whole blood was obtained from the blood bank, and simulated scenarios with known measured blood loss were created using common surgical materials. Visually estimated blood loss was performed by medical personnel before and after a 20-minute didactic session. Percent errors of estimated blood loss were calculated and comparisons were made before and after the lecture. The effects of actual blood volume and clinical experience on estimation of blood loss were assessed.
RESULTS: A total of 53 participants assessed 7 scenarios. There were significant reductions in error for all scenarios. Median percent error in estimated blood loss was not influenced by clinical experience, either before or after the didactic session. Blood loss tends to be overestimated at low volumes and underestimated at high volumes.
CONCLUSION: Error in estimating blood loss is dependent on actual blood loss volume. Medical students and experienced faculty demonstrate similar errors, and both can be improved significantly with limited instruction. This educational process may assist clinicians in everyday practice to more accurately estimate blood loss and recognize patients at risk for hemorrhage-related complications.

Blood loss during normal delivery was measured in 37 primiparas and 25 multiparas who had no obstetric or medical complications and who underwent normal delivery in a teaching hospital following spontaneous onset of labour at term. Measured blood loss was significantly greater than the estimated volume of blood loss. In primigravidas, the mean ( +/- SE, standard error of the mean) estimated blood loss was 260 +/- 12 ml and the mean measured blood loss was 401 +/- 29 ml. In multiparas the mean estimated blood loss was 220 +/- 10 ml and the mean measured blood loss was 319 +/- 41 ml. The mean estimated blood loss was significantly lower (P less than 0.05) than the mean measured blood loss in both groups. The size of the discrepancy between measured and estimated blood loss was proportional to the measured blood loss. These findings show that visual estimation of blood loss was grossly inaccurate.

This paper will examine the literature on blood loss at delivery and report the findings of a small pilot study where midwives and doctors were asked to estimate blood loss at simulated stations. The results were analysed using simple frequency distribution. This simple study demonstrated that midwives and other health professionals underestimate blood loss at delivery by 30-50%. The implication for midwives is that there is a need to double their estimated blood loss at delivery when it is over 500 ml.

OBJECTIVE: To accurately measure blood loss during childbirth in a developing country.
METHOD: The alkaline hematin technique was used to quantify blood lost during delivery and 24 h postpartum in 158 women in Pemba Island, Zanzibar.
RESULT: Women were found to lose less blood during childbirth and 24 h postpartum than previously reported. Compared with laboratory values, nurse-midwives approximated blood loss accurately (mean difference, i.e., mean underestimation by nurse-midwives, 4.90 mL); however, their imprecision was greater for higher laboratory values.
CONCLUSION: This study may prompt further investigation, as no comparable data exist for developing countries where maternal mortality is high and severe anemia prevalent.

OBJECTIVE: To evaluate the blood ordering practice and blood transfusion for Caesarean sections at our institution and to compare the estimated blood loss between anaesthetists and obstetricians.
METHODS: A review of 126 patients undergoing both elective and emergency Caesarean section was undertaken in 2002. Information collected included the number of blood units cross-matched preoperatively, type of surgery (emergency or elective), type of anaesthesia, parity of the patient, estimated blood loss by both anaesthetists and obstetricians, intraoperative and postoperative transfusion within 48 hours and pre and post operative haemoglobin (Hb) and haemocrit (Hct).
RESULTS: A total of 215 units were cross-matched for 126 patients undergoing Caesarean section delivery. A small amount (9.5%) were transfused intraoperatively and 5.5% postoperatively. The average blood loss estimated by anaesthetists was 498 +/- 176 ml and that by obstetricians was 592 +/- 222 ml. The calculated blood loss based on patients blood volume and drop in Hct was 787 +/- 519 ml. The cross-match transfusion ratio was 9.7.
CONCLUSION: Only 13% of our patients needed blood transfusion. The mean blood loss was estimated to be more by the obstetricians as compared to the anaesthetists. We recommend that the practice of routine cross-match practice prior to Caesarean section should be re-looked by institutions practicing obstetric anaesthesia.

