Cardiac arrest in pregnancy is estimated to occur in less than 1 in 20,000 women; this number has risen over the last decade (Vanden Hoek et al., 2010). Advanced cardiac life support (ACLS) courses do not routinely address care of this population and ACLS course completion and retention vary widely among obstetric healthcare providers (Lipman et al., 2014). From approximately 20 weeks gestation on, the uterus is large enough to cause aortocaval compression and reduce cardiac output, necessitating changes to ACLS including additional staff, position changes, and the need to evacuate the uterus (Lipman et al.). This gestational age may vary among women due to multiple gestation, polyhydramnios, and the like (Vanden Hoek et al.).

Three teams are required to respond to cardiac arrest in pregnancy: a regular code response team, an obstetric team, and a neonatal team. A study of simulated maternal cardiac arrests showed there was a delay in calling the neonatal team over 80% of the time (Lipman et al., 2014). Initiation of high-quality chest compressions (approximately 2-3 inches higher on the sternum) is recommended by the American Heart Association (AHA) in the third trimester and early defibrillation should not be delayed (Lipman et al.). Left uterine displacement is necessary to maximize cardiac output (Lipman et al.). A 30-degree tilt of the bed or the patient can also achieve uterine displacement; however, it has been associated with poorer quality of chest compressions (Lipman et al.). Although automated external defibrillation use has not been studied in pregnancy, its use is acceptable; and, if defibrillation is performed, the regular ACLS recommended energy doses should be used (Vanden Hoek et al., 2010). Cardioversion and defibrillation are considered safe at any stage of pregnancy. There is very low risk of transferring energy from a shock to the chest to a fetal monitor; however, it is reasonable to remove fetal monitors before the shock is delivered (Vanden Hoek et al.). Medications routinely used in resuscitations (such as epinephrine and amiodarone) are considered safe in pregnancy at the doses outlined by AHA (Lipman et al.).

The greatest difference in the cardiac arrest algorithm during pregnancy is the need to emergently facilitate birth. When a woman is at a gestational age or condition thought to cause aortocaval compression, the obstetric team able to perform an emergency cesarean (or operative vaginal birth) and the neonatal team should be simultaneously activated along with the cardiac arrest team at the onset of cardiac arrest (Lipman et al., 2014; Vanden Hoek et al., 2010). The goal is to achieve skin incision at 4 minutes and birth by 5 minutes after cardiac arrest occurred if there has not been return of spontaneous circulation (ROSC) (Lipman et al.). Achieving this timeframe is challenging and necessitates institutional planning and coordination of efforts across the three response teams. Birth should occur at the site of arrest rather than moving to an operating room (Lipman et al.). Although an emergent birth may optimize neonatal survival, it is also indicated in a previable pregnancy past 20 weeks to optimize maternal outcome since perimortem delivery has demonstrated maternal benefit (Lipman et al.). Similarly, if birth is delayed past 5 minutes for a viable gestation, preparations should continue to urgently evacuate the uterus to maximize maternal survival unless there is ROSC (Vanden Hoek et al.).

Although this is an event every obstetric and neonatal team hopes to avoid, it remains a risk as our maternal population continues to have complicating comorbidities in pregnancy. Preplanning and multidisciplinary simulation may help to improve outcomes and team response.

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