Course Authors
Dr. Carey reports no commercial conflict of interest.
Estimated course time: 1 hour(s).
Albert Einstein College of Medicine – Montefiore Medical Center designates this enduring material activity for a maximum of 1.0 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.
In support of improving patient care, this activity has been planned and implemented by Albert Einstein College of Medicine-Montefiore Medical Center and InterMDnet. Albert Einstein College of Medicine – Montefiore Medical Center is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.
Upon completion of this Cyberounds®, you should be able to:
Discuss the unique challenges an emergency medicine physician can face when managing a pregnant patient with trauma
Describe the physiological changes of pregnancy relevant in the management of the trauma victim
List the clinical features of the pregnant trauma patient in the United States
Discuss diagnostic modalities used to assess the pregnant trauma patient.
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First Case. You are the only emergency physician in a well-equipped emergency department. It is an hour before handover in the morning. You are a little tired after a busy night. EMS calls to say they are bringing in three patients from a rollover car wreck. Two of the patients -- an elderly couple -- appear critically injured. They both require intubation, but EMS is unable to perform this because of 'laryngeal spasm.' The third patient -- a restrained rear seat passenger -- is a 22-year-old female, complaining of some low back pain and left upper quadrant abdominal pain. |
When the patients arrive, within minutes of each other, you quickly examine the 22-year-old. She has no airway compromise, but has a respiration rate of 22 secondary to the pain on the left side of the chest inferiorly. She is awake and aware. Her pulse rate is 92 and her blood pressure is 110/75 mm Hg. She is complaining bitterly of low back pain. She says that she was struck on the left side when the car hit the first pole and is tender in the left upper quadrant of the abdomen. You order intravenous fluids, bloods, urinalysis, and an x-ray of the cervical spine, chest and pelvis, together with lumbar spine views. You also order oral contrast for the CT of the abdomen and pelvis to be given as soon as the lumbar spine views are completed. You quickly head off to deal with the other two victims.
Q. OK, this is an easy one given the title of this Cyberounds®! What did you forget to order specifically?
A. A pregnancy test! Moreover, of course, it is positive. A quickly ordered quantitative b-HCG shows that she is between 6 and 8 weeks pregnant. Talking with the patient reveals that her last period was about 7 weeks earlier. She has never been pregnant before.
Q. So, given that she has had the x-rays ordered (cervical spine, chest, pelvis, lumbar spine) and has completed the CT of the abdomen and pelvis, (all of which were reported as 'normal'), what would you tell her now?
A. In general, the fetus will be exposed to about 50-100 millirads (mrad) during the course of the 9-month pregnancy. Radiological exposures to the fetus can be divided into a 'low dose' group and a 'high dose' group. Examinations in the 'low dose' group include cervical spine, thoracic spine, chest and all extremities. Each of these examinations, correctly performed, should result in less that 1 mrad exposure to the fetus. 'High dose' examinations include lumbar spine, pelvis and hip. The lumbar spine is the highest exposure, with a range between about 200 and 1200 mrad. The pelvis and hip x-rays produce about 200 to 400 mrad each. In addition, intravenous pyelograms (IVP), urethrocystograms and the 'KUB' (or 'flat plate abdomen') are considered 'high dose'. An IVP causes 500-800 mrad exposure, while a KUB is between 200 and 500 mrad. A urethrocystogram produces about 1500 mrad.
Estimating exact exposure of any individual fetus is very difficult, as it can vary according to the equipment used, the technique, maternal size and the age of the fetus. With modern radiographic machines, coned views aimed more than 10 cm away from the fetus result in very low exposure to the fetus.
Computerized tomography (CT) can produce more significant exposure levels. CTs of the head result in about 50 mrad of exposure, while chest CT produces about 1000 mrad (significantly less if shielded). CTs of the upper abdomen can produce up to 3000 mrad of exposure, while, understandably, CT of the pelvis produces a much higher exposure level of between 3000 and 9000 mrad.
