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

Intraoperative cell salvage is associated with reduced allogeneic blood requirements and has no significant impairment on coagulation function in patients undergoing cesarean delivery: a retrospective study

OBJECTIVE

The aim of the study is to examine the association between Intraoperative cell salvage (ICS), allogeneic blood transfusion (ABT) and coagulation function in obstetrics.

METHODS

A total of 486 pregnant women undergoing cesarean delivery, of whom 157 were enrolled in this retrospective study. Patients were divided into ICS group (n = 101, ICS used during operation) and control group (n = 56, ICS not used during operation). Clinical data, including plasma prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fib) and thrombin time (TT) levels, were collected from all patients preoperatively (within 12-24 h) and postoperatively (within 6-12 h) and analyzed by t test, two-way repeated-measures ANOVA and Spearman's correlation.

RESULTS

The use of ICS is associated with lower requirement rate for ABT (P < .001), while the blood loss was similar between the two groups (P = .990). Mean volume of ICS transfusion was 432.65 mL. Compared to preoperative values, the postoperative PT and APTT levels were significantly increased, while Fib was decreased in the two groups (all P < .01). No significant difference in coagulation function was observed between groups in preoperative and postoperative phase (P > .05). Furthermore, PT, APTT and TT after surgery were not correlated with the transfused volume of salvaged blood (P > .05) while the levels of Fib were negatively correlated with the volume (P < .01). In addition, there were no transfusion reactions in both two groups.

CONCLUSIONS

Intraoperative cell salvage is correlated with reduced allogeneic blood requirements but did not impair blood coagulation significantly in patients undergoing cesarean delivery.

A randomised controlled trial and economic evaluation of intraoperative cell salvage during caesarean section in women at risk of haemorrhage: the SALVO (cell SALVage in Obstetrics) trial

BACKGROUND

Caesarean section is associated with blood loss and maternal morbidity. Excessive blood loss requires transfusion of donor (allogeneic) blood, which is a finite resource. Cell salvage returns blood lost during surgery to the mother. It may avoid the need for donor blood transfusion, but reliable evidence of its effects is lacking.

OBJECTIVES

To determine if routine use of cell salvage during caesarean section in mothers at risk of haemorrhage reduces the rates of blood transfusion and postpartum maternal morbidity, and is cost-effective, in comparison with standard practice without routine salvage use.

DESIGN

Individually randomised controlled, multicentre trial with cost-effectiveness analysis. Treatment was not blinded.

SETTING

A total of 26 UK obstetric units.

PARTICIPANTS

Out of 3054 women recruited between June 2013 and April 2016, we randomly assigned 3028 women at risk of haemorrhage to cell salvage or routine care. Randomisation was stratified using random permuted blocks of variable sizes. Of these, 1672 had emergency and 1356 had elective caesareans. We excluded women for whom cell salvage or donor blood transfusion was contraindicated.

INTERVENTIONS

Cell salvage (intervention) versus routine care without salvage (control). In the intervention group, salvage was set up in 95.6% of the women and, of these, 50.8% had salvaged blood returned. In the control group, 3.9% had salvage deployed.

MAIN OUTCOME MEASURES

Primary - donor blood transfusion. Secondary - units of donor blood transfused, time to mobilisation, length of hospitalisation, mean fall in haemoglobin, fetomaternal haemorrhage (FMH) measured by Kleihauer-Betke test, and maternal fatigue. Analyses were adjusted for stratification factors and other factors that were believed to be prognostic a priori. Cost-effectiveness outcomes - costs of resources and service provision taking the UK NHS perspective.

RESULTS

We analysed 1498 and 1492 participants in the intervention and control groups, respectively. Overall, the transfusion rate was 2.5% in the intervention group and 3.5% in the control group [adjusted odds ratio (OR) 0.65, 95% confidence interval (CI) 0.42 to 1.01; p = 0.056]. In a planned subgroup analysis, the transfusion rate was 3.0% in the intervention group and 4.6% in the control group among emergency caesareans (adjusted OR 0.58, 95% CI 0.34 to 0.99), whereas it was 1.8% in the intervention group and 2.2% in the control group among elective caesareans (adjusted OR 0.83, 95% CI 0.38 to 1.83) (interaction p = 0.46, suggesting that the difference in effect between subgroups was not statistically significant). Secondary outcomes did not differ between groups, except for FMH, which was higher under salvage in rhesus D (RhD)-negative women with RhD-positive babies (25.6% vs. 10.5%, adjusted OR 5.63, 95% CI 1.43 to 22.14; p = 0.013). No case of amniotic fluid embolism was observed. The additional cost of routine cell salvage during caesarean was estimated, on average, at £8110 per donor blood transfusion avoided.

CONCLUSIONS

The modest evidence for an effect of routine use of cell salvage during caesarean section on rates of donor blood transfusion was associated with increased FMH, which emphasises the need for adherence to guidance on anti-D prophylaxis. We are unable to comment on long-term antibody sensitisation effects. Based on the findings of this trial, cell salvage is unlikely to be considered cost-effective.

FUTURE WORK

Research into risk of alloimmunisation among women exposed to cell salvage is needed.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN66118656.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 2. See the NIHR Journals Library website for further project information.

Cost savings of red cell salvage during cesarean delivery

OBJECTIVE

To use decision analysis to evaluate whether and under what conditions routine setup of intraoperative cell salvage during cesarean delivery is cost-saving.

METHODS

We developed a decision model to compare costs associated with two strategies for cesarean delivery: 1) routine setup of intraoperative cell salvage; or 2) standard care without intraoperative cell salvage. One-, two-, and three-way sensitivity analyses as well as Monte Carlo simulation were used to assess the robustness of our findings.

