Today’s algorithm is all about Trauma in pregnancy. Its a quick breakdown of the need-to-know basics!
PRIMARY SURVEY
1. Oxygen supplementation should be given to maintain maternal oxygen saturation > 95% to ensure adequate fetal oxygenation
2. If needed, a thoracostomy tube should be inserted in an injured pregnant woman 1 or 2 intercostal spaces higher than usual
3. vasopressors in pregnant women because of their adverse effect on uteroplacental perfusion should be used only for intractable hypotension that is unresponsive to fluid resuscitation
4. After mid-pregnancy, the gravid uterus should be moved off the inferior vena cava. This may be achieved by manual displacement of the uterus or left lateral tilt.
5. To avoid rhesus D (Rh) alloimmunization in Rh-negative mothers, O-negative blood should be transfused when needed until cross-matched blood becomes available
6. A Caesarean section should be performed for viable pregnancies (≥ 23 weeks) no later than 4 minutes following maternal cardiac arrest to aid with maternal resuscitation and fetal salvage
ADJUCNTIVE TESTING
1. FAST is recommended in pregnancy Sn and Sp similar to non-pregnant females
2. Radiation exposure with a cumulative dose of > 5 rads (50 mGy) is associated with an increased risk to fetus but limited to < 18 weeks gestation. See Appendix for details
3. Approximate values for CT radiation for >16 wks with cutoff of 250 mGy recommended:
a. CT Head/Neck and CXR are negligible
b. CT chest = 0.66 mGy
c. CT abd = 35 mGy
d. CT pelvis = 50 mGy
e. Total for CT C/A/P = 85.66 mGy
SECONDARY/TERTIARY SURVERY
1. If the fetus is viable (≥ 23 weeks), fetal heart rate auscultation and fetal monitoring can be initiated as soon as feasible.
2. In cases of vaginal bleeding at or after 23 weeks, speculum or digital vaginal examination should be deferred until placenta previa is excluded by a prior or current ultrasound scan
3. In addition to the routine blood tests, a pregnant trauma patient should have a coagulation panel including fibrinogen.
4. KB testing should be done in all Rh- negative pregnant trauma patients.
5. RhogamTM, anti-D IgG, should be given to all Rh D-negative pregnant trauma patients. In Rh-negative pregnant trauma patients, quantification of maternal–fetal hemorrhage by Kleihauer-Betke should be done to determine the need for additional doses.
a. A single dose of 300 mcg, administered within 72 hours of injury, provides protection against sensitization for up to 30 mL of fetal blood in the maternal circulation.
b. The feto-placental blood volume is estimated to be 120 mL/kg of fetal weight.
c. In most cases of traumatic maternal–fetal hemorrhage, the estimated volume of fetal blood in the maternal circulation is less than 15 mL and in more than 90% of cases it is less than 30 mL.
d. Therefore, the vast majority of Rh-negative patients are protected by one dose.
e. If the KB test indicates transplacental hemorrhage in excess of 30 mL fetal blood, additional doses of anti-D IgG may be required.
6. Tetanus vaccination is safe in pregnancy and should be given when indicated
OBSERVATION
1. All pregnant trauma patients with a viable pregnancy (≥ 23 weeks) should undergo electronic fetal monitoring for at least 4 hours. Ctxs <6/hour consider discharge, Ctxs ≥6/hour consider admission
a. ACOG recommends a minimum of 2-6 hours of monitoring post-trauma
b. Abruption has been reported to occur up to 24 hours after a traumatic insult. It has not been reported when <1 contraction is present in any 10-minute interval over a 4-hour period.
c. Thus, fetal monitoring can be discontinued after 4 hours if uterine contractions occur less frequently than every 10 minutes, the fetal heart tracing is reassuring, and there is no maternal abdominal pain or vaginal bleeding.
2. Pregnant trauma patients (≥ 23 weeks) should be admitted for 24-hour observation in the setting of: uterine tenderness, significant abdominal pain, vaginal bleeding, sustained contractions, rupture of the membranes, atypical or abnormal fetal heart rate pattern, high risk mechanism of injury(motorcycle, pedestrian, high speed crash), or serum fibrinogen < 2 g/L
a. In a prospective cohort study, 85 pregnant women (12 to 41 wks gestation) were compared with a control group of pregnant women matched for gestational age. Study subjects whose placentas were anteriorly placed were at increased risk for fetomaternal transfusion on comparison with other placental positions (47% vs 23.5%, p less than 0.05). Immediate adverse outcomes including abruptio placentae occurred frequently in the study group (9.4%) and were not predictable on the basis of injury severity. Four hours of CTM used as a screening tool was found to be an extremely sensitive (100%) but nonspecific indicator of immediate adverse outcomes. This study recommended that routine screening for fetomaternal transfusion occur in all pregnant women who suffer trauma during pregnancy beyond 11 weeks’ gestation and that a minimum of 4 hours of cardiotocographic monitoring occur in women greater than 20 weeks’ gestation. Patients were discharged home if contractions ceased or were less frequent than once every 15 minutes. Source: Pearlman MD, Tintinalli JE, Lorenz RP. A prospective controlled study of outcome after trauma during pregnancy. Am J Obstet Gynecol.
b. Another retrospective study of 271 pregnant patients, suggested monitoring for at least 24 hours only for a selected group of patients at high risk conditions. This high-risk group consisted of patients involved in motorcycle, pedestrian or high velocity collisions, those ejected from motor vehicles and patients demonstrating maternal tachycardia, abnormal fetal heart rate pattern, and high injury severity scores. Source: Curet MJ, Schermer CR, Demarest GB, Bieneik EJ 3rd, Curet LB. Predictors of outcome in trauma during pregnancy: identification of patients who can be monitored for less than 6 hours. J Trauma 2000;49:18–24.
ANTICIPATORY GUIDANCE
1. Every woman who sustains trauma should be questioned specifically about domestic or intimate partner violence.
2. During prenatal visits, the caregiver should emphasize the importance of wearing seatbelts properly at all times
RADIATION DOSE
1. MEASURES OF IONIZING RADIATION
a. DOSE measured in Rads or Gray(Gy) [1000mGy = 1Gy]
i. Amount of energy deposited per kg of tissue
b. Relative Effective Dose measured in Sieverts
i. Amount of energy deposited per kg of tissue normalized for biological effectiveness
ii. 1 Gy ~ 1 Sievert
2. Effect of Gestation Age on Exposure
a. 0-2 weeks all or none effect (Death of embryo) 50-100 mGy
b. 2-8 weeks Birth Defect/IUGR 200-250 mGy
c. 8-15 weeks Intellectual disability (high risk) 60-310 mGy
d. 8-15 weeks IQ drop 25pts / 1Gy
e. 8-15 weeks microcephaly 200 mGy
f. 16-25 wks Intellectual disability (low risk) 250-280 mGy
3. Fetal Radiation with Common Testing
a. Very low dose <0.1mGy
i. C-spine x-ray 2view
ii. Head or neck CT
iii. Extremity x-ray
iv. Chest x-ray (two views)
b. Moderate dose <10mGy
i. Abdominal x-ray (3mGy)
ii. Lumbar x-ray (10mGy
iii. Chest CT or CT PE (0.66mGy)
c. Higher-dose examinations (10–50 mGy)
i. Abdominal CT (35 mGy)
ii. Pelvic CT (50 mGy)
Source: ACOG Guidelines for Diagnostic Imaging During Pregnancy and Lactation e210 VOL. 130, NO. 4, OCTOBER 2017. Obstetrics and Gynecology
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