Collapse In A Pregnant Patient

Question 1

A 35-year-old female patient has collapsed on labour ward. She is 39 weeks pregnant and has been induced for reduced foetal movements. She has an epidural catheter in situ.

What are the causes of collapse in a pregnant patient?

Answer 1

Medical causes:
* Intracranial haemorrhage.
* Aortic dissection.
* Cardiac causes: arrhythmias, cardiomyopathy and myocardial
ischaemia/infarct.
* Respiratory causes: acute asthma attack and pulmonary embolus.
* Hypoglycaemia.
* Sepsis.
* Drug toxicity.

Obstetric causes:
* Eclampsia.
* Amniotic fluid embolus.
* Haemorrhage.

Anaesthetic causes:(commonest causes of arrest in pregnancy)
* Anaphylaxis.
* Local anaesthetic toxicity.
* High or total epidural blockade.

Question 2

How would you manage this patient?

Answer 2

• Request immediate senior help with an anaesthetic and obstetric emergency or cardiac arrest call to include senior registrars/ consultants, the labour ward ODP, the midwife in charge and the neonatal team.
• Rapid assessment of the patient: If there are no signs of life, commence the ALS protocol. If the patient is breathing and has a pulse, carry out an urgent ABCDE assessment to establish the likely cause of the
  collapse.
• Stop the epidural infusion if running and check the last known rate and concentration of the infusion.
• Key treatment early on includes:
• Manual uterine displacement (or left lateral tilt if this is not possible).
• 100% oxygen via a non-rebreathe mask.
• Large bore IV access and a crystalloid fluid bolus.
• Immediate specific treatment if the likely cause is identified.
• Consideration of foetal condition if the mother has not arrested.
• Consideration of the partner if present.

Question 3

How does the ALS protocol differ in pregnant patients?

Answer 3

The key differences are listed below and focus on restoring the mother’s circulation.

• Manual displacement of the uterus in pregnant patients while ensuring adequate chest compressions.
• A peri-mortem caesarean section within 5 minutes of the cardiac arrest.
• Consideration of specifc obstetric causes of arrest (“BEAUCHOPS”):
• Bleeding.
• Embolism.
• Anaesthetic causes.
• Uterine atony.
• Cardiac.
• Hypertension.
• Other – 4Hs and 4Ts.
• Placental abruption.
• Sepsis.
• Human factors: heightened emotions and anxiety/stress levels.

Question 4

What is the incidence of amniotic fluid embolism?

Answer 4

• Approximately five in every 100,000 pregnancies.
• However, this varies due to the difficulty in accurate diagnosis.

Question 5

What are the risk factors for development of an amniotic fluid embolus?

Answer 5

• It is thought that there may be an increased risk with the following:
• Induction of labour.
• Use of oxytocin.
• Assisted/operative delivery.
• Maternal age >35 years old.
• Multiple pregnancy.
• Eclampsia.
• Placental abnormalities (praevia or abruption).
  However, no risk factors have been clinically proven.

Question 6

What is the pathophysiology of an amniotic fluid embolism developing?

Answer 6

• The presence of amniotic fluid or foetal cells (squames, hair and vernix) in the maternal circulation leads to either or both of the theories mentioned below.
• “Mechanical” theory: blockage of the pulmonary vessels by the
  foetal cells.
• “Immune-mediated” response: an abnormal activation of the
  maternal immune system in response to the presence of foreign cells, causing an anaphylactoid response.

Question 7

How is a diagnosis of amniotic fluid embolism made?

Answer 7

• Amniotic fluid embolus is a diagnosis of exclusion, where maternal collapse occurs together with:
• Foetal compromise.
• Cardiac arrest, instability or arrhythmias.
• Coagulopathy or DIC.
• Major obstetric haemorrhage.
• Seizures.
• Dyspnoea.

Question 8

The patient undergoes two cycles of chest compressions and a peri- mortem caesarean section is carried out. An initial diagnosis of amniotic fluid embolus is made. ROSC is obtained, and the patient is taken to theatre where closure of the abdomen takes place. What are the next steps in the management of this patient?

Answer 8

Patient management:
* Bleeding is likely. Consider early use of uterotonics, uterine packing and a hysterectomy if necessary. Regular monitoring of clotting (including fibrinogen levels and TEG) can be used to direct the administration of blood products.

• Multidisciplinary management and transfer of the patient to intensive care once stable.
• Initiate supportive care based on the patient’s physiological abnormalities including lung protective ventilation and inotropes or vasopressors to maintain cardiovascular stability.
• Counselling and discussion with the patient and their family about events.

Staff management:
* “Hot” and “cold” debriefing of staff and counselling or further training where appropriate.

• Escalation to supervisors within the appropriate teams.