Trauma in a pregnant patient

Trauma in Pregnancy

1. Description of the problem

What every clinician should know

Although diagnostic modalities and treatment priorities and options are similar for pregnant women with trauma, examination of the pregnant woman with chest and/or abdominal trauma will be complicated by the presence of a large gravid uterus.

Initial assessment and resuscitation of the pregnant patient with trauma should follow standard trauma protocols, including radiographic studies.

Early fetal monitoring is mandated even after minor trauma if the fetus is viable (>24 weeks gestation).

Clinical features

Changes typically consistent with hemorrhagic shock:

Hypotension

Tachycardia and tachypnea

Oliguria

Pale skin and diaphoresis

Altered level of consciousness: be aware that neurologic symptoms of eclampsia may mimic signs and symptoms of head injury

Key management points

Optimal management of the pregnant trauma patient is the best way to improve fetal outcome.
Diagnostic modalities and treatment priorities and options for the pregnant patient with traumatic injury are the same as those for nonpregnant patients.
Pregnant patients with major traumatic surgical injuries should be admitted to hospitals with surgical obstetric resources.
Fetal risks from radiation and medication exposure are highest early in the pregnancy (during the 1st trimester).
Risk of direct trauma to the fetus is directly correlated to the gestational age because of the increasing size of the uterus and fetus.
Fetal viability occurs >24 weeks gestation, at which time resuscitation of both the mother and the fetus are prioritized.

2. Emergency Management

Stabilizing the patient

Whenever possible, and If there is no evidence for spinal cord injury, pregnant patients, particularly those in their 2nd and 3rd trimesters, should be placed in the left lateral decubitus position to avoid aortocaval compression by the gravid uterus while supine and further compromise of maternal hemodynamics.
Manual displacement of the gravid uterus can also be performed as well as raising the right hip with a Cardiff wedge or pillow to displace the uterus off the inferior vena cava.
If spinal injury is suspected, spinal alignment should be maintained and the patient is log-rolled.
A minimum of 4 to 6 hours of fetal monitoring is required even after relatively minor trauma to the mother because of delayed uterine irritability and subsequent risk to the fetus resulting in abruptio placentae and/or fetal demise.

Management points not to be missed

Adequate hemodynamic and respiratory resuscitation

Treat all pregnant patients as “full stomach” patients if bag-valve-mask ventilation and intubation are required. Use rapid sequence induction with cricoid pressure. Cricoid pressure should be used during both mask ventilation and intubation.
Stabilization of the mother with fluid and blood product resuscitation using standard trauma protocols
Stabilization of the mother at the bedside with immediate treatment modalities, such as placement of central venous lines for resuscitation, placement of chest tubes for hemo- or pneumothorax, and diagnostic peritoneal lavage (DPL), among others
Continuous fetal monitoring if >24 weeks gestation
Radiographic studies necessary for specific traumatic injury diagnosis
Multidisciplinary team management of the obstetricians with appropriate surgical and critical care expertise
Emergent cesarean section may be required if there is evidence of fetal instability and compromise. The cesarean section cannot delay appropriate surgical management of the mother if required.

Drugs and dosages

Definitive Therapy

Expectant management, medical management, and/or surgical management depending on the type of traumatic injury

The indications for surgery for most types of traumatic injury are similar for pregnant and nonpregnant patients.

Management of pregnant patients with traumatic injuries below the uterine fundus is somewhat controversial. Expectant management has been advocated, with close monitoring of maternal vital signs and fetal heart tracings and no evidence of intra-abdominal hemorrhage.

If the mother is Rh-negative, a single intramuscular dose of 300 micrograms (1500 IU) Rh°(D) immune globulin (RhoGAM) should be given within 72 hours of injury, even when the antecedent trauma is mild.

For postoperative patients, a single dose of antibiotics should be given prophylactically to cover aerobic and anaerobic organisms. Continue antibiotics for 24 hours if there has been a hollow viscus injury.

Tetanus prophylaxis should be given intramuscularly after penetrating traumatic injuries with 0.5 mL of tetanus toxoid and 250 units of tetanus immune globulin (TIG).

3. Diagnosis

Initial Survey

Assessment of the adequacy of airway, breathing, and circulation
Screen all patients of child-bearing age for possibility of pregnancy with measurement of the beta-human choriogonadotropin test.
If pregnancy is documented, perform assessment of the fetal heart tones with a fetoscope or a Doppler fetoscope. May be difficult to differentiate between maternal and fetal heart tones with a stethoscope if the mother is tachycardic. Normal fetal heart rates are between 120 to 150 beats/minute. Bedside ultrasonography can be used for documenting fetal cardiac activity and function.
Perform a brief but focused external physical examination of the mother.
Chemistry and hematologic laboratory tests should be sent initially.

Secondary Survey

Conduct a more detailed and comprehensive physical examination of the patient.
Evaluate uterine irritability (uterine spasms), fetal heart rate, and fetal movement.
Pelvic examination may be necessary if there is any blood seen coming from the vagina. Should evaluate for the presence of blood or amniotic fluid, cervical effacement, dilation, and fetal station.
Ideally, a sonographic exam is done prior to the manual exam to exclude undiagnosed placenta previa.
Follow-up hematologic laboratory indices depending on the extent of injury and hemorrhage
The Kleihauer-Betke (KB) stain is used to assess the amount of fetal red blood cells in the maternal circulation.
pH levels of 7 to 7.5 suggest the presence of amniotic fluid using Nitrazine paper.

Radiographic tests

Standard initial chest, abdominal, and pelvic radiographs should be ordered initially.

