Beyond The Basics: Trauma During Pregnancy

     This CE activity is approved by EMS Magazine, an organization accredited by the Continuing Education Coordinating Board for Emergency Medical Services (CECBEMS), for 1.5 CEUs.

To take the corresponding test to this article online visit www.rapidce.com.

     OBJECTIVES

• Review epidemiology of trauma in pregnant women
• Discuss anatomic changes during pregnancy
• Review management of the pregnant trauma patient

     Pregnant patients who are involved in trauma pose a special challenge to EMS. Instead of a single patient with a normal physiological response to the injuries sustained, you have two patients with special needs depending on you: the mother and her unborn fetus. Whether the trauma is minor or severe, it will require you to understand and apply your knowledge of the pregnant patient to your assessment and emergency care.

     Trauma occurs in approximately 6%–7% of all pregnancies and is the leading cause of death for pregnant women. The morbidity and mortality associated with these patients depends on the mechanism of injury, gestational age of the fetus and severity of the trauma.

     Motor vehicle collisions account for more than half of all injuries sustained by pregnant trauma patients. One factor that can directly influence a pregnant patient's outcome when involved in a motor vehicle collision is the use of proper restraints. In order to be properly restrained, a pregnant woman should wear her lap belt placed snugly against her pelvis beneath her abdomen and should utilize the shoulder restraint between her breasts. Properly restrained pregnant women are half as likely to experience vaginal bleeding or give birth after a motor vehicle collision as women who are unrestrained. Fetal death resulting from a motor vehicle collision is three to four times more likely to occur if the mother is unrestrained. The severity of the collision can affect both the maternal and fetal outcome, even if the patient is properly secured. Maternal death is the primary cause of fetal death following a motor vehicle collision.

     Falls are another common mechanism of injury during pregnancy. Pregnant women, especially after their 20th week, are prone to falling, because their pelvic ligaments are loosened, their abdomen is protruding and their center of gravity changes. The incidence of injury is often associated with how the patient falls and the force of the fall. About 2% of pregnant women sustain repeated blows to the abdomen because they fall more than once. Women who fall are at risk for premature uterine contractions that could result in delivery.

     Pregnant women, especially teenagers, are susceptible to physical abuse that can result in various injuries, usually involving the abdomen and genitalia. Domestic violence carries a high risk of morbidity for the pregnant patient and fetus. Approximately 4% to 17% of all pregnant females will experience physical abuse, although most cases of abuse go unreported. Most often, the perpetrator of physical abuse is the patient's husband or boyfriend. Sixty-four percent of previously abused women report an increase in attacks when they are pregnant.

     Gunshot wounds and stab wounds are the most frequent causes of penetrating trauma to this population. Penetrating trauma to the abdomen alone accounts for approximately 36% of overall maternal mortality. Because the woman's abdominal organs are pushed upward by the growing uterus, she is highly susceptible to bowel, hepatic or splenic injuries resulting from penetrating trauma to the upper abdomen; however, if the injury is lower, it poses fewer visceral injuries to the mother, who is shielded by the uterus, but poses significantly higher risks to the developing fetus. Penetrating trauma directly to the uterus has a 67% fetal death rate.

     Several cardiovascular changes occur within the pregnant female that can mask, mimic or alter the presentation of shock in these patients. Throughout pregnancy, there is about a 50% increase in total blood volume, which can increase further if the patient is expecting a multiple birth. The pregnant female also experiences progesterone-related smooth muscle relaxation, resulting in a decrease in the total peripheral resistance. This precipitates a gradual decline of about 2–4 mmHg in systolic pressure and a decline of 5–15 mmHg in diastolic pressure during the first two trimesters of pregnancy. Blood pressure will return to almost a normal pre-pregnancy level by the third trimester, partially due to an increase in the mother's estrogen levels, resulting in a 10–15-beat-per-minute increase in heart rate above the pre-pregnancy baseline. The pregnant patient also has a 30%–50% increase in cardiac output, which increases more during uterine contractions. Bloodflow to the pregnant patient's uterus increases from 60 mL/min pre-pregnancy to 600 mL/min by the third trimester in order to provide the fetus with the oxygen necessary for survival. These changes help prepare the woman for childbirth, but can mask the signs and symptoms of shock in the trauma patient. During shock or hemorrhage, vasoconstriction attempts to preserve the blood pressure, which is beneficial in maintaining perfusion of the mother, but the bloodflow is diverted away from the uterus, decreasing perfusion of the uterus and placenta and placing the fetus in jeopardy.

     During pregnancy, a woman's diaphragm gradually elevates 4 cm upward, contributing to about a 25% decrease in residual capacity. This diaphragmatic elevation may also cause electrocardiographic changes to the left axis and show Q waves in leads III and aVF. This elevation contributes to an increase in oxygen consumption and may result in hyperventilation and relative alkalosis. These respiratory changes can increase the patient's risk of developing a tension pneumothorax.

