Maternal Collapse (Cardiac Arrest in Pregnancy)

Question 1

What are the 4T’s reversible causes of cardiac arrest in pregnancy?

Answer 1

• Thrombosis (i.e. PE or MI)
• Tension pneumothorax
• Toxins
• Tamponade (cardiac)

Question 2

What are the 4H’s reversible causes of cardiac arrest in pregnancy?

Answer 2

• Hypoxia
• Hypovolaemia
• Hypothermia
• Hyperkalaemia, hypoglycaemia, and other metabolic abnormalities

Question 3

Major causes of maternal collapse?

Answer 3

• Obstetric haemorrhage
• Pulmonary embolism
• Sepsis leading to metabolic acidosis and septic shock

Question 4

What is a major cause of severe hypovolaemia and cardiac arrest?

Answer 4

Obstetric haemorrhage is a major cause of severe hypovolaemia and cardiac arrest.

Question 5

What are the causes of massive obstetric haemorrhage?

Answer 5

• Ectopic pregnancy (early pregnancy)
• Placental abruption (including concealed haemorrhage)
• Placenta praevia
• Placenta accreta
• Uterine rupture

Question 6

What is aortocaval compression?

Answer 6

After 20 weeks gestation, the uterus is a significant size. When a pregnant woman lies on her back (supine), the mass of the uterus can compress the inferior vena cava and aorta.

Question 7

In aortocaval compression, why is compression on the vena cava very significant?

Answer 7

Reduces the blood returning to the heart (venous return). This reduces the cardiac output, leading to hypotension.

In some instances, this can be enough to lead to the loss of cardiac output and cardiac arrest.

Question 8

Why is the solution to aortocaval compression is to place the woman in the left lateral position, lying on her left side, with the pregnant uterus positioned away from the inferior vena cava?

Answer 8

Should relieve the compression on the inferior vena cava and improve venous return and cardiac output.

Question 9

What factors can make resuscitation more complex in pregnancy?

Answer 9

• Aortocaval compression
• Increased oxygen requirements
• Splinting of the diaphragm (inhibition of diaphragm movement) by the pregnant abdomen
• Difficulty with intubation
• Increased risk of aspiration
• Ongoing obstetric haemorrhage

Question 10

Resuscitation in pregnancy involves the same principles except as usual, with the exception of additional factors?

Answer 10

• A 15 degree tilt to the left side for CPR, to relieve compression of the inferior vena cava and aorta
• Early intubation to protect the airway
• Early supplementary oxygen
• Aggressive fluid resuscitation (caution in pre-eclampsia)
• Delivery of the baby after 4 minutes, and within 5 minutes of starting CPR

Question 11

When is immediate C-section used in maternal collapse?

Answer 11

There is no response after 4 minutes to CPR performed correctly

CPR continues for more than 4 minutes in a woman more than 20 weeks gestation

Question 12

What is the purpose of immediate delivery in maternal cardiac arrest?

Answer 12

Improves the survival of the mother.

Delivery improves the venous return to the heart, improves cardiac output and reduces oxygen consumption. It also helps with ventilation and chest compressions.

Delivery increases the chances of the baby surviving, although this is secondary to the survival of the mother.