Fetal risks highest at < 15 weeks gestation

Low to moderate teratogenic and oncogenic risks to the fetus with standard chest and abdominal radiographs, including computed tomography scanning

If possible, always shield the abdomen and pelvis.

The need for follow-up radiographic studies will depend on the the initial radiographic results and the possible need for operative intervention.
Ultrasonography, diagnostic peritoneal lavage (DPL), and the focused abdominal sonogram (FAST) for trauma are all acceptable diagnostic modalities. With both the DPL and the FAST examinations, it is important to remember that there is superior displacement of the abdominal organs because of the enlarged uterus, and probe placement should be assessed appropriately.

Pathophysiology

Due to the relative hypervolemic state associated with normal pregnancy, the pregnant patient can lose up to 35% of her blood volume before significant tachycardia, tachypnea, hypotension, and other signs of hypovolemia are seen. The fetus may be significantly hypoperfused although maternal vital signs may be apparently normal.
Mechanisms of traumatic injuries are similar in pregnant and nonpregnant patients, although gastrointestinal injuries are less frequent as the uterus enlarges.
Pregnant patients experience many anatomic and physiologic changes that may significantly affect anatomic injury patterns and the response to injury.

The normal respiratory changes associated with pregnancy, with a decrease in the functional residual capacity by 25% and an increase of up to 30% in oxygen consumption, decrease the respiratory reserve of the mother and increase the hypoxic risk to both the mother and fetus in response to maternal hypoventilation or apnea.

Although blood volume may be increased up to 50% by 28 weeks of gestation, red blood cell mass does not increase proportionately, resulting in a relative physiologic anemic state.

Coagulation factors and fibrinogen levels increase in preganncy and plasminogen activator levels decrease, thereby increasing the risk of venous thromboembolism.

Trauma to the gravid uterus can result in the release of thromboplastic factors that lead to disseminated intravascular coagulation (DIC).
Height of the uterus is at the symphysis pubis at 12 weeks gestation and the umbilicus at 20 weeks, and increases by 1 cm weekly up to the 36th to 40th week of gestation. Late in pregnancy, a widened symphysis pubis and sacroiliac joints may be seen. The risk of direct trauma to the uterus is highest after 12 weeks gestation, since the uterus is now intra-abdominal.
When shearing forces from traumatic injuries are applied to the developing uterus, abruptio placentae often results with fetal hypoxemia, acidosis, and fetal death.
Cephalad displacement of the abdominal contents and upward dispalcement of the urinary bladder result from the enlarging uterus.

Epidemiology

Trauma is the most common non-obstetric cause of death in pregnant women, accounting for 46% of maternal deaths.
5% to 7% of all pregnancies in the United States are complicated by trauma.
Most common cause of trauma in pregnancy is blunt trauma.

Motor vehicle accidents account for 55% to 70% of cases, assaults for 11% to 21% of cases, and falls for 9% to 22%.
Penetrating abdominal trauma often results in uterine injury because of the enlarging uterus in the intra-abdominal compartment.

60% to 70% of gunshot wounds to the pregnant abdomen result in fetal injury, with fetal mortality rates as high as 65%.

Penetrating trauma to the upper abdomen often damage small and large bowel loops.
Most common causes of maternal death are from head injury and hemorrhagic shock, which results in a fetal mortality rate of up to 80%.
Most common causes of fetal death from maternal trauma are:

Maternal hemorrhagic shock

Abruptio placentae

Uterine rupture

Maternal pelvic fracture(s) in late pregnancy, when the fetal head is in the pelvis
Prognosis of both the mother and the fetus depends on many factors, such as the mechanism and severity of the injuries.

Highest fetal mortality is seen in < 28 weeks gestation.

Maternal and fetal mortality is highest with internal injuries to the thorax, abdomen, and pelvis.
Maternal and fetal complications of trauma in pregnancy

Maternal hemorrhagic shock

Abruptio placentae

Amniotic fluid embolism

Premature labor

Uterine rupture

Fetal demise

Emergent cesarean section indicated for fetal distress, abruptio placentae, and uterine rupture

Maternal cardiac arrest

Maternal head trauma – continuing life support in head-injured and brain-dead patients has been sustained for safe delivery of a viable fetus at a later time.

What's the evidence?

Cusick, SS, Tibbles, CD. “Trauma in pregnancy”. Emerg Med Clin North Am. vol. 25. 2007. pp. 861-72.

Brent, RL. “Saving lives and changing family histories: appropriate counseling of pregnant women and men and women of reproductive age, concerning the risk of diagnostic radiation exposure during and before pregnancy”. Am J Obstet Gynecol. vol. 200. 2009. pp. 4-24.

Weiss, HB, Songer, TJ, Fabio, A. “Fetal deaths related to maternal injury”. JAMA. vol. 286. 2001. pp. 1863-8.

Ikossi, DG, Lazar, AA, Morabito, D. “Profile of mothers at risk: an analysis of injury and pregnancy loss in 1,195 trauma patients”. J Am Coll Surg. vol. 200. 2005. pp. 49-56.

“American College of Obstetricians and Gynecologists. Obstetric aspects of trauma management”. ACOG Educational Bulletin #251. 1998.

Schiff, MA, Holt, VL. “The injury severity score in pregnant trauma patients: Predicting placental abruption and fetal death”. J Trauma. vol. 53. 2002. pp. 946-9.

Kady, DE, Gilbert, WM, Anderson, J. “Trauma during pregnancy: an analysis of maternal and fetal outcomes in a large population”. Am J Obstet Gynecol. vol. 190. 2004. pp. 1661-8.

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