Amniotic Fluid Amniotic Fluid Embolism (AFE) Embolism (AFE)

羊水栓塞羊水栓塞

Definition of AFEDefinition of AFE

AFE is a rare obstetric emergency in AFE is a rare obstetric emergency in which amniotic fluid, fetal cells, hair,which amniotic fluid, fetal cells, hair, or other debris enter the maternal ci or other debris enter the maternal circulation, causing cardiorespiratory rculation, causing cardiorespiratory collapse. collapse.

epidemiologyepidemiology The incidence of clinically detectable AFE is lThe incidence of clinically detectable AFE is l

ow ow estimated to be 1 in 20,000 to 80,000 live birtestimated to be 1 in 20,000 to 80,000 live birt

hs. hs. Maternal mortality approaches 80%. Maternal mortality approaches 80%. 5%- 10% of maternal mortality in the United 5%- 10% of maternal mortality in the United

States is due to AFE.States is due to AFE. Of patients with AFE, 50% die within the first Of patients with AFE, 50% die within the first

hour of onset of symptoms.hour of onset of symptoms. Of survivors of the initial cardiorespiratory Of survivors of the initial cardiorespiratory

phase, 50% develop a coagulopathy. phase, 50% develop a coagulopathy. Neonatal survival is 70%. Neonatal survival is 70%.

Current data suggest that the process Current data suggest that the process is more similar to anaphylaxis than tis more similar to anaphylaxis than to embolismo embolism

term anaphylactoid syndrome of preterm anaphylactoid syndrome of pregnancy has been suggested gnancy has been suggested

Major causes and factorsMajor causes and factors occurs in obstetric terms or during laboroccurs in obstetric terms or during labor multiparous woman with a large baby multiparous woman with a large baby a short tumultuous labor a short tumultuous labor use of uterine stimulantsuse of uterine stimulants occurred during abortionoccurred during abortion amnioinfusion amnioinfusion AmniocentesisAmniocentesis caesarian sectioncaesarian section placenta accretaplacenta accreta ruptured uterusruptured uterus

pathologypathology

Amniotic fluid and fetal cells enter tAmniotic fluid and fetal cells enter the maternal circulation, possibly trighe maternal circulation, possibly triggering an anaphylactic reaction to fegering an anaphylactic reaction to fetal antigens. tal antigens.

(1) Clinical symptoms result from ma(1) Clinical symptoms result from mast cell degranulation with the release st cell degranulation with the release of histamine and tryptase, of histamine and tryptase,

(2) Clinical symptoms result from act(2) Clinical symptoms result from activation of the complement pathway. ivation of the complement pathway.

. Progression usually occurs in 2 . Progression usually occurs in 2 phases. phases.

phase I:phase I: pulmonary artery vasospasm with pulmonary artery vasospasm with

pulmonary hypertension and elevated pulmonary hypertension and elevated right ventricular pressure cause right ventricular pressure cause hypoxia.hypoxia.

Hypoxia causes myocardial capillary Hypoxia causes myocardial capillary damage and pulmonary capillary damage and pulmonary capillary damage, left heart failure, and acute damage, left heart failure, and acute respiratory distress syndrome.respiratory distress syndrome.

Women who survive these events maWomen who survive these events may enter y enter phase II. phase II.

This is a hemorrhagic phase charactThis is a hemorrhagic phase characterized by massive hemorrhage with erized by massive hemorrhage with uterine atony and DICuterine atony and DIC

however, fatal consumptive coagulohowever, fatal consumptive coagulopathy may be the initial presentation.pathy may be the initial presentation.

PresentationPresentation

The clinical presentation of AFE is geThe clinical presentation of AFE is generally dramaticnerally dramatic

in the late stages , acutely dyspnea ain the late stages , acutely dyspnea and hypotension with rapid progressind hypotension with rapid progression to cardiopulmonary arrest on to cardiopulmonary arrest

In 40% of cases, followed by some deIn 40% of cases, followed by some degree of consumptive coagulopathy, gree of consumptive coagulopathy,

HypotensionHypotension: Blood pressure may drop signi: Blood pressure may drop significantly with loss of diastolic measurement.ficantly with loss of diastolic measurement.

