The Ability of the Haemonetics[registered sign] 4 Cell Saver System to Remove Tissue Factor from Blood Contaminated with Amniotic Fluid

Intraoperative cell salvage as an effective intervention for postpartum hemorrhage—Evidence from a prospective randomized controlled trial

Background

Postpartum hemorrhage (PPH) is one of the leading causes of maternal mortality. Promptly recovering blood loss is critical for PPH. Intraoperative cell salvage (ICS) is a method to collect and process red blood cells (RBCs) from the blood lost during surgery and transfuse them to the patient’s circulation during or immediately after surgery. Its effectiveness in reducing the demand for allogeneic blood transfusion has been proven, but its effectiveness and safety as a sole treatment for PPH during Cesarean sections are unclear. This is particularly important for patients who cannot or do not want to accept allogeneic blood transfusion.

Materials and methods

In this prospective randomized controlled study, patients with high risks of PPH were randomized into the ICS group or the control group, receiving ICS or allogeneic RBC transfusion if their hemoglobin level was less than 80 g/L during operation. Data collected include clinical examination, blood cell count, hemoglobin level, coagulation function, and plasma levels of fetal hemoglobin, tissue factor, and alpha-fetoprotein before and after fetal delivery and 0, 2, and 12 h after treatment. Adverse events were recorded.

Results

A total of 130 patients were enrolled, aged 33 ± 1 years with a mean gestation period of 37 ± 1 week. The most common cause of Cesarean section was placenta previa, followed by twin pregnancy, scarred uterus, preeclampsia, placental abruption, fetal distress, and placenta accreta spectrum. Bleeding amount was similar between the two groups. The ICS group, compared to controls, had more efficient increases in levels of hemoglobin, RBC, and hematocrit (all p < 0.05). Coagulation function was maintained in the ICS group but reduced in controls 24 h after transfusion, indicated by significantly reduced fibrinogen level and prolonged prothrombin time (PT), thrombin time (TT), and activated partial thromboplastin time (aPTT) (all p < 0.05). There was a transient but significant decrease in plasma tissue factor and alpha-fetoprotein levels and an increase in plasma fetal hemoglobin level with ICS treatment in the postpartum period. No adverse event occurred with ICS intervention.

Conclusion

ICS is an effective and safe intervention for patients with a high risk of PPH during elective or emergency Cesarean section. It can effectively clear tissue factors and alpha-fetoprotein but not fetal hemoglobin.

Placenta Accreta Spectrum: Prenatal Diagnosis and Management

The incidence of placenta accreta spectrum (PAS) is increasing and is now about 3 per 1000 deliveries, largely due to the rising cesarean section rate. Ultrasound is the preferred method for diagnosis of PAS. Ultrasound markers include multiple vascular lacunae, loss of the hypoechoic retroplacental zone, abnormalities of the uterine serosa-bladder interface, retroplacental myometrial thickness less than 1 mm, increased placental vascularity, and observation of bridging vessels linking the placenta and bladder. Patients with PAS should be managed by experienced multidisciplinary teams. Hysterectomy is the accepted management of PAS and conservative or expectant management of PAS should be considered investigational.

Can cell salvage be used for resuscitation in a patient with amniotic fluid embolism and hepatic laceration? A case report

Background

Amniotic fluid embolism (AFE) is a rare disease that can lead to profound coagulopathy and hemorrhage, especially when combined with the laceration and bleeding of other organs. Intraoperative cell salvage (ICS) has been widely used for treating obstetric hemorrhage, but it remains unclear whether ICS can be used in the treatment of AFE.

