Resuscitation of the Pregnant Trauma Patient – Pearls and Pitfalls

Authors: Geoff Jara-Almonte, MD (PEM Fellow, New York Methodist Hospital) and Hilary Fairbrother, MD  (EM Attending Physician, NYU) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital)

While on shift at a busy urban emergency department, you are notified by EMS dispatch of an ambulance en-route with a patient involved in a high-speed MVC.  They report she is a female, in her 20s or 30s, who is obviously gravid, but of unknown gestational age.  According to EMS vital signs are: HR 104, RR 25, BP 104/54, and SpO2 98% on room air.  They are requesting activation of your trauma team.

Trauma is the most common cause of non-obstetrical maternal death in the United States, and is estimated to complicate 1 in 12 pregnancies.  Blunt trauma is most common, with motor-vehicle accidents, assaults – often a result of intimate partner violence – and falls being the most common mechanisms.  Despite this, only a small percentage of trauma patients evaluated at any one institution are pregnant.  This novel clinical situation can lead to increased anxiety in an otherwise well-functioning team and may cause providers to become distracted from normal evaluation and treatment algorithms.

It is important to recall that the best fetal resuscitation is good maternal resuscitation.  Doing the simple things well, such as optimizing maternal hemodynamics and oxygenation, will ensure the best fetal outcomes.  Preparing ahead of time with simulated resuscitations or mental rehearsal will improve your chance of successfully managing this stressful situation.

Once the patient arrives she is in much worse condition than you expected.  She is confused, agitated, and not following commands.  She is breathing rapidly and shallowly, her vital signs: HR 140, BP 90/40 and SpO2 92% on 2L NC.  She has bruising to the abdomen, subcutaneous emphysema of the chest wall.  You decide she needs immediate airway management due to impending respiratory failure, and chest tube placement for suspected pneumothorax.  While your team members are preparing for intubation and thoracostomy, you perform a rapid extended FAST exam.  You have difficulty visualizing her left chest or heart due to subcutaneous emphysema, you do not see good lung sliding on the left, and you do not see any abdominal free fluid.  There is a fetal heartbeat.  As you perform the exam, you wonder if the FAST is as reliable for detecting free fluid in the gravid patient…

The FAST is less sensitive for free fluid in the pregnant patient than in non-pregnant patients.  Sensitivity decreases with increasing gestational age, likely due to altered fluid flow within the abdomen.

• Three retrospective case studies examined the sensitivity and specificity of abdominal ultrasound in detecting intra-abdominal injury in pregnant trauma patients.  The largest from UC Davis enrolled 328 pregnant trauma patients including 23 who had intra-abdominal injuries.  Sensitivity of FAST was 61% (95% CI 39 – 80) and specificity 94.4% (95% CI 91 – 97) in this group.  This was lower than in non-pregnant female patients of child-bearing age in whom sensitivity of FAST was 71.2% (95% CI 64 – 77) and specificity 97.4% (95% CI 97 – 98).  FAST was most sensitive in the 1st trimester and least in the 3rd.  The authors theorize this may be due in part to compression of the paracolic gutters and altered intra-abdominal fluid flow in late pregnancy.  The other two case series reported higher sensitivities, but were both much smaller.,  By comparison, a recent unstructured review of studies of the FAST exam in non-pregnant patients, reported sensitivities from 64% – 98%.

Your nurses have RSI meds drawn up and you have your tube ready.  The patient has been placed on a NRB and her sats are 100%.  Your intern is preparing to place a left sided chest tube.  As your nurses prepare to push your RSI meds you try to recall if there is anything special you should recall about airway management of the pregnant patient.

Expect a difficult airway, optimize pre-oxygenation and positioning, and expect significant edema and mucosal friability.

