Pregnancy

General principles

• Excellent maternal resuscitation is the best treatment for the fetus
• While fetal radiation exposure is an important consideration – this needs to be balanced with investigations which are in the best interests of the mother
• Even seemingly minor mechanisms (eg: fall from standing, low speed RTC) can cause placental abruption and significant blood loss
• The altered anatomy and physiology in pregnancy can conceal clues to potentially life-threatening injuries
• Early involvement of the gynaecology/obstetric and neonatology teams is essential especially if potentially viable or suspicion of complication.
  • Consult local policy regarding the gestational cut-off for gynae vs obstetric review, usually around  20/40 gestational age, which can be estimated by a fundal height above the umbilicus (below umbilicus likely <20/40), or by using or USS to measure the fetal head biparietal diameter,  >6cm is likely to be viable
  • Any history of post traumatic PV bleeding or amniotic fluid loss, abdominal pain/contractions
• Anti-D must be administered to rhesus negative pregnant  trauma patients (even with minor trauma). Kleihauer test allows dose titration.
• Domestic violence is an important cause of trauma in pregnancy

 

Important additional features on history

• Mechanism of injury
  • If in RTC, type of restraint and where placed in relation to uterus
    • Lap belts worn over high the uterus increases the risk of placental abruption
  • Consider domestic violence as a cause of the injuries

Initial treatment considerations

Airway/breathing

• Due to a decreased respiratory reserve, hypoxia can develop more rapidly. Place supplemental oxygen early
• Intubation can be more challenging due to rapid desaturation, airway oedema, breast enlargement, and increased gastric pressures leading to aspiration risk
• In later pregnancy, the diaphragm will be elevated due to uterine displacement. Therefore, if an intercostal catheter is to be placed, it should be done in the 3^rd or 4^th intercostal space.

Circulation

• Left lateral uterine displacement is an essential element in the resuscitation of the pregnant woman (>20/40) by relieving pressure off the aorto-caval vessels. This can be achieved by
  • Manual displacement by an assistant
  • 30 degree wedge under patient’s right side (tilt patient to left)

 

• Pregnancy is a relatively hypervolaemic state, so significant blood loss can occur before usual clinical signs (hypotension, tachycardia) are apparent
  • However: note that a mild tachycardia and a lower BP are normal vital signs, especially in later pregnancy (as well as a dilutional anaemia)

 

• Placental abruption can occur even with minor injury and can result in significant blood loss (>2-4 litres) and fetal demise. It is usually heralded by abdominal pain, uterine firmness and PV bleeding but can be asymptomatic. Uterine rupture is usually caused by higher force mechanisms and can also result in major haemorrhage.

 

• If cardiac arrest occurs, early consideration of a resuscitative caesarean section is essential if the gestation is >20/40 (note that even if the fetus not viable, relief of aortocaval pressure can result in improved maternal circulation). Ideally this should be performed within 5 minutes after the onset of cardiac arrest.

 

Investigations

Blood tests

• standard trauma blood tests
• if rhesus negative, perform a Kleihauer test in order to ascertain the amount of anti-D to administer

CTG

• if >26 weeks, CTG monitoring should be performed for at least 4 hours even if the trauma is seemingly minor in order to detect placental abruption (as well as the onset of labour)
  • 24-26/40 CTG can be difficult to interpret so prolonged fetal heart beat auscultation is recommended, involve midwifery

Radiology

• major trauma patients with significant injuries should have all imaging performed as indicated , including CT. CT is the most sensitive imaging for placental abruption. Even with multi-regional CT the radiation dose is below that at which observable fetal effects have been recorded.
• in patients that are less severely injured, other imaging modalities may be appropriate in the first instance eg: MRI, USS, plain xrays
  • decisions should be made in conjunction with surgery and radiology
• fetal shielding should be used where appropriate eg: for CXR, and decreased radiation doses utilised if possible
• The sensitivity of a FAST scan is similar to non-pregnant patients, though there may be higher rate of false positives due to misinterpretation of amniotic fluid as free fluid.