Anesthetic management of amniotic fluid embolism -- a multi-center,retrospective, cohort study

Introduction: Amniotic fluid embolism (AFE) is a rare and potentially lethal obstetric complication, commonly occurring during labor, delivery, or immediately postpartum. There is a paucity of data regarding incidence, risk factors, and clinical management. Our primary objective in this study was to evaluate clinical presentation of AFE and delineate anesthesia management of these cases.

Methods: This 10 years retrospective multi-center cohort study was performed in five tertiary university-affiliated medical centers, between the years 2005 and 2015. All documented cases of AFE identified according to the ICD guidelines were reviewed manually to determine eligibility for AFE according to Clark’s criteria. All cases confirming Clark’s diagnosis were included in the cohort.

Results: Throughout the study period, 20 cases of AFE were identified, with an incidence of 4.1 per 100,000 births. Average age at presentation was 35?±?5 years. Seventy percent of cases presented during vaginal delivery, 20% occurred throughout a cesarean delivery, and 10% occurred during a dilation and evacuation procedure. The most common presenting symptom was sudden loss of consciousness in 12 parturients (66.7%), fetal bradycardia in 11 parturients (55%), and shortness of breath in 10 parturients (50%). Perimortem cesarean section was performed in 55% of cases, although only one case was performed in the delivery suite, while all others were performed in the operating room. Echocardiography was performed in 60% of the cases and all were pathological. Furthermore, 20% of cases were connected to an extracorporeal membrane oxygenation machine. There was a 15% mortality rate of 15%. A further 15% suffered major neurological disability, 25% suffered minor neurological morbidity, and 45% survived without severe complications.

Conclusion: AFE is associated with significant maternal morbidity. This study highlights the importance of providing advanced training for the delivery suite staff for cases of maternal cardiovascular collapse secondary to AFE and increasing awareness for this rare and devastating obstetric condition.     

Amniotic fluid embolism: an overview and case report

This article gives an overview of amniotic fluid embolism, which still carries a fatality rate of approximately 86% and which accounts for 9% of all maternal deaths. A case report is presented which ended with a fatal outcome. Photomicrographs show fetal squames and lanugo hairs in the pulmonary capillaries as well as ones aspirated from the right atrium. The treatment is discussed in terms of acute primary and acute secondary care. Acute primary care centers around the prompt recognition and treatment of pulmonary edema. This is apparently due to the mechanical blockade of the pulmonary vasculature and particulate matter from the amniotic fluid and also to an anaphylactoid reaction adding to the pulmonary arteriolar spasm. The acute secondary treatment deals with combating the almost inevitable disseminated intravascular coagulation and uterine atony. Being always alert to the possible occurrence of this condition and being able to institute appropriate therapy rapidly are necessary for a successful outcome.     

Amniotic fluid embolism

Amniotic fluid embolism (AFE) is a rare but severe complication of pregnancy characterised by a catastrophic systemic dysfunction involving the respiratory, cardiovascular and haematological systems. It was the fourth leading direct cause of maternal deaths ascertained by the UK confidential enquiry into maternal deaths (2006–2008), with incidence in the UK of approximately 1 in 50,000. It should no longer be considered as resulting in inevitable mortality, and increasing evidence shows that supportive care can result in good outcomes for mother and baby. Current data puts case fatality rates for AFE in the UK at around 20%, much lower than previously thought. This review collates the latest literature looking at how and when the condition occurs, its presentation, diagnosis and management.     

羊水栓塞75例分析

目的：总结、分析上海市１９８５～１９９５年间的７５例羊水栓塞（ＡＦＥ）患者，以冀今后降低ＡＦＥ的发生，保障母亲的安全。方法：研究ＡＦＥ患者的临床表现、诊断及处理。结果：７５例ＡＦＥ患者中死亡５４例，占６８％；存活２４例、占３２％。诱发ＡＦＥ的因素以宫缩过强、急产、胎膜早破、人工破膜，催产素引产等为主，有一种以上诱因者更易发生ＡＦＥ。ＡＦＥ着重预防，治疗推荐ＤＲＯＰ－ＣＨＨＥＢＳ方案，并应予以正确的产科处理。２４例存活者均因此种措施而获救。结论：ＤＲＯＰ－ＣＨＨＥＢＳ方案与正确、适时地结束分娩是抢救ＡＦＥ患者成功的经验。     

Amniotic fluid embolism: antepartum,intrapartum and demographic factors

Objective: To describe the incidence, antepartum, intrapartum and postpartum risk factors, and mortality rate of amniotic fluid embolism (AFE).

