The primary initial goal in treating a pregnant
trauma victim is to stabilize the mother's condition. The priorities
for treatment of an injured pregnant patient remain the same as those
for the nonpregnant patient.
As with any other injured patient, the primary survey of the injured
pregnant patient addresses the airway/cervical spine control, breathing
and circulation (ABC; volume replacement/hemorrhage control), with
the mother receiving treatment priority. Supplemental oxygen is
essential to prevent maternal and fetal hypoxia. Severe trauma stimulates
maternal catecholamine release, which causes uteroplacental vasoconstriction
and compromised fetal circulation. Prevention of aortocaval compression
is also essential to optimize maternal and fetal hemodynamics. Pregnant
patients beyond 20 weeks' gestation should not be left supine during
the initial assessment. Left uterine displacement should be used
by tilting the backboard to the left or as a final measure, the
uterus can be manually displaced.
Hypovolemia should be suspected before it becomes apparent because
of the relative pregnancy induced hypervolemia and hemodilution
that may mask significant blood losses. Aggressive volume resuscitation
is encouraged even for normotensive patients. The pneumatic antishock
garment (PASG) may be used to stabilize lower extremity fractures
and perhaps control hemorrhage. In the pregnant patient, inflation
of the abdominal compartment of the PASG should be avoided because
if compromises uteroplacental blood flow.
The secondary survey consists of obtaining a complete history, including
an obstetrical history, performing a physical examination, and evaluating
and monitoring the fetus. The obstetrical history is important because
the identification of comorbid factors may alter management decisions.
A history of preterm labor or placental abruption puts the patient
at increased risk for the recurrence of the condition. The obstetrical
history should include the date of the last menstruation, expected
date of delivery and any problems or complications of the current
and previous pregnancies. Determination of the uterine size provides
an approximation of gestational age, i.e. measurement of fundal
height is a rapid method for estimating fetal age. Determination
of fetal age and hence of fetal maturity is an important factor
in the decision approach regarding early delivery.
The fetus is usually considered viable when it has a 50% chance
of extrauterine survival. If neonatal facilities are available,
this usually means at 25 to 26 weeks' gestation or an estimated
weight of 750 g. More aggressive institutions use 24 weeks' gestation
or an estimated weight of 500 to 600 g as the cut-off point, although
chances of survival are then reduced to 20 to 30%. It should be
noted that, even with the best of ultrasound dating criteria, unless
the time of conception is known exactly, the assignment of gestational
age is subject to 1 to 2 weeks of uncertainty. Decisions on fetal
viability are made on the basis of the best gestational age available.
When estimating the fetal age in the resuscitation area, a rough
guide might be that when the fundus of the uterus extends beyond
the umbilicus, the fetus is potentially viable.
Pelvic and rectal examinations should be performed. Aside from
the usual secondary survey, assessment of the injured pregnant patient
should rule out vaginal bleeding, ruptured membranes, a bulging
perineum, the presence of contractions, and an abnormal fetal heart
rate and rhythm.
Fetomaternal hemorrhage (FMH), the transplacental hemorrhage of
fetal blood into the normally separate maternal circulation, is
a unique complication of trauma during pregnancy. The reported incidence
of FMH after trauma is 8 to 30%. There is no real correlation between
severity of trauma, gestational age and frequency and volume of
FMH. Complications of FMH include Rh sensitization in the mother,
fetal anemia, fetal paroxystic atrial tachycardia or fetal death
from exsanguination. In theory, FMH is possible by the 4th week
of gestation; some say that FMH becomes a concern after 12 weeks
gestation when the uterus rises above the pelvis and becomes an
organ susceptible to direct trauma. FMH is detected by the Kleihauer-Betke
(KB) acid elution technique on maternal blood. Upon examination,
adult cells remain colorless while fetal red cells turn bright purple-pink.
The ratio of fetal cells to maternal cells is recorded, enabling
calculation of the volume of fetal blood leaked into the maternal
Most clinical laboratories will screen 1000 red blood cells taken
from the mother. A maternal blood volume of 5 liters is commonly
assumed in laboratory formulas so that one fetal cell per 1000 cells
counted corresponds to a FMH of 5 ml. Unfortunately, the amount
of FMH sufficient to sensitize most Rh-negative women is well below
the 5-ml sensitivity level of the typical laboratory's KB test.
