Pregnant trauma patients

Learning objectives

Trauma is the leading cause of nonobstetric mortality and affects 7% of all pregnancies
The most common traumatic injuries are motor vehicle crashes, assaults, falls, or partner violence
Major trauma has been associated with 7 percent of maternal and 80 percent of fetal mortality
Placental abruption is the most common cause of fetal death:
- First trimester: the thick-walled uterus is protected from trauma by the pelvic girdle
- Second trimester: the fetus is protected by relatively abundant amniotic fluid volume
- Third trimester: the thin-walled uterus is exposed to blunt and penetrating abdominal trauma
Pregnant trauma patients should be approached and managed like any other trauma patient using a standard ABCD approach
Clinical decision-making is complicated by:
- The needs of both mother and fetus must be considered
- Anatomical and physiological changes in pregnancy can mask or mimic injury
- Life-threatening obstetric complications can occur even after seemingly minor trauma and may require urgent delivery of the fetus
- Fetal injury can predominate of that the mother
Establishing maternal stability may not be possible without obstetric intervention

System	Changes	Implications
Pulmonary system	↑ Tidal volume The respiratory rate is unchanged ↓ FRC ↑ Oxygen consumption ↑ Minute ventilation ↓ Arterial CO2 tension ↓ Thoracic compliance Elevated diaphragm	Apply supplementary oxygen to avoid hypoxia Consider desaturation Bag mask ventilation may be difficult Place chest drains higher (3rd or 4th intercostal space)
Airway	↑ Airway edema ↑ Vascular engorgement ↑ Tissue friability ↑ Breast size and neck adiposity ↑ Aspiration risk	Difficult intubation Consider cricoid pressure insert early NGT
Cardiovascular system	↑ Plasma volume (40-50%) ↑ Heart rate (15-25%) ↑ Cardiac output (50%) ↓ SVR (20%)	Increased blood volume may initially mask the shock Supine hypotension due to IVC compression may reduce CO
Hematological changes	Hypercoagulability Anemia Thrombocytopenia ↑ Factors VII, VIII, IX, X, XII, von Willebrand, and fibrinogen ↓ aPTT, PT, and INR	All Rhesus-negative mothers should receive anti-D within 72 hours of injury Consider rhesus status when initiating blood product transfusion
Renal system	↑ Renal blood flow ↑ Glomerular filtration rate (60%) ↓ Serum creatinine and bicarbonate
Gastrointestinal system	↓ Esophageal sphincter tone Cephalad displacement of the stomach ↑ Intra-gastric pressure Delayed gastric emptying	Perform early gastric decompression with NGT The bladder becomes an intra-abdominal organ after 1st trimester Other abdominal organs are displaced by the uterus

Discharge criteria:

Resolution of contractions
A reassuring fetal heart tracing
Intact membranes
No vaginal bleeding
No uterine tenderness
Administer Rh immune globulin therapy to all Rh-negative patients unless the injury is remote from the uterus