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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