Amniotic Fluid Embolism

Page 251

Defition

• Amniotic Fluid Embolism is a complex condition characterized by the abrupt onset of pulmonary embolism, shock and DIC.

• Incidence varies greatly.

Etiology

• Pressure increasing:• uterinehypertonus,tetanic,oxytocin

• open vessles:traumatic, laceration

• membrane changing:fetal death,dystocia

pathophysiology

• Emblus(amniotic fluid component+fibrin)-----allergic reaction

• --mechanic block+vagus nerve(spasm)----blood return decreasing---peripheral circulation faiture

• --hypertetion of pulmonary artery---pulmonary edema---left heart faiure+respiratory failure

• --general ischemia—renal failure• --coagulopathy---DIC

Clinical manifestation

• A. time of onset

• B. circulation and respiratory failure

• C. DIC----bleeding

• D. renal failure

diagnosis

• Emergent : typical clinical manifestation

• Pulmonary edema

• Definitive diagnosis: aspiration:debris +DIC

• autopsy

treatment

• 1.correct R&C failure

• 2.correct coagulopathy, DIC, renal dysfunction

• 3.Anti-allergic reaction

• 4.obstetric management

You should rember!

• It is axiomatic that when a choice must be made, maternal considerations take perference over those of the fetus

Prognosis

• Perinatal outcomes are dismal with amniotic fluid embolism. Few conditions in medicine have potential for such sudden devastation. We are aware of one case during labor in which mother and baby not only died, but the visiting grandmother also suffered a fatal myocardial infarction during resuscitation efforts on her daughter!

Chapter 20genetic counseling, genetic

screening, prenatal diagnosispage202

Genetic counseling

• 1.significance of genetic counseling• 2.steps• A.make the definitive diagnosis• genetic disease/congenital disease/familial di

sease/• B.predict the effects on their offspring• Autosomal dominant disease:expressed even when o

nly one chromosome of a pair carries an abnormal allele

• Autosomal recessive disease: expressed only when both chromosomes of a pair carry an abnormal allele.

• X-linked dominant

• X-linked recessive

• Multiple-gene disorders

• Chromosomal disorders

3.risk assessment

• Appreciation of disk for a genetic condition is directly related to the degree of assurance that a diagnosis truly exists without an exact diagnosis, a risk assessment is difficult or impossible. Four questions present themselves each time a patient is seen by a geneticist or genetic counselor:

• 1. What diagnostic entity is being considered?

• 2.what is the cause?

• 3.might it happen again?

• 4.what diagnostic or management options are available?

• An accurate diagnosis or possible diagnosis helps address the first two questions. Risk assessment and calculations aim to answer the third question. Finally , patients’ perception of risk is directly tied to their understanding of the diagnostic tests and avaible treatments.

Genetic counseling

• A.premarriage counseling• B.counseling contents• (1) comprehend the medical facts,including the

diagnosis,probable course of the disorder and the available management

• (2)appreciate the may heredity contributes to the disorder and the risk of recurrence in specified relatives

• (3)understand the options for dealing with the risk of recurrence

• (4)choose the course of action that seems appropriate to them in view of their risk and the family goals and act in accordance with that decision

• (5)make the best possible adjustment to the disorder in an effected member and to the risk of recurrence of that disorder.

notes

• It must be provided in the atmosphere of reproductive choice and options.Sophisticated prenatal diagnostic testing requires coordinated educational and psychosocial support. Patients referred for prenatal diagnosis should be provided some information before their arrival regarding the tests for which they are being referred.

words

• Genotype Phenotype

• Alleles Polymorphisms

• Homozygous Heterozygous

• Pedigree sibship

• Risk of recurrence

Genetic screening

• Carrier screening• Methods for genetic screening• 1.amniocentesis( traditional---,early----)• 2.chorionic villus sampling• 3.fetograthy 4.fetoscopy• 5.B-ultrasound • 6.percutaneous umbilical blood sampling• 7.fetocardiogram 8.MRI

Fetal Distress

Page 161

Definition

• Fetal distress is a kind of syndrome presenting signs of fetal hypoxia which will threaten the health and life of fetus

Etiology

• Fetal oxygen supplied from:– maternal circulation-----placenta------umbilical

cord------fetus

• maternal factors– cardiovescular diseases– acute bleeding– uterus placental blood supplied

Etiology

• Fetal factors– cardiovescular dysfunction– deformity

• umbilical cord and placental factors– abnormal cord (page 211):entanglement,nuchal

umbilical cord

pathophysiology

• Hypoxia!– Acidosis----sympathetic nerve excited----

• hypertension,

• tachycardia(initial signs)

