Obstetrics & Gynaecology
Question 165 of 300
A 23 year old woman is brought to the Emergency Department after collapsing at home. She is 30 weeks pregnant with her second pregnancy. Whilst you are assessing the patient she becomes unresponsive and you cannot feel a central pulse. Which of the following statements regarding cardiac arrest management in the pregnant patient is TRUE?
Answer:
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.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 |
