The Management of Pregnant Trauma Patients: A Narrative Review

Trauma in pregnancy involves unique clinical considerations as both maternal and fetal factors need to be balanced during resuscitation efforts. Trauma is the leading nonobstetric cause of maternal death and affects about 1 in 12 pregnancies in the United States.1 Overall, trauma in a pregnant patient results in a 3.8% maternal and 9.4% fetal mortality rate, respectively.2 The most common causes of trauma in pregnant women include motor vehicle accidents (49%–70%), domestic violence (11%–25%), and falls (9%–23%).3–6 When classified by injury type, blunt trauma (69%) is far more common than penetrating trauma (1.5%).5 While severe trauma is associated with premature labor, low birth weight, and fetal demise (40%–50% risk), minor injuries are also significantly associated with increased fetal mortality (adjusted odds ratio of 1.78; 95% CI, 1.05–3.03 in the first trimester and 1.65; 95% CI, 1.01–2.73 in the second trimester).7

An audit at 2 trauma centers on the management of pregnant patients who experienced motor vehicle accidents suggests that fetal care may be overemphasized at the expense of basic trauma care to the mother.8 While most patients underwent a fetal ultrasound evaluation (233 of 236, 98.7%) and had fetal heart monitoring for viable pregnancies (162 of 169, 96%), maternal vital signs were often not documented while focused assessment with sonography for trauma (FAST) was either omitted or delayed.8

F1Figure 1.:

Physiologic changes of pregnancy. aPTT indicates activated partial thromboplastin clotting time; FRC, functional residual capacity; GFR, glomerular filtration rate; INR, international normalized ratio; Paco 2, arterial partial pressure of carbon dioxide; PT, prothrombin time; SVR, systemic vascular resistance.

All pregnant trauma patients warrant a comprehensive trauma assessment that takes priority over the assessment of the fetus.6,8,9 While this is an expert recommendation, the overriding principle is that maternal resuscitation is the best means of fetal resuscitation, and achieving maternal hemodynamic stability should be the first priority in the management of obstetric trauma. During initial assessment, it is imperative to account for physiological changes of pregnancy, especially with regard to the cardiovascular, respiratory, and hematologic systems. Clinicians should also be aware of modifications in airway management and advanced cardiac life support when caring for pregnant trauma patients.

PHYSIOLOGIC CHANGES IN PREGNANCY AND THEIR IMPLICATION ON THE MANAGEMENT OF THE TRAUMA PATIENT

The resuscitative and anesthetic management of the obstetric trauma patient is greatly impacted by numerous physiologic changes that occur during pregnancy. The multisystem changes are summarized in the sections below and in Figure 1.10–22

Cardiovascular

The cardiovascular system must undergo multiple adaptations during pregnancy to ensure adequate blood flow to the uterus and growing fetus. Blood volume increases significantly beginning in the first trimester and peaking at 32 to 34 weeks gestational age (GA). This primarily consists of an expansion of plasma volume, which can increase as much as 40% to 50% above nonpregnant values.10 In addition, heart rate will typically increase by 15% to 25%.11 The combination of expanding blood volume and heart rate results in a rise in cardiac output at term to as much as 50% above prepregnancy values.12 On the other hand, systemic vascular resistance declines by about 20%.13 This is accompanied by a decrease in both systolic and diastolic blood pressure by about 5 to 15 mm Hg. However, the decline in blood pressure nadirs midpregnancy and returns to baseline near term.11 The concomitant changes in blood pressure and heart rate, along with the other compensatory cardiovascular changes, may obscure the diagnosis of hypovolemia or hemorrhagic shock in the trauma patient. Clinicians should be careful not to be falsely reassured by normal hemodynamic parameters, as these patients can initially tolerate acute blood loss until they eventually reach a critical point.5 Therefore, hypotension in a pregnant trauma patient usually presents with profound hemorrhagic shock with substantial loss of circulating volume and should prompt initiation of a massive transfusion protocol.

