Obstetrics & Gynaecology
Question 34 of 180
You are called urgently to the waiting room by a receptionist. A 23 year old woman who presented with chest pain has collapsed. She is 32 weeks pregnant. You find no signs of life and a nurse has started chest compressions. A maternal cardiac arrest call is made. What action should you take first?
Answer:
- All the principles of basic and advanced life support apply
- Summon help immediately; obtain expert help including an obstetrician, anaesthetist and neonatologist
- Start CPR according to ALS guidelines; ensure high quality chest compressions with minimal interruptions; the hand position may have to be slightly higher on the sternum in advanced pregnancy
- Manually displace the uterus to the left to minimise IVC compression
- Add left lateral tilt only if this is feasible; the patient's body will need to be supported on a firm surface to allow effective chest compressions (the use of soft pillows or wedges is ineffective)
Cardiac Arrest in Pregnancy
Obstetrics & Gynaecology / Resuscitation
Last Updated: 4th August 2021
- Mortality related to pregnancy in developed countries is rare.
- Both the mother and foetus must be considered in emergencies during pregnancy.
- Effective resuscitation of the mother is often the best way to optimise foetal outcome.
- Significant physiological changes occur during pregnancy including:
- Cardiovascular system
- Peripheral vasodilation
- Increased cardiac output (increased stroke volume and increased heart rate)
- Increased circulatory volume (increased plasma volume)
- Respiratory system
- Increased minute ventilation (increased tidal volume)
- Increased oxygen consumption
- Cardiovascular system
- The gravid uterus can cause compression of the abdominal vessels when the mother is in the supine position, resulting in reduced cardiac output, hypotension, and reduced uterine perfusion.
- Resuscitation guidelines for pregnancy are based largely on cases series, manikin studies and expert opinion.
Causes of cardiac arrest in pregnancy
Cardiac arrest in pregnancy is most commonly caused by:
- Cardiac disease (congenital and acquired)
- Pulmonary embolism
- Psychiatric disorders (suicide)
- Hypertensive disorders of pregnancy
- Sepsis
- Haemorrhage
- Amniotic fluid embolism
- Ectopic pregnancy
- Plus, usual causes of cardiac arrest (e.g. anaphylaxis, trauma, drug overdose)
Prevention of cardiac arrest in pregnancy
- In an emergency, use the ABCDE approach
- Many cardiovascular problems in pregnancy are caused by compression of the inferior vena cava; place the patient in the left lateral position or manually displace the uterus to the left
- Give high-flow oxygen, guided by pulse oximetry
- Give a fluid bolus if there is hypotension or evidence of hypovolaemia
- Immediately re-evaluate the need for any drugs currently being given
- Seek expert help and involve obstetric and neonatal specialists early in treatment
- Identify and treat the underlying cause
Modifications for cardiac arrest in pregnancy
- All the principles of basic and advanced life support apply
- Summon help immediately; obtain expert help including an obstetrician, anaesthetist and neonatologist
- Start CPR according to ALS guidelines; ensure high quality chest compressions with minimal interruptions; the hand position may have to be slightly higher on the sternum in advanced pregnancy
- IVC compression
- After approximately 20 weeks gestation, the pregnant woman's uterus can press down against the inferior vena cava (IVC) and the aorta, impeding venous return, cardiac output and uterine perfusion; IVC compression limits the effectiveness of chest compressions
- The potential for IVC compression suggests that IV or IO access should ideally be established above the diaphragm
- Manually displace the uterus to the left to minimise IVC compression
- Add left lateral tilt only if this is feasible; the patient's body will need to be supported on a firm surface to allow effective chest compressions (the use of soft pillows or wedges is ineffective); the optimum angle of tilt is unknown; aim for between 15 - 30 degrees; even a small amount of tilt may be better than no tilt; if tilting on a firm surface is not possible then maintain left uterine displacement and continue effective chest compressions with the patient supine
- Start preparing for emergency caesarean section; the foetus will need to be delivered if initial resuscitation efforts fail
- There is an increased risk of pulmonary aspiration of gastric contents in pregnancy; early tracheal intubation decreases this risk; tracheal intubation may be more difficult in the pregnant patient; expert help, a failed intubation drill, and the use of alternative airway techniques may be required
- Attempt defibrillation using standard energy doses; left lateral tilt and large breasts can make it difficult to place an apical defibrillator pad
- Post-resuscitation care should follow standard guidelines; targeted temperature management (TTM) has been used safely and effectively in early pregnancy with foetal heart monitoring
Reversible causes of cardiac arrest in pregnancy
- Haemorrhage
- May occur both antenatally and postnatally
- Causes include ectopic pregnancy, placental abruption, placenta praevia, uterine rupture
- Maternity units should have a massive haemorrhage protocol
- Treatment is based on the ABCDE approach and may include:
- Fluid resuscitation including use of a rapid transfusion system and cell salvage
- Tranexamic acid and correction of coagulopathy
- Oxytocin, ergometrine, prostaglandins and uterine massage to correct uterine atony
- Uterine compression sutures, uterine packs and intrauterine balloon devices
- Interventional radiology to identify and control bleeding
- Surgical control including aortic cross-clamping/compression and hysterectomy
- Drugs
- Overdose can occur in women with eclampsia receiving magnesium sulfate
- Central neural blockade for analgesia or anaesthesia can cause problems due to sympathetic blockage (hypotension, bradycardia) or local anaesthetic toxicity
- Cardiovascular disease
- Myocardial infarction and aneurysm or dissection of the aorta or its branches, and peripartum cardiomyopathy cause most deaths from acquired cardiac disease
- Women with congenital heart disease should be managed in specialist centres
- Preeclampsia and eclampsia
- Eclampsia is defined as the development of convulsions and/or unexplained coma during pregnancy or postpartum in patients with signs and symptoms of preeclampsia
- Magnesium sulfate may prevent eclampsia developing during labour or immediate postpartum in women in pre-eclampsia
- Amniotic fluid embolism
- Amniotic fluid embolism usually presents around the time of delivery with sudden cardiovascular collapse, breathlessness, cyanosis, arrhythmias, hypotension and haemorrhage associated with disseminated intravascular coagulopathy
- Treatment is supportive based on the ABCDE approach and correction of coagulopathy
- Pulmonary embolism (PE)
- PE causing cardiopulmonary collapse can present throughout pregnancy
Perimortem caesarean section
- See separate article
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