DyspneaDyspnea: Labored breathing and tachypnea : Labored breathing and tachypnea may occur.may occur.

Seizure:Seizure: The patient may experience tonic-cl The patient may experience tonic-clonic seizures.onic seizures.

CoughCough: This is usually a manifestation of dys: This is usually a manifestation of dyspnea.pnea.

CyanosisCyanosis: As hypoxia/hypoxemia progresses,: As hypoxia/hypoxemia progresses, circumoral and peripheral cyanosis and cha circumoral and peripheral cyanosis and changes in mucous membranes may manifest.nges in mucous membranes may manifest.

Pulmonary edema: identified on chest Pulmonary edema: identified on chest radiograph.radiograph.

Cardiac arrestCardiac arrest Uterine atony: Uterine atony: Fetal bradycardia: In response to the Fetal bradycardia: In response to the

hypoxichypoxic Uterine atony usually results in excesUterine atony usually results in exces

sive bleeding after delivery. sive bleeding after delivery.

DifferentialsDifferentials

Anaphylaxis Anaphylaxis Aortic Dissection(Aortic Dissection( 动脉瘤） 动脉瘤） Cholesterol Embolism Cholesterol Embolism Myocardial Infarction Myocardial Infarction Pulmonary Embolism Pulmonary Embolism Septic Shock Septic Shock

Lab StudiesLab Studies

Arterial blood gas (ABG) levels: ExpeArterial blood gas (ABG) levels: Expect changes consistent with ypoxia/hyct changes consistent with ypoxia/hypoxemiapoxemia

.. Decreased pH levels Decreased pH levels Decreased PO2 levels Decreased PO2 levels Increased PCO2 levels Increased PCO2 levels Base excess increasedBase excess increased

Hemoglobin and hematocrit /ThromHemoglobin and hematocrit /Thrombocytopenia is rare/ platelets /bocytopenia is rare/ platelets /

Prothrombin time (PT) Prothrombin time (PT) Activated partial thromboplastin timActivated partial thromboplastin tim

e (aPTT) e (aPTT) fibrinogen (Fg)fibrinogen (Fg) Blood type and screen Blood type and screen Chest radiograph Chest radiograph A 12-lead ECG A 12-lead ECG

TreatmentTreatment

Administer oxygen to maintain normaAdminister oxygen to maintain normal saturation. l saturation.

Initiate cardiopulmonary resuscitatioInitiate cardiopulmonary resuscitation (CPR) if the patient arrests. n (CPR) if the patient arrests.

Treat hypotension with crystalloid anTreat hypotension with crystalloid and blood products. d blood products.

Consider pulmonary artery catheterizConsider pulmonary artery catheterization in patients who are hemodynamation in patients who are hemodynamically unstable.ically unstable.

Treat coagulopathy with fresh frozen Treat coagulopathy with fresh frozen plasma(FFP) for a prolonged aPTT, cplasma(FFP) for a prolonged aPTT, cryoprecipitate for a fibrinogen level lryoprecipitate for a fibrinogen level less than 100 mg/dL, and transfuse pless than 100 mg/dL, and transfuse platelets for platelet counts less than 2atelets for platelet counts less than 20,000/mL. 0,000/mL.

Continuously monitor the fetus.Continuously monitor the fetus. Delivery quickly (forceps)Delivery quickly (forceps)

Surgical Care: Perform emergent cesSurgical Care: Perform emergent cesarean delivery in arrested mothers warean delivery in arrested mothers who are unresponsive to resuscitation. ho are unresponsive to resuscitation.

hemorrhage was controlled with bilhemorrhage was controlled with bilateral uterine artery embolization. ateral uterine artery embolization.