Case presentation

We report the case of a 27-year-old woman at 39 weeks’ gestation who suddenly developed severe abdominal pain, convulsions, loss of consciousness, and decreased vital signs during labor. Despite an emergency cesarean section being performed, the parturient experienced sudden cardiac arrest. Fortunately, the heart rate spontaneously recovered after effective cardiopulmonary resuscitation (CPR). Further abdominal exploration revealed right hepatic laceration with active bleeding. ICS was performed and the salvaged blood was promptly transfused back to the patient. Subsequently, the patient was diagnosed with AFE based on hypotension, hypoxia, coagulopathy, and cardiac arrest. The patient was transfused with 2899 mL salvaged blood during surgery with no adverse effects. At 60- and 90-day follow-ups, no complaints of discomfort or abnormal laboratory test results were observed in the mother or the baby.

Conclusion

ICS was used to rescue patient with AFE, and ICS did not worsen the condition of patients with AFE. For pregnant women who received CPR, clinicians should explore the presence of hepatic laceration which can be fatal to patients.

Biochemical effects of intraoperative cell salvage and autotransfusion during cesarean section: A prospective pilot study

AIM

Intraoperative cell salvage and autotransfusion (ICSA) is a useful technique for women undergoing cesarean sections who are predicted to experience significant bleeding. This method can reduce allogeneic transfusions as well as its associated risks and costs. Amniotic fluid embolism (AFE) is an abnormal maternal response to ICSA similar to the classic systemic inflammatory response syndrome, but its mechanism is not well understood. This study was conducted to investigate the biochemical aspects of AFE.

METHODS

A prospective case-controlled pilot study was conducted in a general perinatal hospital in Japan. ICSA was performed using a two-step retransfusion process. Blood samples were collected presurgery, immediately postsurgery, and 24 h after surgery. Changes in sialyl Tn antigen (STN), complement C3 and C4, fibrinogen, and fibrin degradation product and D-dimer, C1 esterase inhibitor, and interleukin-8 (all considered AFE-related markers) activities were compared between patients who underwent cesarean sections with ICSA (ICSA group) versus without ICSA (control group).

RESULTS

Fibrinogen levels were significantly lower in the ICSA group than in the control group before surgery but not immediately after or 24 h after surgery. D-dimer was significantly higher immediately after surgery but not 24 h later. STN was significantly lower only before surgery. None of the AFE-related markers showed significant differences between the groups after 24 h. No adverse events were observed in the ICSA group.

CONCLUSIONS

There is no clinical evidence that ICSA alters the biochemical statuses of AFE-related markers in a manner that could lead to adverse maternal responses.

Comparison of cell salvage with one and two suction devices during cesarean section in patients with placenta previa and/or accrete: a randomized controlled trial

Background

Cell salvage has recently been recommended for obstetric use in cases with a high risk of massive hemorrhage during cesarean section (CS). However, limited data are available to support the use of one suction device to collect lost blood. This study aimed to investigate the volume of red blood cells (RBCs) salvaged and the components of amniotic fluid (AF) in blood salvaged by one suction device or two devices during CS in patients with placenta previa and/or accrete.

Methods

Thirty patients with placenta previa and/or accrete undergoing elective CS in the Women's Hospital of Zhejiang University School of Medicine were recruited for the present study from November 1, 2017 to December 1, 2018. The patients were randomly assigned to one of the two groups according to an Excel-generated random number sheet: Group 1 (n = 15), in which only one suction device was used to aspirate all blood and AF, and Group 2 (n = 15), in which a second suction device was mainly used to aspirate AF before the delivery of the placenta. Three samples of blood per patient (pre-wash, post-wash, and post-filtration) were collected to measure AF components. The salvaged RBC volumes were recorded. Continuous data of pre-wash, post-wash, and post-filtration samples were analyzed by using one-way analysis of variance with Tukey's test for multiple comparisons, or Kruskal-Wallis test with Dunn test for multiple comparisons. Comparisons of continuous data between Group 1 and Group 2 were conducted using Student's t test or Mann-Whitney U test.

