Maternal collapse and resuscitation in pregnancy — structured SAQ (15 marks)

(a) Definition and reversible causes (5 marks)

One mark for the definition; four marks for a structured reversible-cause framework that includes the obstetric additions. ^[1]

Definition (RCOG Green-top Guideline 56): an acute event involving the cardiorespiratory systems and/or brain, resulting in a reduced or absent conscious level (and potentially death), at any stage in pregnancy and up to six weeks after birth.^[1]

In this specific woman, the epidural top-up 40 minutes ago puts high or total spinal block and local anaesthetic systemic toxicity at the top of the list; her obesity and gestation put pulmonary embolism and haemorrhage close behind. ^[3][6]

(b) Modifications to CPR, with reasons (4 marks)

One mark per modification with its physiological justification. ^[2][4]

• Supine and flat with continuous manual left uterine displacement, not lateral tilt. The gravid uterus compresses the inferior vena cava and reduces venous return; tilting relieves that but degrades compression force and depth, so displacement is preferred.^[5][1]
• Hand position slightly higher on the sternum. The heart is displaced upward and to the left in pregnancy, shown on maternal MRI.^[4]
• Early tracheal intubation by the most experienced operator, with a smaller tube and a declared failed-intubation plan. Airway oedema, capillary engorgement, breast tissue and aspiration risk make intubation harder; reduced functional residual capacity and raised oxygen consumption make desaturation faster.^[1][2]
• Intravenous or intraosseous access above the diaphragm. Drugs given below a compressed inferior vena cava may not reach the central circulation.^[1][2]
• Drug doses and defibrillation energies are unchanged, and defibrillation is safe in pregnancy — an explicit statement earns credit because candidates often halve them.^[2]

(c) Four specific antidotes or rescue therapies (4 marks)

One mark per cause with the correct agent, dose and route. No mark for the agent alone. ^[1][6][7]

(d) No return of spontaneous circulation at four minutes (2 marks)

One mark for the action, one for the justification. ^[8][2]

• Perform perimortem caesarean birth (resuscitative hysterotomy) in the room, aiming for delivery by five minutes from the arrest. At 33 weeks her fundus is well above the umbilicus.^[8][2]
• Justification: this is a maternal resuscitation manoeuvre. Emptying the uterus relieves aortocaval compression, restores venous return, redistributes uterine blood flow to the maternal brain and heart, and improves ventilation. No anaesthetic and no consent are required, and CPR with uterine displacement continues until the baby is delivered.^[1][8][3]