What is the appropriate management of a 27-week-gestation pregnant woman involved in a motor vehicle accident?

Management of a 27-Week Pregnant Woman Following Motor Vehicle Accident

Immediate Resuscitation and Stabilization

Maternal stabilization is the absolute priority, as the best hope for fetal survival is maternal survival. 1, 2

Primary Survey - Airway and Breathing

• Administer 100% oxygen immediately to maintain maternal oxygen saturation >95%, as pregnant women have reduced oxygen reserves and increased metabolic demands 1, 3
• Insert a nasogastric tube if the patient is semiconscious or unconscious to prevent aspiration of acidic gastric content, as pregnancy increases aspiration risk 3
• Consider early intubation if airway compromise is suspected; use a 6.0-7.0mm inner diameter endotracheal tube (smaller than standard due to airway edema in pregnancy) 1
• If thoracostomy is needed, insert the chest tube 1-2 intercostal spaces higher than usual due to elevated diaphragm 3

Circulation and Hemodynamic Management

• Place two large-bore (14-16 gauge) IV lines above the diaphragm 1, 3
• Position the patient supine initially for assessment, then perform manual left uterine displacement by pulling the uterus to the left to relieve aortocaval compression, as the gravid uterus at 27 weeks can reduce cardiac output by 30% 1, 2, 4
• Avoid left lateral tilt positioning if spinal injury is suspected; instead use manual uterine displacement 3
• Aggressively resuscitate with IV fluids; maternal hypotension (systolic BP <100 mmHg or <80% of baseline) reduces placental perfusion 1, 3
• Use vasopressors only for intractable hypotension unresponsive to fluid resuscitation, as they adversely affect uteroplacental perfusion 3
• If blood transfusion is needed and patient is Rh-negative, use O-negative blood until cross-matched blood is available 3

Diagnostic Evaluation

Maternal Assessment

• Perform all medically indicated radiographic studies including CT scans without delay; fetal radiation exposure from typical trauma CT is well below thresholds for adverse effects (<50 mGy) 2, 3, 5
• Use CT with IV contrast (preferred over non-contrast) for detecting visceral organ and vascular injuries 2
• Perform focused abdominal sonography for trauma (FAST) to detect intraperitoneal bleeding, though it is specific but not sufficiently sensitive to exclude hemorrhage 3, 6, 7
• Order coagulation panel including fibrinogen in addition to routine trauma labs 3

Fetal Assessment

• Initiate continuous electronic fetal heart rate monitoring for at least 4-6 hours, as this is required for all pregnant trauma patients ≥23 weeks gestation, even after minor trauma 1, 2, 3, 5
• Extend monitoring to 24 hours if any high-risk features are present: uterine tenderness, vaginal bleeding, sustained contractions (>1 per 10 minutes), rupture of membranes, abnormal fetal heart rate pattern, or fibrinogen <200 mg/dL 1, 2, 3
• Perform obstetrical ultrasound to assess gestational age, fetal viability, placental location, and amniotic fluid volume 3, 5
• Defer speculum or digital vaginal examination until placenta previa is excluded by ultrasound if vaginal bleeding is present 3

Rh Status Management

• Administer anti-D immunoglobulin to all Rh-negative pregnant trauma patients 2, 3, 5
• Perform Kleihauer-Betke testing to quantify maternal-fetal hemorrhage and determine if additional doses of anti-D immunoglobulin are needed 3, 5

Obstetrical Complications to Monitor

Placental Abruption

• Do not delay management of suspected placental abruption waiting for ultrasound confirmation, as ultrasound is not sensitive for this diagnosis 3
• Clinical signs include vaginal bleeding, uterine tenderness, sustained contractions, abnormal fetal heart rate patterns, and coagulopathy 3

Uterine Rupture

• Suspect with severe abdominal pain, abnormal fetal heart rate, palpable fetal parts, or hemodynamic instability 3
• Requires urgent obstetrical consultation 3

Cardiac Arrest Management (If Occurs)

If maternal cardiac arrest occurs, prepare for perimortem cesarean delivery (PMCD) immediately upon recognition of arrest. 1, 2

• Place patient supine on firm surface and begin standard chest compressions with hands slightly higher on sternum than usual 1
• Perform continuous manual left uterine displacement while maintaining supine position 1, 4
• Summon resources for PMCD immediately; if no return of spontaneous circulation (ROSC) by 4 minutes, begin PMCD at the site of arrest without transporting to operating room 1, 2, 4
• Maternal survival has been reported up to 15 minutes after cardiac arrest onset; neonatal survival documented with delivery up to 30 minutes after arrest 1, 2

Disposition

Transfer Considerations

• Transfer to a facility with obstetrical capabilities when injuries are neither life- nor limb-threatening and fetus is viable (≥23 weeks) 3
• Transfer to trauma center if injuries are major, regardless of gestational age 3
• Maintain low threshold for transfer to tertiary care center, as even minor trauma correlates with adverse fetal and maternal outcomes 7

Admission Criteria

• Admit for 24-hour observation if any adverse factors present: uterine tenderness, significant abdominal pain, vaginal bleeding, sustained contractions, ruptured membranes, abnormal fetal heart rate, high-risk mechanism of injury, or fibrinogen <200 mg/dL 3

Critical Pitfalls to Avoid

• Do not defer or delay medically indicated imaging due to fetal radiation concerns 2, 3, 5
• Do not use military anti-shock trousers with abdominal portion inflated, as this reduces placental perfusion 3
• Do not rely on normal maternal vital signs to exclude significant hemorrhage; pregnant women can lose 30-35% of blood volume before showing signs of shock due to increased plasma volume 8
• Do not assume minor trauma is benign; minor trauma contributes to the majority of fetal mortality 8