Although the basic principles of cardiopulmonary resuscitation (CPR) are the same as in the non-pregnant state, the underlying causes of collapse are generally different, and the presence of the fetus has major implications for management and outcome.
Problems and special considerations
Because most mothers are healthy, cardiac arrest is rare in this group (estimated at 1 in 30,000) and thus resuscitative skills are easily forgotten, especially by those not regularly exposed to patients requiring cardiorespiratory support. There may be delay in recognising and responding to cardiorespiratory arrest. Midwives and obstetricians (and also anaesthetists) may be unfamiliar with protocols for life support and the drugs and equipment required, which may easily become faulty or out of date if not checked regularly. The maternity suite is often an unfamiliar place to the regular cardiac arrest team.
Although the pregnant population is fit and healthy generally, all causes of cardiac arrest pertaining to the non-pregnant population should be considered, as well as those specifically associated with pregnancy. Most cases of peripartum cardiorespiratory arrest or collapse will involve causes other than ischaemic heart disease (see Chapter 80, Collapse on the labour ward).
The effect of the gravid uterus needs to be taken into account, and left uterine displacement must be continuously applied during resuscitative measures. Although previously left lateral tilt was recommended during CPR, it is now thought to be less effective than manual uterine displacement. Similarly, current guidance states that hand placement for chest compressions should be at the lower part of the sternum as for non-pregnant patients rather than higher up as previously recommended. Effective chest compressions are important for resuscitation to be successful, and the patient can remain supine, allowing this, if manual uterine displacement is applied. However, even with manual uterine displacement, return of spontaneous circulation is unlikely in the presence of a heavily gravid uterus.
The pregnant patient has limited oxygen reserve, thus requiring prompt oxygenation/ ventilation. However, airway management may be more difficult, and the presence of a gravid uterus may hinder effective artificial ventilation and increase the risk of regurgitation by exerting pressure on the stomach. It may also increase the risk of injury to the liver, spleen and ribs because of the increased intra-abdominal pressure and altered shape of the chest.
Management options
Some cases of cardiac arrest may be prevented by general training and development of protocols in airway management and cardiovascular monitoring, identification of high-risk cases, good communication and organisation of facilities, equipment, etc.
All staff who work in the maternity suite must receive training and regular updates in CPR, including use of the defibrillator and other equipment. Drills have been shown to improve retention of skills, although they may be very disruptive to a busy unit.
Actual management of cardiac arrest is as for the non-pregnant patient, including the positioning of the hands on the sternum (previously recommended as placed higher up on the sternum). Relief of aortocaval compression is paramount, as mentioned above. Intravenous access must be secured above the diaphragm. If CPR is unsuccessful after 4 minutes, the decision to perform a perimortem caesarean section should be made, aiming for delivery of the fetus by 5 minutes; the purpose of this is to improve maternal venous return rather than for the benefit of the fetus, and fetal monitoring should not occur during resuscitative attempts. The only equipment required is a scalpel (although clamps and forceps may be useful), which should therefore be included on all cardiac arrest trolleys on the labour ward. The operator should use whichever technique he/she feels most comfortable with, but a vertical incision may allow better access and reduce blood loss. There are many reported cases of return of spontaneous cardiac output and maternal survival once delivery has been achieved, where CPR has failed initially. Neonatal outcome is usually poor, although this depends on the gestation, the cause of collapse, the delay before delivery and the effectiveness of CPR; speedier delivery is associated with improved outcome.
The risk of regurgitation and aspiration of gastric contents should be remembered, and cricoid pressure should be applied, if hands are spare, until the trachea has been intubated.
If resumption of cardiac output does occur, there is some evidence that mild induced hypothermia may improve neurological outcome in the non-pregnant population; as cardiac arrest in pregnancy is rare, data in this patient group are limited to anecdotal reports.
Key points
• For CPR, the same principles apply to the pregnant population as to the non-pregnant population.
• Regular training of staff and maintenance of equipment are required.
• Maternal cardiopulmonary resuscitation is usually impossible in late pregnancy unless aortocaval compression is relieved.
Further reading
Eldridge AJ, Ford R. Perimortem caesarean deliveries. Int Journal Obs Anesth 2016; 27: 46-54.
Jeejeebhoy FM, Zelop CM, Lipman S, et al. Cardiac arrest in pregnancy: a scientific statement from the
American Heart Association. Circulation 2015; 132: 1747-73.
Kikuchi J, Deering S. Cardiac arrest in pregnancy. Semin Perinatol 2018; 42: 33-8.
Lipman S, Cohen S, Einav S, et al. The Society for Obstetric Anesthesia and Perinatology Consensus
Statement on the Management of Cardiac Arrest in Pregnancy. Anesth Analg 2014; 118: 1003-16. Truhlar A, Deakin CD, Soar J, et al. European Resuscitation Council Guidelines for Resuscitation 2015: Section 4. Cardiac arrest in special circumstances. Resuscitation 2015; 95: 148-201.