Uterine RuptureUterine Rupture

is one of the most feared is one of the most feared complications of pregnancy complications of pregnancy

the fetus, placenta, and a lot of the fetus, placenta, and a lot of blood extruding into the mother's blood extruding into the mother's abdomenabdomen

from a weak spot in the uterine from a weak spot in the uterine wall or uterus scar wall or uterus scar

epidemiologyepidemiology the risk of uterine rupture was 1 per 625 womthe risk of uterine rupture was 1 per 625 wom

en who chose repeat cesarean without labor,en who chose repeat cesarean without labor, 1 per 192 women who went into labor and trie1 per 192 women who went into labor and trie

d for VBAC, d for VBAC, 1 per 129 for those who had their labor induc1 per 129 for those who had their labor induc

ed without prostaglandins (usually with Pitoced without prostaglandins (usually with Pitocin)in)

1 per 41 when prostaglandin medications we1 per 41 when prostaglandin medications were used for inductionre used for induction

When the uterus did rupture, 1 in 18 babies dWhen the uterus did rupture, 1 in 18 babies died, and 1 in 23 of the women required a hystied, and 1 in 23 of the women required a hysterectomy.erectomy.

Causes and factorsCauses and factors

previous surgery on the uterusprevious surgery on the uterus Prior classical cesareans, where Prior classical cesareans, where

the incision is near the top of the the incision is near the top of the uterusuterus

prior removal of fibroid tumors prior removal of fibroid tumors any other uterine surgery that went any other uterine surgery that went

through the full depth of the through the full depth of the muscular portion of the uterus,muscular portion of the uterus,

multiple (three or more) prior low multiple (three or more) prior low transverse cesareans transverse cesareans

having had more than five full-term phaving had more than five full-term pregnanciesregnancies

having an overdistended uterus (as wihaving an overdistended uterus (as with twins or other multiples),th twins or other multiples),

abnormal positions of the baby such aabnormal positions of the baby such as transverse lies transverse lie

the use of Pitocin and other labor-indthe use of Pitocin and other labor-inducing medications like prostaglandinsucing medications like prostaglandins

presentationpresentation

Most uterine ruptures occur Most uterine ruptures occur without symptoms and do not without symptoms and do not cause problems for the mother or cause problems for the mother or fetus. fetus.

This mild type is only noticed This mild type is only noticed when surgery is required for when surgery is required for other reasons. other reasons.

In the most severe form , the In the most severe form , the laceration is large or cuts across laceration is large or cuts across the uterine blood vesselsthe uterine blood vessels

the mother may hemorrhage and the mother may hemorrhage and require a blood transfusionrequire a blood transfusion

the uterus may not be repairable the uterus may not be repairable and must be surgically removed and must be surgically removed (hysterectomy) (hysterectomy)

Many women will be advised not to Many women will be advised not to get pregnant again, due to the risk get pregnant again, due to the risk of repeated ruptureof repeated rupture

the baby may not survive the baby may not survive the mother's life cannot be savedthe mother's life cannot be saved

Signs of uterine ruptureSigns of uterine rupture severe, localized pain severe, localized pain abnormalities of the fetal heart abnormalities of the fetal heart

raterate vaginal bleedingvaginal bleeding the vaginal examination may the vaginal examination may

show that the baby is not as low show that the baby is not as low in the birth canal as he had been in the birth canal as he had been earlier. earlier.

Preventing and Preventing and TreatmentTreatment

Some uterine ruptures occur before labor Some uterine ruptures occur before labor and are considered unpreventable. and are considered unpreventable.

Sudden severe abdominal pain in later Sudden severe abdominal pain in later pregnancy should be reported pregnancy should be reported

Women with risk factors ( prior classical Women with risk factors ( prior classical cesareans, deep fibroid excisions, and cesareans, deep fibroid excisions, and other major uterine surgeries )should not other major uterine surgeries )should not attempt laborattempt labor

should be scheduled for cesarean usually should be scheduled for cesarean usually between 36 and 39 weeks' gestation.between 36 and 39 weeks' gestation.

If trying for vaginal birth after low transIf trying for vaginal birth after low transverse cesarean(VBAC), fetal monitoring iverse cesarean(VBAC), fetal monitoring is importants important

When uterine rupture is diagnosed duriWhen uterine rupture is diagnosed during labor, an emergency cesarean is perfng labor, an emergency cesarean is performed.ormed.

Usually the baby's life can be saved. Usually the baby's life can be saved.