• The anesthesia literature estimates the rate of failed intubation during emergency cesarean section from 1 in 250 to 1 in 750.  This is significantly higher than in the general anesthesia population.  Much of this data comes from older studies conducted prior to the age of video laryngoscopy and other modern airway adjuncts, so it may be in a modern cohort that this rate would be lower.  This assumption is supported by a 2009 study which reported 0 failed and 23 difficult intubations in 3,430 cases of obstetric general anesthesia.  However a more recent survey-based study from Britain estimated a rate of failed intubation of 1 in 224.11
• The same factors that predict a difficult airway in the non-pregnant population (Mallampati score, body habitus, short neck, and large incisors) are also predictive of a difficult airway in pregnancy.  However there are other changes in pregnancy that can increase the difficulty of intubation.  These include airway edema associated with the progesterone-mediated increase in total-body water as well as increased mucosal friability and as a result a higher likelihood of bleeding during manipulation.
• The risk of aspiration is also increased due to decrease in lower esophageal sphincter tone and increased intra-abdominal pressure from the gravid uterus.  In order to decrease the risk of aspiration, positive pressure ventilation should be avoided if possible.  If bagging is required lower volumes and slower inhalation times are recommended. Some authors recommend routine use of cricoid pressure during intubation of pregnant patients (controversial).
• Oxygen consumption increases throughout pregnancy by 30-60%, however there is a decrease in total lung volume due to upward displacement of the diaphragm.  Minute ventilation is increased, primarily through an increase in tidal volume (rather than an increase in RR).  As a result patients may desaturate much more quickly when hypopnea or apnea are present.14,16  Estimation of minute ventilation based solely on respiratory rate will underestimate ventilatory needs due to increased tidal volume. Close attention should be paid to maximizing pre-oxygenation and de-nitrogenation.

You have a surprisingly difficult time obtaining a view, and there is some mild bleeding, but you manage to pass a bougie; the 7.5 tube meets resistance, but you had a 6.5 prepared as well, and that passes easily.   As you look up your intern is about to place a chest tube.  She asks you if there’s anything different about performing tube thoracostomy in the pregnant patient.

In late pregnancy, consider placing a chest tube higher than you would in a non-pregnant patient.

• In advancing pregnancy there may be cephalad displacement of the diaphragm up to 4 cm.   Caution should be taken to avoid inadvertent trans-hepatic or trans-splenic thoracostomy tube placement. Some authors suggest insertion of a chest tube in the 3rd or 4th intercostal space instead of the 5th.,

Your intern successfully places a chest tube, there is return of air and blood, however your patient’s hemodynamics do not improve.  On the next cuff cycle you see that her pressure is 70/30 and HR of 170.  One of your nurses asks if you want to try rolling the patient to see if that helps, you also want to place additional access, and are debating between placing a femoral cordis or trying to find better upper extremity access.

The patient should be positioned to reduce compression of the great vessels by the gravid uterus.

• The weight of the gravid uterus falls posteriorly in the supine patient, and may compress the IVC and aorta causing reduced venous return and resultant hypotension.  It is commonly reported that placing the patient in 15 – 30 degrees of left lateral tilt may improve cardiac output by 30-50%, but it is unclear where this data comes from.ix,, In one study of manual leftward displacement versus lateral tilt in patients undergoing cesarean section, leftward displacement was associated with less hypotension and decreased pressor requirements. The AHA guidelines on cardiac arrest give supine positioning and manual leftward uterine displacement during CPR a IIa recommendation, and left lateral tilt IIb.

Attempt to obtain supra-diaphragmatic intravenous or intraosseous access for volume resuscitation and medication administration.

• The gravid uterus causes compression of the IVC and may reduce venous return from the lower extremities, limiting the utility of volume or resuscitation or medication administration by infra-diaphragmatic access.

You get two more 16ga IVs in the upper extremities, you order blood and activate your massive transfusion protocol.  One of your teams is assigned to maintain manual leftward uterine displacement.  While waiting for the blood to arrive, you hang 2L NS on pressure bags, when blood arrives you hang the blood on a Level 1 infuser.  You’ve paged trauma surgery and OB, but they’ve yet to arrive.  You repeat the FAST exam but still see no abdominal free fluid.  It seems that her hemodynamics are improving, her HR is down to 130, though BP remains 80/30.  Portable chest xray is done showing ET and chest tube in good position. You also note bilateral pulmonary contusion, small residual L pneumothorax and hemothorax.  Xray of the pelvis demonstrates no obvious fracture.  Surgery calls down and asks for a CT scan to look for retroperitoneal injury.  As you prepare her for the scanner your medical student asks if it’s safe to get a CT of a pregnant patient.