As little as 1 ml of Rh-positive blood can sensitize 70% of Rh-negative
women. Currently, several commercial kits expedite and simplify
the test process. Unfortunately, the sensitivity of all the KB test
is relatively low. Therefore, all Rh-negative mothers who present
with a history of abdominal trauma should receive one 300-ug prophylactic
dose of Rh immune globulin (anti-D immunoglobulin; Rhogam) within
72 hours of the traumatic event. Although controversial, we believe
that the KB test should be reserved for Rh-negative women who are
at risk for massive FMH that will exceed the efficacy of one dose
of immune globulin, i.e. more than 30 ml. According to some studies,
fewer than 1% of all trauma cases and only 3.1% of major trauma
cases exceed the coverage of one 300-ug Rh immune globulin dose.
As a general rule, 300 ug of Rh immune globulin should be given
for every 30 ml of fetal blood found in the maternal circulation.
The KB test is probably unnecessary before 16 weeks' gestation because
the fetal blood volume is below 30 ml before this gestational age.
For cases of documented FMH, some studies recommend repeating the
KB test in 24 hours to check for increased bleeding.
Fetal evaluation begins with checking fetal heart rate and noting
fetal movement. Fetal heart tones can be detected by auscultation
or doppler probe. This should be done early in the secondary survey
and repeated frequently. The normal range for the fetal heart rate
is 120 to 160 beats/minute. Continuous electronic fetal heart-rate
monitoring (EFM) remains the most widely used modality for evaluation
of the fetus, and is an adjunct to the monitoring of the maternal
condition. The use of EFM permits prompt identification of the fetus
at great risk for asphyxia and fetal death. Any viable fetus of
24 or more weeks' gestation requires monitoring after a trauma event.
This includes patients with no obvious signs of abdominal injury
because direct impact is not necessary for fetoplacental pathology
to be present.
Controversy exists concerning the duration of fetal monitoring
following a traumatic event to identify potential trauma-related
fetal problems. The objective of the monitoring period is to identify
premature labor, abruptio placenta and fetal distress. The combination
of high-resolution real-time ultrasonography and cardiotocographic
monitoring seems to have the highest sensitivity and specificity.
They should both be instituted as soon as feasible without interfering
with maternal resuscitative efforts.
The most common obstetric problem caused by trauma is uterine
contractions. Myometrial and decidual cells, damaged by contusion
or placental separation, release prostaglandins that stimulate uterine
contractions. Progression to labor depends upon the size of uterine
damage, the amount of prostaglandins released, and the gestational
age of the pregnancy. Some studies question the routine use of tocolytics
for premature labor after trauma because the majority (90%) of contractions
stop spontaneously and those contractions that are not self-limited
are often pathological in origin, thus, contraindications to tocolytic
Placental abruption after trauma occurs in 2 to 4% of minor accidents
and in up to 50% of major injuries. Separation results as the inelastic
placenta shears away from the elastic uterus during sudden deformation
of the uterus. Abruption can occur with little or no external signs
of injury to the abdominal wall. Maternal mortality from abruption
is less than 1%, but fetal death ranges from 20 to 35%. Clinical
findings that indicate abruption include vaginal bleeding, abdominal
cramps, uterine tenderness, amniotic fluid leakage, maternal hypovolemia,
a uterus larger than normal for the gestational age, or a change
in the fetal heart rate. When present after trauma, vaginal bleeding
is a ominous sign often indicative of placental separation. The
first-line test to try to confirm the presence of abruption is the
transabdominal ultrasound. Unfortunately, it is less than 50% accurate.
In general, cardiotocographic monitoring is more sensitive in picking
up placental abruption by fetal distress than ultrasound is by visualization.
Most cases of abruption become evident within several hours after
trauma. Cardiotocographic monitoring should be started in the resuscitation
room and continued for a minimum of 4 hours. A minimum of 24 hours
of cardiotocographic monitoring is recommended for patients with
frequent uterine activity ( more than 6 contractions per hour ),
abdominal or uterine tenderness, ruptured membranes, vaginal bleeding,
or hypotension. For patients without any of these signs or symptoms,
normal findings on the cardiotocographic monitor for at least 4
hours duration and a normal ultrasound, discharge may be considered.
Fetal distress is associated with placental abruption 60% of the
time and immediate intervention is required.
In the trauma setting, ultrasound may help identify other problems
related to the maternal event besides placental abruption such as
cord prolapse and placenta previa. It is also routine to evaluate
the fetus for gestational age, cardiac activity and movement. If
time permits, a complete biophysical profile may be performed.
Diagnostic Modalities/Radiation Exposure
Following maternal stabilization and assessment, and fetal evaluation,
the extent of maternal and fetal injury is determined with the help
of specific diagnostic modalities. Sensitivity to radiation is greater
during intrauterine development than at any other time of life.
