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Trauma in Obstetrics
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Trauma in Pregnancy
Major physiologic changes Altered anatomical relationships Signs and symptoms of injury may
be altered Treatment priorities are the same Usually the best treatment for the
fetus is the best treatment for the mother
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Trauma in Pregnancy
Resuscitation and stabilization may need to be modified to accommodate the altered physiologic and anatomic changes of pregnancy
2 patients Consult OB/GYN early Don’t withhold X-rays (10 rads or
more are teratogenic
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Priorities
A. Airway B. Breathing C. Circulation
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Trauma in Pregnancy
Physical trauma complicates 1/12 of pregnancies
Trauma is the #1 cause of non Obstetrical maternal deaths
Serious retroperitoneal bleeding following blunt abdominal trauma is more common in pregnant women as opposed to non pregnant
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Trauma in pregnancy
Bowel injuries are less common in pregnant patients as opposed to non pregnant patients
The presence of vaginal bleeding and uterine hypertonicity is presumptive evidence of placental abruption
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Objectives
A. Oxygen requirements B. Blood replacement
requirements C.Proper patient positioning D.Significance of fetal monitoring E. Vaginal bleeding
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Anatomic and Physiologic Alterations of Pregnancy The Uterus is an intra pelvic organ
until the twelfth week of gestation At 20 weeks the uterus is at the
umbilicus At 36 weeks the uterus is at the
costal margins In the last 2-8 weeks the fetal head
descends to become engaged in the pelvis
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Anatomic and Physiologic Alterations of Pregnancy Intestinal tract is displaced upward
and posterior As gestation continues the uterus
becomes more vulnerable as the walls thin and there is less protection by amniotic fluid
Thromboplastin and plasminogen activator can be released with trauma to the placenta and uterus
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Hemodynamics
Cardiac Output- Increases 1-1.5 L per minute by 10 weeks (Vena cava compression in the supine position can decrease CO by 30-40%)
Heart Rate- Increases up to 15-20 beats per minute at term
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Hemodynamics
Blood Pressure- 5-20mmHG decrease (maximum in the second trimester) Returns near normal at term
Some women may exhibit profound hypotension in the supine position, turn patient to the left lateral decubitus position
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Hemodynamics
Venous pressure- CVP is variable in pregnancy, the response to volume is the same as in the non pregnant state, (venous hypertension in the lower extremities is normal during the third trimester)
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Hemodynamics
EKG- There may be a left axis shift of about 15 degrees
Flattened or inverted T waves in leads III, AVF and the precordial leads may be normal
Ectopic beats are slightly increased in pregnancy-
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Blood Volume and composition Plasma volume is increased and
reaches its maximum at about 34 weeks (40-50% above pre-pregnant levels)
RBC volume increases but not as much as the plasma volume resulting in a lower hematocrit (the “so called” physiologic anemia of pregnancy)
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Volume
Late pregnancy hematocrit of 31-35% is normal
Overall blood volume is up 50% With hemorrhage a healthy
pregnant women may lose 30-35% of their blood volume before exhibiting symptoms
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Blood composition
WBC- can be up to 20,000 Fibrinogen and other clotting
factors are elevated Prothrombin and partial
thromboplastin times may be shortened
Bleeding and clotting times are unchanged
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Blood composition
Albumin falls (2.-2.8g/dl) Serum osmolarity remain at about
280mOsm/L A pregnant women is twice as
likely as a non pregnant women to develop a DVT or PE (adding trauma to this increases the likelihood
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Respiratory
Respiratory rate is unchanged Tidal Volume is increased by 40% Residual volumes fall PCO2 pf 30mmHg is normal “Hyperventilation” of pregnancy Chest X-ray shows increased lung
markings and prominent pulmonary vessels
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Gastrointestinal
Gastric emptying is greatly prolonged (Pregnant women all have full stomachs)
The uterus may shield the intestines
The liver and spleen are unchanged
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Urinary tract
GFR and renal blood flow increase during gestation
BUN and Creatinine are about half non pregnant levels
