Trauma in Pregnancy

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Trauma in Pregnancy

• James Huffman
• Resident Rounds October 12, 2006
• Thanks to Yael and Shawn

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Epidemiology

• Trauma occurs more often during the 3rd trimester
  than at any other time in a womans life
• 7 of pregnancies are complicated by trauma
• It is the leading cause of maternal death,
  accounting for 46 of fatalities in pregnant
  women
• Most common causes are MVCs, falls, assults, and
  domestic violence plays a very significant role
  in this population

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Challenges

• Smaller evidence base
• Two patients
• Determining fetal viability
• Physiologic and anatomic changes
• 1-3 of minor trauma results in fetal death!

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Approach

• Four groups
• Early pregnancy mothers not aware, vulnerable
  to radiation
• Fetus not yet viable well protected in bony
  pelvis, required maternal survival for
  development
• Viable pregnancies (gt24-26 weeks) most
  challenging, two patients to consider
• Perimortem resuscitation /- C-section
• Being pregnant does not affect maternal survival
• The most common causes of fetal death are
  maternal death and placental abruption

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Anatomic Changes

• Uterus pelvic in T1, then pushes structures out
  of the way
• Decreased sensitivity to peritoneal injury
• Pelvic outlet widening
• Symphysis pubis and SI joint spaces increase in
  the 7th month ? pelvic x-rays
• Supine Hypotensive Syndrome
• At gt20 weeks GA, the uterus can compress the IVC,
  decreasing preload

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Cardiovascular Changes

• Some changes present like shock
• Hypotension
• declines in T1, stabilizes in T2, returns to
  normal in T3
• SBP (2-4 mmHg) lt DBP 5-15mmHg
• d/t progesterone and supine hypotensive syndrome
• Increased baseline HR (usu. 10-15 bpm)
• CVP decreases to 4 from 9mm Hg by term
• Do not attribute changes in BP or HR entirely to
  physiology consider them harbingers of shock!

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Cardiovascular Changes - 2

• Some changes mask shock
• Increased blood volume as much as 48-58,
  peaking at 32-34/52
• Cardiac output increased by 40 at term (6L/min)
• With significant blood loss, maternal BP is
  preserved at the expense of the uteroplacental
  and splanchnic circulation ? early fetal
  monitoring
• Blood loss will exceed 30 of total blood volume
  before hypotension is manifest

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Respiratory Changes

• Pregnancy significantly reduces oxygen reserve
• 20 reduction in FRC 2 to diaphragm elevation
• 15 increase in oxygen consumption related to the
  growing fetus, uterus and placenta
• Progesterone stimulates the respiratory centre in
  the medulla, leading to hyperventilation and
  respiratory alkalosis with metabolic compensation
  (pCO2 usually ranges from 27-32)
• Significance Intubation and Chest-tube placement!

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Gastrointestinal Changes

• ? GE sphincter tone and gastrointestinal motility
  
• ? acid production in stomach
• Increased risk of aspiration!

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Hematologic Changes

• Blood volume increased more than RBC mass ?
  dilutional anemia (Hg as low as 100, and Hct of
  32-34)
• ? WBC (up to 18 000)
• ESR increased but CRP unchanged
• Increased risk of thromboembolism
• ? stasis (venous compression, capacity, bed rest)
• ? coagulation factors V, VII, VIII, IX, X, XII
  and fibrinogen (by T3) exceeds fibrinolytic
  activity.

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ECG changes

• The elevated diaphragm causes a leftward axis
  shift averaging 15
• Q waves in leads III and aVF
• Flattening of T-waves in III and aVF

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Mechanisms of Injury Blunt Trauma

• Most common cause is MVCs half of pregnant women
  are not using seatbelts correctly or at all
• Next are assaults (domestic violence) and falls
• 20 incidence of domestic violence in the
  pregnant population
• 80 of falls occur after 32 weeks GA
• If the mother survives, placental abruption is
  the most common cause of fetal mortality
• Incidence in minor trauma is 2-4 30-50
  incidence in survivors of major trauma
• Sensitivity of US is lt50, clinical signs and
  symptoms are often also unreliable
• Incidence of fetal loss from minor trauma is 1.7

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Penetrating Trauma

• Maternal visceral injuries are less common during
  pregnancy
• Fetus is at high risk
• Fetal injury complicates 66 of gunshot wounds to
  the uterus
• Fetal mortality ranges from 40-70 in cases of
  penetrating trauma (stab wounds carry a lower
  mortality for both mother and fetus)