Methods: We used 2001–2007 California health discharge data to identify cases of AFE by ICD-9 codes.

Results: Of 3?556?567 deliveries during the time period, we identified 182 cases of AFE, resulting in a population incidence of 5.1 in 100?000. Twenty-four of the cases resulted in death, giving a case fatality rate of 13.2%. Non-Hispanic blacks had a higher than 2-fold odds of developing AFE. AFE increased significantly with maternal age, most significantly after age 39. Cardiac disease had a nearly 70-fold higher association with AFE, cerebrovascular disorders had a 25-fold higher association, while conditions such as eclampsia, renal disease, placenta previa and polyhydramnios had nearly 7- to 13-fold higher associations. Classical cesarean delivery, abruption placentae, dilation and curettage, and amnioinfusion were all procedures highly associated with AFE.

Conclusion: Several antepartum and peripartum conditions and procedures are associated with significantly higher risks of amniotic fluid embolism. This information may contribute to a better understanding of the pathophysiology of AFE and potentially help identify those at the highest risk of developing this morbid condition.     

羊水栓塞心脏骤停成功救治一例并文献复习

目的探讨羊水栓塞的临床特征、诊断、治疗策略和母婴预后。 方法根据北京大学深圳医院收治的1例及文献报道的61例羊水栓塞患者的临床资料,对羊水栓塞的诊断、治疗方法及母婴预后进行回顾性分析。 结果本例患者39岁,妊娠39周因胎膜早破入院;分娩过程二次胎膜自破,破膜后出现全身抽搐、意识丧失,随后出现心脏骤停;立即进行紧急床边剖宫产和成功心肺复苏,最终母婴痊愈出院。文献检索61例羊水栓塞患者中的前驱症状包括呼吸困难27例(44.3%)、紫绀14例(21.3%)、血压降低11例(18.0%)、精神状态改变9例(14.8%)、烦躁8例(13.1%)等;临床表现循环功能障碍52例(85.2%)、呼吸功能障碍47例(77.0%)及血液功能障碍39例(63.9%)等;使用体外膜肺氧合治疗8例(13.1%),预后均良好;死亡16例(26.2%),存活45例(73.8%),存活患者中仅3例(4.9%)有后遗症;35例(57.4%)有描述新生儿结局,其中24例(39.3%)健康,4例(6.6%)死亡,7例(11.5%)转入儿科结局未知。 结论羊水栓塞主要表现为循环、呼吸衰竭及凝血功能异常,早期识别、高质量心肺复苏和及时终止妊娠是主要救治方法。     

Intrauterine growth restriction and absent or reverse end-diastolic blood flow in umbilical artery (Doppler class II or III): A retrospective study of short- and long-term fetal morbidity and mortality

OBJECTIVE: Absent or reverse end-diastolic flow (Doppler II/III) in umbilical artery is correlated with poor perinatal outcome, particularly in intrauterine growth restricted (IUGR) fetuses. The optimal timing of delivery is still controversial. We studied the short- and long-term morbidity and mortality among these children associated with our defined management. STUDY DESIGN: Sixty-nine IUGR fetuses with umbilical Doppler II/III were divided into three groups; Group 1, severe early IUGR, no therapeutic intervention (n = 7); Group 2, fetuses with pathological biophysical profile, immediate delivery (n = 35); Group 3, fetuses for which expectant management had been decided (n = 27). RESULTS: In Group 1, stillbirth was observed after a mean delay of 6.3 days. Group 2 delivered at an average of 31.6 weeks and two died in the neonatal period (6%). In Group 3 after a mean delay of 8 days, average gestational age at delivery was 31.7 weeks; two intra uterine and four perinatal deaths were observed (22%). Long-term follow-up revealed no sequelae in 25/31 (81%) and 15/18 (83%), and major handicap occurred in 1 (3%) and 2 patients (11%), respectively, for Groups 2 and 3. CONCLUSION: Fetal mortality was observed in 22% of this high risk group. After a mean period of follow-up of 5 years, 82% of infants showed no sequelae. According to our management, IUGR associated with umbilical Doppler II or III does not show any benefit from an expectant management in term of long-term morbidity.     

Uterine rupture: the road ahead?

The worldwide increase in caesarean sections, as well as that in laparoscopic and hysteroscopic surgery, augments the risk for women to suffer a uterine rupture. Also the use of misoprostol for the termination of pregnancy and induction of labour, particularly in developing countries, contributes to the greater incidence of uterine rupture. In developing countries, again, neglected obstructed labour remains a very frequent cause of uterine rupture. Diagnosis of uterine rupture may be difficult and, if made too late, serious and even devastating complications may follow, culminating in infant and/or maternal death. A high index of suspicion is indicated when dealing with women at risk. Options in terms of managing uterine rupture include simple repair of the tear, subtotal, and total hysterectomy. Counselling women before and after surgical interventions on the genital tract, especially caesarean section on request, should include information concerning the subsequent risk of uterine rupture.     

