Maternal and Neonatal Outcomes Following Resuscitative Hysterotomy for OHCA. Time and survival #dogmalysis.

Background

Resuscitative hysterotomy, also known as perimortem caesarean section, is a high-stakes, time-critical intervention performed in pregnant women who experience cardiac arrest. It’s also one of the most daunting HALO procedures that we encounter in EM/PHEM. The aim of this procedure is twofold: to relieve aortocaval compression, thereby improving maternal circulation (and hopefully ROSC/survival), and to maximise neonatal survival. Current guidelines from the European Resuscitation Council, the Australian and New Zealand Committee on Resuscitation, and the American Heart Association recommend early intervention, particularly in cases where maternal resuscitation is not yielding results. However, most of the evidence underpinning these recommendations comes from in-hospital maternal cardiac arrests. It also commonly recommends a very short window of opportunity to perform the procedure with an oft quoted time of ‘4 minutes’ to start the C-section from cardiac arrest. Unless the patient arrests in front of you then this is almost certainly an impossible target to achieve in EM/PHEM practice so is it worth it and is that time window born (sic) out by the evidence?

In the out-of-hospital setting (OHCA), the situation is far more challenging. The likelihood of witnessed collapse is lower, bystander CPR may be delayed or absent, and there may be substantial delays in reaching a clinician with the expertise to perform a resuscitative hysterotomy. Additionally, logistical barriers, lack of specialist obstetric or neonatal support, and the unpredictability of OHCA scenarios complicate decision-making. This week we have a great paper that challenges some of the traditional thinking and teaching that I and others have given with regard to this procedure. It’s going to change the way I think about perimortem c-section and I think it might change your perspective too. It’s arguably an example of #dogmalysis, which regular readers will know is one of my favourite words (originally pinched from Cliff Reid). The systematic review in Resuscitation has examined maternal and neonatal survival rates in OHCA where resuscitative hysterotomy was performed, and whether timing of the procedure influenced outcomes. The abstract is below, but as always please read the full paper yourself and draw your own conclusions.

What Kind of Study is This?

This was a systematic review registered with PROSPERO (CRD42023445064) and conducted in line with PRISMA guidelines. The authors searched multiple databases, including MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials, for studies involving pregnant women with OHCA where resuscitative hysterotomy was performed. Randomised controlled trials, observational studies, case series, and case reports were included. Two independent reviewers assessed eligibility, extracted data, and evaluated risk of bias using validated tools. Given the heterogeneity of study designs, a meta-analysis was not performed, and the findings were synthesised narratively. I think this is appropriate, it was not just the herterogeneity, but also the quality of the trials that made a formal meta-analysis difficult. If the data is not good enough, then it’s best not to.

Tell Me About the Patients

The review included a total of 66 women and 68 neonates drawn from 42 publications. These consisted of one cohort study, three case series, and 38 case reports. The median maternal age was 30 years, with a range from 17 to 44 years. The median gestational age at the time of cardiac arrest was 35 weeks, with a range from 24 to 41 weeks.

A majority of the cardiac arrests were of medical origin, accounting for 68.2% of cases. Conditions such as pulmonary embolism, cardiac complications, haemorrhage, and amniotic fluid embolism were commonly implicated. Trauma-related causes, including road traffic collisions, gunshot wounds, and falls, comprised 31.8% of cases. The arrest occurred in a variety of locations, with the most common being at home, followed by public places and ambulances. Only 34.8% of cases were witnessed, and bystander CPR was reported in a mere 6.1% of cases (this does worry me and seems low – is it because they were pregnant and does that make people less likely to do CPR?). The presenting rhythm was shockable in 10.6% of cases, while pulseless electrical activity (PEA) and asystole were recorded in 15.1% and 25.8% of cases, respectively.

What Were the Measured Outcomes in This Study?

The primary outcomes assessed included maternal survival at various time points, such as return of spontaneous circulation (ROSC), survival to hospital admission, survival to discharge or 30 days, and neurological status. Neonatal survival was also evaluated based on the need for resuscitation, survival to hospital admission, survival to discharge or 30 days, and neurological status. Additionally, the timing of intervention was closely examined, with a particular focus on the interval from maternal collapse to resuscitative hysterotomy.

What Are the Main Results?