CT imaging should be performed as clinically indicated; diagnostic studies, including CT of the abdomen and pelvis, will not expose the fetus to an unsafe amount of radiation.  Contrast agents should be used if indicated.

• According to the American College of Radiology, doses of less than 50 mGy are not associated with increased rates of fetal anomaly or loss. The typical dose of radiation to which a fetus would be exposed during the initial trauma evaluation should be less than this.  For example a CT of the head, C-spine, chest, abdomen, and pelvis exposes the fetus to 25.2 mGy.2  Nevertheless, exposure to ionizing radiation is not without consequence.  A fetal dose of 50 mGy increases the risk of childhood cancer from 1:2000 to 1:1000, and increases the lifelong risk of cancer by 2%.
• Iodinated contrast material should be used in the setting of trauma.2 It is a pregnancy category B drug; the benefit in diagnostic imaging of the trauma patient likely outweighs the risks.

As you prepare the patient for CT scan, her HR continues to drop and she becomes precipitously bradycardic and loses pulses.  On ultrasound you see agonal cardiac activity without pericardial effusion.  Your team starts chest compressions and you ask for epinephrine and bicarbonate.  You re-examine the abdomen, and note a uterine fundus about 6 cm above the umbilicus.  You have the NICU and OB paged again.  After your first pulse check at 2 min she has bradycardic electrical activity on the monitor with no pulses and agonal activity on ultrasound.  You try to decide if it would be appropriate to emergently deliver the fetus.

Perimortem cesarean section should be performed by emergency providers in cases of maternal cardiac arrest and a pregnancy sufficiently advanced to cause aortocaval compression.  Ideally this would be initiated within 4 minutes of arrest; however even after substantial delay may be beneficial to both mother and fetus.

• AHA guidelines recommend prompt perimortem C-section to alleviate aortocaval compression and allow extra-uterine fetal resuscitation.  Prior guidelines have recommended waiting 4-5 minutes after arrest before beginning perimortem cesarean section to determine if medical therapy will be effective in achieving ROSC.  The 2010 AHA guidelines do not recommend a mandatory trial of medical therapy prior to initiating cesarean section, and suggest that in some cases including clearly non-survivable maternal injury, it may be beneficial to the fetus to begin the procedure as soon as maternal arrest occurs.20
• Even in the case of a nonviable fetus, perimortem cesarean section may improve maternal hemodynamics by alleviating aortocaval compression.  The 2010 AHA guidelines suggest that it should be considered for pregnancies thought to be 20 weeks or greater, which can be estimated by finding the uterine fundus at or above the level of the umbilicus.20
• For viable fetuses, outcomes are best when delivery occurs within 5 minutes of maternal arrest, however there have been fetal survivors delivered after delay as great as 30 minutes.20
• In a large structured review of case reports of perimortem cesarean section 29 of 38 cases produced a fetal survivor.  Maternal condition improved in 12 of the 18 cases in which it was recorded.  However the primary cause of arrest in this series was medical, with only 8 of 38 arrests due to trauma.
• Lack of a complete surgical tray should not prevent initiation of perimortem cesarean section.  Knife and scissors are the only instruments needed.  Due to the low cardiac output associated with maternal arrest, minimal bleeding should be expected unless ROSC occurs.  Consideration should be given to concomitant thoracotomy if indicated.
• For an excellent review of the procedure, see this EMCRIT podcast

You make a midline incision, make a large midline uterine incision, and manage to extract a cyanotic baby whom you pass off to the NICU team.  Almost immediately maternal hemodynamic status begins to improve.  You note a marked increase in bleeding from the hysterotomy site, pulses return, and you and the OB resident quickly sew the uterus closed, pack the abdomen, and her heart rate returns to 150.  OB and trauma surgery arrive, and rush the patient to the OR.

Managing the resuscitation of a critically ill pregnant trauma patient is a novel, high-stress clinical scenario.  You must be prepared for not only the medical challenges of the resuscitation but also the interpersonal dynamics of leading a team that includes multiple consultants with diverse interests.  Both simulation and mental rehearsal are excellent ways to prepare, anticipate challenges, and formulate algorithms you can easily access when the situation does occur.