BACKGROUND: Excessive bleeding is one of the major threats to women at childbirth. The aim of this study was to validate estimation of blood loss during delivery.
METHODS: Bleeding was estimated after 29 elective cesarean sections and 26 vaginal deliveries and compared to blood loss measured by extraction of hemoglobin using the alkaline hematin method, according to Newton.
RESULTS: Inter-individual agreement of estimation showed good results. Estimated loss in comparison with measured loss resulted in an over-estimation. In vaginally delivered women, there was no correlation between estimated and measured blood loss (r2=0.13), and in women delivered by elective cesarean section, the correlation was moderate (r2=0.55). Agreement, according to Bland and Altman, indicated that measured blood loss could vary from 570 ml less to 342 ml more than estimated blood loss.
CONCLUSIONS: The standard procedure of estimation of obstetric bleeding was found to be unreliable. In this study, blood loss was over-estimated in cesareans. In vaginal deliveries, there seemed to be no correlation. Estimated blood loss as a quality indicator or as a variable in studies comparing complications must be used with caution. For clinical purposes, estimation of blood loss and measurement of post partum hemoglobin is of low value and may lead to the wrong conclusions.

OBJECTIVE: To compare (1) visual estimation of postpartum blood loss with estimation using a specifically designed blood collection drape and (2) the drape estimate with a measurement of blood loss by photospectrometry.
METHODS: A randomized controlled study was performed with 123 women delivered at the District Hospital, Belgaum, India. The women were randomized to visual or drape estimation of blood loss. A subsample of 10 drape estimates was compared with photospectrometry results.
RESULTS: The visual estimate of blood loss was 33% less than the drape estimate. The interclass correlation of the drape estimate to photospectrometry measurement was 0.92.
CONCLUSION: Drape estimation of blood loss is more accurate than visual estimation and may have particular utility in the developing world. Prompt detection of postpartum hemorrhage may reduce maternal morbidity and mortality in low-resource settings.

BACKGROUND: Visual blood loss estimation often underestimates blood loss. In this study we sought to determine the effect of calibrated drape markings on blood loss estimation in a simulated vaginal delivery.
METHODS: Subjects were randomized to estimate simulated blood loss (300, 500, 1000, and 2000 mL) in calibrated or noncalibrated vaginal delivery drapes and then crossover.
RESULTS: Visual blood loss estimation with noncalibrated drapes underestimated blood loss, with worsening accuracy at larger volumes (16% error at 300 mL to 41% at 2000 mL). The calibrated drape error was <15% at all volumes.
CONCLUSIONS: Calibrated vaginal delivery drapes improve blood loss estimation.

OBJECTIVE: Depending on the country and the publications, post-partum hemorrhage (PPH) is either the first or second cause of maternal death in the world, including in developed countries. It remains a significant source of morbidity, severe anemia, blood transfusion, transfusion complications, acquired coagulation disorders and hemostasis hysterectomy. Visual assessment underestimates the amount of blood loss in around 45% of cases. Emergency treatment is therefore sometimes undertaken with some delay, giving time for Disseminated Intravascular Coagulation (DIC) to occur, which worsens the prognosis. A collecting plastic bag put under the pelvis of the mother just after delivery is a quantitative and objective method of measuring blood loss. The objective was to assess sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), studying correlation between bag's volume and hemoglobin and hematocrit variation.
MATERIALS AND METHODS: Included outpatients were women with unique pregnancy at term. Breech presentations were excluded. We measured serum hemoglobin and hematocrit just after admission for labor. A collecting bag, placed under the pelvis of each woman just after birth, was weighted after delivery. Serum hemoglobin and hematocrit were again assessed at three days. Post-partum hemorrhage was defined by a fall of hematocrit more than 10 points (delta Ht), or by a fall of hemoglobin more than 3g/dL (delta Hb).
RESULTS: From January 2003 to May 2003, 272 patients were included. 8.9% of the results were unuseful (n=24). The mean volume of blood loss was 190 ml (5th p=29 ml, 10th p=48 ml, 90th p=610 ml, 95th p=824 ml). The mean delta Ht was 2.7 +/- 4 pts (16.5 / -4.8). The mean delta Hb was 1.2 +/- 1.4 g/dL (5.9 / -1.5). For a delta Ht=10 the calculated bag volume was 564 ml. With this cut off we noted 5.5% PPH (n=15) prevalence=0.06. Sensitivity=34.21%. Specificity=99%. PPV=86%. NPV=90.38%. For a delta Hb=3 the calculated bag volume was 486 ml. With this cut off we noted 10.7% PPH (n=24) prevalence of PPH=0.1. Sensitivity=38.77%. Specificity=95.96%, PPV=67. 85%. NPV=87.7%.
CONCLUSION: The collecting pelvis bag is a rapid and precise procedure to diagnose PPH in the delivery room. It also enables a visual and quantitative non-subjective estimation of blood loss. Because of its simplicity and very low cost, the collecting pelvis bag should be used widely as a routine preventive measure. [Article in French]