Blunt trauma in pregnancy

Blunt trauma in
pregnancy
BY
DR. SEFEEN SAIF ATTYA
SURGERY DEPARTMENT
SOHAG TEACHING HOSPITAL

TOPICS
Demographics
Anatomy
 Maternal Physiology
Resuscitation and assessment
Laboratory Evaluation
Imaging
Anesthesia in the Pregnant
Patient
injuries unique to the pregnant
trauma patient

demographics
 An estimated 5 to 8% of all
pregnancies are complicated by
trauma and it is the leading cause of
non-obstetric maternal deaths
 Maternal trauma is associated with
significant fetal morbidity and
mortality
 Estimates of fetal death rates
following trauma vary widely ranging
from 5 to 60% of cases

 Risk factors associated with fetal
loss include
high maternal injury severity score
and shock in the mother
 maternal injury, both major and
minor, have resulted in spontaneous
abortion, premature labor, fetal
hypoxia, fetal skull fractures, uterine
rupture, placental abruption.

 The most common mechanism of maternal injury is
motor vehicle crashes, accounting for
approximately 55% of maternal trauma
 Falls and physical abuse account for an additional
10 to 30% of injuries.
 Motor vehicle crashes (MVC) have
been shown to be the leading cause of fetal death
related to maternal trauma;
 an examination of fetal death certificates found
that MVCs are responsible for 82% of fetal deaths
associated with maternal trauma.

Anatomy
Early in the gestational period, the
fetus is well protected in the uterus
which lies within the pelvis.
 After the 12th week, the uterus begins to
expand out of the pelvis and into the
abdomen reaching the umbilicus
at 20 weeks gestational age and the
costal margin at 36 weeks.
 In the final 4 weeks, the fetus descends
into the pelvis and fundal height is lower.

Anatomy
 As pregnancy advances, maternal organs are displaced upward
and the diaphragm may be elevated as much as 4 cm from the
nonpregnant state.
 While the gravid uterus may provide a degree of protection to the
maternal viscera, the fetus is at increased risk of direct injury as
the pregnancy progresses.
 In the third trimester, the uterine wall thins, the amount of
amniotic fluid decreases, and the fetal head rotates down
into the pelvis all of which place the fetus at increased risk
for injury.
 In particular, the location of the fetal head within the pelvis
places the fetus at risk of skull fractures and traumatic brain
injury secondary to maternal pelvic fractures.

Maternal Physiology
 Pregnancy results in dramatic changes in maternal
physiology affecting virtually every organ system.
 Over the course of a normal pregnancy, there is an
increase of maternal total body water of 5– 8 l.
 The water content of the fetus, placenta, and amniotic
fluid accounts for 3.5 l.
 Maternal blood volume is expanded by approximately
1,500 mL,( plasma volume by 1,200 mL, and red blood cell
volume by 300–400 mL.)
 Because the plasma volume expands more than red blood
cell mass, the result is a physiologic anemia of
pregnancy

Maternal Physiology
 The increased blood volume protects the mother from
hemorrhage and hypotension.
 As a result, the presence of hypotension in the pregnant
patient indicates a significant volume loss and should
be addressed promptly.
 The vasculature of the placenta is dilated
at baseline, but very responsive to catecholamines.
 A decrease in maternal circulating volume and
catecholamine release may result in a significant
increase in uterine vascular resistance, diminished
placental blood flow, and a reduction in fetal
oxygenation even in the presence of normal maternal
vital signs.
 In fact, maternal volume loss may first be manifested as
fetal distress

Maternal Physiology
 Pregnancy results in profound changes in the
cardiovascular system.
Cardiac output is significantly increased in pregnancy
by
an average of 30 to 50% as compared to the nonpregnant
state.
 Cardiac output is the product of stroke volume and heart
rate
and both of these parameters are altered in pregnancy.
 There is an initial rise in maternal heart rate (HR) at
about 5 weeks;
the HR continues to increase until about the 32nd week
when it peaks at 15–20 beats per minute
above the patient’s pregravid state.
 Stroke volume begins to increase at 8 weeks and at 32
weeks it reaches a maximum value of 20 to 30% increase
over pre-pregnant values.