Below is a table summarizing some of the key points discussed above. Copy it, put it in your Evernote, on an index card, or whatever peripheral brain you keep.  Next time you see a pregnant patient ask yourself – what would I do in this or that scenario.  Take a second to re-familiarize yourself with these pearls of traumatic resuscitation of the pregnant patient.  Be ready when EMS dispatch calls in a notification.

References

Brown, Michèle A., et al. “Screening sonography in pregnant patients with blunt abdominal trauma.” Journal of ultrasound in medicine 24.2 (2005): 175-181.

Richards, John R., et al. “Blunt Abdominal Injury in the Pregnant Patient: Detection with US 1.” Radiology 233.2 (2004): 463-470.

Goodwin, Hillary, James F. Holmes, and David H. Wisner. “Abdominal ultrasound examination in pregnant blunt trauma patients.” Journal of Trauma-Injury, Infection, and Critical Care 50.4 (2001): 689-694.

Körner, Markus, et al. “Current Role of Emergency US in Patients with Major Trauma 1.” Radiographics 28.1 (2008): 225-242.

Quinn, A. C., et al. “Failed tracheal intubation in obstetric anaesthesia: 2 yr national case–control study in the UK.” British journal of anaesthesia 110.1 (2013): 74-80.

Djabatey, E. A., and P. M. Barclay. “Difficult and failed intubation in 3430 obstetric general anaesthetics*.” Anaesthesia 64.11 (2009): 1168-1171.

Rocke, D. A., et al. “Relative risk analysis of factors associated with difficult intubation in obstetric anesthesia.” Anesthesiology 77.1 (1992): 67-73.

Hill, Christina C., and Jennifer Pickinpaugh. “Physiologic changes in pregnancy.” Surgical Clinics of North America 88.2 (2008): 391-401.

Dennehy, Kevin C., and May CM Pian-Smith. “Airway management of the parturient.” International anesthesiology clinics 38.3 (2000): 147-159.

ACEP News; Focus On: Emergency Airway Management in the Pregnant Patient, July 2007 http://www.acep.org/Clinical—Practice-Management/Focus-On–Emergency-Airway-Management-in-the-Pregnant-Patient/ Accessed 10/31/2014

Stewart, Charles J. “The diaphragm in pregnancy.” Tubercle 32.2 (1951): 40-43.

Brown, Haywood L. “Trauma in pregnancy.” Obstetrics & Gynecology 114.1 (2009): 147-160.

Mendez-Figueroa, Hector, et al. “Trauma in pregnancy: an updated systematic review.” American journal of obstetrics and gynecology 209.1 (2013): 1-10.

Shah, Amol J., and Bradford A. Kilcline. “Trauma in pregnancy.” Emergency medicine clinics of North America 21.3 (2003): 615-629.

Hill, Christina C., and Jennifer Pickinpaugh. “Trauma and surgical emergencies in the obstetric patient.” Surgical Clinics of North America 88.2 (2008): 421-440.

Kundra, P., et al. “Manual displacement of the uterus during Caesarean section.” Anaesthesia 62.5 (2007): 460-465.

Hoek, Terry L. Vanden, et al. “Part 12: Cardiac Arrest in Special Situations 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.” Circulation 122.18 suppl 3 (2010): S829-S861.

American College of Radiology and the Society for Pediatric Radiology. ACR-SPR practice guideline for imaging pregnant or potentially pregnant adolescents and women with ionizing radiation. http://www.acr.org/~/media/9e2ed55531fc4b4fa53ef3b6d3b25df8.pdf. Published 2013. Accessed Oct 30th 2014

Raptis, Constantine A., et al. “Imaging of Trauma in the Pregnant Patient.”RadioGraphics 34.3 (2014): 748-763.

Katz, Vern, Keith Balderston, and Melissa DeFreest. “Perimortem cesarean delivery: were our assumptions correct?.” American journal of obstetrics and gynecology 192.6 (2005): 1916-1920.