Results

The salvaged RBC volume was significantly higher in Group 1 than that in Group 2 (401.6 ± 77.2 mL vs. 330.1 ± 53.3 mL, t = 4.175, P < 0.001). In both groups, squamous cells, lamellar bodies, and fat were significantly reduced by washing (all P<0.001) and squamous cells were further reduced by filtering (P < 0.001). Squamous cells were found in six post-filtration samples (three from each group). Lamellar bodies and fat were completely removed by filtering. Insulin-like growth factor binding protein 1, alpha-fetoprotein, albumin, lactate dehydrogenase, and potassium were significantly reduced post-wash (all P < 0.05), with no further significant reduction after filtration in either group (all P > 0.05). The mean percentage of fetal RBCs post-filtration was (1.8 ± 0.8)% with a range of 1.0% to 3.5% and (1.9 ± 0.9)% with a range of 0.7% to 4.0% in Groups 1 and 2, respectively, showing no significant difference between the two groups (U = 188.5, P = 0.651).

Conclusion

Cell salvage performed by one suction device could result in higher volume of salvaged RBCs and can be used safely for CS in patients with placenta previa and/or accrete when massive hemorrhage occurs.

Trial registration number

ChiCTR-INR-17012926, http://www.chictr.org.cn/ Chinese Clinical Trial Registry.

Placenta Accreta Spectrum

Placenta accreta spectrum, formerly known as morbidly adherent placenta, refers to the range of pathologic adherence of the placenta, including placenta increta, placenta percreta, and placenta accreta. The most favored hypothesis regarding the etiology of placenta accreta spectrum is that a defect of the endometrial-myometrial interface leads to a failure of normal decidualization in the area of a uterine scar, which allows abnormally deep placental anchoring villi and trophoblast infiltration. Maternal morbidity and mortality can occur because of severe and sometimes life-threatening hemorrhage, which often requires blood transfusion. Although ultrasound evaluation is important, the absence of ultrasound findings does not preclude a diagnosis of placenta accreta spectrum; thus, clinical risk factors remain equally important as predictors of placenta accreta spectrum by ultrasound findings. There are several risk factors for placenta accreta spectrum. The most common is a previous cesarean delivery, with the incidence of placenta accreta spectrum increasing with the number of prior cesarean deliveries. Antenatal diagnosis of placenta accreta spectrum is highly desirable because outcomes are optimized when delivery occurs at a level III or IV maternal care facility before the onset of labor or bleeding and with avoidance of placental disruption. The most generally accepted approach to placenta accreta spectrum is cesarean hysterectomy with the placenta left in situ after delivery of the fetus (attempts at placental removal are associated with significant risk of hemorrhage). Optimal management involves a standardized approach with a comprehensive multidisciplinary care team accustomed to management of placenta accreta spectrum. In addition, established infrastructure and strong nursing leadership accustomed to managing high-level postpartum hemorrhage should be in place, and access to a blood bank capable of employing massive transfusion protocols should help guide decisions about delivery location.

Acute hypotension associated with intraoperative cell salvage using a leukocyte depletion filter during management of obstetric hemorrhage due to amniotic fluid embolism

Amniotic fluid embolism (AFE) is a rare but catastrophic obstetric complication that can lead to profound coagulopathy and hemorrhage. The role of cell salvage and recombinant human Factor VIIa (rFVIIa) administration in such cases remains unclear. We present a case of AFE and describe our experience with the use of cell salvage and rFVIIa administration during the resuscitation. Cell salvage and transfusion through a leukocyte depletion filter was attempted after the diagnosis of AFE was made, but the attempted transfusion was immediately followed by hypotension and a worsening of hemodynamics. rFVIIa, on the contrary, was used with clinical improvement in coagulopathy and without apparent adverse thrombotic effect.

Intraoperative cell salvage in obstetrics

The use of Intraoperative Cell Salvage (ICS) in obstetrics has been slow to develop as a result of theoretical concerns relating to amniotic fluid embolism and fetal red cell contamination. In this article we examine the current UK position on the use of ICS in this clinical speciality and the recommendations for its safe and appropriate use.

