What is the proper CPR protocol for an obstetric patient in cardiac arrest?

CPR Protocol for Obstetric Cardiac Arrest

In pregnant patients with cardiac arrest, initiate standard high-quality CPR immediately with manual left uterine displacement, and if return of spontaneous circulation (ROSC) is not achieved within 4 minutes, begin perimortem cesarean delivery at the bedside to achieve delivery by 5 minutes. 1, 2

Immediate Resuscitation Priorities

High-quality chest compressions are the foundation of maternal cardiac arrest management. 1

• Position hands on the lower half of the sternum and compress hard and fast, achieving a depth of at least 2 inches at a rate of 100-120 compressions per minute 1
• Allow complete chest recoil between compressions and minimize interruptions to less than 10 seconds 1
• Switch compressors every 2 minutes to prevent fatigue and maintain compression quality 1

Relief of Aortocaval Compression

Manual left uterine displacement (LUD) must be performed continuously during CPR if the fundus is at or above the umbilical level (approximately ≥20 weeks gestation). 1, 2

• An assistant should manually displace the uterus to the left while compressions continue, as this relieves compression of the inferior vena cava and aorta 1
• This is more effective than left lateral tilt positioning, which compromises compression quality 1
• Aortocaval compression significantly impairs venous return and cardiac output, making relief of this compression critical for successful resuscitation 2

Airway Management Considerations

Early bag-mask ventilation with 100% oxygen is essential, as hypoxemia develops more rapidly in pregnant patients. 1

• Use a 30:2 compression-to-ventilation ratio initially, transitioning to continuous compressions with asynchronous ventilation once an advanced airway is placed 1
• Pregnant patients have more difficult airways due to edema, obesity, and anatomical changes—consider starting with a smaller endotracheal tube (6.0-7.0 mm) 1, 3
• Limit laryngoscopy attempts to no more than 2 before placing a supraglottic airway device 1
• Do not delay chest compressions or defibrillation for airway management—oxygenation and circulation take priority over intubation 1
• Cricoid pressure is not recommended as it may impede ventilation and laryngoscopy without preventing aspiration 1

Defibrillation Protocol

Use the same defibrillation protocol as for non-pregnant patients without modification. 1

• Deliver biphasic shocks at 120-200 J with escalation if the first shock is ineffective 1
• Use anterolateral pad placement with the lateral pad positioned under the breast tissue 1
• Remove fetal monitors if present, but do not delay defibrillation for their removal 1
• Resume chest compressions immediately after shock delivery 1

The Critical 4-Minute Decision Point

Perimortem cesarean delivery (PMCD) must be initiated at 4 minutes after cardiac arrest onset if ROSC has not been achieved. 1, 2

This timing is based on the following evidence:

• The procedure must begin at 4 minutes to achieve delivery by 5 minutes, which is the critical window for optimal maternal and fetal outcomes 2
• The primary goal is maternal resuscitation, not just fetal salvage—delivery relieves aortocaval compression and improves cardiac output and coronary perfusion pressure 2
• In a case series of 38 PMCD cases, 12 of 20 women achieved ROSC immediately after delivery 2
• Best fetal survival occurs when delivery happens within 5 minutes, particularly at gestational ages >24-25 weeks 1, 2

Practical Implementation

• Designate a timekeeper to call out elapsed time at 1-minute intervals 3
• Activate the maternal cardiac arrest team immediately, including an obstetrician capable of bedside cesarean delivery 3
• Perform PMCD at the bedside where the arrest occurred—do not move to an operating room unless it can be accomplished in 1-2 minutes 2, 3
• Continue CPR throughout the procedure until delivery is complete 1

Medication Administration

Medication doses and choices do not require alteration from standard ACLS protocols. 1

• For refractory ventricular fibrillation/tachycardia, administer amiodarone 300 mg rapid infusion with 150 mg repeated as needed 1
• Standard vasopressor doses (epinephrine 1 mg every 3-5 minutes) should be used 1
• Fetal medication concerns are overshadowed by the maternal arrest situation 1

Team Activation and Preparation

A multidisciplinary maternal cardiac arrest team must be activated immediately using a universal call (e.g., "maternal code blue"). 1, 3

Essential team members include:

• ACLS-trained emergency physicians or intensivists to lead resuscitation 3
• Obstetrician capable of immediate bedside cesarean delivery 3
• Experienced airway provider (anesthesiologist preferred) 3
• Neonatologist with neonatal resuscitation team 3
• At least 4 BLS-trained responders for compressions and assistance 3

Common Pitfalls to Avoid

• Do not delay PMCD waiting for ROSC—if 4 minutes have elapsed without ROSC, begin the procedure immediately 1, 2
• Do not transport the patient to an operating room—PMCD must be performed at the bedside 1, 2
• Do not use left lateral tilt positioning—manual left uterine displacement is superior and maintains compression quality 1
• Do not stop resuscitation prematurely—maternal survival has been documented with PMCD performed up to 15 minutes after arrest onset, and prolonged resuscitation may be appropriate in young, previously healthy mothers with reversible causes 1, 4
• Do not forget continuous capnography—use it to assess CPR quality, confirm endotracheal tube placement, and detect ROSC (abrupt increase in ETCO2 by ≥10 mmHg suggests ROSC) 1

Post-Resuscitation Care

Therapeutic hypothermia may be considered for comatose pregnant patients after ROSC, following the same protocols as non-pregnant patients. 1

• Continuously monitor the fetus for bradycardia during therapeutic hypothermia 1
• Obtain obstetric and neonatal consultation 1