Clinical Review

Amniotic fluid embolism: Management using a checklist

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Because AFEs are rare, with a high mortality rate, using a visual aid that includes several time-critical steps for management can allow for life-saving patient care


 

References

ILLUSTRATION BY KIMBERLY MARTENS FOR OBG MANAGEMENT

CASE Part 1: CPR initiated during induction of labor

A 32-year-old gravida 4 para 3-0-0-3 is undergoing induction of labor with intravenous (IV) oxytocin at 39 weeks of gestation. She has no significant medical or obstetric history. Fifteen minutes after reaching complete cervical dilation, she says “I don’t feel right,” then suddenly loses consciousness. The nurse finds no detectable pulse, calls a “code blue,” and initiates cardiopulmonary resuscitation (CPR). The obstetrician is notified, appears promptly, assesses the situation, and delivers a 3.6-kg baby via vacuum extraction. Apgar score is 2/10 at 1 minute and 6/10 at 5 minutes. After delivery of the placenta, there is uterine atony and brisk hemorrhage with 2 L of blood loss.

Management of AFE: A rare complication

This case demonstrates a classic presentation of amniotic fluid embolism (AFE) syndrome—a patient in labor or within 30 minutes after delivery has sudden onset of cardiorespiratory collapse followed by disseminated intravascular coagulation (DIC). AFE is rare, affecting only about 2 to 6 per 100,000 births, but classic cases have a reported maternal mortality rate that exceeds 50%.1 It is thought to reflect a complex, systemic proinflammatory response to maternal intravasation of pregnancy material, such as trophoblast, thromboplastins, fetal cells, or amniotic fluid. Because the syndrome is not necessarily directly caused by emboli or by amniotic fluid per se,2 it has been proposed that AFE be called “anaphylactoid syndrome of pregnancy,” but this terminology has not yet been widely adopted.3

Guidelines from the Society for Maternal-Fetal Medicine (SMFM) recommend several time-critical steps for the initial stabilization and management of patients with AFE.4 However, because AFE is rare, most obstetric providers may not encounter a case for many years or even decades after they have received training, so it is unrealistic to expect that they will remember these guidelines when they are needed. For this reason, when AFE occurs, it is important to have a readily accessible cognitive aid, such as a checklist that summarizes the key management steps. The SMFM provides a checklist for initial management of AFE that can be used at your institution; it is presented in the FIGURE and provides the outline for this discussion.5

Provide CPR immediately

Most AFE cases are accompanied by cardiorespiratory arrest. If the patient has no pulse, call a “code” to mobilize additional help and immediately start CPR. Use a backboard to make cardiac compressions most effective and manually displace the uterus or tilt the patient to avoid supine hypotension. Designate a timekeeper to call out 1-minute intervals and record critical data, such as medication administration and laboratory orders/results.

Expedite delivery

Immediate delivery is needed if maternal cardiac activity is not restored within 4 minutes of starting CPR, with a target to have delivery completed within 5 minutes. Operative vaginal delivery may be an option if delivery is imminent, as in the case presented, but cesarean delivery (CD) will be needed in most cases. This was previously called “perimortem cesarean” delivery, but the term “resuscitative hysterotomy” has been proposed because the primary goal is to improve the effectiveness of CPR6 and prevent both maternal and perinatal death. CPR is less effective in pregnant women because the pregnant uterus takes a substantial fraction of the maternal cardiac output, as well as compresses the vena cava. Some experts suggest that, rather than waiting 4 minutes, CD should be started as soon as an obstetrician or other surgeon is present, unless there is an immediate response to electrical cardioversion.6,7

In most cases, immediate CD should be performed wherever the patient is located rather than using precious minutes to move the patient to an operating room. Antiseptic preparation is expedited by simply pouring povidone-iodine or chlorhexidine over the lower abdomen if readily available; if not available, skip this step. Enter the abdomen and uterus as rapidly as possible using only a scalpel to make generous midline incisions.

If CPR is not required, proceed with cesarean or operative vaginal delivery as soon as the mother has been stabilized. These procedures should be performed using standard safety precautions outlined in the SMFM patient safety checklists for cesarean or operative vaginal delivery.8,9

Continue to: Anticipate hemorrhage...

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