Dr A Hards, Dr S Davies, Dr A Salman, Dr M Balki
Mount Sinai Hospital 2010
Aim
 To enable you to competently manage a case of
maternal cardiac arrest
Objectives
 To review relevant maternal physiology
 To review standard ACLS guidelines
 To review ACLS modifications for pregnancy
Physiology of pregnancy
 Respiratory System
1. 60% increase in oxygen consumption & decreased FRC
Implications – rapid desaturation & hypoxemia
2. increased minute ventilation and hypoxic ventilatory response
Implications - chronic respiratory alkalosis, difficult determining
benign vs. sinister causes of dyspnea
3. increased capillary engorgement & mucosal edema
Implications – airway bleeding, nasal congestion, difficult airway,
failed intubation
Physiology of pregnancy
 Cardiovascular System
1.
cardiac output increases by 50% (due to increased HR & SV).
Increased contractility and LVEF.
2.
SVR and PVR fall by up to 35%. SBP, DBP, MAP decrease during
mid preganancy, return to baseline near term
3.
Aorto-caval compression occurs from 13-16 weeks
Implications
- supine hypotension
- higher femoral/IVC pressures
Physiology of Pregnancy
 Gastrointestinal System
1. Anatomical changes
2. Reduced lower esophageal sphincter pressure
3. Increased intra-gastric pressure
4. Delayed gastric emptying in labour but probably normal at other
times
 Implications
- High incidence of gastro-oesophageal reflux
- Increased risk of aspiration from ~ 16-20 weeks gestation
Physiology of Pregnancy

Hematological System
1.
50% increase in plasma volume
2.
30% increase in red cell volume
3.
Increased platelet turnover, clotting and fibrinolysis
Implications
- delayed presentation of hypovolaemia
- physiological anemia of pregnancy
- pro-coagulopathic state
ACLS in pregnancy
 Essentially follows same guidelines as for non-
pregnant patients
 AHA recommend some modifications based on
physiology
ACLS Cardiac Arrest Algorithm 2010
AHA Modifications for pregnancy
 Ventilate with cricoid pressure (remove if impeding ventilation,
oxygenation or intubation)
 Early intubation with a smaller diameter ETT (such as 6.5 cm)
 Left Uterine Displacement
 Position hands 1-2cm higher on sternum for chest compressions
 Remove fetal monitoring for defibrillation
 Do not use femoral or leg veins for IV access
 Consider emergency cesarean section
Emergency cesarean section
 Rationale for early CS
- Provides effective maternal resuscitation (improves venous return
& cardiac output)
- If fetus > 24-25 weeks may save the life of the baby
 Management
Do not move patient to OR prior to CS
Continue maternal resuscitation during CS
Aim for skin incision by 4 minutes
Aim for delivery by 5 minutes
Cause of arrest
 Always consider the “Hs and Ts”
Hypovolemia
Hypoxia
Hydrogen ions
Hypo/erkalemia
Hypothermia
Tension PTX
Tamponade
Toxins
Thrombosis, cardiac
Thrombosis, coronary
 Pregnancy-specific causes mnemonic “BEAU-
CHOPS”
Maternal cardiac arrest algorithm
Copyright © American Heart Association
Vanden Hoek T L et al. Circulation 2010;122:S829-S861
Any questions?
Summary
 Reviewed relevant maternal physiology
 Reviewed standard ACLS guidelines
 Reviewed modifications for pregnancy