Care must also be taken to avoid aortocaval compression by the gravid uterus when positioning pregnant patients. Supine hypotension can occur as a result of decreased venous return due to compression of the inferior vena cava and can further compromise both mother and fetus.23,24 This can occur as early as 20 weeks GA, which corresponds to when the uterus can be palpated at the level of the umbilicus. Supine hypotension can be alleviated by placing the patient in a left lateral tilt of 30°.25 Lesser degrees of lateral tilt are not effective in relieving the compression, while larger degrees are not beneficial and may impede care of the patient.25 Clinicians should be mindful to avoid placing the patient in the supine position especially during the initial survey and while obtaining imaging. However, should chest compressions be deemed necessary, the patient should be placed supine with a firm backboard underneath them, and 2-handed manual left uterine displacement (LUD) should be performed during resuscitation.26

Respiratory

An increase in minute ventilation occurs during pregnancy as a result of increased tidal volumes.14 By contrast, respiratory rates remain essentially unchanged. This relative hyperventilation results in a respiratory alkalosis, which will be evident on arterial blood gases. Both pH and arterial partial pressure of carbon dioxide (Paco2) may be slightly changed from baseline with normal pH values in pregnancy ranging from 7.42 to 7.46 and Paco2 values decreasing to 27 to 32 mm Hg.15 Improvements in alveolar ventilation also result in a higher Pao2 (100–107 mm Hg) beginning early in pregnancy.27 This is increased from normal, nonpregnant Pao2 values of 75 to 100 mm Hg on room air.28 These changes should be considered in patients receiving mechanical ventilation. Functional residual capacity (FRC), on the other hand, is significantly reduced due to cephalad displacement of the diaphragm by the gravid uterus.14 FRC begins to significantly decrease at around 6 months GA and continues to decrease during the remainder of pregnancy.29 This decline in FRC, in combination with a higher oxygen consumption due to utilization by the growing uterus and fetus, will result in rapid desaturation during periods of apnea.30 It is with this in mind, that if induction and tracheal intubation are required, they occur with precision and haste.

F2Figure 2.:

Management of the obstetric trauma patient. ACLS indicates advanced cardiac life support; GA, gestational age; LUD, left uterine displacement; Paco 2, arterial partial pressure of carbon dioxide; ROSC, return of spontaneous circulation; ROTEM, rotational thromboelastometry; TEG, thromboelastography; TXA, tranexamic acid. Adapted from Varon AJ, Smith CE (eds.). Essentials of Trauma Anesthesia, 2nd Ed. Cambridge, Cambridge University Press, 2018 and Chestnut DH, Wong CA, Tsen LC, et al (editors). Chestnut’s Obstetric Anesthesia: Principles and Practice 6th Ed. Philadelphia, Elsevier, 2020.

Multiple changes to the airway will also impact management when considering tracheal intubation. The proportion of women with Mallampati IV airways increases during pregnancy. Furthermore, even women with favorable appearing airways may prove to be difficult to intubate due to edema of the soft tissues as a result of vascular engorgement.16,31 Practitioners should opt for smaller tracheal tubes (6–6.5 mm internal diameter) due to these changes.32 The edema may also lead to increased friability of the tissues and bleeding into the airway, which may obscure laryngoscope views. Therefore, opting for the practitioner and technique with the highest chance of first-pass intubation may be warranted.

Renal

As a consequence of elevated cardiac output and blood volume, renal blood flow is significantly increased resulting in a rise in glomerular filtration rate (GFR) of up to 60% above prepregnancy values.17 As a result, creatinine and blood urea nitrogen (BUN) values are significantly reduced, which may obscure the diagnosis of acute kidney injury.33 Furthermore, renal compensation of respiratory alkalosis leads to a decrease in serum bicarbonate (19–22 mEq/L) and a reduction in buffering capacity. Normal base deficit is around 2 to 3 mEq/L.18

Hematologic

A physiologic anemia develops during pregnancy as a result of plasma volume expanding out of proportion to red blood cell (RBC) volume growth.19 Consequently, hemoglobin levels are slightly lower than nonpregnant values (roughly 10–12 g/dL).20 In addition, pregnancy is a hypercoagulable state resulting from significantly increased levels of fibrinogen, von Willebrand factor, and factors VII, VIII, IX, X, and XII.21 In contrast, profibrinolytics, such as protein C and S, remain unchanged and slightly decreased, respectively.34 The result is slightly lower than normal activated partial thromboplastin time (aPTT), prothrombin time (PT), and international normalized ratio (INR) and significantly higher than normal fibrinogen level with expected values increasing by almost 200%.21,22 These changes are meant to help mitigate acute blood loss and coagulopathy and may actually prove protective during trauma. However, clinicians should not be falsely reassured by laboratory tests alone. Normalization of fibrinogen values, for example, may be a warning sign of severe hemorrhage and impending disseminated intravascular coagulation (DIC). Viscoelastic testing has gained wide acceptance to diagnose and manage trauma-induced coagulopathy. If available, viscoelastic testing should be utilized in all pregnant trauma patients given the complex coagulation picture when the hypercoagulable state of pregnancy is intertwined with full spectrum of trauma-induced coagulopathy.