– profound acidosis-----vagus nerve----• hypotension,

• bradycardia,

• hyperperistalsis----meconium discharge

– chronic condition: • nutritional deficiency----IUGR

Clinical manifestation

• Chronic fetal distress– IUGR (FGR)– dysfunction of maternal-placental-fetal unit– fetal heart monitoring– fetal movement calculation– amnioscopy

产前的监护• 产前监护包括检查胎动，胎心率，生物物理相评分，

宫内 Apgar 评分，胎儿生长速度，胎盘、脐带、胎儿血流以及一些生化检查。

• 1 ． 胎动：母亲感知胎动的记录：胎动是胎儿情况良好的一种表现，从孕 18-20 周起，孕妇可以自觉胎动，正常情况下， 12 小时内胎动不得少于 10 次，若少于 10 次或逐日下降超过 50% ，表示胎儿有缺氧的可能；如果胎儿突然剧烈活动，接着胎动停止，往往提示胎儿宫内急性缺氧，它的危险性更大。国外有文献报道，分娩前 7 天孕妇感到胎动减少预示“不良围生期结局”，包括分娩时胎心异常，低 Apgar 评分甚至胎死宫内或死胎等。

羊水检查• 羊水检查：尽管羊水减少与胎儿宫内窘

迫关系的机制目前还不清楚，但临床观察确实证实了这一现象，但关于羊水过少的诊断标准也不完全一致，有研究表明，羊水最深处 <3cm 比羊水指数 <8cm预测缺氧的价值更大。

Clinical manifestation

• Acute fetal distress– fetal heart rate– characteristics of fluid– fetal movement– acidosis

分娩时的监测• 1. 羊水胎粪污染：宫内有胎粪排入羊

水可能是一种正常的生理现象，是随着胎儿成熟过程中不断增强的迷走神经的张力而引起的。足月儿中羊水胎粪污染占 10-15% ，过期儿中占 25-50% 。因而关于分娩过程中羊水胎粪污染的重要意义尚有争议，羊水有胎粪污染时应将胎粪排出分为早期与晚期

continuous

• 早期胎粪排出是指在活跃期或其前破膜的时候就发现羊水胎粪污染，又进一步分为轻或重度，轻重程度的区分是以胎粪排出量（羊水的颜色）为基础；晚期胎粪排出指第二产程中发盅蛩シ辔廴荆庖郧把蛩乔辶恋摹Ｔ缙谇岫却笤颊佳蛩シ辔廴镜 54% ，分娩后与对照组相比无明显差异；早期重度占 25% ，这种情况下的新生儿结局不良甚至胎死宫内或新生儿死亡的比例大大增加，与胎心异常及其他导致新生儿异常的产科因素相关； 而晚期羊水胎粪污染大约占 21% ， 其 1 分钟及 5 分钟 Apgar 评分 <7 分者是对照组的 2-3倍以上，但无统计学差异，与某些宫内胎心异常联合出现使 Apgar 评分大大降低。

continuous

• 因此，有羊水胎粪污染的胎儿是否异常，最关键的是判断胎粪排出的时间及量的多少，临床上估计胎粪排出的时间可以通过检查胎盘胎膜及新生儿来加以判断，如下表 1-1 ：

• 表 1-1 出生前胎粪排出时间的判断• 临床 /病理特点 距出生的大致时间• 羊膜见载满色素的巨噬细胞 >1 小时• 绒毛见载满色素的巨噬细胞 >3 小时• 胎儿指甲有胎粪污染 >4-6 小时

Premature rupture of membranes(PROM) page163

definition

• The diagnosis of PROM is made whenever the bag of water ruptures before the onset of true labor.

incidence

• Varied greatly 2.7%--17%

• PROM is causally related to about 10% perinatal deaths regardless of gestation age. Its occurrence before term adds the risk of neonatal respiratory distress syndrome (RDS)from hyaline membrane disease to the risk of chorioamnionitis neonatal sepsis associated with ascending infection.

etiology

• The exact etiology of PROM remains unknown, there have been many postulated causes, but a single common denominator has not yet been found.

• Such as: trauma/cervical incompetence/cervical lacerations/cervical operations/polyhydramnios/multiple gestations/smokers/infection:subclinical infection, chorioamnionitis, patients who had coitus within 7 days before delivery.

diagnosis

• Fern pattern detection

• PH determination

• accuracy rate:93-96%

• False-positive:

• cervicitis/vaginitis/presence of semen ,alkaline urine/blood in vagina

management• Gestational age• immature:<28w----- induction• preterm:28—35w---controversial• tocolytics----controversial1)labor can be on

e of the signs of chorioamnionitis---infection problem may worsen2)less effective:only 24 hours can be gained by using tocolytics in these patients, all of these patients should be kept at bed rest and evaluated for first signs of infection.

• >36w---inducible cervix---induction• not favorable---24-48hs,90%labor