With respect to the management of cardiac arrest in the pregnant patient:
a) Outline the factors that govern the decision to perform peri-mortem Caesarian section (PMCD). (70% marks)
b) List the other modifications to the standard advanced life support (ALS) protocol that need consideration in this situation. (30% marks)
Guidelines recommend PMCD for pregnant women in cardiac arrest > 24/40 weeks (with fundus height at or above the umbilicus) when ROSC has not been achieved with usual resuscitation measures with manual lateral uterine displacement (LUD). In extreme circumstances may be considered in 20 – 24/40 week pregnancy but evidence for benefit is limited.
Decisions on the optimal timing of a PMCD for both the infant and mother are complex and require consideration of factors such as the cause of the arrest, maternal pathology and cardiac function, foetal gestational age, and resources. Shorter arrest-to-delivery time is associated with better outcome.
PMCD should be strongly considered for every mother in whom ROSC has not been achieved after ≈4 minutes of resuscitative efforts.
If maternal viability is not possible (through either fatal injury or prolonged pulselessness), the procedure should be started immediately; the team does not have to wait to begin PMCD.
There is no requirement for transfer to an operating theatre, obstetric/surgical expertise, and equipment beyond a scalpel or lengthy antiseptic procedures
- Manual lateral uterine displacement +/- left lateral tilt to avoid aorto-caval compression. Early intubation to decrease risk of aspiration – likely to be more difficult in pregnant patient Hand placement for chest compressions may need to be slightly higher.
- Standard pad placement may be difficult because of breast size so consider bilateral (biaxillary) placement.
- Early call for obstetric and paediatric help.
"Factors that govern the decision " is a strange thing to ask for, and could have been worded better. Unfortunately, the college could not have directly ased for "indications and contraindications" because no guidelines exist to strictly define them. In the absence of hard evidence, the following expert suggestions act as criteria for perimortem caesarian section:
- Less than 4-5 minutes from arrest
- Without a prolonged period of unwitnessed collapse
- At or after 23 weeks of gestation
If the delivery is being performed with foetal survival as the rationale, further criteria apply:
- Without a prolonged period of maternal haemorrhage or hypoxia
- With foetal heart beat confirmed as present
Other "factors that govern" could be listed. In fact, the whole things could really be interpreted as a "critically evaluate perimortem caesarian" sort of question. In which case, one should offer arguments for and against PMCD, as well as the current evidence. Thus:
Arguments for peri-mortem Caesarian
- Improved venous return to the heart
- Improved efficiency of external cardiac compressions (sans pelvic tilt)
- A chance for foetal survival if the mother is unsalvageable
- Allows transabdominal direct cardiac massage.
Arguments against peri-mortem Caesarian
- Strong evidence is lacking.
- The procedure must occur within 4 minutes of arrest
- Rarely can the procedure be performed that fast. Average time is 16 minutes (Einav et al, 2012).
- Of the infants delivered "late", many will have severe neurological sequelae (Katz et al, 1986)
Theoretical risks of perimortem Caesarian
- Foetal injury during the rushed procedure
- Maternal complications consistent with survival, but resulting in disability.
- Medicolegal risks, eg. patient/spouse/siblings will object in the future.
- One may also be determined negligent for not performing this potentially lifesaving procedure.
Evidence regarding the efficacy and safety of peri-mortem Caesarian
- Morris, 1996: 75% foetal survival in non-arrest trauma setting.
- Beckett et al (2015): improved maternal survival and increased rates of ROSC
Modifications to standard protocols consist of the following points:
Modifications to diagnostic thinking
- Though pregnant women may die of the same causes as non-pregnant non-women (i.e. the four Hs and four Ts), one needs to keep in mind the following alternative causes of arrest:
- Amniotic fluid embolism
- Hypertensive disorder of pregnancy (with ensuing cardiac failure)
- Seizures (with ensuing hypoxia and arrest)
- Haemorrhage from liver rupture
- Haemorrhage from uterine rupture
Issues which complicate the pregnant arrest and peri-arrest scenario
- Difficult intubation
- Increased risk of aspiration (the stomach just doent't empty)
- Venous return is impaired by the gravid uterus
- Systemic oxygen consumption is increased
- Cardiac output and circulating volume are greater; decompensation occurs later.
Modifications to basic life support
- Manually displace the uterus to the left (off the aorta and vena cava)
- Add a left lateral tilt (the ideal angle is unknown, and is thought to be between 15° and 30°).
- A left lateral tilt may compromise effective CPR, but is still recommended by the ARC Guideline 11.10 (2011) "Special Circumstances". In contrast, ECC and AHA no longer recommend the left lateral tilt (see the 2015 AHA update and the 2015 ECC guidelines). Presumably, once the ARC get around to it, their guidelines will fall in line with international consensus.
- Prepare for an emergency perimortem caesarian.
- Biaxillary defibrillator pad placement
Einav, Sharon, Nechama Kaufman, and Hen Y. Sela. "Maternal cardiac arrest and perimortem caesarean delivery: evidence or expert-based?." Resuscitation 83.10 (2012): 1191-1200.
Morris Jr, John A., et al. "Infant survival after cesarean section for trauma." Annals of surgery 223.5 (1996): 481.
Beckett, V. A., P. Sharpe, and M. Knight. "CAPS—A UKOSS STUDY OF CARDIAC ARREST IN PREGNANCY AND THE USE OF PERI-MORTEM CAESAREAN SECTION. IMPLICATIONS FOR THE EMERGENCY DEPARTMENT." Emergency Medicine Journal 32.12 (2015): 995-995.
Elkady, A. A. "Peri-mortem Caesarean Section Delivery: A Literature Review and Comprehensive Overview." Enliven: Gynecol Obstet 2.3 (2015): 005.
Campbell, Tabitha A., and Tracy G. Sanson. "Cardiac arrest and pregnancy." Journal of emergencies, trauma, and shock 2.1 (2009): 34.
Katz, Vern L., Deborah J. Dotters, and William Droegemueller. "Perimortem cesarean delivery." Obstetrics & Gynecology 68.4 (1986): 571-576.
Manner, Richard L. "Court-Ordered Surgery for the Protection of a Viable Fetus:, 247 6a. 8b, 274 SE 2d 457 (1981)." (1982).