Advanced Trauma Life Support ATLS Student Course Manual 2018

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CHAPTER 12 n Trauma in Pregnancy and Intimate Partner Violence
table 12-3 distribution of blunt
and penetrating abdominal injury
in pregnancy
MECHANISM
Blunt 91
Penetrating
Gunshot wound
Stab wound
Shotgun wound
are similar to those sustained by nonpregnant
patients, but certain differences must be recognized
in pregnant patients who sustain blunt or
penetrating injury. The distribution of blunt and
penetrating abdominal injury in pregnancy is shown
in n TABLE 12-3.
Blunt Injury
9
73
23
4
PERCENTAGE
Source: Data from Petrone P, Talving P, Browder T, et al. Abdominal
injuries in pregnancy: a 155-month study at two level 1 trauma centers.
Injury, 2011;42(1):47–49.
The abdominal wall, uterine myometrium, and
amniotic fluid act as buffers to direct fetal injury from
blunt trauma. The presence of external contusions
and abrasions of the abdominal wall, as demonstrated
in n FIGURE 12-4, are signs of possible blunt uterine
injury. Nonetheless, fetal injuries may occur when
the abdominal wall strikes an object, such as the
dashboard or steering wheel, or when a pregnant patient
is struck by a blunt instrument. Indirect injury to the
fetus may occur from rapid compression, deceleration,
the contrecoup effect, or a shearing force resulting in
abruptio placentae.
Compared with restrained pregnant women involved
in collisions, unrestrained pregnant women have a
higher risk of premature delivery and fetal death. The
type of restraint system affects the frequency of uterine
rupture and fetal death. Using a lap belt alone allows
forward flexion and uterine compression with possible
uterine rupture or abruptio placentae. A lap belt worn
too high over the uterus may produce uterine rupture
because it transmits direct force to the uterus on impact.
Using shoulder restraints in conjunction with a lap
belt reduces the likelihood of direct and indirect fetal
injury, presumably because the shoulder belt dissipates
deceleration force over a greater surface area and helps
prevent the mother from flexing forward over the
gravid uterus. Therefore, in the overall assessment it
is important to determine the type of restraint device
worn by the pregnant patient, if any. The deployment
of airbags in motor vehicles does not appear to increase
pregnancy-specific risks.
Penetrating Injury
As the gravid uterus grows larger, the other viscera are
relatively protected from penetrating injury. However,
the likelihood of uterine injury increases. The dense
uterine musculature in early pregnancy can absorb
a significant amount of energy from penetrating
objects, decreasing their velocity and lowering the
risk of injury to other viscera. The amniotic fluid and
fetus also absorb energy and contribute to slowing of
the penetrating object. The resulting low incidence
of associated maternal visceral injuries accounts for
the generally excellent maternal outcome in cases of
penetrating wounds of the gravid uterus. However, fetal
outcome is generally poor when there is a penetrating
injury to the uterus.
severity of Injury
n FIGURE 12-4 External contusions and abrasions of the abdominal
wall are signs of possible blunt uterine trauma.
The severity of maternal injuries determines maternal
and fetal outcome. Therefore, treatment methods
also depend on the severity of maternal injuries.
All pregnant patients with major injuries require
admission to a facility with trauma and obstetrical
capabilities. Carefully observe pregnant patients
with even minor injuries, since occasionally minor
injuries are associated with abruptio placentae and
fetal loss.
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