 While cardiac output is increased in pregnancy, it is
highly variable with respect to maternal position,
particularly with advanced pregnancy.
 In late pregnancy, the gravid uterus may
completely occlude the vena cava
when the patient is in the supine position,
dramatically reducing venous return, stroke
volume, and as a result, cardiac output.
 Stroke volume and cardiac output are optimized
when the pregnant patient is in the left lateral
position with the knees brought toward the chest to
alleviate the compression of the inferior vena cava.

 In addition to the increased red cell mass as noted above,
there are other changes in the hematologic system in the pregnant
patient.
 The peripheral white blood cell count (WBC) rises
throughout pregnancy.
In the first trimester 5,000 to 10,000/mm3,
second and third trimesters 5,600 to 12,200/mm3.
In labor, 20,000 to 30,000/mm3
 Additionally, changes occur to protect against peripartum
hemorrhage the etiology of which is multifactorial
Various procoagulants are increased
There is also decreased activity in the fibrinolytic system.
Consequently, pregnancy is a hypercoaguable state
and the pregnant trauma patient
is at increased risk for venous thromboembolic complications.

Maternal Physiology
The respiratory system also undergoes
a significant change in the course of pregnancy.
The upper respiratory tract becomes hyperemic and
edematous .
Care should be taken when placing nasogastric tubes
in pregnant patients to avoid excessive bleeding.
The chest wall undergoes reconfiguration as the
subcostal angle increases and the chest
circumference expands by 5–7 cm.
The level of the diaphragm rises 4 cm, decreasing
the volume of the lungs in the resting state,
reducing both total lung capacity
and functional residual capacity (FRC).

 Pregnancy also is a state of chronic
hyperventilation with a 30 to 40% increase in
minute ventilation
driven by an increase in tidal volume.
 As a result, the arterial pCO2 is decreased.
Whereas a normal pCO2 is generally considered
to be 37–40 mmHg, in the pregnant patient the
expected pCO2 is 27–32 mmHg
creating a chronic respiratory alkalosis.
 increased maternal excretion of bicarbonate lowers
the serum bicarbonate levels to 18–21 meq/L
and maintains the maternal pH between 7.4 and
7.45

 The decrease in maternal pCO2
results in a gradient between maternal
and fetal CO2 that facilitates
the transfer of CO2 from the fetal to
maternal circulation for excretion.
 It is of the utmost importance to avoid
acidosis in the pregnant patient
as maternal acidosis compromises fetal–
maternal gas exchange.

Glucose metabolism is altered during
pregnancy. The changes in carbohydrate
metabolism result in
fasting hypoglycemia,
postprandial hyperglycemia,
and hyperinsulinemia.
 In the fasting state The constant demands of
The fetal–placental unit for glucose results in early
depletion of maternal glycogen stores with fasting
and a rapid conversion from carbohydrate to fat
utilization.
 In the fed state, insulin resistance begins in the
first trimester. In the normal pregnancy,
the pancreas compensates with an exaggerated
insulin response.

 If the patient has limited pancreatic reserve in the
pre-pregnant state, then patient may not produce
enough insulin to overcome the resistance
resulting in gestational diabetes.
 As the fetus is primarily dependent on maternal
glucose, normal maternal glucose levels are critical
for proper fetal development.
 Hyperglycemia in the first trimester is associated
with birth defects and in the third trimester
with fetal macrosomia.
 Normal blood glucose levels should be maintained
in the pregnant trauma patient to optimize
maternal–fetal outcome.

gastrointestinal tract
 diminished lower esophageal sphincter
pressure
 reduced gastric tone and motility
Consequently, the pregnant patient is at
risk for aspiration and early gastric
decompression should be considered,
especially prior to intubating the
injured pregnant patient.

initial resuscitation and
assessment
Maternal assessment
 One of the leading causes of fetal demise following trauma is
maternal demise.Therefore, the primary focus on the initial
assessment must be the prompt evaluation and treatment of
the mother following the guidelines as outlined in the American
College of Surgeons on Trauma
Advanced Trauma Life Support manual.
 As a result of the anatomic and physiologic changes
that occur during pregnancy, there are a few special
considerations in the primary survey.
 The decreased gastric motility places a pregnant
woman at increased risk for aspiration and early gastric
decompression is appropriate.

