Cardiac arrest is a very rare event during pregnancy, with an incidence of approximately 1 in 30 000 pregnancies [3, 4]. Rising maternal age and associated increased incidence of medical conditions may increase the risk of cardiac arrest during pregnancy .
Although chest compressions in the event of a cardiac arrest in pregnancy can produce 30% of normal cardiac output, this is dependent on the woman being in a supine position. In advanced pregnancy, aorto-caval compression by the gravid uterus hinders this process and cardiac output obtained is only around 10% of cardiac output . Hence, chest compressions should be carried out with the woman in lateral tilt position which decompresses aorto-caval vessels to optimize
Further, delivery of the fetus can, theoretically, facilitate effective cardiopulmonary resuscitation and is believed to increase cardiac output by another 60%–80%, which in turn may improve maternal survival. In addition to relieving mechanical difficulties and pressure on the great vessels, delivery of the fetus increases the functional residual capacity (FRC) of the maternal lungs and hence improves oxygenation. Moreover, there is a concomitant reduction of oxygen demand by the feto-placental unit, aiding further maternal oxygenation .
Since the 1980s, many cases of unexpected maternal recovery following perimortem caesarean section have been reported. The evidence does seem to suggest that perimortem caesarean section will enhance maternal survival and may increase the likelihood of the birth of a viable fetus .
However, the primary aim is to increase the likelihood of maternal survival by facilitating cardiopulmonary resuscitation .
Perimortem caesarean section is performed under a stressful, unfamiliar situation – with a collapsed mother, without any analgesia, with ongoing cardiac compressions and usually in an unfamiliar environment (e.g. Accident & Emergency [A&E] department or a labour room) without recourse to appropriate equipment and support.
The most senior obstetrician in the team should demonstrate leadership and undertake this procedure in conjunction with the anaesthetist and the cardiac arrest team. The primary intention is to save the life of the mother and it should be anticipated that the fetus may be neurologically compromised due to prolonged circulatory collapse. Hence, the neonatal team should be informed.
The timing of the caesarean section is the key factor that determines the success of the neonatal outcome and evidence so far suggests that if the baby survives the early neonatal period, the chances of abnormal long-term sequelae are low .
Obtaining an informed consent for the procedure is not necessary, as the clinician is acting in the best interest of the woman to save her life, unless she has signed an advanced directive. The decision to do perimortem caesarean section should be taken by a senior member of medical staff and the team should preferably involve the next of kin, if possible. However, the circumstances can vary widely and the common law doctrine of necessity may become applicable and the doctor is required to do whatever is necessary to preserve life.
The outcome of a resuscitation attempt in cardiac arrest depends on the underlying cause of the arrest and the effectiveness of initial resuscitation . The same causes of cardiac arrest in non-pregnant women can occur during pregnancy.
○ Venous thromboembolism
○ Amniotic fluid embolism.
○ Massive obstetric haemorrhage.
○ Maternal ischaemic or congenital heart disease or cardiomyopathy
○ Vasovagal attack (e.g. uterine rupture)
○ Poisoning (e.g. organophosphates or yellow oleander)
○ Iatrogenic causes such as magnesium sulphate toxicity and anaesthetic complications (e.g. total spinal).
Key Actions: Performing a Rapid Perimortem Caesarean Section
‘The 4-minute rule’ is the recommended approach . The patient should be resuscitated in the left lateral position and any treatable cause such as magnesium sulphate toxicity or poisoning should be addressed at the same time.
The caesarean section should be carried out after 4 minutes of arrest and should be completed in 1 minute. This is because if CPR does not restore circulation within 4 minutes, further intervention becomes necessary at this stage to prevent maternal neurological damage resulting from inadequate cerebral perfusion.
There are no specific technical recommendations that exist to deliver the baby in a speedy manner via perimortem caesarean section. The ‘midline approach’ is often advocated because of the likelihood of a quick extraction. However, it is recognised that the current generation of obstetricians are competent in delivering via supra-pubic transverse incisions equally rapidly in extreme emergencies .
The most senior obstetrician should carry out the procedure, though this may not always be feasible, especially outside the labour ward setting.
A caesarean section can be performed with a scalpel and strict aseptic precautions may/may not be adhered to in these circumstances. However, care should be taken to avoid bowel or bladder injury and resuscitation efforts should not be interrupted during the delivery .
Full surgical scrub is not required and only basic personal protective equipment (PPE) should be worn. Wearing full gowns or masks can cause delays and full sterility is not needed.
The abdomen should be cleansed where possible, but this should not delay starting the procedure.
Minimal equipment is required to perform a perimortem caesarean section : a scalpel and two ligatures or clamps for the umbilical cord. This equipment should be available in hospital departments where obstetric patients are commonly If maternal recovery seems a likely possibility, careful closure of the incision is required, as the patient may start bleeding once the circulation is restored.