Presentation on theme: "Trauma in Pregnancy James Huffman Resident Rounds – October 12, 2006 Thanks to Yael and Shawn."— Presentation transcript:
Trauma in Pregnancy James Huffman Resident Rounds – October 12, 2006 Thanks to Yael and Shawn
Epidemiology Trauma occurs more often during the 3 rd trimester than at any other time in a woman’s 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
Challenges Smaller evidence base Two patients Determining fetal viability Physiologic and anatomic changes 1-3% of minor trauma results in fetal death!
Approach Four groups: 1. Early pregnancy – mothers not aware, vulnerable to radiation 2. Fetus not yet viable – well protected in bony pelvis, required maternal survival for development 3. Viable pregnancies (>24-26 weeks) – most challenging, two patients to consider 4. Perimortem – resuscitation +/- C-section Being pregnant does not affect maternal survival The most common causes of fetal death are maternal death and placental abruption*
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 7 th month pelvic x-rays “Supine Hypotensive Syndrome” At >20 weeks GA, the uterus can compress the IVC, decreasing preload
Cardiovascular Changes Some changes present like shock: Hypotension declines in T1, stabilizes in T2, returns to normal in T3 SBP (2-4 mmHg) < DBP 5-15mmHg d/t progesterone and supine hypotensive syndrome Increased baseline HR (usu 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!
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
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!
Gastrointestinal Changes ↓ GE sphincter tone and gastrointestinal motility ↑ acid production in stomach Increased risk of aspiration!
Hematologic Changes Blood volume increased more than RBC mass dilutional “anemia” (Hg as low as 100, and Hct of 32-34%) ↑ WBC (up to ) 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.
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
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 <50%, clinical signs and symptoms are often also unreliable Incidence of fetal loss from minor trauma is 1.7%
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)
Burns In severe burns there is a dramatic increase in fetal mortality, approaching 100% for burns >50% TBSA; only 6% survival for burns >30% TBSA Risk to the fetus is maternal death, fetal death, and preterm labor (PGE 2 ) Maternal carbon monoxide levels are a poor predictor of fetal carboxyhemoglobin
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)
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 >110), chest pain, LOC, and 3 rd trimester GA all independently correlate with the need for a trauma centre
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
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)
Intellectual Breather… Who needs a preg test?
Intellectual Breather… Oldest person to give birth? Adriana Iliescu Age 66 Romania 2005
Intellectual Breather… Youngest person to give birth? Lina Medina 5 years, 7 months Peru 1939
Laboratory “trauma labs” plus Rh status, coags, fibrinogen levels βhCG: +’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 >5mL, therefore all Rh –’ve mothers should receive prophylactic RhIG
RhIG 1 st trimester patients should receive 50mcg dose (covers 5mL bleeding); patients >12 weeks should get 300mcg dose (protects against 30mL FMH) KB test quantifies FMH – >12 weeks may have more than 30mL FMH and need a second dose of RhIG RhIG effective if given in first 72 hours after FMH
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 >20 weeks, radiation is unlikely to cause fetal anomalies, particularly if the exposure is <10 rads A CT abdo pelvis exposes the fetus to 5-10 rads
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
Fetal Evaluation - FHT Fetal heart tones can be heard by doppler beginning at weeks If FHR 160, 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
Fetal Evaluation CTM has an excellent sensitivity for detecting abruption; 100% NPV for adverse outcomes if reassuring clinical exam and normal observation period If >3 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 >20 weeks GA with any multisystem or minor abdominal trauma Increase to 24 hours if any abnormalities
CTM – what are we looking for? Baseline FHR ( ) Variability – indicator of oxygenation Beat-to-beat (CNS) Long term (fetal activity) Periodicity Accelerations Decelerations
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 60’s: decel to 60 below baseline, >60s in duration
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
CTM - Decelerations
Discharge and Disposition Mother stable/fetus stable: Should be instructed to record fetal movements for 1 week Should return to hospital if <4 FM over 1 hour or <10 FM in 12 hours Should also return if any abdominal pain, leaking fluid, vag bleeding, or >6 uterine contractions/hr
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 >26 weeks, infant survival for emergency C/S is 75% in the trauma setting
Discharge and Disposition Mother unstable/fetus unstable If mom’s 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
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)
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