Gastrointestinal

All trauma patients are considered to have a full stomach, and pregnant patients are no exception. In addition, due to diminished lower esophageal sphincter tone and cephalad displacement of the stomach by the gravid uterus, pregnant patients are at an even higher risk for aspiration. This period of increased risk for aspiration begins as early as 18 to 20 weeks gestation. While patients who are in labor are considered to have delayed gastric emptying, the pregnant, nonlaboring patient has an equivalent gastric emptying to that of the nonpregnant individual. Aspiration precautions should always be utilized in the obstetric trauma patient during tracheal intubation including the use of rapid sequence induction with succinylcholine or high-dose rocuronium (1.2 mg/kg). Both succinylcholine and rocuronium are unlikely to cross the placenta and, therefore, are at low risk for having an effect on the fetus. The Society for Obstetric Anesthesia and Perinatology (SOAP), in their consensus statement regarding sugammadex, recommends against its use in pregnant patients due to its unknown safety profile and potential for precipitating preterm labor.35 It may be prudent, therefore, to preferentially use succinylcholine.

INITIAL ASSESSMENT

The most important message regarding the initial care of pregnant trauma patients is that the presence of the fetus should not distract from the conventional advanced trauma life support (ATLS) framework, including the use of radiographic imaging when indicated.6,8,9,36 As with all trauma patients, the initial assessment of the airway, breathing, and circulation takes precedence above all else. That said, early notification of obstetric personnel of an incoming pregnant trauma patient is essential because they can aid with the secondary and fetal assessments as long as it does not interfere with primary resuscitation. A framework for the management of obstetric trauma patients is shown in Figure 2.6,37

Airway

The status of an adequate airway and level of consciousness can be quickly determined by a patient’s ability to speak. Airway interventions need to occur for patients with decreased ability to protect their airway from aspirate, in respiratory distress, or requiring anesthesia for procedural intervention. Due to respiratory changes, there is a greater emphasis on preoxygenation, use of smaller tracheal tubes (6–6.5 mm internal diameter), proper patient positioning and equipment, first attempt intubation by the most experienced practitioner, and avoidance of nasopharyngeal devices.38 Trauma to the airway by multiple intubation attempts may result in swelling and bleeding in patients who are already at high risk for airway edema and friability due to physiologic changes in pregnancy. Furthermore, trauma to the nasal passages by placing nasopharyngeal devices can lead to bleeding. Clinicians should be familiar with the American Society of Anesthesiologists (ASA) difficult airway algorithm.39 The Obstetric Anesthetists Association (OAA) has a difficult airway algorithm specific for obstetric patients, and others have recommended modifications to the ASA algorithm for pregnant patients.40,41 For example, the OAA covers decision-making on proceeding with a general anesthesia mediated cesarean delivery without a tracheal tube based on various maternal, fetal, and situational factors. In general, the OAA’s recommendations augment the preexisting ASA algorithm. Video laryngoscopy may facilitate first-pass attempt;42 however, if direct laryngoscopy is used, video laryngoscopes should be available. If providers are unable to intubate the trachea, preparations should be made for invasive, front-of-neck access.39 Closed claim data suggest that the most serious complication of invasive intubation techniques is the failure to pursue this approach earlier in the difficult airway algorithm.43

Breathing

The differential diagnosis of breathing-related issues includes both obstetric and traumatic causes of respiratory failure (eg, preeclamptic pulmonary edema or pneumothorax). Patients may need a spectrum of care ranging from supplemental oxygen to invasive mechanical ventilation. Clinicians should also be aware of changes to the thoracic cavity that begin in the first trimester, including increased rib cage circumference, cephalad displacement of the diaphragm, and an increase in the subcostal angle.44 As a result, if insertion of thoracostomy tubes is necessary, they may need to be placed more cephalad by 1 or 2 intercostal spaces.44 Pregnant patients are normally in a state of respiratory alkalosis. Therefore, mechanical ventilation should target a Paco2 level that is normal for pregnancy (27–32 mm Hg).15,45 Paco2 levels nearing normal adult levels of 35 to 40 mm Hg should raise concern for potential hypercarbic respiratory failure in a spontaneously breathing pregnant trauma patient.

