Perimortem Cesarean Section (PCS) / Resuscitative Hysterotomy — Short Notes

Definition

1. Salvaging a viable fetus
2. Improving maternal resuscitation by relieving aortocaval compression

Rationale (Why it helps the mother)

• After ~20 weeks' gestation, the gravid uterus causes aortocaval compression in the supine position, reducing venous return and cardiac output.
• CPR in pregnancy generates only 30-40% of normal cardiac output even with correct technique (left lateral tilt/manual uterine displacement).
• Delivery of the fetus increases maternal venous return and cardiac output by 25-30%, which can be the deciding factor in achieving return of spontaneous circulation (ROSC).
• PCS itself may be "the most important variable for successful maternal resuscitation" (Roberts and Hedges' Clinical Procedures in Emergency Medicine, p. 1369).

Indications

• Maternal cardiac arrest with gestational age ≥ 24 weeks (fundus at or above the umbilicus) - the threshold of fetal viability.
• No ROSC despite adequate ACLS-guided CPR.
• If gestational age is uncertain, estimate quickly: between 18-30 weeks, fundal height (cm from symphysis pubis) ≈ gestational age in weeks (e.g., fundus at umbilicus ≈ 20 weeks; fundus halfway between umbilicus and xiphoid ≈ 28-30 weeks).
• Common causes of maternal arrest necessitating consideration: hemorrhage, amniotic fluid embolism, cardiomyopathy/other cardiac disease, pulmonary embolism, hypertensive disorders (eclampsia), sepsis, trauma, anaphylaxis (Creasy & Resnik's Maternal-Fetal Medicine, p. 6122).

Timing - The "4-5 Minute Rule"

• Begin the procedure within 4 minutes of maternal cardiac arrest (if no ROSC with CPR).
• Complete delivery within 5 minutes of arrest.
• Neonatal outcome is best when delivery occurs within 4 minutes and poor after 20 minutes.
• CPR must continue throughout and after the procedure, with manual uterine displacement/left lateral tilt maintained until delivery.
• Do NOT delay to: wait for obstetric/neonatology backup, check fetal heart tones, get ultrasound confirmation of viability, or transport to OT/prep a sterile field - all performed at the bedside/in the ED.

Technique

1. Continue CPR (with left uterine displacement) throughout.
2. Most experienced available person performs it (ideally obstetrician; neonatologist if available - but don't wait).
3. Midline vertical (classical) skin incision from symphysis pubis to umbilicus (use the linea nigra as a guide), through all abdominal layers into the peritoneum.
4. Retract laterally, reflect/decompress the bladder inferiorly.
5. Small (~5 cm) vertical classical uterine incision until amniotic fluid/uterine cavity entered.
6. Insert fingers to lift uterine wall off the fetus; extend incision to the fundus with bandage scissors under direct digital protection.
7. Deliver the infant (breech-style extraction by the feet if the head is high), clamp/cut cord, hand off for neonatal resuscitation.
8. Continue maternal CPR; consider uterine massage/hemostasis once resuscitation permits.

Perimortem cesarean delivery technique - midline vertical incision and delivery of the fetus (Roberts and Hedges' Clinical Procedures in Emergency Medicine).

Key Points for Exams

• Gestational age cutoff for PCS: ≥24 weeks
• Time to start: within 4 minutes of arrest; complete by 5 minutes
• Skin incision: vertical midline; Uterine incision: classical (vertical) - fastest access, not low transverse
• Primary benefit demonstrated is to the mother, via relief of aortocaval compression
• No time wasted on sterile prep, transport, or fetal heart tone confirmation
• CPR continues during and after the procedure

Note on evidence currency