Although there is much concern about radiation exposure, a diagnostic
modality deemed necessary for maternal evaluation should not be
withheld on the basis of its potential hazard to the fetus.
The fetal dose of radiation received in individual cases may vary
by a factor of 50 or more, depending on the equipment used, technique
used, number of radiographs done in a complete study, maternal size,
and fetal/uterine size. In general, x-ray beams aimed more than
10 cm away from the fetus are not dangerous.
The major effects of exposure to the fetus include congenital
malformations, growth retardation, postnatal neoplasia, and death.
In the first week of life, before implantation, the embryo is very
sensitive to lethal effects of radiation but has a low probability
of sustaining teratogenic or growth-retarding effects if it is able
to implant and grow. During major organogenesis of the 2nd to 7th
weeks, the embryo is sensitive to the teratogenic, growth-retarding,
lethal, and postnatal neoplastic effects of radiation. Organs are
less sensitive to radiation teratogenesis in the 8th to 40th weeks,
but growth retardation, central nervous system dysfunction, and
postnatal neoplastic effects may occur. Studies show that exposure
of the fetus to less than 5 to 10 rad (5000 to 10000 mrad) causes
no significant increase in the risk of congenital malformations,
intrauterine growth retardation, or miscarriage. Although this does
not mean that there are definitely no risks in exposures less than
5 rad, it does mean that this level of radiation carries little
risk for the fetus when compared to spontaneous risks. At a radiation
dose of 15 rad, there is approximately a 6% chance that the child
could develop severe mental retardation, a less than 3% chance of
developing childhood cancer, and a 15% chance of having a small
When performing radiographic evaluation of the mother, fetal irradiation
should be minimized by shielding the abdomen when feasible with
a lead apron. When many radiographs are required over a long period,
a thermoluminescent dosimeter may be attached to the patient to
serve as a guide to the dosage of radiation delivered. As a guide
to physicians, reports from some studies indicate that the radiation
dose from a plain AP chest x-ray is in general below 0.005 rad,
a pelvic film below 0.4 rad, CT-scan of the head (1-cm slices) 0.05
rad, CT-scan of the upper abdomen (20 1-cm slices) below 3.0 rad
and CT-scan of the lower abdomen (10 1-cm slices) 3.0 to 9.0 rad.
Blunt Abdominal Trauma
There are several important considerations
when addressing blunt thoracoabdominal trauma in the pregnant patient.
The physical examination may be unreliable because the enlarged uterus
displaces the abdominal content and stretches the peritoneum thus
perhaps diminishing the response to peritoneal irritation. The evaluation
of possible injury to the abdomen is different because of the presence
of the gravid uterus. The preferred diagnostic modalities for evaluation
during the first trimester of pregnancy are ultrasound, diagnostic
peritoneal lavage (DPL), and CT-scan, in that order. Because the first
trimester is the period of organogenesis, ultrasound is preferable
for the detection of hemoperitoneum. Because of its sensitivity, DPL
can be used to evaluate the abdomen using the supraumbilical, open
technique to avoid injury to the gravid uterus. The major disadvantage
of DPL with respect to the pregnant patient is its invasiveness. If
CT-scan is necessary, both oral and intravenous contrast media should
be administered. During the second trimester, ultrasound or CT-scan
may be used to evaluate the abdomen. DPL may be difficult to perform
because the enlarged uterus may interfere with the dependent catheter
position and return of fluid. On the other hand, several studies have
shown its safety and usefulness. During the third trimester, the injured
pregnant patient can best be assessed by ultrasound or CT-scan.
Although motor vehicle accidents are the most common cause of
serious blunt trauma in pregnancy, assaults, abuse and falls are
frequent. In addition to maternal mortality from blunt trauma, which
is estimated to be about 7%, the fetus is at significant risk, especially
if placental abruption, placenta previa, or uterine rupture occur.
Penetrating Thoracoabdominal Trauma
As mentioned before, as pregnancy progresses,
intra-abdominal organs change position, with important implications
(Figure 1). Because the bowel is pushed upward by the enlarged uterus,
penetrating injury to the upper part of the abdomen is more likely
to be associated with multiple gastrointestinal injuries. Organs involved
in decreasing frequency are the small bowel, liver, colon, and stomach.
During the third trimester, injuries to the lower quadrants of the
abdomen almost exclusively involve the uterus. This may be advantageous
to the mother because the uterus and amniotic fluid absorb most of
the energy of the missile, resulting in less destruction to other
organs. If the uterus is involved in penetrating trauma, fetal injury
may occur in 60 to 90% of cases. Gunshot wounds to the uterus carry
a maternal mortality of 7 to 9% and a fetal mortality of around 70%.
