Historically, there has been very limited data regarding the epidemiology of OHCA in pregnant females. Two recently-published studies tried to shed some light on the issue.

Both Maurin et al.¹ and Lipowicz et al.² looked at all-cause out-of-hospital maternal cardiac arrest (MCA) data in terms of numbers and management, in Paris and Toronto respectively, from 2009/2010 to 2014. Collectively, they found: 

• MCA was relatively rare: 0.8 MCA per 1000 OHCA (Maurin) and 1.71 MCA per 100,000 pregnant females (Lipowicz)
• Low incidence of bystander CPR in witnessed MCA (33% and 0%)
• Adherence to PMCS guidelines was poor 
• Maternal survival was lower than what has been previously quoted for in-hospital CA: 12.5 and 16.7% compared to 40-50%^3,4

A few reminders from the 2015 AHA guidelines for the management of cardiac arrest in pregnancy: 

• Hand location for chest compressions should be in the center of the chest as for nonpregnant patients (previous recommendations had been to shift upward to accommodate for the gravid uterus but there is no data to support this).

• Chest compressions should be performed with the patient supine, using manual lateral uterine displacement for aortocaval decompression. Left lateral tilt position is no longer recommended due to poorer quality of cardiac compressions, the lack of full aortocaval decompression, and further complication of other procedures such as airway management.

• IV or IO access should be obtained above the diaphragm, to ensure no interference to flow to the heart by the gravid uterus.

• Rate and depth of chest compressions, ACLS drugs and doses, and defibrillation all remain the same as in nonpregnant OHCA patients.
  • NB: As opposed to nonpregnant patients periarrest, oxygen saturation in the pregnant female should be maintained at 95% or greater, or PaO2 > 70mmHg, to ensure appropriate oxygen delivery to the fetus. The goal PCO2 is ~28-32 mmHg, to facilitate fetal CO2 removal.⁶  

• If advanced airway is pursued, the most experienced provider should perform intubation due to the higher intrinsic difficulties, more rapid decompensation, and propensity for airway trauma and bleeding in the pregnant female.

• Perimortem c-section should occur within the first 5 minutes of cardiac arrest / arrival to the ED in ongoing arrest. 

 

Bottom Line: Although maternal cardiac arrest is relatively rare, survival in OHCA is lower than perhaps previously thought. Areas to improve include public education on the importance of bystander CPR in pregnant females, and appropriate physician adherence to PMCS recommendations, with decreased on-scene time by EMS in order to decrease time to PMCS. 

 

 

Additional Information

Maurin et al. looked at documented out-of-hospital maternal cardiac arrest (MCA) in pregnant females ≥18 years old, in Paris from 2009 to 2014 and reported on some aspects of prehospital care. Prehospital management there includes activation of both a BLS (which usually arrives first) and ALS team, with a prehospital emergency physician being a member of the ALS team. 

• 16 MCAs out of 19,515 OHCA in 5 years ⇔ 0.8 MCA per 1000 OHCA
• Over half were > 20 weeks gestational age
• Only 1/3 of the witnessed arrests received bystander CPR
• 6 (38%) died on scene, 5 achieved ROSC
• 2 (12.5%) women survived to discharge, with one fetal survial
• Average time from ALS arrival on scene to hospital arrival = 94 min 
• 5 underwent ECMO cannulation, 3 received perimortem c-section (PMCS) -- none of these had maternofetal survival

Lipowicz et al. similarly looked at MCA from 2010 to 2014 using data from the Toronto Regional RescuNet cardiac arrest database:

• All women known to be or visibly pregnant, no exclusions
• 6 MCA out of 1085 OHCA ⇔ 1.71 MCA per 100,000 pregnant females
• Median gestational age 36.5 weeks
• No witnessed arrest received bystander CPR
• ROSC in 3 out of the 6
• 1 female surviving to hospital discharge (16.7%), 2 neonates survived to discharge (33%)
• 5/6 (83%) underwent PMCS, none within the recommended 5 minutes (average time to PMCS = 33min, range 15 min - 1 hour)
• No documentation of lateral uterine displacement, 1 documented left lateral tilt
• 100% with IVs above the diaphragm

References

1. Maurin O, Lemoine S, Jost D, et al. Maternal out-of-hospital cardiac arrest: A retrospective observational study. Resuscitation. 2018; pii: S0300-9572(18)31079-7. doi: 10.1016/j.resuscitation.2018.11.001. [Epub ahead of print]
2. Lipowicz AA, Cheskes S, Gray SH, et al. Incidence, outcomes and guidline compliance of out-of-hospital maternal cardiac arrest resuscitations: A population-based cohort study. Resuscitation. 2018; 132:127-132.
3. Einav S, Kaufman N, Sela HY. Maternal cardiac arrest and perimortem caesarean deliver: evidence or expert-based? Resuscitation. 2012;83(10): 1191-1200.
4. Zelop CM, Einav S, Mhyre JM, et al. Characteristics and outcomes of maternal cardiac arrest: A descriptive analysis of Get With the Guidelines data. Resuscitation. 2018;132:17-20.
5. Jeejeeboy FM, Zelop CM, Lipman S, et al. Cardiac Arrest in Pregnancy: A Scientific Statment From the American Heart Association Circulation. 2015;132(18):1747-73.
6. Lapinsky SE. Acute respiratory failure in pregnancy. Obstet Med. 2015; 8(3):126-32.