     The pregnant woman's abdominal viscera are pushed upward and stretched throughout pregnancy, making a bowel injury more likely. This change can also alter her perception of abdominal pain and may desensitize her to an abdominal injury despite its severity. The pregnant patient also has decreased gastrointestinal motility and increased acid production, making her prone to vomiting and aspiration.

     The highly vascular uterus grows throughout pregnancy and rises out of the pelvis into the abdominal area, placing the patient at risk for direct uterine injury. The pregnant bladder is also displaced into the abdominal cavity, making it more susceptible to injury, and renal blood flow is increased, making a renal injury more susceptible to increased hemorrhage.

     The gestational age and size of the fetus can also influence the patient's presentation. Beginning at the 20th week of gestation, the growing uterus and fetus can compress the vena cava and decrease preload, which can result in supine hypotensive syndrome. This can decrease cardiac output by approximately 28% and reduce systolic blood pressure by about 30 mmHg. The reduction in venous bloodflow and cardiac output will trigger a sympathetic response from the sympathetic nervous system that can result in signs and symptoms of shock. The condition can be easily managed and prevented by tilting the backboard, or the patient if no spinal injury is suspected, by 15°–30° on her left side. If left untreated, venous compression can lead to serious physiologic consequences.

     Trauma to a pregnant woman, whether severe or minor, can have significant effects on maternal and fetal health. It is estimated that 1% to 3% of minor trauma involving pregnant women results in fetal loss; 41% of fetuses die when the mother experiences a life-threatening injury. Following are some of the most frequent complications resulting from traumatic injury to the pregnant patient:

     Uterine contractions, which occur in 39% of pregnant trauma patients, may progress into pre-term labor. The frequency, strength and duration of the contractions should be assessed, monitored and documented throughout patient care. Although not all uterine contractions progress into labor, the EMS practitioner should assess the patient for signs and symptoms associated with delivery, including inspecting the vaginal opening for evidence of crowning.

     Preterm labor is defined as labor occurring before the 38th week of gestation, regardless of the cause. The survivability of the fetus will be determined in part by its gestational age. For any chance of surviving outside the uterus, the fetus must typically be at least 24 weeks' gestation. This allows for acceptable growth of the fetus' organs, but does not ensure viability after trauma. The longer the fetus is able to stay within the uterus, the better its chances of survival. Risk factors, outside of trauma, associated with preterm labor include cardiovascular disease, hypertension, pre-eclampsia, eclampsia, diabetes, smoking, placenta previa, abruptio placenta, infection and physical abnormalities.

     Traumatic injuries may result in spontaneous abortion if injury occurs before the 20th week of gestation. The most common signs and symptoms associated with spontaneous abortion due to trauma include abdominal pain or cramping and vaginal bleeding.

     Abruptio placenta is one of the most common injuries, usually associated with blunt trauma, and accounts for 50%—70% of fetal losses. Abruptio placenta is premature partial or complete separation of the placenta from the uterine wall. When separation occurs, the normal gas exchange between mother and fetus is inhibited, leading to fetal hypoxia. The separation also leaves uterine and placental vessels exposed, causing intrauterine hemorrhage. Intrauterine hemorrhage can occur with or without the presence of vaginal bleeding, depending on the location of the fetus in the vaginal canal and whether the blood is trapped behind the intact margins of the placenta. Approximately 63% of abruptio placenta cases involving trauma have no external hemorrhaging. Signs and symptoms associated with this condition are maternal abdominal pain, uterine tenderness, vaginal bleeding and hypovolemia.

     Uterine rupture is a rare event that occurs in fewer than 1% of pregnant trauma patients; however, it is one of the most fatal for the mother and fetus. The most common cause of uterine rupture is severe blunt force trauma to the abdomen, which frequently occurs from a vehicular crash when the pelvis strikes the uterus, leading to rupture. Some uterine rupture also involves penetrating trauma. Uterine rupture often presents with maternal shock and a palpable fetus inside the abdomen.

     Because the patient's uterus has grown in size throughout pregnancy, it can help shield the abdominal organs from penetrating injuries; however, it puts the fetus at greater risk for direct injury. Bowel and abdominal injuries occur more frequently in the upper abdomen and can cause greater injury to the mother; direct trauma to the lower abdomen can result in more injuries or death to the fetus. Stab wounds to the uterus can produce 93% morbidity to the fetus.

     Pelvic fractures, most frequently resulting from blunt trauma to the abdomen, are another concern. Along with significant hemorrhage within the retroperitoneal area, the mother may sustain bladder, urethral or intestinal injuries. Maternal pelvic fractures significantly increase fetal susceptibility to head injury, which accounts for 25% fetal mortality. Patients with pelvic injuries may present with pelvic pain and signs and symptoms of hypovolemia.

     Hemorrhage during pregnancy can result in shock from any of the above conditions or from other injuries. Hemorrhaging, both internal and external, should be suspected and assessed for after any trauma to a pregnant patient.