Medically indicated late preterm delivery and its impact on perinatal morbidity and mortality: a retrospective population-based cohort study

Objective: In the last few decades, attention has been focused on morbidity and mortality associated with late preterm delivery (34–36?+?6/7 weeks), accounting for 60–70% of all preterm births. This study is aimed to determine (1) the prevalence of late preterm deliveries (spontaneous and medically indicated) in our population; and (2) the rate of neonatal morbidity and mortality as well as maternal complications associated with the different phenotypes of late preterm deliveries.

Study design: This retrospective population-based cohort study, included 96,176 women who had 257,182 deliveries, occurred between 1988 and 2011, allocated into three groups: term (n?=?242,286), spontaneous (n?=?10,063), and medically indicated (n?=?4833) late preterm deliveries.

Results: (1) Medically indicated late preterm deliveries were associated with increased maternal morbidity, as well as neonatal morbidity and mortality, in comparison with other study groups (p?Conclusions: (1) Medically indicated late preterm deliveries were independently associated with adverse composite neonatal outcome; and (2) to benefit in term of neonatal outcome from the tool of medically indicated late preterm birth, their proportion should be kept below 35% of all late preterm deliveries, while exceeding this threshold increases the risk of neonatal mortality.     

The importance of extensive sampling and examination of cervix in suspected cases of amniotic fluid embolism

Amniotic fluid embolism is an important complication of pregnancy with high mortality. The diagnosis of amniotic fluid embolism is generally made postmortem and rests upon the histological demonstration of amniotic fluid debris, including foetal epithelial squames and hair, in the pulmonary vasculature. We have made the diagnosis of amniotic fluid embolism in two patients by detection of the amniotic fluid debris in the blood vessels of the cervix in their hysterectomy specimens. These two patients presented with profuse primary postpartum haemorrhage and evidence of disseminated intravascular coagulation after uneventful deliveries. Amniotic fluid debris were only demonstrated in the blood vessels of the cervix but not in the corpus. This observation emphasizes the importance of a thorough histological examination of the cervix in cases of suspected amniotic fluid embolism. Received: 28 January 1994 / Accepted: 6 April 1994     

Risk factors for fatality in amniotic fluid embolism: a systematic review and analysis of a data pool

Purpose: Investigating risk factors for amniotic fluid embolism (AFE)-induced fatality.

Methods: A systematic review of cases of AFE available on PubMed, Scielo, Scopus and AJOL databases that occurred from 1990 to 2015 was carried out. After careful reading of titles, abstracts and full texts, case reports of AFE were reviewed. Risk factors for AFE were considered as independent variables in logistic regression models. The first model was built on the whole data pool. The second model was built on typical cases of AFE, according to the classical triad of symptoms (heart, lungs, coagulopathy). The dependent variable was fatality in both models.

Results: 177 cases of AFE were assessed in the first model, while 121 typical cases of AFE were assessed in the second model. Among typical cases of AFE, only oxytocin infusion during labour increases the likelihood of death (odds ratio 2.890, 95% confidence interval 1.166–7.164, p?=?0.022). No risk factors for fatality were found in the whole data pool.

Conclusions: Further research on national registries should focus on the behaviour of oxytocin infusion during labour in AFE cases.     

Maternal-perinatal morbidity and mortality associated with adolescent pregnancy in Latin America: Cross-sectional study

OBJECTIVE: This study was undertaken to determine whether adolescent pregnancy is associated with increased risks of adverse pregnancy outcomes. STUDY DESIGN: We studied 854,377 Latin American women who were younger than 25 years during 1985 through 2003 using information recorded in the Perinatal Information System database of the Latin American Center for Perinatology and Human Development, Montevideo, Uruguay. Adjusted odds ratios were obtained through logistic regression analysis. RESULTS: After an adjustment for 16 major confounding factors, adolescents aged 15 years or younger had higher risks for maternal death, early neonatal death, and anemia compared with women aged 20 to 24 years. Moreover, all age groups of adolescents had higher risks for postpartum hemorrhage, puerperal endometritis, operative vaginal delivery, episiotomy, low birth weight, preterm delivery, and small-for-gestational-age infants. All adolescent mothers had lower risks for cesarean delivery, third-trimester bleeding, and gestational diabetes. CONCLUSION: In Latin America, adolescent pregnancy is independently associated with increased risks of adverse pregnancy outcomes.     