Circulation

After adequate respiratory status has been established, optimizing cardiovascular function follows. In states of shock, not only is there decreased perfusion of maternal end organs, but uteroplacental perfusion to the fetus is also compromised. Because of increased intravascular volume, pregnant women can lose significantly more blood before signs of shock are evident. A nonreassuring fetal heart rate (FHR) pattern caused by a reduction in uterine blood flow may be the first sign of hypovolemia. Two cardiovascular considerations unique to the obstetric trauma patient include LUD to relieve aortocaval compression and the placement of intravenous lines above the level of the diaphragm.46 One MRI study by Higuchi et al25 found that a tilt of 30°, but not 15°, partially relieved inferior vena cava compression in 10 parturients. Placement of intravenous lines above the level of the diaphragm is preferred practice as compression of the inferior vena cava can potentially impair circulation of medications and fluids from the lower extremities back to the heart and into the systemic circulation.46 Vasopressors, such as ephedrine and phenylephrine, can be used in the setting of traumatic shock but should not be used in place of fluid resuscitation. While permissive hypotension is a suggested strategy to help control bleeding in trauma without traumatic brain injury, there are no data to support its safety in the obstetric patient. Permissive hypotension could impair uteroplacental perfusion and lead to fetal hypoxia, acidosis, and neurologic injury. Without further evidence, it is reasonable to aim for blood pressure values most widely accepted in obstetric patients: a systolic blood pressure of 100 mm Hg or within 20% to 30% of baseline measurements.6

Hemorrhage Resuscitation

Pregnant trauma patients should be assessed for traditional injuries causing hemorrhagic shock as well as uterine rupture and placental abruption. Of note, in motor vehicle accidents, there is notable local uterine compression depending on the location of a seat belt at the time of a crash; however, the exact mechanism of placental abruption, the leading cause of fetal loss, is unknown.47,48 Hemorrhage management largely follows the same principles of nonobstetric trauma. While initial early infusion of crystalloids may be helpful in volume resuscitation and avoidance of vasopressors, which can cause further constriction of blood flow to the uterus, their use should not be overly relied on as they may have a dilutional effect on coagulation factors and further contribute to worsening of trauma-induced coagulopathy. In cases of ongoing hemorrhage, hypovolemia should be managed with early hemostatic resuscitation using a balanced ratio of blood products, known as 1:1:1 ratio of plasma (fresh frozen plasma [FFP]), RBCs, and platelets (PLTs).49 Maintenance of normothermia and normocalcemia is also important for preventing coagulopathy. A retrospective study involving 142 deliveries complicated by postpartum hemorrhage found that higher FFP:RBC ratios (nearing 1:1) were associated with lower odds of advanced interventional procedures.50 A survey of 60 directors of academic obstetric anesthesia units in 2012 found that 48% used a 1:1 RBC:FFP ratio and 35% used a 1:1:1 RBC:FFP:PLT ratio.51 In the survey, the most common laboratory threshold for cryoprecipitate transfusion was a serum fibrinogen level of <150 mg/dL. More recent practices dictate higher infusion thresholds (<200 mg/dL) for the administration of cryoprecipitate or fibrinogen concentrate given the presence of higher serum fibrinogen in healthy pregnant women. Of note, a decrease in serum fibrinogen level is 1 of the most significant and reliable predictors of the severity of postpartum hemorrhage.52 The balanced ratios of blood product transfusions seen in obstetric trauma hemorrhage protocols are largely influenced from preexisting nonobstetric trauma literature. Tranexamic acid (TXA) has been found to significantly reduce mortality while having a good safety profile in the setting of postpartum hemorrhage (as in the WOMAN trial [Effect of Early Tranexamic Acid Administration on Mortality, Hysterectomy, and Other Morbidities in Women with Post-partum Haemorrhage]) and in the setting of trauma hemorrhage (as in the CRASH-2 trial [Effects of Tranexamic Acid on Death, Vascular Occlusive Events, and Blood Transfusion in Trauma Patients with Significant Hemorrhage]) if given within 3 hours of injury and should be considered in all pregnant trauma patients in this time window.53,54 TXA works by inhibiting the hyperfibrinolysis seen in severe life-threatening bleeding with shock, as is seen in both trauma and postpartum hemorrhage. Aside from traditional laboratory measurements, viscoelastic monitoring, including thromboelastography (TEG) and rotational thromboelastometry (ROTEM), allows for real time goal-directed therapy to guide transfusion decisions and should be used in all pregnant trauma patients if available.

