Question 22

a)
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, equipment beyond a scalpel or lengthy antiseptic procedures

b)
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 (bi-axillary) placement.
Early call for obstetric and paediatric help.

Discussion

This question is very similar to Question 9 from the first paper of 2016, except that time the examiners wanted the candidates to "Outline the factors that govern the decision" instead of "Discuss the considerations around the decision". One can only wonder about the rationale for this change of wording. Whatever it was, it clearly did not change the expectations on the trainees, or the marking rubric, because the college model answers to both questions are identical. 

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

So, what are the "considerations around the decision"? Surely, those considerations would fall into the categories of pros, cons and published data. And so:

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

b)

Modifications to standard ALS 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