Amniotic fluid insulin levels in nondiabetic pregnant women: an update

Elevated amniotic fluid insulin levels in diabetes are frequently described but there are few systematic data on metabolically healthy women to define normal ranges. Previous studies had too high normal ranges because they were based on unspecific insulin binding radioimmunoassays. The aim of the study was to update normal amniotic fluid insulin data and to define a reliable normal range in the course of a nondiabetic pregnancy. Amniotic fluid insulin levels were measured in 841 amniotic fluid samples of 707 nondiabetic women undergoing amniocentesis for hydramnios, suspected malformation, determination of lung maturation, Rhesus antibodies and cordocentesis. Mean (±SD) of amniotic fluid insulin level was 3.6 (±2.1) μU/mL at 31.5 (±4.9) weeks of pregnancy. The 97th percentile was 8.2 μU/mL. Insulin levels show a biphasic course between 16th and 42nd weeks of pregnancy with a zenith at 30th week. Only two cases (0.3%) had unexplicably elevated amniotic fluid insulin levels ≥10 μU/mL. Thus, in nondiabetic women amniotic fluid insulin levels >10 μU/mL are unlikely. Received: 13 March 1998 / Accepted: 6 May 1998     

Amniotic fluid index and estimated fetal weight for prediction of fetal macrosomia: a prospective observational study

Objective: The purpose of this study was to assess the value of combining the estimated fetal weight (EFW) and amniotic fluid index (AFI) measured in term patients early in labor with intact membranes for prediction of macrosomia.

Methods: In a single center, prospective observational study, 600 patients in the first stage of labor before rupture of membranes in whom ultrasonography was performed to measure AFI and EFW, and these data were analyzed statistically to evaluate prediction of fetal macrosomia.

Results: Macrosomia occurred in 64 cases (10.6%). The AFI was significantly higher in the macrosomic group (p?=?0.001). It was noted that the area under receiver operating characteristic (ROC) curves for EFW was 0.93 and that of AFI was 0.67. Based on suggested combined EFW and AFI cutoffs of 4000?g and 164?mm, respectively, the positive predictive value (PPV) for combined parameters (92.3%) was higher than that of EFW (75%) and that of AFI (27%) and the likelihood ratio for combination (93.7%) was higher than that of EFW (24.7%) and that of AFI (21%).

Conclusion: Combined use of EFW and AFI improves prediction of macrosomia at birth rather than the EFW alone.     

Primary postpartum haemorrhage in an Australian tertiary hospital: a case-control study

The present study aimed to determine the incidence of primary postpartum haemorrhage (PPH) after vaginal birth at an Australian tertiary hospital, and to investigate risk factors for primary PPH at this hospital. A case-control study of women delivering vaginally at a tertiary hospital from February to June 2003 was performed. Demographic, antenatal, intrapartum, treatment and outcome data were abstracted from patient records. The study population comprised 125 cases and 125 controls, with a primary PPH rate of 12.1 per 100 vaginal births. Risk factors on multivariate analysis were past history of PPH, second stage labour > 60 min, forceps delivery, and incomplete placenta/ragged membranes.     

Using audits to reduce the incidence of uterine rupture in a Malawian district hospital

Objectives

To improve obstetric care and reduce the incidence of uterine rupture through the use of audits.

Methods

Data were collected from medical records and from questioning women who sustained uterine rupture over a 12-month period in Thyolo District Hospital, Malawi. Audit sessions were performed every 2-3 weeks for the first 3 months with relevant members of the hospital staff, after which an extended audit was held with input from two external expert obstetricians. Cases were also audited by the principal investigator for delays in referral, diagnosis, and treatment.

Results

Thirty-five cases of uterine rupture were diagnosed at the facility during the study period. Sixteen ruptures were diagnosed during the first 3 months, an incidence of 19.2 per 1000 deliveries. Following audit and implementation of recommendations, the incidence of uterine rupture decreased by 68% (OR 0.32; 95% CI, 0.16-0.63) to 6.1 per 1000 deliveries over the next 9 months. The overall case fatality rate was 11.4%, and the perinatal mortality rate was 829 per 1000 live births.

Conclusions

Audit is an inexpensive, appropriate, and effective intervention to improve the quality of facility-based maternal care and decrease the incidence of uterine rupture in low-resource settings. Ensuring constructive self-criticism, continuous professional learning, and good participation by district health managers in audit sessions may be important requirements for their success.