Efficiency of leukocyte depletion filters and micro-aggregate filters following intra-operative cell salvage during cesarean delivery.

BACKGROUND: Intra-operative cell salvage is not routinely used during cesarean delivery because it is not cost-effective for patients at low risk of hemorrhage and there are theoretical concerns about amniotic fluid embolism. Some guidelines recommend using leukocyte depletion filters to decrease the risk of amniotic fluid embolism before re-infusing salvaged blood, but these filters are not available in Japan. We compared the efficacy and safety of leukocyte depletion and micro-aggregate filters in combination with intra-operative cell salvage during cesarean delivery. METHODS: Blood was collected in a Cell Saver 5 reservoir during cesarean delivery. Four samples were collected: pre-wash, post-wash, post-filtration with a leukocyte depletion filter and post-filtration with a micro-aggregate filter. Each sample was analyzed for amniotic fluid markers of zinc coproporphyrin-1 and sialyl-Tn, for fetal hemoglobin, and the sample underwent pathological examination for white blood cells and squamous cells. Post-filtration samples were compared using paired t-tests with P <0.05 indicating statistical significance. RESULTS: Zinc coproporphyrin-1 and sialyl-Tn were negative at almost all sample points. Squamous cells decreased by 59.1% post-wash and 91.2% post-filtration using a leukocyte depletion filter. Leukocyte depletion filters removed 99.7% of white blood cells and were more effective in removing white blood cells than micro-aggregate filters (P=0.02). CONCLUSION: Leucocyte depletion filters are more effective in removing white blood cells and squamous cells than micro-aggregate filters, and their introduction for intra-operative cell salvage during cesarean delivery should be considered in Japanese clinical practice.

Maternal Death Due to Amniotic Fluid Embolism: A National Study in France.

BACKGROUND: A structured definition of amniotic fluid embolism (AFE) based on 4 criteria was recently proposed for use in research by the Society for Maternal-Fetal Medicine (SMFM) and the Amniotic Fluid Embolism Foundation. The main objective of this study was to review all AFE-related maternal deaths in France during 2007-2011 according to the presence or not of all these 4 diagnostic criteria. METHODS: Maternal deaths due to AFE were identified by the national experts committee of the French Confidential Enquiry into Maternal Deaths during 2007-2011 (n = 39). The maternal mortality ratio for AFE was calculated. We applied the structured definition proposed by the Society for Maternal-Fetal Medicine and the Amniotic Fluid Embolism Foundation to AFE-related maternal deaths identified by the national experts committee. Characteristics of women, pregnancies and deliveries; clinical and biological features of AFE; and specific laboratory tests used were described by the presence or not of all 4 diagnostic criteria. Management of obstetric hemorrhage and quality of care according to the experts were also described. RESULTS: The maternal mortality ratio from AFE was 0.95/100,000 live births (95% confidence interval, 0.67-1.3). Detailed clinical data were collected for 36 women who died from AFE: 21 (58%) had all 4 proposed diagnostic criteria and 15 (42%) had 1 or more missing criterion. Documented early disseminated intravascular coagulopathy was missing for 14 women, and 2 women exhibited more than 1 missing criterion. Ten of the 15 women with missing criteria had clinical coagulopathy, with standard hemostasis tests performed in only 3. Specific diagnostic examinations for AFE were performed in similar proportions by the presence or not of all diagnostic criteria. Opportunities to improve care included timely performance of indicated hysterectomy (n = 13) and improved transfusion practices (n = 9). In the context of maternal cardiac arrest, for 5 of 13 women, fetal extraction was performed within 5 minutes. CONCLUSIONS: The structured definition of AFE for research studies would exclude more than one-third of AFE-related maternal deaths identified by the national experts committee. Inclusion of clinical coagulopathy as a diagnostic criterion for AFE would reduce this proportion to 14%. There is still room for improvement in the management of obstetric hemorrhage and timely fetal extraction in the context of maternal cardiac arrest, frequently observed in AFE-related maternal death.

Incidence, risk factors, management and outcomes of amniotic-fluid embolism: a population-based cohort and nested case-control study.