 Because the fetus is sensitive to maternal hypoxia,
supplemental oxygen should be provided. Additional care
should also be taken during intubation.
 If rapid sequence intubation is employed, a lower dose
of succinylcholine is required due to decreased
pseudocholinesterase levels in pregnancy.
 If a tube thoracostomy is required, it should be placed
one or two intercostal spaces higher than in nonpregnant
patients secondary to the diaphragm elevation.
 It is especially helpful to use the sagittal thoracic
ultrasound examination to identify the location of the
diaphragm.

 Finally, compression of the vena cava by the gravid
uterus and resultant hypotension can be minimized
by either manually displacing the gravid uterus to the left
or tilting the long spine board to the left.
 A focused abdominal ultrasound examination should be
performed to evaluate the mother for intraperitoneal
hemorrhage.
 A focused abdominal ultrasound in pregnant trauma
patients has been found to detect intraperitoneal
fluid with a sensitivity, specificity, and accuracy
similar to that of nonpregnant patients.

FAST
(Focused
Assessment
by
Sonography
in Trauma)

(Morison’s
pouch)
showing (A)
normal
(B)
hemoperitone
um, with fluid
(blood) in
Morison’s
pouch (arrow)
and anterior
to the liver.

(A) normal
image, and
(B) image
positive
for fluid
(blood) in
the
spleno-
renal
recess.

(A) normal
bladder
(B) Pelvis
with bladder
surrounded
by
hypoechogen
ic fluid
(blood).

Fetal Assessment
 After maternal assessment is completed and all immediately
lifethreatening issues addressed in the mother,
it is appropriate to perform a fetal assessment
 An estimated gestational age of 20–24 weeks should prompt
uterine and fetal monitoring under the supervision of the
obstetric service.
 If the mother is unable to provide obstetric history, the fundal
height can be used as an estimation of gestational age.
 In general, if the fundus is at the level of the umbilicus, the
gestational age is at least 20 weeks and it should be assumed
that the pregnancy is viable until an obstetrician
determines otherwise.

 Cardiotocographic monitoring should be
initiated as soon as possible and
preferably immediately following the
secondary survey in all potentially viable
pregnancies.
 The monitoring should be in place for a
minimum of 2–6 h and the duration
of monitoring should be increased in all
patients with abdominal pain,
contractions, or significant maternal injury.

 Ideally, the obstetrician or maternal fetal
medicine specialist will be involved early
in the care of these patients and be
present to perform the initial fetal
assessment.
 The fetal ultrasound examination should
include fetal heart rate and position,
assessment of gestational age,
biophysical profile, fetal middle cerebral
artery Doppler examination, and
evaluation of the placenta for abruption.

 Normal fetal heart rate varies between 120 and
160 bpm; both fetal bradycardia and tachycardia
may have great clinical importance.
 It is important to note that ultrasound has a
sensitivity of about 50% for placental abruption;
however, the positive predictive value of the test is
high.
 If abruption is suspected and there is evidence of
fetal compromise in a viable gestation,
emergent operative delivery should be considered.

Secondary Survey
 The secondary survey of the mother is then
performed followed by definitive care of both
maternal and fetal injuries.
 In the pregnant patient , the secondary survey must
include a vaginal examination to assess for cervical
effacement and dilation, fetal position as well as
for the presence of blood or amniotic fluid.
 Vaginal bleeding is abnormal and may be a sign of
labor, placental abruption, placenta previa,
or uterine rupture.

Laboratory
Evaluation
 All laboratory studies routinely ordered in trauma
patients should be obtained
in the pregnant patient.
 At a minimum this should include hemoglobin,
hematocrit, coagulation profile including
fibrinogen, and ABO type and cross-matching.
 Patients with a significant mechanism of injury and
hemodynamic instability should also have an arterial
blood gas assessed.
 In addition, the Kleihauer–Betke (KB) test should be
obtained in all Rh-negative women to ascertain whether
fetal blood has entered the maternal circulation.

