Trauma in pregnancy

Question 1

List the top three causes of trauma in pregnant patients

Answer 1

• MVAs
• Falls
• Domestic abuse

Question 2

What clinical signs suggest fetal viability.

Answer 2

• >24/40 gestation
• Fundus palpable above the umbilicus
• >500g fetus (??)

Question 3

List common physiological changes in pregnancy.

Answer 3

CV

• Inc’d HR
• Inc’d CO
• Dec’d MAP in 1st and 2nd trimester - usually normalises in third
• Inc’d blood volume - 40-50%
• Inc’d RBC production - only 20%, therefore ->
• Dec’d HCT/relative anemia

Resp

• Inc RR
• Inc MV - 40% -> hypocapnia and inc’d pH (physiologic resp alkalosis)
• Reduced VC

GI

• Dec’d gastric emptying
• Incompetent oeshophageal sphincter -> inc’d reflux and risk of aspiration

Anatomic

• Diaphragm pushed up
• Abdo contents pushed up
• Uterus in abdo
  
  • emerges from pelvis at 12/40
  • umbilicus at 20/40
  • costal margins 34/40
• Bladder and intestines more vulnerable to injury due displacement

Lab

• 50% inc in BV + 20% inc in RBCs -> physiological anemia
• placental progesterone -> inc’d MV -> pCO2 ~30 -> physiologic resp alkalosis
• ECG -> Leftward axis shift ~15degrees; T-waves flatten +/- Q-waves in III

Question 4

List the important specific considerations in the mgt of the pregnant trauma patient.

Answer 4

1. Physiologic changes of pregnancy can mimic shock:
   
   1. Inc’d baseline HR (~10bpm)
   2. DBP falls more than SBP -> widened pulse pressure
2. Gravid uterus syndrome
   
   1. IVC compressed -> dec’d VR -> dec’d CO
   2. Left lateral tilt 15-30degs
   3. Elevate legs
3. Physiologic changes of pregnancy can mask shock:
   
   1. BV inc’s by 40-50% -> greater circulatory reserve -> more able to compensate -> precipitous decompensation
4. Physiologic changes of pregnancy can exacerbate traumatic bleeding:
   
   1. Inc’d CO
   2. Uterine bleeding -> major source of bleeding and vulnerable to trauma
5. Pulmonary issues
   
   1. Higher O2 demands, lower VC - reduced oxygen reserve -> faster desaturation
   2. Inc’d MV -> baseline hypocapnia - normal CO2 may suggest tiring!
   3. Difficult to ventilate (BVM)
   4. Rapid desaturation at RSI
6. GI issues:
   
   1. Reduced oesophageal sphincter tone
   2. Dec’d GI motility
   3. Both lead to inc’d risk of aspiration

Question 5

List the indications of fetal distress.

Answer 5

• Dec’d fetal mvts
• Monitoring
  
  • Baseline HR - outside normal 120-160bmp
  • Dec’d beat-to-beat variability
  • Variable decelerations
  • Late decelerations

Question 6

List 6 signs of placental abruption.

Answer 6

• Painful PV bleeding
• Signs of fetal distress on CTG
  
  • Abnormal HR
  • Lack of beat-tobeat variability and long term variability
  • Variable decelerations
  • Late decelerations
• Maternal shock
• Evidence of maternal abdominal trauma
• Premature labour, contractions
• Uterus painful on palpation

Question 7

How can placental abruption be diagnosed?

Answer 7

• Predominantly a clinical diagnosis
• USS - only 50% sensitive
• Kleihauer-Betke blood test
• Fetal CTG monitoring

Question 8

How is placental abruption managed?

Answer 8

• If fetus stable or <32wks -> monitoring/expectant mgt
• >32/40 + fetal distress -> emergent caesarian section

Question 9

List four complications (fetal and maternal) of placental abruption.

Answer 9

1. Premature labour
2. Fetal hypoxia/demise
3. Maternal haemorrhage
4. Maternal DIC

Question 10

List the two most common uterine injuries that result from trauma.

Answer 10

1. Uterine irritability - prostaglandin release -> uterine contractions
2. Uterine rupture - usually associated with pelvic fractures - difficult to diagnose:
   
   1. fetal parts palpable
   2. massive haemoperitoneum
   3. shock

Question 11

What is the safe dose of radiation in pregnancy?

Give examples of radiation doses for CT head, CXR

What imaging modalities can therefore be considered.

Answer 11

Fetal damage is rare < 5-10rads

Fetus more sensitive in first trimester.

XR

1CXR + 1 pelvic XR < 200-2000mRAD

Shield the fetus!

CT

CT head ~15mRAD

CT pelvis ~9rads

CT abdo ~3rads

CT head and chest <1rad

Question 12

List the changes to the primary survey in a pregnant woman.

Answer 12

As per normal, except

1. A + B - early O2, difficult RSI, inc’d risk of aspiration
2. C - shock may be mimicked or masked. Tilt mum!
3. Is the baby viable? >24wks
   
   1. if no -> ignore the fetus.
   2. if yes -> resus mum and check fetal HR ? emergency c/s
4. Has the mother arrested?
   
   1. if yes + >24/40 + fetal heart rate present -> consider peri-mortem c/s
   2. if yes and <24/40 or no fetal heart rate -> consider ceasing resus
   3. if no - cont maternal resus

Question 13

What is the name of the test to diagnose feto-maternal haemorrhage?

Answer 13

The Kleihauer-Betke test