• Maternal survival to hospital discharge was just 4.5% (3/66 women).
  • Two survivors had a diagnosis of pulmonary embolism, one had amniotic fluid embolism.
  • Two had good neurological outcomes; one was left profoundly disabled.
• Neonatal survival was much higher at 45.0% (27/60 viable neonates with follow-up data).
  • 17 were neurologically normal, 6 had significant disability.
  • Neonates born at 26 weeks gestation or later had good neurological outcomes in some cases.
• Timing mattered: The longest interval from maternal arrest to delivery associated with good neonatal outcome was 47 minutes, and for maternal survival, 29 minute this is much longer than is usually taught.
• Prehospital procedures were rare (27.3% of cases) but were associated with a higher neonatal survival rate (62.5%) than in-hospital procedures (42.9%).

So my headline take away here is that perimortem c-section is equally if not more about resuscitating the neonate. That’s not what I was taught and I think it’s a real change in approach where we absolutely need to ensure that we resuscitate the child AND the mother. We are also not bound to a very restrictive time window and should absolutely consider this procedure even if beyond the very short time windows previously taught. A good neonatal outcome at 47 minutes seems exceptional, and it’s a good reason to stop and reevaluate our recommendations.

How robust are the findings?

The overall quality of the studies included in this review was low, with very low certainty of evidence due to reliance on case reports and small case series. Many studies lacked standardised data collection and comprehensive follow-up for neonatal neurological outcomes, further limiting the ability to draw firm conclusions.

Selection bias is a significant concern. Cases that were not reported in the literature, particularly those with poorer outcomes, could have led to overestimation of survival rates. The timing estimates for intervention were frequently imprecise, with many cases lacking clear timestamps for maternal collapse, intervention, and delivery. Additionally, trauma-related cardiac arrests had particularly poor maternal outcomes, with no documented survivors.

Interestingly, while prehospital resuscitative hysterotomy appeared to result in better neonatal survival rates, maternal survival was only observed in cases where the procedure was performed in a hospital setting. This raises questions about the role of hospital-based resources and personnel in improving maternal outcomes. Again though, this is not a comprehensive or exhaustive set of data and therefore there may well be (there are) maternal survivors out there.

Should We Change Practice Based on This Study?

This study reinforces the poor maternal survival rates associated with resuscitative hysterotomy for OHCA but also highlights the possibility of neonatal survival, even after prolonged maternal resuscitation.

For me it means that we should consider resuscitative hysterotomy more readily, particularly for viable gestations beyond 24 weeks, even if maternal prognosis appears unfavourable.

That said, the evidence base here is not great and I’d love to see some more prospective research to establish clearer guidelines on optimal intervention timing and maternal-neonatal outcomes in OHCA.

Summary

Resuscitative hysterotomy for OHCA is associated with low maternal survival rates but reasonable neonatal survival rates, even in cases with prolonged maternal resuscitation. This suggests that emergency and prehospital clinicians should not discount resuscitative hysterotomy, even after extended resuscitation attempts, particularly when dealing with viable gestations. Prehospital training, early recognition, and improved decision-making could optimise both maternal and neonatal outcomes in these rare but critical cases.

References

1. Leech, C., Nutbeam, T., Chu, J., Knight, M., Hinshaw, K., Appleyard, T.-L., Cowan, S., Couper, K., & Yeung, J. (2024). Maternal and neonatal outcomes following resuscitative hysterotomy for out-of-hospital cardiac arrest: A systematic review. Resuscitation. https://doi.org/10.1016/j.resuscitation.2024.110479
2. Simon Carley, “Perimortem C-section at St.Emlyn’s,” in St.Emlyn’s, February 4, 2013, https://www.stemlynsblog.org/peri-mortem-c-section-at-st-emlyns/.
3. Simon Carley, “Training for HALO procedures. Part 1: Background and psychomotor skills. St Emlyn’s,” in St.Emlyn’s, April 2, 2023, https://www.stemlynsblog.org/training-for-halo-procedures-part-1-background-and-psychomotor-skills-st-emlyns/.
4. Simon Carley, “Training for HALO procedures. Part 2: Personal Preparation. St Emlyn’s,” in St.Emlyn’s, May 11, 2023, https://www.stemlynsblog.org/training-for-halo-procedures-part-2-personal-preparation-st-emlyns/.
5. Simon Carley, “Training for HALO procedures. Part 3: The Team.,” in St.Emlyn’s, July 29, 2023, https://www.stemlynsblog.org/training-for-halo-procedures-part-3-the-team-st-emlyns/.
6. Cliff Reid #dogmalysis https://litfl.com/resuscitation-dogmalysis/