 Any Rh-negative woman with a positive test should
receive Rh-immune globulin.
The initial dose is 300 μg followed by 300 μg for
each 30mL of estimated fetomaternal transfusion.
 Recent data have also suggested that the KB test
is an accurate predictor of the risk of preterm labor
following maternal trauma.
 In a retrospective review, Meunch et al. found that
a positive KB test was a sensitive
way to detect preterm labor and conversely, a
negative KB test excluded preterm labor.

Imaging
 Imaging studies should be obtained in the pregnant
patient for the same indications as they are performed
in the nonpregnant patient.
 While various adverse effects on the fetus including
microcephaly and mental retardation have been noted
with high-dose radiation, no increase in teratogenicity
for a fetus exposed to less than 10-rad or 100-mGy
of radiation has ever been documented.
 The American College of Obstetricians and
Gynecologists has published guidelines for imaging
during pregnancy and state that a 5-rad or 50-mGy
exposure is not associated with adverse fetal outcome.

 Shields such as a lead apron should always be employed
when possible as they reduce the radiation exposure of the
fetus by30%.
 If the patient is severely injured and multiple imaging studies
are anticipated, it may be reasonable to consult a radiation
specialist to assist in planning.
 Furthermore, a radiation dosimeter badge may be attached
to the mother so that the radiation dose may be easily tracked.
 This badge may be very helpful in those patients who are
admitted to the intensive care unit and may need daily chest
radiographs or other frequent studies.
 Pregnancy alone, however, should not deter the physician
from ordering necessary diagnostic and therapeutic tests.

Indications for
Laparotomy
 The indications for laparotomy in the pregnant trauma
patient remain the same as for the nonpregnant trauma
patient.
 These include hypotension in the presence
of intraperitoneal fluid detected on ultrasound,
peritonitis, and failed nonoperative management
of solid organ injury.
 During laparotomy, the obstetrician should be present
and if delivery of the fetus is anticipated, a
neonatologist should also be immediately available as
well as the resources to resuscitate the infant.

Anesthesia in the
Pregnant Patient
 As mentioned previously, the pregnant patient
should be considered at high risk for aspiration.
Intubation should be conducted by the
anesthesiologist as expeditiously as possible using
rapid sequence intubation with cricoid pressure.
 Pregnancy alters the anatomy of the airway and the
larynx is pushed anteriorly. The need to maintain
inline cervical immobilization and friable,
edematous oral, nasal and tracheal mucosa that is
prone to bleeding may further complicate the
intubation.

 Pregnant trauma patients should be considered to
have “difficult” airways until proven otherwise
and it is advisable to have a “difficult” airway cart
equipped with a flexible fiberoptic bronchoscope in
the room.
 The trauma surgeon should be present during the
induction of anesthesia to perform an emergent
surgical airway if needed as the fetus is especially
sensitive to hypoxia.
 Once the patient is intubated, she should be
slightly hyperventilated to a pH of 7.4–7.45 to mimic
the normal physiology of pregnancy.

 Thiopental or etomidate are useful induction agents. Ketamine
should be avoided as it causes increased uterine tone and
decreased uteroplacental perfusion.
 As noted previously, smaller doses of succinylcholine are
required in pregnant patients. Both depolarizing
and nondepolarizing neuromuscular blocking agents cross
the placenta and can result in hypotonic and apneic infants for
which the neonatal resuscitation team must be prepared.
 If the patient can tolerate a volatile anesthetic,
one should be used as these agents relax uterine smooth muscle
and decrease circulating catecholamines thus improving uterine
perfusion.

Technical
Considerations
 Following the induction of anesthesia, a fetal monitor should be placed by
the obstetrician if indicated.
 If the planned incision makes intraoperative monitoring of the fetus
impossible, then, at a minimum, fetal heart rate should be measured
immediately before and at the termination of the procedure.
 A wedge should be placed under the patient ‘s right side to displace the
uterus and avoid inferior vena cava compression
 Laparotomy is carried out though a vertical midline incision in the
standard fashion and all indicated procedures are performed.
 If the uterus is found to be intact at laparotomy and the fetus is not in
distress, intraoperative delivery is rarely indicated.
 On rare occasion, intraoperative delivery may be indicated to expose and
control nonobstetric-related hemorrhage in the mother.

injuries unique to the pregnant
trauma patient
Placental Abruption
 The vast majority of fetal losses following blunt trauma to the
abdomen are the result of placental abruption. Although the
reported incidence of abruption in patients with minor injuries
is 1 to 5%, it is estimated to occur in 40 to 50% of significant
maternal trauma.
 While the uterus has a great deal of elasticity, the placenta does not.
 In blunt trauma, shearing forces occur at the uterine–placental
interface resulting in separation of the placenta.
 Patients present with vaginal bleeding, abdominal pain, uterine irritability
as seen on fetal monitoring, shock, or fetal distress. It should be
noted that abruption can occur in the absence of significant uterine
bleeding.
 The only treatment for a significant abruption is
immediate delivery of the fetus.