Fetal mortality is higher if injury is caused before 37 weeks of gestation.
When evaluating the pathway of a bullet, radiographs (anteroposterior
and lateral views) of the chest and abdomen, with the entrance and
the exit wounds marked with paper clips may help the physicians.
Some controversy exits but the prevailing opinion at this time is
that pregnant women with gunshot wounds to the abdomen should generally
undergo mandatory celiotomy. Stab wounds to the abdomen are managed
similarly in pregnant and nonpregnant patients if signs of obvious
intra-abdominal injury are present (shock, peritoneal signs, evisceration)
or positive investigation.
A midline celiotomy should be performed, with exploration as in
the nonpregnant state. If extrauterine intra-abdominal injuries
are identified, organs are repaired or resected in the usual manner.
Whenever the enlarged uterus interferes with adequate examination
or repair, cesarean section is required. Celiotomy alone does not
justify cesarean section because it prolongs the operation and increases
blood loss by at least 1000 ml. Specific indications for cesarean
section during celiotomy include maternal shock and pregnancy near
term, threat to life from exsanguination from any cause, mechanical
limitation for maternal repair, irreparable uterine injury, instability
in a potentially viable fetus, unstable thoracolumbar spine injury,
and maternal death.
Treatment priorities are the same when managing
pregnant and nonpregnant burn victims. Maintenance of a normal intravascular
volume, avoidance of hypoxia, and prevention of infection are important.
Burned areas of tissue should be debrided and cleaned. Silver sulfadiazine
cream should be used sparingly because of the risk of kernicterus
associated with sulfonamide absorption.
In cases of electrical burns, fetal mortality is high at 73% even
with a rather low electrical current because of the fetus' lack
of resistance to electrical shock. This is probably related to the
fact that the fetus is floating in amniotic fluid with a low resistance
to current. No matter how trivial their injury may seem, fetal monitoring
and ultrasound assessment are indicated for all pregnant victims
of electrical shock.
Perimortem Cesarean Delivery
During maternal resuscitation, adequate oxygenation,
fluid loading, and left lateral decubitus should be tried to see if
maternal circulation can be improved. Maternal survival after delivery
of the fetus during unsuccessful cardiopulmonary resuscitation (CPR)
has been reported. If there is no response to advanced cardiac life
support within a few minutes (2 to 3 minutes), maternal cardiopulmonary
resuscitation must be continued, anterior thoracotomy with open-chest
cardiac massage (OCM) but without aortic cross-clamping should be
considered, and emergency cesarean section for a viable fetus should
Studies have shown that conventional external cardiac massage
(ECM) becomes less effective as the patient approaches term because
of mechanical factors. The only method of assessing adequacy of
fetal oxygenation during CPR is to monitor fetal heart rate (FHR).
Carotid pulse and end-tidal CO2 monitoring should be used to monitor
adequacy of maternal vital organ perfusion during CPR.
When the gestational age is less than 24 weeks, emergency cesarean
delivery is usually not performed because the fetus is too small
to survive and the birth is unlikely to have much effect on maternal
hemodynamics. However, when gestational age is greater than 24-25
weeks, emergency cesarean birth probably will favorably affect maternal
or fetal outcome. At a gestational age of 26 to 32 weeks, when external
cardiac massage is not effective, as indicated by failure to generate
a carotid pulse, inadequate end-tidal CO2 levels, or fetal bradycardia,
OCM should be seriously considered before an emergency cesarean
section is performed. If OCM prove successful, the delivery may
be delayed so that chances of postnatal survival improve. Even slight
prolongation of fetal intrauterine life will probably improve the
chances of fetal survival, especially when gestational age is less
than 28 weeks. If, however, OCM proves to be ineffective, the fetus
must be delivered immediately. After 32 weeks gestation, when ECM
is not effective, an emergency cesarean section must be performed
immediately. Delivering the infant improves maternal cardiac filling,
thereby improving the success of CPR. The longer the delay between
the onset of cardiac arrest and delivery, the less are the chances
of fetal and maternal survival. If, however, the ECM appears to
be effective, ECM may be continued for 5 minutes. If a spontaneous
circulation is not restored within 5 minutes, an emergency cesarean
delivery must be performed. If this fails to revive the mother,
OCM may be considered. Ideally, personnel trained in neonatal resuscitation
should be available to attend the infant.
Trauma has become the most frequent cause
of maternal death in the United States of America. The main principle
guiding therapy must be that resuscitating the mother will resuscitate
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