The introduction of intra-operative cell salvage in obstetric clinical practice: a review of the available evidence

Intra-operative blood salvage is common practice in many surgical specialties but its safety is questioned with concerns about the risks of contamination of recovered blood with amniotic fluid and of maternal-foetal alloimmunization. However, the role of cell salvage as a blood-saving measure in this clinical setting is progressively acquiring relevance thanks to the growing body of evidence regarding its quality and safety. Modern cell savers remove most particulate contaminants and leukodepletion filtering of salvaged blood prior to transfusion adds further safety to this technique. Amniotic fluid embolism is no longer regarded as an embolic disease and the contamination of the salvaged blood by foetal Rh-mismatched red blood cells can be dealt with using anti-D immunoglobulin; ABO incompatibility tends to be a minor problem since ABO antigens are not fully developed at birth. Maternal alloimmunization can be caused also by other foetal red cell antigens, but it should also be noted that the risk of alloimmunization of the mother from allogeneic transfusion may be even greater. Therefore the use of cell savers in obstetric clinical practice should be considered in patients at high risk for haemorrhage or in cases where allogeneic blood transfusion is difficult or impossible.

Placenta accreta

OBJECTIVE

We sought to review the risks of placenta accreta, increta, and percreta, and provide guidance regarding interventions to improve maternal outcomes when abnormal placental implantation occurs.

METHODS

Relevant documents were identified through a search of the English-language literature for publications including ≥1 of the key words "accreta" or "increta" or "percreta" using PubMed (US National Library of Medicine; January 1990 through January 2010); with results limited to studies involving human beings. Additional information was obtained from references identified within selected articles; from additional review articles; and from guidelines by organizations including the American College of Obstetricians and Gynecologists. Each included article was evaluated according to study design and quality in accordance with the scheme outlined by the US Preventative Services Task Force.

RESULTS AND RECOMMENDATIONS

Abnormal placentation--encompassing placenta accreta, increta, and percreta--is increasingly common. While randomized controlled trials and large observational cohort studies that can be used to define best practice are lacking, strategies to enhance early diagnosis, enhance preparation, and coordinate peripartum management can be undertaken. Women with a placenta previa overlying a uterine scar should be evaluated for the potential diagnosis of placenta accreta. Women with a placenta previa or "low-lying placenta" overlying a uterine scar early in pregnancy should be reevaluated in the third trimester with attention to the potential presence of placenta accreta. When the diagnosis of placenta accreta is made remote from delivery, the need for hysterectomy should be anticipated and arrangements made for delivery in a center with adequate resources, including those for massive transfusion. Intraoperatively, attention should be paid to abdominal and vaginal blood loss. Early blood product replacement, with consideration of volume, oxygen-carrying capacity, and coagulation factors, can reduce perioperative complications.

The role of the anesthesiologist in management of obstetric hemorrhage

Hemorrhage after childbirth, whether the delivery is vaginal or operative, is a clinical situation where knowledge, communication, and the availability and utilization of resources all play prominent roles. In this article we describe the thought processes and decisions that should occur, and the actions that should be taken by the anesthesiologist in the face of suspected, expected, or unexpected hemorrhage in the labor and delivery suite.

Cell salvage in obstetrics

The safety of cell salvage in obstetrics has been questioned because of the presumed risk of precipitating amniotic fluid embolism and, to a lesser extent, maternal alloimmunisation. For these reasons, experience in this field is limited and has lagged far behind that in other surgical specialties. There has, however, been renewed interest in its use over recent years, mainly as a result of problems associated with allogeneic blood transfusion. Our aim was to review the medical literature to ascertain the principles of cell salvage, the ability of the process to remove contaminants, and its safety profile in the obstetric setting. The search engines PubMed and Google Scholar were used and relevant articles and websites hand searched for further references. Existing cell salvage systems differ in their ability to clear contaminants and all require the addition of a leucocyte depletion filter. Although large prospective trials of cell salvage with autotransfusion in obstetrics are lacking, to date, no single serious complication leading to poor maternal outcome has been directly attributed to its use. Cell salvage in obstetrics has been endorsed by several bodies based on current evidence. Current evidence supports the use of cell salvage in obstetrics, which is likely to become increasingly commonplace, but more data are required concerning its clinical use.

