Caring for the Pregnant Trauma Patient
““Pregnancy can complicate the evaluation of a trauma patient, and we must be aware of the normal anatomic and physiologic changes that occur during pregnancy…”
INTRODUCTION
Trauma affects an estimated 8% of all pregnancies and is the leading cause of non-obstetric maternal morbidity and mortality. Pregnancy can complicate the evaluation of a trauma patient, and we must be aware of the normal anatomic and physiologic changes that occur during pregnancy, as well as the adjustments that must be made to our trauma algorithm. This post will review the keys to managing a pregnant trauma patient, as well as injuries and interventions specific to pregnancy.
EMERGENCY ROOM MANAGEMENT
Primary Survey
Airway: At baseline, pregnant patients have a decreased functional residual capacity due to the manual displacement of the diaphragm from the uterus. Additionally, they have higher rates of oxygen consumption due to the fetus. Pregnant patients will therefore have a decreased tolerance of hypoxia and apnea. Thus, supplemental oxygen should be given early.
All intubations in pregnant patients should be considered “difficult” airways. Data from anesthesia literature shows that rates of failed intubation are higher in the pregnant population compared to their non pregnant cohorts [2]. Increased mallampati scores, increased airway edema, mucosal friability and hyperemia can all contribute to a difficult airway [2]. Additionally, lower esophageal sphincter (LES) tone will be decreased during pregnancy due to hormonal changes, leading to a higher risk of aspiration. Prompt placement of an orogastric tube should follow intubation.
RSI medications that one would use in a non-pregnant patient are generally safe to use during pregnancy [3].
Breathing: The diaphragm is displaced cephalad from the uterus. If thoracostomy is necessary, this is typically done 1-2 rib spaces higher than normal (3rd-4th intercostal space). Hormonal changes will increase respiratory drive at baseline causing a respiratory alkalosis, thus recognize that a “normal” PaCO2 may represent impending respiratory failure.
Circulation: As with all trauma patients, patietns should have adequate access, with two large bore IVs. Recognizing subtle vital sign changes can be difficult but is extremely important. Knowing the changes in physiology during pregnancy will allow providers to recognize abnormal vital signs early. The table below outlines a rough estimate of physiologic changes that occur during pregnancy.
Lateral Supine Hypotension Syndrome occurs due to a gravid uterus compressing the IVC and decreasing venous return. Placing the patient in left lateral decubitus position or manually displacing the uterus to the left can improve cardiac output by as much as 30 percent. Large bore IVs in the upper extremities is reccomended over femoral cordis access to improve volume resuscitation.
If blood administration is necessary, give type O Rh (-) blood to reduce the risk of alloimmunization until cross matched products can be obtained.
Imaging During Pregnancy
FAST: There is limited data comparing sensitivity of bedside US for detection of intra-abdominal free fluid following trauma in pregnant vs. non-pregnant cohorts. Current data suggests that there is an equivalent to slightly lower sensitivity in the pregnant patient. Recognize that the growing uterus will cause “standard” FAST views to be more difficult to obtain, especially during later stages of pregnancy. The takeaway here is that a negative FAST is not a replacement for CT imaging if clinically indicated.
CT IMAGING: There is no data to support adverse outcomes in a fetus due to radiation exposure from CT imaging. Providers should discuss the potential risk of pregnancy loss, teratogenesis and neoplasm from high radiation exposure with pregnant patients, however, typically the benefits of imaging outweigh the risks. On average, imaging of the abdomen and pelvis will result in the highest dose of radiation to the fetus and ranges from 10 – 50 mGY. CDC and ACOG recommend radiation exposure be limited to less than 50 mGy throughout pregnancy [13].
PREGNANCY SPECIFIC COMPLICATIONS
Placental abruption is second only to maternal death as the most common cause of fetal death. It is defined as premature separation of the placenta from the uterine wall. In the setting of trauma, this occurs because the elastic musculature of the uterus moves relative to the rigid placenta. The clinical presentation can vary widely, ranging from asymptomatic (detected only upon delivery of placenta at birth) to severe abdominal pain associated with hemorrhagic shock. Diagnosis in the emergency department can commonly be made with CT, which is highly sensitive for abruption [10]. Ultrasound is not sensitive for placental abruption because hemorrhaging blood in the acute phase will be isoechoic to the surrounding placenta [3]. In a viable pregnancy, placental abruption can be diagnosed via tocometry after initial trauma work up is complete.
Uterine rupture is overall an uncommon complication of trauma during pregnancy (<1%), but should remain on the differential especially during penetrating trauma. Fetal bradycardia is often associated with uterine rupture. It carries a high fetal mortality but a low maternal mortality risk. Treatment involves initial stabilization of the mother as necessary and emergent c-section.
Premature rupture of membranes (PROM) is defined as rupture of membranes prior to onset of labor. Typical presentation will include report of “gush of fluid” or abdominal cramping. PROM puts the patient at higher risk for intra-amniotic infection and digital exam is contra-indicated. However, sterile speculum exam can assist in the diagnosis. Consultation with OB-GYN dictates further management, and patients should be transferred for definitive care following completion of the trauma workup.
Pre-term labor (PTL) is defined as parturition that occurs between 20 weeks and 36 weeks 6 days. Early consultation of OB-GYN is the mainstay of management. It should be noted that tocolytics are not indicated in PTL in the setting of trauma.
