Cardiac arrest is rare in pregnancy, it is estimated to occur once in every 30000 deliveries. Significant changes in maternal physiology occur in pregnancy with increases in cardiac output, blood volume, minute ventilation and oxygen consumption. Furthermore, the gravid uterus may cause significant compression of iliac and abdominal vessels when mother is in the supine position, resulting in reduction in cardiac output and hypotension. It is also important to recognize that the etiology of cardiac arrest in pregnancy may be variable, and includes amniotic fluid embolism, pulmonary embolism, eclampsia, drug toxicity (magnesium sulphate, epidural anaesthetics), congestive cardiomyopathy, aortic dissection, trauma and haemorrhage.

Prompt consideration of immediate cesarean section(within 5 min of arrest) must be made. This may improve the outcome for mother and fetus.

Pregnant women are generally healthy women because the child bearing age is usually up to the middle of the fourth decade of life which is always invariably the prime of life.

Pregnancy brings the adaptable physiological changes and may affect the physical strength of the mother. Since the mothers are in the fittest period of their lives. The risk factors or complication leading to cardiopulmonary arrest are few.

Cardiopulmonary resuscitation (CPR) activities, are not usually called for, except where is traumatic accident or complications of pregnancy are setting in. Other events which may develop and call for resuscitation are the events of complicated local nerve blocks. Congenital or acquired heart diseases. Analgesia for labour using amide local anaesthetics, may produce in rare occasions toxicity and collapse. Also with the advances of medical care mothers with cardiac diseases are getting pregnant and progressing to full term delivery. All the above factors made it imperative that it is essential to have a clear idea about what should be done in the case of such calamity^1-5

All the following have been reported as reasons of cardiac arrest in pregnancy ^1-4,6-10 Accidents, pre-eclampcia eclampcia, Hypertensive heart diseases, sickle cell disease, complication of tocolytic therapy, complicated epidural analgesia, drug toxicity or hypersensitivity, pulmonary embolism, amniotic fluid embolism, peripartum haemorrhage with hypovolaemia, water intoxication, prostaglandin administration, ischemic heat diseases, decompensation of preexisting cardiac diseases such as cardiomyopathies and in special situation like the drug abuse victim, septic shock and HELLP syndrome.

The most common cause irrespective of its etiology is the hypovolaemia and hypotension. Therefore intravenous therapy in the light of loss of volume should be immediately cared for.

Reviewing the CPR manual of cardiac emergency procedures of Saudi Heart Association and the American Heart Association, we found little reference to CPR in pregnancy. The observer would conclude that the general algorithm for adult emergency cardiac care should be followed. Then the question arise: Is the full term pregnant women, similar to a non pregnant women of the same age and state of health in regard the physiological reserve and oxygen demand. We all know that the physiologic changes of pregnancy do complicate the picture. The pregnant women undergoes the following important changes:

1. Expanded blood volume.
2. Physiological anaemia.
3. Increased oxygen consumption which means decrease cardiopulmonary reserve.
4. Deceased functional residual capacity of the lungs.
5. After 20 weeks of gestation, in a women on her back Aortocaval compression and specially vena caval compression will lead to a reduced venous return to the heart, as exerted by the large uterus; lateral uterine displacement will release the vessels (ease the vessels at the pelvic rime).
6. The gastric contents are increased in volume and are high in acidity. In addition the delayed emptying of the stomach makes aspiration of the gastric content to the lungs a horrible possibility.

The occurrence of cardiac arrest or the respiratory obstruction may happen outside or inside the hospital i.e. the labour ward, operative theater and post operative ward.

Logically the chain of survival approach should be followed. This includes: Early CPR, early defibrillation, early advanced care, and early stabilization.

Outside the hospital; Ideally; basic and advanced life support should be applied, using automated external defibrillators. In case of foreign body airway obstruction, chest ( sternal) thrust and finger seep of the mouth can be used in pregnant woman instead of abdominal thrust. For airway protection the use of cricoid pressure during ventilation should reduce the incidence of aspiration, the chest compression should be performed while an assistant is lifting the uterus away from the great vessels. This can be done by manual lifting or wedging the body by pillows under the right side of the abdomen or abdominal flanks. A second rescuer should lift the body of the victim by sliding his knee joints under the flanks of the abdomen or the pelvis while he is in the kneeling position beside the body.

Inside the hospital; basic and advanced cardiac life support should be followed as usual, i.e. Activating the emergency services, early CPR, early defibrillation and stabilization. Due to the special risk of gastric aspiration, early endotracheal intubation is recommended in order to protect the trachea. Immediate cesarean delivery should be done in order to save both the mother and child, many reports indicated the importance of immediate delivery for the good outcome of the resuscitation. There is a case report which indicated the importance of immediate delivery within four minutes of the cardiac arrest gave the best outcome for mother and child, and there is another case report which showed good result even after prolonged resuscitation for twenty minutes.^7,8

This should follow the universal algorithm for adult emergency cardiac care, and the algorithm for ventricular fibrillation, asystole or electromechanical dissociation

or pulseless electrical activity. The drugs should be used as stated in those algorithm. The new American Heart Association (AHA) algorithm stipulate the use of DC shock and drugs in CPR.^1,5

Both elective cardioversion and emergency defibrillation can be used with success in pregnant women. Fetal arrhythmia due to electrical induction by defibrillator can be minimized by proper placement of the paddles. The left breast should be pushed out of the way and wide posterior paddle is used if available.¹¹

Patients with artificial heart valves are at increased risk of cardiac trauma when closed chest cardiac compression is used, so open chest cardiac massage should be considered ¹². Wherever a pregnant women with severe cardiac disease is electively taken to surgery, communication with cardiac surgery team and perfusionist are recommended. Since cardiopulmonary bypass may be life saving. This may be done as femoral artery-vein bypass or as more drastically via sternotomy.

Pregnant women are more susceptable to local anaesthetic neurotoxicity and cardiotoxicity. Bupivacaine is 10 times more cardiotoxic than lidocaine ¹³. It has also a strong affinity for myocardial tissue and will exert its affinity for many hours. So a massive intravascular overdose may result in maternal asystole due to its effects on the cardiac electrical conducting system and contractile myocardial cells. If CPR in this situation is confronted with failure, then immediate cesarean section delivery is warranted since the foetal heart may also be affected. The institution of open chest CPR and then cardiopulmonary bypass to treat the local anaesthetic cardiac toxicity has been successfully carried out ¹³.

Place pregnant patient in the left lateral position (or manually replace the uterus)

Give 100% oxygen

Give fluid bolus

immediate revaluation of any drugs being administered.

BLS modifications during arrest

Relieve aortocaval compression by manually displacing the gravid uterus or by using a wedge(A pillow, or position the pregnant patient’s back on the rescue’s thighs)

ALS modifications during arrest

Consider possible etiologies, e.g. magnesium sulphate toxicity

If the above plus standard application of ALS have failed, and fetal viability exists, consider immediate perimortum cesarean section (ideally within 5 minutes arrest to delivery)

Involve obstetric and neonatal personnel when possible.^14-19

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