RESULTS

Among nonselected women undergoing cesarean delivery, our base case estimate was that 3.2% would require red blood cell transfusion. Under this assumption, cell salvage is cost-saving only if each woman requires at least 60 units. Conversely, if only two units on average are required, the probability of transfusion needs to be at least 58% for cell salvage to be cost-saving. In our base case analysis, setup of intraoperative cell salvage during routine cesarean deliveries is not cost-saving, increasing the cost per cesarean delivery by $223.80. We found that cell salvage would be cost-saving only in very high-risk scenarios. For example, severe maternal anemia or abnormal placentation, in which 54% and 75% of women are transfused three and two units per case, respectively, would make cell salvage cost-saving.

CONCLUSION

Setup of intraoperative cell salvage during cesarean delivery is cost-saving and should be considered only when there is a predictably high probability of transfusion or when a massive transfusion is reasonably likely.

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.

[Obstetric bleeding: an update]

Massive bleeding in obstetrics still ranks among the most frequent causes of maternal morbidity and mortality worldwide. The most frequent type is primary postpartum hemorrhage, which is usually the result of an atonic uterus. The clinical priorities are to assure hemodynamic stability and to correct coagulation abnormalities. If pharmacologic treatment cannot achieve these goals, invasive methods such as interventional vascular radiology or artery ligation must be used. Hysterectomy is the last resort when the previous methods fail. For the best prognosis, in terms of preventing death, maintaining maternal fertility and minimizing morbidity, every maternity ward should have a well-defined multidisciplinary protocol that facilitates diagnosis and immediate treatment.

Use of a leucocyte filter to remove tumour cells from intra-operative cell salvage blood

SUMMARY

The intra-operative blood loss of 50 consecutive gynae-oncology patients undergoing surgery for endometrial, cervical or ovarian cancer was cell salvaged and filtered. In each case blood samples were taken from the effluent tumour vein, a central venous line, the cell saver reservoir, the cell salvage re-transfusion bag after processing but before filtration and from the cell salvage re-transfusion bag after processing and filtration. Samples were examined using immunohistochemical monoclonal antibody markers for epithelial cell lines. Viable, nucleated malignant cells were detected in 2/50 central venous samples, 34/50 reservoir samples and 31/50 unfiltered cell salvaged samples. After passage through a Pall RS leucocyte depletion filter no remaining viable, nucleated malignant cells were detected in any sample. The clinical risks of cell salvage in these circumstances should be reviewed in the light of the risks of allogeneic blood transfusion.

Anaesthetic issues related to postpartum haemorrhage (excluding antishock garments)

The obstetric anaesthetist is a key member of the multidisciplinary team required to manage postpartum haemorrhage, having been trained in resuscitation and being experienced in managing haemorrhage and in monitoring and caring for the critically ill patient. The diagnosis of shock, initial resuscitation controversies surrounding fluid replacement, cell salvage in obstetrics and monitoring are discussed.

The Use of Cell Salvage during Obstetric Procedures: An Audit of Scotland's Maternity Units

Background

Concerns about the safety and supply of donor blood mean that clinicians are increasingly looking for alternatives to allogenic blood transfusion. One such alternative is cell salvage. Theoretical concerns about the safety of giving salvaged blood to obstetric patients have so far limited its use in maternity patients, but its use in obstetrics is now growing.

Aims

To determine how many Scottish maternity units use cell salvage and what barriers anaesthetists see to its use in obstetrics.

Methods

A survey was posted to one consultant anaesthetist at each of Scotland's 18 consultant led maternity units.

Results

Two out of 18 maternity units in Scotland use cell salvage. Perceived barriers to use include lack of machine, insufficient cases and lack of familiarity with the technology. Only 4/15 anaesthetists saw safety concerns as a barrier to using the technology.

Conclusion

It would appear that practical issues such as staff training and maintaining familiarity with the technology are greater barriers to the use of cell salvage during obstetric procedures than concerns over safety or financial costs. Although cell salvage would appear to be safe, its use in obstetrics must be accompanied by ongoing audit and detailed data should be collected for each case.

Contamination of salvaged maternal blood by amniotic fluid and fetal red cells during elective Caesarean section

Background

Cell salvage in obstetrics is still a controversial subject and has yet to be fully embraced. The aim of this exploratory study was to measure amniotic fluid (AF), heparin, and fetal red cell contamination of washed filtered salvaged maternal blood and to investigate differences based on the number of suction devices used.

Methods

Patients undergoing elective Caesarean section were assigned alternately to one of two groups. In Group 1, all blood and AF was collected with one suction. In Group 2, AF was aspirated to waste with a second separate suction device before collection of any blood.

Results

In both groups, alpha-fetoprotein (AFP), squames cells, and heparin were significantly reduced (P<0.001) by the washing and filtering process. Mean AFP levels post-filtration were 2.58 IU ml⁻¹ in Group 1 and 3.53 IU ml⁻¹ in Group 2. Squames cells were completely removed in all but two cases. Fetal red blood cells were still present in the final product, range 0.13–4.35%. In Group 1, haemoglobin and haematocrit were higher than in Group 2, with lower white blood cell, AFP, and fetal red cell counts.

Conclusions

This study adds to the growing body of evidence that there is little or no possibility for AF contamination to enter the re-infusion system when used in conjunction with a leucodepletion filter.

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 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.

Maternal deaths from anaesthesia. An extract from Why Mothers Die 2000–2002 , the Confidential Enquiries into Maternal Deaths in the United Kingdom † †This article is accompanied by the Editorial

This is the first of two extracts from Why Mothers Die 2000-2002, issued on 12 November 2004 by the Confidential enquiry into Maternal and Child Health (CEMACH), reproduced with permission. The full report can be accessed via their web site: http://www.cemach.org.uk/