Preterm Labor
 There is about a 5% incidence of preterm labor
following maternal trauma.
 Labor is initiated following trauma by one of two
mechanisms: either premature rupture of the
membranes or destabilization of lysosomal
enzymes resulting in prostaglandin production.
 If the membranes are intact, tocolytic therapy
should be considered if deemed appropriate by the
treating obstetrician.

Uterine Rupture
 Uterine rupture is a rare, catastrophic
complication of blunt abdominal trauma.
 The incidence is approximately 0.6% of
cases of all blunt trauma during pregnancy.
 Occurring primarily late in pregnancy,
the fetal mortality approaches 100% with a
maternal death rate of 10% from
associated injuries.

Direct Fetal Injury
 Direct fetal injury is very rare in blunt trauma
complicating less
than 1% of all significant maternal trauma. The
maternal
soft tissue, uterus, and amniotic fluid all provide a
significant
degree of protection to the fetus.
 Those cases of direct fetal injury that do occur are
usually
late in the gestational period.
 The most commonly reported direct fetal injury is
head injury.

 If the head of the fetus is engaged in the pelvis,
the fetus is at increased risk for brain and skull injuries.
Even if the head is not engaged, the fetus is at risk for
shearing injury to the brain.
 Overall, pelvic fractures are the most common specific
maternal injury resulting in fetal mortality.
 Of note, pelvic fractures are not an absolute contraindication to
vaginal delivery.
 Women who have suffered a pelvic fracture are, however,
more likely to require an operative delivery than women that
have not suffered a pelvic fracture.
 Severe traumatic fetal brain injury secondary to airbag
deployment has also been reported.

Emergency Cesarean
Section
Indications for emergency operative delivery include
 a potentially viable fetus by gestational age,
 the presence of fetal heart tones,
 maternal distress, or fetal distress.
A multicenter study documented infant survival rate
of 75% of potentially viable gestations that underwent
emergent operative delivery.
The obstetrician, if available, should be involved in
the decision-making process.

Perimortem Section
 Perimortem section should be considered
in the case of maternal arrest with a
potentially viable fetus.
 Delay in recognition of fetal distress
is a preventable cause of fetal demise.
 The best fetal outcomes have been
documented if the infant
is delivered within 5 minutes of the
cardiovascular collapse of the mother. This
leaves very little time for decision making.

 Factors that should be considered include
the estimated gestational age of the fetus and the
resources available at the hospital.
 A vertical midline incision should be used from the
xiphoid to the pubic symphysis.
The uterus is incised vertically
and opened. The umbilical cord is clamped and cut
and resuscitation of the neonate is initiated.
 Maternal resuscitative efforts should be carried out
simulataneously.

Fetal Outcome
 About 80% of women who suffer trauma during their
pregnancy are released from the hospital
without requiring delivery of the fetus.
 Several studies have been published that suggest that
injuries during pregnancy
are associated with increased risk of both maternal
and fetal adverse outcomes at the time of eventual
delivery.
 These include prematurity, low birth weight, fetal
distress, and requirement of transfusion at delivery.
 The etiology for these adverse outcomes may be related
to subclinical abruption at the time of trauma.

Other studies have contradicted this
and suggested that in the absence of
complications at the
time immediately surrounding the
trauma, there is no difference in
pregnancy outcome between
injured and noninjured patients.

if the pregnant trauma patient leaves
the hospital undelivered, the trauma
and sequalae should be directly
communicated to the patient’s
obstetrician to allow for
additional assessment and care
during the remainder of the
pregnancy and delivery.

Blunt trauma in pregnancy

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