OBJECTIVE: To describe the incidence, risk factors, management and outcomes of amniotic-fluid embolism (AFE) over time. DESIGN: A population-based cohort and nested case-control study using the UK Obstetric Surveillance System (UKOSS). SETTING: All UK hospitals with obstetrician-led maternity units. POPULATION: All women diagnosed with AFE in the UK between February 2005 and January 2014 (n = 120) and 3839 control women. METHODS: Prospective case and control identification through UKOSS monthly mailing. MAIN OUTCOME MEASURES: Amniotic-fluid embolism, maternal death or permanent neurological injury. RESULTS: The total and fatal incidence of AFE, estimated as 1.7 and 0.3 per 100 000, respectively, showed no significant temporal trend over the study period and there was no notable temporal change in risk factors for AFE. Twenty-three women died (case fatality 19%) and seven (7%) of the surviving women had permanent neurological injury. Women who died or had permanent neurological injury were more likely to present with cardiac arrest (83% versus 33%, P < 0.001), be from ethnic-minority groups (adjusted odds ratio [OR] 2.85, 95% confidence interval [95% CI] 1.02-8.00), have had a hysterectomy (unadjusted OR 2.49, 95% CI 1.02-6.06), had a shorter time interval between the AFE event and when the hysterectomy was performed (median interval 77 minutes versus 248 minutes, P = 0.0315), and were less likely to receive cryoprecipitate (unadjusted OR 0.30, 95% CI 0.11-0.80). CONCLUSION: There is no evidence of a temporal change in the incidence of or risk factors for AFE. Further investigation is needed to establish whether earlier treatments can reverse the cascade of deterioration leading to severe outcomes.

Embolismo de líquido amniótico: nuestra casuística en la última década / Amniotic fluid embolism: a case history over the last 10 years

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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.

Incidence of amniotic fluid embolism: relation to cesarean section and to age.

AIMS: To determine the incidence of amniotic fluid embolism and the incidence as modified by cesarean section and age. METHODS: Data are from the National Hospital Discharge Survey. We examined the number of patients discharged from short-stay nonfederal hospitals throughout the United States, from 1980 through 2005, with a diagnostic code for amniotic fluid embolism. RESULTS: From 1980 through 2005, there were 112,712,000 deliveries, of which 12,000 patients (11/100,000) had amniotic fluid embolism. The incidence of amniotic fluid embolism was lower in 1993-2005 than in 1980-1992 (9/100,000 vs. 12/100,000)(p < 0.0001). The incidence of amniotic fluid embolism was higher with cesarean section, 5,000 of 22,937,000 (22/100,000) than with vaginal delivery, 7,000 of 89,775,000 (8/100,000) (relative risk 2.80, 95% CI 2.70-2.90) (p < 0.0001). The incidence was also higher in women aged 30-39 years, 6,000 of 35,039,000 (17/100,000) than in women aged 15-29 years, 6,000 of 77,673,000 (8/100,000) (relative risk 2.22, 95% CI 2.14-2.30) (p < 0.0001). CONCLUSIONS: The incidence of amniotic fluid embolism has decreased since the early 1990s. The risk is higher with cesarean section and higher in women aged > or =30 years.

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.

Amniotic fluid removal during cell salvage in the cesarean section patient.

BACKGROUND: Cell salvage has been used in obstetrics to a limited degree because of a fear of amniotic fluid embolism. In this study, cell salvage was combined with blood filtration using a leukocyte depletion filter. A comparison of this washed, filtered product was then made with maternal central venous blood. METHODS: The squamous cell concentration, lamellar body count, quantitative bacterial colonization, potassium level, and fetal hemoglobin concentration were measured in four sequential blood samples collected from 15 women undergoing elective cesarean section. The blood samples collected included (1) unwashed blood from the surgical field (prewash), (2) washed blood (postwash), (3) washed and filtered blood (postfiltration), and (4) maternal central venous blood drawn from a femoral catheter at the time of placental separation. RESULTS: Significant reductions in the following parameters were seen when the postfiltration samples were compared to the prewash samples (median [25th-75th percentile]): squamous cell concentration (0.0 [0.0-0.1 counts/high-powered field (HPF)] vs. 8.3 counts/HPF [4. 0-10.5 counts/HPF], P < 0.05); bacterial contamination (0.1 [0.0-0. 2] vs. 3.0 [0.6-7.7] colony-forming units (CFU)/ml, P < 0.01); and lamellar body concentration (0.0 [0.0-1.0] vs. 22.0 [18.5-29.5] thousands/microl, P < 0.01). No significant differences existed between the postfiltration and maternal samples for each of these parameters. Fetal hemoglobin was in higher concentrations in the postfiltration sample when compared with maternal blood (1.9 [1.1-2. 5] vs. 0.5% [0.3-0.7] ). Potassium levels were significantly less in the postfiltration sample when compared with maternal (1.4 [1.0-1.5] vs. 3.8 mEq/l [3.7-4.0]). CONCLUSIONS: Leukocyte depletion filtering of cell-salvaged blood obtained from cesarean section significantly reduces particulate contaminants to a concentration equivalent to maternal venous blood.

