Patient positioning

To reinforce: Pregnant patients should be positioned with manual left uterine displacement or a left sided tilt of 15–30 degrees to facilitate blood flow and venous return. This positioning reduces the aortocaval shunt caused by uterine pressure on the great vessels, and should be maintained while managing neutral spinal positioning on a spine board and while in transit.

Airway management

Intubation should occur if the patient is unable to maintain an adequate airway, has an oxygen saturation below 94 per cent or has a GCS under 9. Aim to keep the ETCO2 reading around 30-35 mmHg in the absence of a head injury. This is normal physiology for a pregnant woman. Blood gas analysis should be used to assist setting ventilation parameters (if available). ETCO2 monitoring (if available) should also be used to assess respiratory status and adequacy of ventilation.

Always have emergency airway equipment available by the bedside.

Radiology

Notify radiology staff if available of the arrival of a pregnant trauma patient. Remember that in an emergency situation the optimal resuscitation, imaging and treatment of the mother will ensure the optimal chance of fetal survival.

Most diagnostic procedures pose no substantial risk to the mother or fetus, and necessary investigations should not be delayed or avoided because of concerns for the pregnancy. Radiation risks are greatest in the early stages of pregnancy (less than eight weeks); however, it is highly unlikely that the fetal-effective dose from diagnostic or most interventional procedures will exceed 100 mSv, which is the dose range at which the possibility of fetal complications is more concerning.

X-ray

Plain x-ray imaging of the head, neck, chest, pelvis or extremities pose no substantial risk and should be undertaken as indicated for trauma patient management. Shielding of the abdomen or pelvis may be considered where appropriate.

CT scanning

CT scanning of the abdomen and pelvis may increase the total radiation dose to the fetus and therefore should be used only after a risk-benefit analysis. However, in a critically injured patient, fetal outcomes are directly related to maternal outcomes, and the best care for the mother is also the best care for the unborn child.

If it appears that the patient will require transfer to a MTS, the decision to conduct a CT prior to retrieval must be carefully considered.

FAST

Consider need for FAST if available and if staff trained in its use are present or available. In haemodynamically stable patients, FAST can be delayed until the secondary survey and is ideally performed by a second operator while the remainder of the secondary survey is completed.

Ultrasound

Ultrasound may be used to: assess a large organ injury; determine the presence of peritoneal fluid or blood; calculate gestational age and fetal heart rate; assess fetal wellbeing, fetal movement and placental location; and calculate amniotic fluid volume. However, ultrasound has a low sensitivity for placental abruption and should not be used to exclude this diagnosis.

Pathology tests

In a ventilated patient, arterial blood gases can have a significant impact on the ability to monitor and adjust the adequacy of ventilation and perfusion. Ventilation parameters should be based on blood gas analysis and adjusted accordingly; aim for a carbon dioxide of 30–35 mmHg and an oxygen saturation of 94-98%.

If the mother is Rh negative, perform a Kleihauer test (within 48–72 hours).

Lab tests should be taken for FBC (full blood count), UEC (urea electrolytes and creatinine) and glucose as a baseline. A group and hold should be taken for all major trauma patients; consider requesting a cross-match as well if the patient is involved in a trauma presentation with a high index of suspicion for further injuries. Coagulation studies including fibrinogen  should be done if accessible to establish baseline measurements in the pregnant trauma patient, and to assist in the management of haemorrhage. This is particularly important if the patient is on anticoagulation therapy.

Preventing hypothermia

Prevention of hypothermia is crucial in pregnant trauma patients. Warmed IV fluids should be administered if high volumes are required and external warming therapies should be commenced. An ideal patient temperature of 36.5 °C is the target for attending staff.

Analgesia and antiemetics

Use of antiemetic’s should be considered early, to anticipate and prevent motion sickness and reduce the known risk of aspiration especially if transfer and retrieval is likely. All antiemetic’s are safe after 8 weeks gestation, prior to this time or if gestation is unknown Ondansetron should be avoided (however evidence regarding any risk associated with Ondansetron use before 8 weeks gestation is incomplete). Effective management of vomiting, reflux and risk of aspiration is a clear priority in managing patients with trauma in early pregnancy.

Analgesia should be carefully considered for a pregnant patient suffering a traumatic injury. The drug of choice will be based on clinical signs, the need for analgesia and whether the drug crosses the placenta into the fetal circulation. Short-acting agents are generally preferred, avoiding continuous infusions.

Most opioids are considered safe for use in therapeutic doses for short periods of time during pregnancy, and many are used routinely for labour analgesia despite crossing the placenta. In most circumstances, opioids would be considered an appropriate choice for analgesia in a pregnant trauma patient. Non-steroidal anti-inflammatory drugs (NSAIDs) are contraindicated in pregnancy and should be avoided.

Advice should be sought from a pharmacist or pregnancy medication advice service where concerns exist.

Sedation

Appropriate sedation may lower intracranial pressure by reducing metabolic demand. Further beneficial effects of sedation include a reduction in hypertension and tachycardia as well as improved patient–ventilator synchrony. Propofol has become a widely used anaesthetic/sedative with pregnant patients because it has a rapid onset and short duration of action.^{14 15}

Monitoring

Monitoring the heart rate, respiration rate, blood pressure and oxygen saturation should take place at 15/60 intervals or less if indicated. All monitoring should be maintained until the retrieval team arrives.