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Burns

• In severe burns there is a dramatic increase in
  fetal mortality, approaching 100 for burns gt50
  TBSA only 6 survival for burns gt30 TBSA
• Risk to the fetus is maternal death, fetal death,
  and preterm labor (PGE2)
• Maternal carbon monoxide levels are a poor
  predictor of fetal carboxyhemoglobin

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Other Mechanisms of Injury

• Domestic Abuse
• between 0.9 and 20.1 of pregnant women are
  victims of domestic violence
• Self-harm
• Suicide was the cause of death in 13 of maternal
  deaths in one study (New York)

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General Management

• The most common cause of fetal death is maternal
  death, so efforts to assess fetal well being are
  second to resuscitation of the mother
• Fetal distress may be the earliest indication of
  maternal injury, so FHR should be used early as
  an adjunct to the secondary survey
• Prehospital tachycardia (HR gt110), chest pain,
  LOC, and 3rd trimester GA all independently
  correlate with the need for a trauma centre

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Primary Survey

• Should be no different in the pregnant patient
• Airway
• Fetal RBC have increased affinity for O2, so
  oxygen can provide significant improvement in
  fetal saturation
• Breathing
• Consider hyperventilation due to chronic resp.
  alkalosis
• ABG for acidosis, Base Deficit (hemorrhage) and
  hypoxia
• Circulation
• IVC compression ? need to displace uterus to the
  left
• Early crystalloid fluid resuscitation (RL vs NS)
• Avoid vasopressors ? reduce uterine blood flow
• Likely little roll for tocolytics
• Caudal central venous access if possible

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Primary Survey - 2

• Abdominal exam/Fetal Primary Survey
• Assess uterine size refetal viability (beware of
  uterine rupture)
• Viable fetus (22-26 weeks) 2-3 finger breadths
  above uterus
• Uterine Rupture/Abrutio Placentae
• Peritoneal finding will likely be masked
• Initial fetal heart tones (FHT) gt10 weeks
• Continuous Cardiotocographic monitoring (CTM) if
  viable fetus

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Algorithm
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Secondary Survey

• The secondary survey includes a more thorough
  fetal assessment, a pelvic exam and a history
  including pertinent prenatal information.
• Re-assessment of fetal viability
• CTM should be initiated in a viable fetus
• The pelvic exam includes a sterile spec exam for
  amniotic fluid, cervical dilation effacement,
  signs pelvic trauma, vaginal bleeding (/-
  cultures) but NO PELVIC IN T3 BLEEDS!
• Diagnostic adjuncts (labs, imaging)

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Intellectual Breather

• Who needs a preg test?

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Intellectual Breather

• Oldest person to give birth?
• Adriana Iliescu
• Age 66
• Romania
• 2005

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Intellectual Breather

• Youngest person to give birth?
• Lina Medina
• 5 years, 7 months
• Peru
• 1939

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Laboratory

• trauma labs plus Rh status, coags, fibrinogen
  levels
• ßhCG
• ve in serum 9d post conception
• ve in urine 28d after last menstrual period
• A Kleihauer-Betke test may be considered in an Rh
  ve mother for evaluation of fetal-maternal
  hemmorhage
• Complications include Rh sensitization, fetal
  anemia or fetal death from exsanguination
• Lab only screens for FMH of gt5mL, therefore all
  Rh ve mothers should receive prophylactic RhIG

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RhIG

• 1st trimester patients should receive 50mcg dose
  (covers 5mL bleeding) patients gt12 weeks should
  get 300mcg dose (protects against 30mL FMH)
• KB test quantifies FMH gt12 weeks may have more
  than 30mL FMH and need a second dose of RhIG
• RhIG effective if given in first 72 hours after
  FMH

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Diagnostic Imaging

• General rule If imaging is indicated, it should
  be done
• 1 rad of exposure no increase risk to the fetus
• 10 rad exposure carries only a small increase
  in the number of childhood cancers
• 15 rads exposure - carries a 6 chance of MR, 3
  chance of cancer, 15 chance of microcephaly
• gt20 weeks, radiation is unlikely to cause fetal
  anomalies, particularly if the exposure is lt10
  rads
• A CT abdo pelvis exposes the fetus to 5-10 rads

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Radiation Doses (mrad)

• Low dose plain film
• Head, c-spine, thoracic spine, chest, extremities
  (lt1 mrad)
• High dose plain film
• L-spine (204-1260)
• Pelvis (190-357)
• Hip (124-450)
• IVP (503-880)
• KUB (200-503)