     Cardiovascular changes during pregnancy may make it difficult to detect signs and symptoms associated with maternal hypotension and shock. Acute blood loss resulting in hypovolemia is masked by maternal vasoconstriction and tachycardia. Vasoconstriction severely impacts uterine blood flow by about 30%, commonly resulting in fetal hypoxia and bradycardia.

     Shock is a frequent cause of death to both fetus and mother. It is important that the EMS practitioner anticipate shock and maternal hypotension and not rely solely on vital sign changes to aggressively manage the patient. If the traditional signs and symptoms of hypovolemic shock are exhibited, fetal mortality can be as high as 85%.

     Cardiorespiratory arrest in a pregnant female poses a significant threat to the viability of the fetus. It is estimated that 41% of fetuses die when the mother suffers a life-threatening injury, and more occur with cardiac arrest. It is difficult to assess the fetus in the field; therefore, aggressive management of the mother is necessary to increase fetal survival. Although the chance of the fetus surviving maternal cardiopulmonary arrest due to trauma is poor, rescuscitative attempts should be provided for patients who are more than 24 weeks pregnant, unless instructed otherwise by medical control. The receiving facility should be notified in advance so staff can prepare for an emergency Caesarean section.

     Prehospital assessment and management of the pregnant trauma patient are focused on identifying, ensuring, maintaining and supporting the vital functions of the patient's airway, breathing and circulation. Unlike other traumatic emergencies, there are two patients to be considered by the EMS provider. The most prudent management of both the mother and fetus involved in trauma is to take a proactive approach and treat the mother aggressively. All pregnant women who have suffered an injury, regardless of the severity, should be evaluated by a physician in the emergency department.

     Management of a pregnant trauma patient includes the following:

• Spinal immobilization is required for a pregnant patient suspected of having a spinal injury. In a backboarded patient at more than 20 weeks' gestation, the backboard will need to be tilted 15° to 30° to the left side and maintained in that position throughout the duration of your care to help prevent supine hypotensive syndrome and venous compression.
• Establish and maintain an open airway. If the patient has an altered mental status, is unresponsive, or for any other reason cannot maintain a patent airway, open the airway by jaw thrust and utilize mechanical devices and endotracheal intubation as directed by your protocol. You should anticipate vomiting with these patients and have suction readily available.
• Determine if the patient is breathing adequately and bilateral breath sounds are present. If the patient's breathing is inadequate, provide positive pressure ventilation with supplemental high-flow oxygen. If it is adequate, provide a high concentration of oxygen via nonrebreather to maintain the SpO₂ as close to 100% as possible, even if the patient is not showing signs or symptoms of hypoxia. Remember that the fetus is very vulnerable to hypoxia.
• Assess the patient's circulation and check for major bleeding. You should suspect internal hemorrhage even if there are no obvious signs or symptoms. If vaginal bleeding is present, absorb the blood flow with a pad and do not pack the vagina. If the patient becomes pulseless, provide CPR and resuscitative treatments as usual for an adult.
• Anticipate, prevent and treat shock. Remember that the usual signs and symptoms associated with hypovolemic shock most often will not be present in the pregnant trauma patient until greater than 30% of the total blood volume is lost. Postponing treatment for an obvious decline in vital signs can put both the mother and fetus at risk.
• Establish two large-bore intravenous lines and infuse lactated Ringer's or normal saline to maintain maternal and fetal perfusion.
• Provide continuous ECG monitoring for the mother.
• Monitor fetal heart tones, if possible. Heart tones less than 110 beats per minute indicate significant fetal distress.
• Treat and manage any other life- threatening injuries. Remember that a significant amount of care for other injuries can be performed en route to the receiving facility.
• Rapidly transport this patient to the closest appropriate receiving facility. Make sure you notify the receiving facility in advance so they can assemble a trauma team and call for an obstetrician and pediatrician, if necessary.

     Bledsoe BE, Porter RS, Cherry RA. Paramedic Care: Principles and Practice, Medical Emergencies, 2nd ed. Upper Saddle River, NJ: Prentice Hall Health, 2006.

     Gabbe. Obstetrics: Normal and Problem Pregnancies, 5th ed. Churchill Livingstone, 2007.

     Hill CC, Pickinpaugh J. Trauma and surgical emergencies in the obstetric patient. Surgical Clinics of North America, 88, 2008.

     Marx JA, Hockberger RS, Walls RM. Rosen's Emergency Medicine: Concepts and Clinical Practice, 6th ed. St. Louis: Mosby, Inc., 2006.

     Muench M,Canterino JC. Trauma in Pregnancy. Obstet Gynecol Clinics 34: 3, 2007.

     Cornelia A. Bryan, BSAS, NREMT-P, is an adjunct faculty member at Youngstown (OH) State University.

     Joseph J. Mistovich, MEd, NREMT-P, is a professor and chair of the Department of Health Professions at Youngstown (OH) State University.

     William S. Krost, MBA, NREMT-P, is director of Emergency Services & Health System Access for Blanchard Valley Health System in Findlay, OH.

     Daniel D. Limmer, AS, EMT-P, is a paramedic with Kennebunk Fire-Rescue in Kennebunk, ME.