SECONDARY SURVEY

After addressing airway, breathing, and circulation, a head-to-toe physical examination of the mother should be performed to evaluate for head, neck, thoracic, abdominal, and extremity injuries, as with any other trauma patient. In the case of vaginal bleeding, placenta previa should be ruled out with ultrasound before vaginal examination.55 Speculum examination may then be performed to assess for pooling of amniotic fluid, bleeding, and cervical dilation. As soon as maternal stabilization allows, fetal assessment may proceed.

Fetal Assessment

Besides the added risks of uterine rupture and placental abruption, pregnant trauma patients are at risk of premature rupture of membranes, preterm labor, stillbirth, and need for cesarean delivery. Estimated gestational age (EGA) can be gathered from an accurate history, which should include documentation of the last menstrual period and anticipated delivery date, as well as physical examination. Palpation of the uterus may provide a rough estimation of age, while measurement of fundal height above the pubic symphysis is more accurate. For reference, palpation of the uterus at the level of the umbilicus corresponds to a GA of roughly 20 weeks. From there, viability can be determined, which may dictate additional extraordinary measures that may be performed. Although the general threshold for viability is considered to be 23 to 24 weeks GA, some centers have reported increased infant survival rates between 22 and 24 weeks GA.6,56

In the nonviable pregnancy, a spot check of fetal heart tones may be performed to confirm cardiac activity. Ultrasound is useful not only in evaluating fetal age and well-being but also for assessment of potential complications such as placental abruption and may be used as long as it does not interfere with maternal stabilization. Continuous electronic FHR monitoring is the standard of care in trauma patients with a fetus of >20 week EGA and should continue for at least 4 hours.57,58 The presence of reassuring fetal heart tones as well as a normal examination of the mother will warrant discharge after 4 to 6 hours.59 Meanwhile, there are no accepted guidelines regarding monitoring a fetus that is <20 EGA; therefore, the decision to monitor and discharge should be made based on clinical context and maternal injury with close obstetric follow-up.59,60 The presence of nonreassuring FHR tracing or concerning maternal features, such as abdominal pain, contractions, or vaginal bleeding, may warrant monitoring to be continued for 24 hours. Diagnosis of placental abruption or uterine rupture should trigger urgent cesarean delivery due to the presence of maternal indications. The decision to proceed with a cesarean delivery for strictly fetal indications (sustained bradycardia or decelerations) is determined largely by whether the mother is adequately resuscitated after a trauma and viability of the fetus. Patients with major trauma, regardless of GA, should always be triaged to medical centers with level 1 trauma capabilities. However, it is possible that the pregnant trauma patient may present to a facility without an obstetric unit. In these instances, after initial survey and stabilization in the emergency department, the patient should be transferred to a facility with a labor and delivery unit so that they may be evaluated and monitored appropriately.55

Imaging

Pregnant trauma patients should not have any indicated imaging studies withheld due to concerns of fetal exposure to ionizing radiation. The fetus is susceptible to the following based on the time of exposure to radiation and conceptional age: embryo death (0–2 weeks), impaired organogenesis (2–8 weeks), and severe intellectual disability (8–25 weeks).40 Based on animal studies and studies on human exposure following atomic bomb radiation, the risk of teratogenicity or malignancy is considered low with radiation exposures below 5 to 10 rads.36 In general, the radiation dose of common imaging modalities (radiography, computed tomography scan, and nuclear medicine imaging) is lower than the dose attributed to fetal harm, and adjustments can be made to minimize fetal exposure.