Blood component therapy in obstetrics

Hemorrhage is the leading cause of intensive care unit admission and one of the leading causes of death in the obstetric population. This emphasizes the importance of a working knowledge of the indications for and complications associated with blood product replacement in obstetric practice. This article provides current information regarding preparation for and administration of blood products, discusses alternatives to banked blood in the obstetric population, and introduces pharmacological strategies for treatment of hemorrhage.

Intraoperative cell salvage in obstetrics

Cell salvage is widely used in many surgical specialties to reduce the use of allogeneic blood, which is associated with well-recognized significant complications such as incorrect transfusion, acute and delayed immunological transfusion reactions and transfusion-transmitted infection. Theoretical concerns over the use of cell salvage in obstetrics have focused on the risk of Rhesus immunization and the risk of contamination of the cell-saved blood with traces of amniotic fluid. This article examines the in vitro and in vivo evidence for the safety of the technique, presents current usage figures from Wales and the entire UK, and discusses the current perception of amniotic fluid embolus as an anaphylactoid reaction. It suggests that patients will have to choose between the risks of allogeneic or cell-saved blood, and concludes that the balance of evidence is now in favour of cell salvage in obstetrics.

Blood conservation techniques in obstetrics: a UK perspective

In the UK, maternal mortality due to haemorrhage appears to be rising, with obstetric haemorrhage accounting for 3-4% of the red cells transfused. Allogeneic blood transfusion carries risks such as administration errors, transmitted infections and immunological reactions. The supply of blood is decreasing, partly due to the exclusion of donors who have themselves received a blood transfusion since 1980, in order to stop transmission of variant-Creutzfeldt-Jakob disease. The cost of blood is significantly increasing, partly because it is now leucocyte-depleted to minimize viral transmission. Various blood conservation techniques can reduce exposure to allogeneic blood thereby reducing risk and conserving the blood supply. These include preoperative autologous donation, acute normovolaemic haemodilution and intra-operative cell salvage. Preoperative autologous donation may produce anaemia, does not eliminate transfusion risk, cannot be used in an emergency and is not acceptable to Jehovah's Witnesses. It should be reserved for exceptional circumstances (rare blood type or unusual antibodies). Acute normovolaemic haemodilution may induce anaemia and cardiac failure and cannot be used in an emergency. It may have a limited role in combination with other techniques. Intra-operative cell salvage is more effective and useful in obstetrics than the other techniques, overcomes their shortcomings and is endorsed by CEMACH, OAA/AAGBI Guidelines, the National Blood Service and NICE.

An Analysis of Transfusion Practice and the Role of Intraoperative Red Blood Cell Salvage During Cesarean Delivery

BACKGROUND

We sought to determine to what extent intraoperative salvaged red blood cells (RBC) might theoretically reduce exposure to appropriately transfused allogenic erythrocytes in Cesarean delivery patients.

METHODS

Medical records of Cesarean delivery patients requiring blood transfusions from January 1, 1992 to June 30, 1996 and June 1, 1998 to June 30, 2003 were reviewed. For each patient, we calculated the number of allogenic RBC units that could have theoretically been avoided had intraoperative autotransfusion been performed, based upon estimated blood loss, preoperative hematocrit, and the amount of retrieved blood needed to yield a single RBC unit. RBC transfusion appropriateness was determined using the recommended guideline of transfusing RBCs if the hemoglobin is <7 gm/dL in a patient with continuing bleeding.

RESULTS

A small percentage of Cesarean delivery patients (1.8%) received blood product transfusions. Of 207 patients receiving blood transfusions, salvaged erythrocytes could have theoretically decreased exposure to allogenic RBCs in 115 (55.6%) patients. Only 75.7% of these 115 patients were appropriately transfused with erythrocytes.