A baseline ECG should be taken if time permits and facilities exist prior to transfer. Additionally, fetal monitoring should be commenced if capacity exists and gestation is 24 weeks or longer.

Wound care

Initial management of the wound in an emergency department is limited to controlling bleeding via external direct pressure.

If vaginal bleeding is unable to be controlled, this may represent severe pathology and discussion with an obstetric team and ARV should take place urgently to guide therapy. Vaginal packs must not be inserted.

In-dwelling catheter

A urinary catheter should be inserted in pregnant trauma patients and their urine output measured hourly. A urinalysis should be performed also to check for blood and protein. The desired urine output for adults is 0.5–1.0 mL/kg/hr.

Nasogastric tube

All patients should be kept nil orally in the initial post-resuscitation phase of injury.

If a base of skull fracture is suspected, and with any maxillofacial injuries, insertion should be avoided until the patient is transferred to the specialist centre. Alternatively, an OGT can be placed under careful direct visualisation. Care should be taken with inserting an NGT in pregnant patients due to mucosal congestion and the added risk of epistaxis.

Tetanus prophylaxis

Tetanus prophylaxis should be administered in any penetrating injury. Adult diphtheria tetanus vaccination (ADT) is a category A drug and is considered safe for use in pregnancy.

Antibiotics

Antibiotic prophylaxis should occur in all open and penetrating injuries as well as when there is suspicion of any base of skull fractures. The risk of local wound infections are particularly high in patients with a penetrating injury due to the presence of contaminated foreign objects such as skin, hair or bone fragments.

The routine prophylactic use of antibiotics remains controversial.

Cephalosporins, penicillins and metronidazole are category A or B medications and are usually considered safe for use where indicated in pregnancy. Tetracyclines and aminoglycosides are category D medications and their use should generally be avoided. Consultation with the ARV clinicians and obstetric specialists is indicated regarding the choice of antibiotics.

Cardiac arrest

A pregnant patient who has a cardiac arrest presents significant problems to the treating team outside a MTS.

Effective CPR is difficult to achieve in late pregnancy due to the effects of aortocaval shunting and compression of the great vessels by the enlarged uterus. Maintenance of manual left uterine displacement or left lateral tilt is essential for effective resuscitation, and must be continued throughout. 

In cases where a trauma presentation results in a cardiorespiratory arrest in a pregnant woman, resuscitation should follow the standard basic and advanced life support guidelines with three important modifications:

• immediate positioning of the pregnant trauma patient in a left lateral tilt of 15–30 degrees
• consideration of early intubation by an experienced airway clinician
• performing a perimortem caesarean section if there is no response to resuscitation within four minutes.

An emergency (perimortem) caesarean section is considered part of the resuscitation protocol for cardiorespiratory arrest in a pregnant patient. CPR should be continued throughout. To provide any benefit, perimortem caesarean section should be commenced four minutes after the loss of maternal cardiac output, and delivery should be achieved by five minutes. This is a highly stressful and extremely rare situation. 

The aim of delivery by caesarean section is to empty the uterus and therefore restore perfusion to vital maternal organs, improving the chances of maternal survival. Since the tolerance of the fetus to reduced blood flow and hypoxia is significantly less than that of the mother, this may also be the only chance for fetal survival. Emergency (perimortem) caesarean section therefore improves the chance of a successful resuscitation for both the mother and child. This is a decisive moment for responding teams and should be made in conjunction with appropriately qualified personnel with skilled support staff and appropriate equipment.

Blood matters

In the absence of cross matched blood, Rhesus negative blood and blood products should be administered. Where possible, for red cell and platelet transfusions the units should be CMV, Kell (K) and Duffy (Fya) negative. A blood group and antibody screen should also be performed to determine the maternal blood type and Rhesus antibody status, and to assess for the presence of any pre-formed anti-D antibody.  

Rhesus isoimmunisation and the use of anti-D ¹⁶

All Rhesus negative women should be given a dose of Anti-D appropriate for their gestation within 72 hours of a sensitising event. If a dose has been missed, some benefit may still be obtained up to 10 days post event and Anti-D should also be offered in these circumstances.  Rhesus positive women do not require Anti-D. A small number of women will have pre-existing antibodies and have already been isoimmunised – these women also do not require Anti-D. 

The recommended doses of anti-D are:
250 IU (50 mcg) for women 12 or fewer weeks’ gestation
625 IU (125 mcg) for women at 12 or more weeks’ gestation.

Any abdominal trauma may cause an injury which allows for exchange of maternal and fetal blood, and is considered to be a sensitising event. Ideally, a maternal blood sample should be taken prior to administration of Anti-D and sent for a Kleihauer test to measure the volume of fetal blood present in the maternal circulation. A Kleihauer test may still be useful in Rhesus positive women, as it can provide evidence of maternal-fetal haemorrhage where an abruption is suspected but cannot be seen on ultrasound or where bleeding is not revealed. 
Anti-D is more effective the sooner it is given and administration of the first dose should not be delayed to await the results of the Kleihauer test, which can take some time. The Kleihauer test results are most useful for determining whether more than one dose is subsequently required.

Reassess

The importance of frequent reassessment cannot be overemphasised. Deterioration in a pregnant patient can be rapid, leading to catastrophic haemorrhage, shock and other complications if not identified early. Patients should be re-evaluated at regular intervals as guided by the patient’s condition.

If in doubt about any aspect of a patient’s condition, repeat the primary survey and assessment.