Evaluation for Maternal-Fetal Hemorrhage

Up to 30% of injuries will result in maternal-fetal hemorrhage, and care must be taken in patients who are Rh-negative to avoid alloimmunization, in which case current and subsequent Rh antigen-positive pregnancies may be vulnerable to maternal antibodies.61 The Kleihauer-Betke (KB) test can be used to detect fetal cells in the maternal circulation and may help determine the severity of hemorrhage.62 This test is recommended for all pregnant trauma patients as it can help quantify transplacental hemorrhage and determine the need for additional doses of anti-D immunoglobulin G (IgG).63 Sensitization may occur even with very small or subclinical hemorrhages; therefore, anti-D IgG should be administered within 72 hours to all Rh-negative mothers who present to the hospital after trauma. The utility of the KB test to predict adverse fetal outcomes (placental abruption, preterm labor, and intrauterine fetal death) is controversial.64,65

ADVANCED CARDIAC LIFE SUPPORT IN THE PREGNANT PATIENT

In the case of cardiac arrest, basic tenets of advanced cardiovascular life support (ACLS) remain the same with a few basic caveats. Aortocaval compression by the gravid uterus can obstruct blood return to the heart; therefore, manual LUD should be applied if the patient is at >20 weeks EGA (Figure 3).66,67 In addition, vascular access should be obtained above the diaphragm. Intraosseous access may be obtained in the humerus, if needed. An advanced airway should be secured keeping in mind the specific challenges to intubation outlined above and 100% oxygen should be provided. High-quality chest compressions with similar hand placement and compression rate to that of nonpregnant patients are key.26 Defibrillation should not be delayed if indicated.26

F3Figure 3.:

Manual left uterine displacement during advanced cardiac life support is routinely done for all parturients after 20 wk GA. For patients with unknown GA, the fundus of the uterus corresponds approximately to the level of the umbilicus on physical examination. For both techniques, downward pressure is avoided so that inferior vena cava compression is not worsened. A, Two-handed technique (preferred). The uterus is pulled leftward and upward. B, One-handed technique. The uterus is pushed leftward and upward. GA indicates gestational age. Adapted from Moaveni D, Varon AJ. Anesthetic management of the pregnant trauma patient. In: Varon AJ, Smith CE (eds.). Essentials of Trauma Anesthesia, 2nd Ed. Cambridge, Cambridge University Press, 2018: 313, with permission.

In obstetric trauma, preparations should be made for a possible resuscitative hysterotomy while the primary and secondary surveys are performed as evacuation of the uterus may improve the quality of the resuscitation.68 Coordination with several teams, including obstetrics, neonatology, respiratory therapy, and possibly blood bank, should occur expeditiously. Delivery should occur within 5 minutes of initiating resuscitation when the GA exceeds 20 weeks. 26,66 Furthermore, in cases of traumatic arrest where chest compressions may be deemed insufficient in the setting of hypovolemia, resuscitative hysterotomy should be considered earlier.68 When GA is unknown, 20 weeks can be estimated by palpating the uterus at the umbilicus. Massive hemorrhage, coagulopathy, vascular injury, and uterine atony should be anticipated and promptly treated. Extracorporeal membrane oxygenation has been safely used in pregnancy and may be considered as a rescue technique.69

DISCUSSION

The care of pregnant trauma patients involves special considerations both with regard to maternal physiological changes as well as the presence of a fetus. The most important message regarding the trauma management of these patients is that ATLS fundamentals should be applied to the mother without delay or distraction due to care provided to the fetus. Obstetric teams should be alerted to the presence of a pregnant trauma admission; however, any fetal assessment should not impede the initial assessment and stabilization of the mother by the trauma team. The most important physiologic changes in pregnancy include respiratory, cardiovascular, and hematological changes. Respiratory changes to be mindful include edematous airways, decreased FRC, and quicker oxygen desaturation during apnea. The most important cardiovascular changes include aortocaval compression of the gravid uterus, increased plasma volume, and increased cardiac output. The most relevant hematologic changes include anemia and relative hypercoagulability. During resuscitation, LUD must be performed to optimize cardiac output and end-organ perfusion. Intravenous lines should be placed above the level of the diaphragm. Resuscitation with a balanced ratio of blood products is essential during hemorrhagic shock and coagulopathy. Fetal assessment includes estimation of GA/viability and continuous FHR monitoring for at least 4 hours. Obstetric complications of trauma include placental abruption, uterine rupture, premature rupture of membranes, preterm labor, and need for cesarean delivery. Imaging studies for maternal trauma usually do not exceed radiation doses known to be harmful to fetal development and should not be avoided in pregnant trauma patients when indicated.