CONCLUSION

Theoretically, based on best, average, and worst RBC salvage recovery calculations, 25.1%, 21.2%, or 14.5% of the appropriately transfused patients, respectively, could have completely avoided allogenic RBC transfusion.

Planning for hemorrhage. Steps an anesthesiologist can take to limit and treat hemorrhage in the obstetric patient

Obstetric hemorrhage continues to be a significant cause of maternal mortality and morbidity. Blood transfusion in such circumstances may be life saving but involves exposing the patient to additional risks. Limiting blood transfusion and using autologous blood when possible may reduce some of these risks. This article outlines the techniques that may be used to limit and more effectively treat hemorrhage in the obstetric patient, with particular attention paid to reducing the use of allogeneic blood transfusion.

Clinical experience with cell salvage in obstetrics: 4 cases from one UK centre

We present 4 cases in which cell salvaged blood was used in maternity patients, including three caesarean sections and one post-partum haemorrhage. All patients were monitored for a minimum of 24 h on either a general Intensive Care Unit (ICU) or specialised obstetric High Dependency Unit (HDU). Postoperative complications are discussed, with particular emphasis on whether the transfusion of cell salvaged blood was a contributory factor. Cell salvage in obstetrics is being used in a haphazard and individual manner and our only present outcome indicators are case reports. We consider the argument for and against cell salvage in obstetrics, and suggest guidelines to reflect current best practice in the use of the machine and filters.

Anaesthesia and analgesia for the critically ill parturient

Anaesthetic and analgesic techniques in the critically ill are determined largely by the nature of the presenting illness. The commonest conditions likely to present as life-threatening emergencies are pre-eclampsia, obstetric haemorrhage, cardiac disease and severe sepsis. Issues dictating choice of anaesthetic technique are the patient's ability to maintain her airway, coagulation status, intravascular volume and haemodynamic dependence upon sympathetic drive, and requirements for ventilatory support and intensive care. Fetal well-being is an issue in the antepartum period, uteroplacental blood flow should be maintained and hypotension avoided. Maternal survival takes priority, however, and occasionally general anaesthetic techniques must be used which lead to neonatal respiratory depression and requirement for ventilatory support. Anaesthesia itself is associated with known hazards. The risks of each technique must be balanced against possible benefits in the context of the presenting illness.

Cell salvage in obstetrics: an evaluation of the ability of cell salvage combined with leucocyte depletion filtration to remove amniotic fluid from operative blood loss at caesarean section

During 27 elective caesarean sections, operative blood loss was collected and processed using the Haemonetics Cell Saver 5 and filtered by Pall RC 100 leucocyte depletion filtration. The efficiency of removal of amniotic fluid, and the degree. of contamination with fetal red cells were assessed in the resulting 'cleaned' blood. Cell saver processing effectively removed alpha-fetoprotein from the red cells of 14 patients whose amniotic fluid was removed by separate suction and from nine of the 13 patients whose amniotic fluid was aspirated into the cell saver along with operative blood loss. Cell saver processing and leucocyte depletion filtration completely removed trophoblastic tissue and white cells, but fetal squames were still clearly present in 10, and possibly in 14 samples after processing and fully removed in only two specimens. Amorphous debris was present in all samples after processing. The maximum mass of fetal red cells contaminating any patient's total salvaged blood was 19 ml (range 2-19 ml). Had this been re-transfused into a rhesus-incompatible mother it would have required 2500 i.u. (500 microg) anti-D immunoglobulin to prevent rhesus-immunization of the mother. Contamination of processed caesarean section blood with fetal red cells and fetal squames is defined and its clinical implications discussed, with an overview of the development and current status of cell salvage. Autotransfusion by cell salvage with leucocyte depletion filtration should be considered in life-threatening obstetric haemorrhage and offered to Jehovah's Witnesses.