RESUSCITATIVE HYSTEROTOMY
It is recommended by the AHA and ACOG that resuscitative hysterotomy be performed within 4 minutes of cardiac arrest with a goal to have the fetus delivered within 5 minutes. The goal of this procedure is to relieve the aortocaval compression by the gravid uterus in attempt to save the mother, and as such should only be performed if the uterus is of “sufficient size” to cause compression (generally 24 weeks and above). As a quick rule of thumb: palpation of the uterus at the umbilicus roughly corelates to gestational age of 22 weeks and increases by about 1cm per week after this.
Procedural Steps:
Vertical incision 4-5cm below xyphoid to pubic symphysis through abdominal wall (skin, rectus abdominis, rectus fascia)
Parietal peritoneum incision and extension superior and inferior to allow visualization of uterus
Application of retraction
Remember that the bladder will be just inferior to uterus, adhered to inferior portion of the uterus
Midline vertical incision of the uterus, can be extended with scissor
Delivery of fetus: suction nose, cut cord, deliver placenta manually
Can leave the abdomen open to assess for continued bleeding, as atony is very common**
If closing, use 0 or 1 chromic suture in running locked stitch in one or two layers for uterus, then close fascia, peritoneum, then skin
** Uterine atony is the most common cause of continued hemorrhage. Consider giving direct injection of oxytocin into the uterus (IV unlikely to reach uterus during cardiac arrest). Can give 10 units of oxytocin in 9mL of saline.
TAKE-AWAYS
1. Trauma during pregnancy is common and is the leading cause of non-obstetric maternal morbidity and mortality.
2. Always expect a difficult airway.
3. Utilize left lateral decubitus positioning or manual uterine displacement to combat Supine Hypotension Syndrome.
4. FAST may be less sensitive during pregnancy. Obtain CT imaging when necessary, as it is generally considered safe.
5. Resuscitative Hysterotomy is intended to improve aortocaval compression in mother. Perform within 4 minutes of cardiac arrest.
AUTHOR: Ben Hagan, MD, is a fourth year emergency medicine resident at Brown Emergency Medicine
FACULTY REVIEWER: Michelle Myles, MD, is an attending physician/clinician educator at Brown Emergency Medicine
REFERENCES
1. Pilkington S, Carli F, Dakin MJ, Romney M, De Witt KA, Dore CJ, Cormack RS: Increase in Mallampati score during pregnancy. Br J Anaesth 1995; 74:638–42
2. Mushambi MC, Kinsella SM, Popat M, Swales H, Ramaswamy KK, Winton AL, Quinn AC; Obstetric Anaesthetists' Association; Difficult Airway Society. Obstetric Anaesthetists' Association and Difficult Airway Society guidelines for the management of difficult and failed tracheal intubation in obstetrics. Anaesthesia. 2015 Nov;70(11):1286-306. doi: 10.1111/anae.13260. PMID: 26449292; PMCID: PMC4606761.
3. Bryant, R. Post-intubation sedation for pregnant patients. R.E.B.E.L. EM. https://rebelem.com/post-intubation-sedation-for-pregnant-patients/
4. Sista, P. Chukwulebe, S. (2021, Jan 18). Intubating the pregnant patient in the ED. [NUEM Blog. Expert Commentary by Patel, S]. Retrieved from http://www.nuemblog.com/blog/intubating-the-pregnant-patient.
5. Richards JR, Ormsby EL, Romo MV, Gillen MA, McGahan JP. Blunt abdominal injury in the pregnant patient: detection with US. Radiology. 2004 Nov;233(2):463-70. doi: 10.1148/radiol.2332031671. PMID: 15516618.
6. Schmidt P, Skelly CL, Raines DA. Placental Abruption. [Updated 2022 Apr 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482335/
7. Loarca Chávez, A.D. (2021). Pneumonia During Pregnancy. In: Montufar, C., Hidalgo, J., Gei, A.F. (eds) Obstetric Catastrophes. Springer, Cham. https://doi.org/10.1007/978-3-030-70034-8_29
8. Pilkington S, Carli F, Dakin MJ, Romney M, De Witt KA, Doré CJ, Cormack RS. Increase in Mallampati score during pregnancy. Br J Anaesth. 1995 Jun;74(6):638-42. doi: 10.1093/bja/74.6.638. PMID: 7640115.
9. Suman V, Luther EE. Preterm Labor. [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK536939/
10. Brown MA, Sirlin CB, Farahmand N, Hoyt DB, Casola G. Screening sonography in pregnant patients with blunt abdominal trauma. J Ultrasound Med. 2005 Feb;24(2):175-81; quiz 183-184. doi: 10.7863/jum.2005.24.2.175. PMID: 15661948.
11. Wei SH, Helmy M, Cohen AJ. CT evaluation of placental abruption in pregnant trauma patients. Emerg Radiol. 2009 Sep;16(5):365-73. doi: 10.1007/s10140-009-0804-z. Epub 2009 Mar 11. PMID: 19277736; PMCID: PMC2716448.
12. Yoon I, Slesinger TL. Radiation Exposure In Pregnancy. [Updated 2022 May 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551690/
13. Guidelines for diagnostic imaging during pregnancy and lactation (no date) ACOG. Available at: https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/10/guidelines-for-diagnostic-imaging-during-pregnancy-and-lactation (Accessed: February 9, 2023).