DISCLOSURES

Name: Carmen E. Lopez, MD.

Contribution: This author helped with conception, drafting, editing, and approval of final version.

Conflicts of Interest: None.

Name: Joe Salloum, MD, MBA.

Contribution: This author helped with conception, drafting, editing, and approval of final version.

Conflicts of Interest: None.

Name: Albert J. Varon, MD, MHPE.

Contribution: This author helped with conception, editing, and approval of final version.

Conflicts of Interest: A. J. Varon receives royalties from Cambridge University Press.

Name: Paloma Toledo, MD, MPH.

Contribution: This author helped with conception, editing, and approval of final version.

Conflicts of Interest: None.

Name: Roman Dudaryk, MD.

Contribution: This author helped with conception, editing, and approval of final version.

Conflicts of Interest: R. Dudaryk receives lecture fees from Haemonetics and is a consultant for Phillips Health care.

This manuscript was handled by: Richard P. Dutton, MD.

REFERENCES 1. Sakamoto J, Michels C, Eisfelder B, Joshi N. Trauma in pregnancy. Emerg Med Clin North Am. 2019;37:317–338. 2. Rogers FB, Rozycki GS, Osler TM, et al. A multi-institutional study of factors associated with fetal death in injured pregnant patients. Arch Surg. 1999;134:1274–1277. 3. Baerga-Varela Y, Zietlow SP, Bannon MP, Harmsen WS, Ilstrup DM. Trauma in pregnancy. Mayo Clin Proc. 2000;75:1243–1248. 4. Drost TF, Rosemurgy AS, Sherman HF, Scott LM, Williams JK. Major trauma in pregnant women: maternal/fetal outcome. J Trauma. 1990;30:574–578. 5. Petrone P, Jimenez-Morillas P, Axelrad A, Marini CP. Traumatic injuries to the pregnant patient: a critical literature review. Eur J Trauma Emerg Surg. 2019;45:383–392. 6. Chestnut DH, Wong CA, Tsen LC, et al. Chestnut’s Obstetric Anesthesia: Principles and Practice. 6th ed. Elsevier; 2020. 7. Fischer PE, Zarzaur BL, Fabian TC, et al. Minor trauma is an unrecognized contributor to poor fetal outcomes: a population-based study of 78,552 pregnancies. J Trauma. 2011;71:90–93. 8. Sela HY, Weiniger CF, Hersch M, Smueloff A, Laufer N, Einav S. The pregnant motor vehicle accident casualty: adherence to basic workup and admission guidelines. Ann Surg. 2011;254:346–352. 9. Pearlman MD, Tintinalli JE, Lorenz RP. Blunt trauma during pregnancy. N Engl J Med. 1990;323:1609–1613. 10. Aguree S, Gernand AD. Plasma volume expansion across healthy pregnancy: a systematic review and meta-analysis of longitudinal studies. BMC Pregnancy Childbirth. 2019;19:508. 11. Ouzounian JG, Elkayam U. Physiologic changes during normal pregnancy and delivery. Cardiol Clin. 2012;30:317–329. 12. Capeless EL, Clapp JF. Cardiovascular changes in early phase of pregnancy. Am J Obstet Gynecol. 1989;161:1449–1453. 13. Clark SL, Cotton DB, Lee W, et al. Central hemodynamic assessment of normal term pregnancy. Am J Obstet Gynecol. 1989;161:1439–1442. 14. Alaily AB, Carrol KB. Pulmonary ventilation in pregnancy. Br J Obstet Gynaecol. 1978;85:518–524. 15. Bobrowski RA. Pulmonary physiology in pregnancy. Clin Obstet Gynecol. 2010;53:285–300. 16. Ende H, Varelmann D. Respiratory considerations including airway and ventilation issues in critical care obstetric patients. Obstet Gynecol Clin North Am. 2016;43:699–708. 17. Dunlop W. Serial changes in renal haemodynamics during normal human pregnancy. Br J Obstet Gynaecol. 1981;88:1–9. 18. Dayal P, Murata Y, Takamura H. Antepartum and postpartum acid-base changes in maternal blood in normal and complicated pregnancies. J Obstet Gynaecol Br Commonw. 