• CT
• Head (lt50)
• Chest (lt1000)
• Upper abdomen (lt3000)
• Lower abdomen (3000-9000)

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Diagnostic Imaging Adjuncts

• Ultrasound/FAST
• Best modality for assessment of mother and fetus
  in setting of trauma, rapid and safe
• Sensitivity of 88, specificity of 99 for
  detecting abdominal injury in blunt trauma
• Screens for free fluid and establishes fetal well
  being, GA and placental location
• DPL
• Supra-umbilical approach, open technique
• Useful in the first trimester patient with an
  equivocal FAST, and later in pregnancy to help
  differentiate intraperitoneal bleeding from a
  uteroplacental source

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Algorithm
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Fetal Evaluation - FHT

• Fetal heart tones can be heard by doppler
  beginning at 10-14 weeks
• If FHR lt120 or gt160, fetal distress is likely and
  urgent obstetric consultation is indicated (they
  should hopefully be there already!)
• If FHR is normal, proceed to continuous CTM for
  at least four hours

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Fetal Evaluation

• CTM has an excellent sensitivity for detecting
  abruption 100 NPV for adverse outcomes if
  reassuring clinical exam and normal observation
  period
• If gt3 uterine contractions/hr, persistent uterine
  tenderness, non-reassuring fetal monitoring
  strip, vag bleeding, ROM, or serious maternal
  injury admit for long term monitoring
• CTM recommended for a minimum of 4 hours for all
  patients gt20 weeks GA with any multisystem or
  minor abdominal trauma
• Increase to 24 hours if any abnormalities

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CTM what are we looking for?

• Baseline FHR (120-160)
• Variability indicator of oxygenation
• Beat-to-beat (CNS)
• Long term (fetal activity)
• Periodicity
• Accelerations
• Decelerations

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CTM - Decelerations

• Early Decelerations
• Gradual and uniform in shape
• Early in contraction and quick return to baseline
• Benign, vagal response to head compression
• Variable Decelerations
• Variable in shape, onset and duration
• Usually due to cord compression
• Benign unless meets the rule of 60s
• decel to lt60bpm, gt60 below baseline, gt60s in
  duration

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CTM - Decelerations

• Late Decelerations
• Uniform shape
• Onset is late in contraction
• Must see 3 in a row (same shape)
• Due to fetal hypoxia, acidemia, maternal
  hypotension
• Sign of uteroplacental insufficiency

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CTM - Decelerations
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Discharge and Disposition

• Mother stable/fetus stable
• Should be instructed to record fetal movements
  for 1 week
• Should return to hospital if lt4 FM over 1 hour or
  lt10 FM in 12 hours
• Should also return if any abdominal pain, leaking
  fluid, vag bleeding, or gt6 uterine
  contractions/hr

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Algorithm
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Discharge and Disposition

• Mother stable/fetus unstable
• In trauma, fetal death rates are 3-9 times that
  of maternal death rates
• If a viable fetus remains in distress despite
  maternal optimization, c-section should be
  performed
• No survival if no fetal heart tone before
  emergency C-section begins
• If FH tones present and gt26 weeks, infant
  survival for emergency C/S is 75 in the trauma
  setting

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Algorithm
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Discharge and Disposition

• Mother unstable/fetus unstable
• If moms conditions is critical, primary repair
  of her wounds is the best course even if fetus is
  in distress
• However, extended and exclusive attention to the
  mother in cardiac arrest mother may prevent
  recovery of a potentially viable fetus
• If no response to ACLS and there is a potentially
  viable fetus (fundal height above the umbilicus
  FHT ve) a decision for perimortem c-section
  must be made

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Algorithm
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Perimortem Cesarean Section

• If performed at appropriate time, can benefit
  both fetus and mother (due to improvement in
  maternal circulation)
• If mother arrests and does not respond to
  resuscitative efforts within 4 minutes,
  preparation for open cardiac massage and
  C-section should begin
• 70 of children who survived perimortem
  C-sections were delivered in less than 5 min of
  onset of arrest (4 min resuscitation and prep
  time, 1 min delivery time)

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Perimortem Cesarean Section

• Vertical midline incision from epigastrum to
  symphysis pubis
• Penetrate all abdominal layers into peritoneum
• Vertical midline incision in anterior aspect of
  uterus from fundus to bladder (avoid paired
  uterine vessels laterally)
• Extend caudally using blunt dissection
  (scissors), placing your hand between the uterine
  wall and the fetus
• Deliver head and shoulders, body follows
  spontaneously
• Suction, clamp and cut cord, resuscitate neonate
  prn

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Questions?