Physiologic dilation of the renal calyxes,pelves and ureters
Creatinine clearance increased to 150
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Endocrine
Pituitary gland gets 30-50% heavier during pregnancy
Shock may cause Sheehan’s syndrome(pituitary necrosis)
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Neurologic
Ecclampsia is a condition that may mimic a head injury
If a seizure occurs make sure the patient is evaluated for ecclampsia
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Initial assessment
Position patient to avoid supine hypotension unless spinal injury is suspected
Left lateral positioning is preferred If transport is needed displace
uterus to left and elevate right hip
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Initial Assessment
Primary survey ABC’s Supplemental oxygen (re-breather
mask If ventilation is required mild
hyperventilation Crystalloid fluid resuscitation and
early blood product administration
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Initial assessment
Blood is shunted away from the uterus in a hypotensive state
The gravida can lose up to 35% of her blood volume before tachycardia, hypotension, and other signs of hypovolemia occur
The fetus may be in shock and the mother appear stable
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Initial assessment
Avoid vasopressors because these further reduce uterine blood flow
2 large bore lines (14-16 gauge) fluid should be LR or NS replace at 3-1 for estimated blood loss
O2 saturations above 90%
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Initial Assessment
With gun shot wounds to the abdomen exploration is mandatory
Stab wounds to the abdomen may be able to be observed in selected cases
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Secondary Assessment
Uterine irritability Fundal height and tenderness Fetal heart rate and movement Pelvic exam ( look for bleeding,
premature dilation, rule out ROM by fern and nitrazine if indicated
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Secondary Assessment
If possible place patient on fetal monitor to assess contractions and fetal heart rate reactivity
With any trauma an ultra sound exam is required to look for placental separation and possibly to obtain biophysical profile
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Secondary Assessment
Ultrasound can be useful for determining gestation age, placental location, fetal status, amniotic fluid volume, and fetal position
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Monitoring
Mother-BP, pulse, CVP if needed, respiratory rate, pulse oximeter
Fetus-preferentially continuous fetal and uterine monitoring
Placental abruptions can be seen 24-48 hours following trauma( if contractions are present Abruptio placenta is more likely)
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Monitoring
If no contractions are present and the fetal heart rate is reassuring ACOG recommends 2-6 hours of monitoring
If less than 20 weeks monitoring may not be needed as long
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Definitive care
Uterine rupture can present in massive shock with hemorrhage to a patient with minimal symptoms
Signs of uterine rupture on radiologic exams can be extended fetal extremities, abnormal fetal presentations, or free intraperitoneal air
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Definitive care
If uterine rupture is suspected immediate surgical exploration is necessary
Abruptio placenta is the leading cause of fetal death after blunt trauma
Signs of abruption- Irritable uterus, tetanic contractions, tenderness, enlarging uterus
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Definitive care
Other signs of abruptio- bleeding, Consumptive coagulopathy, maternal shock, pain
Retroperitoneal hemorrhage can be massive after blunt trauma or pelvic fracture
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Definitive care
Remember Rh sensitization (Kleihauer-Betke)
Administration of Rho gam (D immunoglobin within 72 hours
Tetanus prophylaxis is the same as in the non pregnant patient
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Definitive care
Perimortem cesarean delivery is unlikely to produce a living fetus if the mother has been dead for more than 20 minutes
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Summary
Recognize the effect of anatomic and physiologic changes
Vigorous shock therapy Recognize the unique spectrum of
potential injuries Stabilize the mother first because
the fetuses life is dependant on the mother integrity
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Summary
Fetal heart rate monitoring should be maintained during resuscitation and after stabilization
Less than 20 weeks gestation the fetus is non viable so treat the mother
Do not withhold diagnostic X-rays Get an Obstetrician fast
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Summary
Changes in vital signs can occur relatively late so the patient may be worse off than the vitals indicate
Ultrasound will miss an abruption less than 30% so be clinically aware