1972;79:612–624. 19. Pritchard JA. Changes in the blood volume during pregnancy and delivery. Anesthesiology. 1965;26:393–399. 20. Abbassi-Ghanavati M, Greer LG, Cunningham FG. Pregnancy and laboratory studies: a reference table for clinicians. Obstet Gynecol. 2009;114:1326–1331. 21. Thornton P, Douglas J. Coagulation in pregnancy. Best Pract Res Clin Obstet Gynaecol. 2010;24:339–352. 22. Talbert LM, Langdell RD. Normal values of certain factors in the blood clotting mechanism in pregnancy. Am J Obstet Gynecol. 1964;90:44–50. 23. Kerr MG. The mechanical effects of the gravid uterus in late pregnancy. J Obstet Gynaecol Br Commonw. 1965;72:513–529. 24. Abitbol MM. Supine position in labor and associated fetal heart rate changes. Obstet Gynecol. 1985;65:481–486. 25. Higuchi H, Takagi S, Zhang K, Furui I, Ozaki M. Effect of lateral tilt angle on the volume of the abdominal aorta and inferior vena cava in pregnant and nonpregnant women determined by magnetic resonance imaging. Anesthesiology. 2015;122:286–293. 26. Jeejeebhoy FM, Zelop CM, Lipman S, et al.; American Heart Association Emergency Cardiovascular Care Committee, Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation, Council on Cardiovascular Diseases in the Young, and Council on Clinical Cardiology. Cardiac arrest in pregnancy: a scientific statement from the American Heart Association. Circulation. 2015;132:1747–1773. 27. Templeton A, Kelman GR. Maternal blood-gases, (PAo2–Pao2), physiological shunt and VD/VT in normal pregnancy. Br J Anaesth. 1976;48:1001–1004. 28. Ortiz-Prado E, Dunn JF, Vasconez J, Castillo D, Viscor G. Partial pressure of oxygen in the human body: a general review. Am J Blood Res. 2019;9:1–14. 29. Prowse CM, Gaensler EA. Respiratory and acid-base changes during pregnancy. Anesthesiology. 1965;26:381–392. 30. Archer GW Jr, Marx GF. Arterial oxygen tension during apnoea in parturient women. Br J Anaesth. 1974;46:358–360. 31. Kodali BS, Chandrasekhar S, Bulich LN, Topulos GP, Datta S. Airway changes during labor and delivery. Anesthesiology. 2008;108:357–362. 32. Munnur U, de Boisblanc B, Suresh MS. Airway problems in pregnancy. Crit Care Med. 2005;33:S259–S268. 33. Lind T, Godfrey KA, Otun H, Philips PR. Changes in serum uric acid concentrations during normal pregnancy. Br J Obstet Gynaecol. 1984;91:128–132. 34. Bremme KA. Haemostatic changes in pregnancy. Best Pract Res Clin Haematol. 2003;16:153–168. 35. Willett A, Butwick A, Togioka B, et al. Society for Obstetric Anesthesia and Perinatology statement on sugammadex during pregnancy and lactation. 2019. 36. Jain C. ACOG committee opinion No. 723: guidelines for diagnostic imaging during pregnancy and lactation. Obstet Gynecol. 2019;133:186. 37. Varon A. Essentials of Trauma Anesthesia. 2nd ed. Cambridge University Press; 2018. 38. Mushambi MC, Athanassoglou V, Kinsella SM. Anticipated difficult airway during obstetric general anaesthesia: narrative literature review and management recommendations. Anaesthesia. 2020;75:945–961. 39. Apfelbaum JL, Hagberg CA, Connis RT, et al. American Society of Anesthesiologists practice guidelines for management of the difficult airway. Anesthesiology. 2022;2022:31–81. 40. Balki M, Cooke ME, Dunington S, Salman A, Goldszmidt E. Unanticipated difficult airway in obstetric patients: development of a new algorithm for formative assessment in high-fidelity simulation. Anesthesiology. 2012;117:883–897. 41. Mushambi MC, Kinsella SM, Popat M, et al.; Obstetric Anaest

留言 (0)

沒有登入
gif