Successful pregnancy after suspected anaphylactoid syndrome of pregnancy (amniotic fluid embolus). A case report.

BACKGROUND: Limited information is available on the recurrence risk of anaphylactoid syndrome of pregnancy. CASE: A successful pregnancy followed suspected anaphylactoid syndrome of pregnancy. CONCLUSION: A review of the literature revealed five cases of successful subsequent pregnancies following anaphylactoid syndrome of pregnancy. No instances of recurrent anaphylactoid syndrome of pregnancy have been reported.

Sudden maternal deaths probably due to obstetrical pulmonary embolism in Malaysia for 1991.

Obstetric pulmonary embolism forms the most serious vascular problem during pregnancy. The following report is a retrospective study into maternal deaths in Malaysian mothers probably due to obstetrical pulmonary embolism. Obstetric pulmonary embolism can be divided into amniotic fluid embolism and obstetric blood clot embolism. There were 37 maternal deaths attributable to this cause -9.9 per cent of all maternal deaths to blood clot embolism and 6.7 per cent to amniotic fluid embolism. Most cases were diagnosed clinically because a postmortem examination was not done. Eleven cases of embolism were associated with Caesarean delivery. The typical profile of a Malaysian mother dying from obstetrical pulmonary embolism is that of a Malay mother in the "non-risk" parities of one to four and usually aged between 31-35 years. In the management of these patients, there should be an urgency in diagnosis and improvement in diagnostic procedures. Health staff at all levels should be trained to pick up patients who present with features of deep vein thrombosis.

[A statistical study of the countermeasures to reduce the maternal mortality based on the relationship between the maternal mortality rate and perinatal mortality rate].

Although both the Japanese maternal mortality rate (MMR) and the perinatal mortality rate (PMR) have decreased remarkably in recent decades, the former is still high compared with other advanced countries. A statistical analysis on the relationship between the MMR and the PMR was performed to investigate this discrepancy. During the period of study, both rates fell by over 50 percent. There were definite statistical differences among the PMR for each prefecture but almost none among the MMR. The prefectures with high PMR remained generally high in the PMR and the prefectures with low PMR also remained low in the MMR. There was no significant correlation between the PMR and the MMR. Both maternal and perinatal deaths due to common causes decreased in number, and there were few regional differences concerning effective measures against them. The leading causes of maternal death which are irrelevant to perinatal death are emboli, bleeding, and some other rare medical complications. Emphasis should therefore be laid upon the early diagnosis and treatment of amniotic fluid embolism apart from measures against haemorrhage. Countermeasures for rare complications are also of great importance.

Amniotic fluid embolism: prophylaxis with heparin and aspirin.

The thromboplastic activity of amniotic fluid (AF) from women in labor may be a significant factor in amniotic fluid embolism (AFE) and obstetric disseminated intravascular coagulation (DIC). Infusion of AF from women in labor into laboratory animals was found to depress the platelet count, as seen in DIC. In this study we also investigated the ability of heparin and aspirin to block the thromboplastic activity and thrombocytopenia subsequent to AF infusion. In animals, heparin prophylaxis before infusion of AF prevented thrombocytopenia, whereas aspirin prophylaxis did not. Heparin prophylaxis may be useful in the management of coagulation defects associated with AFE and labor.