Thus, our patient has had some low risk examinations -- chest and cervical spine x-rays, and some significant exposures from the pelvis and lumbar spine x-rays, the abdominal CT and, especially, the pelvic CT. Total dose could be between about 5000 and 13,000 mrad, depending upon exact technique, equipment, number of CT cuts and size of patient.
Q. Given this information, what is considered a 'dangerous' dose, and what are the risks?
A. Information about radiation exposure of fetuses has been gathered from observational studies of radiation exposures from the use of nuclear weapons in Japan and from unintentional exposures to fetuses as a part of medical therapy. Additional information has been extrapolated from animal studies. The highest risk for fetal viability is in the earliest stages of pregnancy, especially within the first two weeks, while malformations are greatest if radiation exposure occurs between 2 and 8 weeks gestational age. This is the period of maximum organogenesis in the developing fetus. Abnormalities described include prenatal or neonatal death, multiple types of congenital abnormalities, severe mental retardation and either temporary or permanent growth retardation. In addition, there may be an increased risk of carcinogenesis, sterility and germ cell mutations. In the Japanese cohort, the major congenital abnormality described has been microcephaly.
In general, exposures of less that 5000 mrad have negligible effects.(5) Between 5000 and 10,000 mrad there appears to be a slight increase in the incidence of childhood cancers. At doses above 15,000 mrad, there is a greater risk. Figures quoted indicate a 6% chance of mental retardation and about a 2-3% chance of developing childhood cancers. Another article(1) quotes a risk of 1 adverse event/1000/1000 mrad of exposure (i.e, for every 1000 infants exposed to 1000 mrad, there is one adverse event).
Thus, our patient probably did receive a dose that puts her fetus at a slightly increased risk for childhood cancer and at very low risk for fetal malformations. I would counsel the patient about the slightly increased risk of fetal abnormality, suggest she see an obstetrician as soon as possible -- even when in the emergency department if she wished -- and arrange this for her if she lived in the catchment area of the hospital. I would also caution her that the radiation dose is cumulative and she should be sure to mention that she has already had exposure should she require any further studies during the course of this pregnancy.
The take home message here should be that although we should take every precaution to reduce fetal exposure to radiation -- through shielding, minimizing numbers of x-rays or using alternative investigative techniques -- we should not deprive the mother of adequate investigation in the setting of trauma because of the theoretical risks from radiation.
A recent article addresses how often this scenario actually happens.(2) Bochicchio and colleagues studied trauma admissions over a four-year period and they found that 114(2.9%) of 3976 women admitted were pregnant. Of these women, 13(11%) were incidental pregnancies. Mean gestational age was lower in this group, as one might expect, at about 7 weeks. The estimated mean initial radiation exposure of all patients was 4500 mrad. The cumulative radiation exposure exceeded 5000 mrad in about 85% of patients. In this article, fetal loss was significantly higher in the incidental pregnancy group when compared with the 'known' pregnancy group.
After being given information about the risks of the pregnancy and discussing it with an obstetrician in the department, our first patient elected to leave against medical advice to return to her home out of state. She was lost to follow up.
Epidemiology of Trauma in Pregnancy
Trauma is the leading cause of non-obstetric morbidity and mortality in the pregnant patient in the United States. It is estimated to occur in about 7% of pregnancies. During pregnancy, the commonest cause of trauma in the United States is motor vehicle crashes, accounting for up to 70% of blunt abdominal trauma. The next leading cause is falls, followed by direct assault.
The incidence of domestic violence in pregnancy is alarming and emergency physicians should be attuned to this as a possibility if they see a pregnant patient who has apparently been assaulted. Domestic violence is thought to account for as much as 30% of all trauma seen in pregnancy. Very few women will admit to physical abuse and thus the physician must maintain a high index of suspicion for this problem. Direct questioning, with the partner out of the room, will often elicit the truth.
Penetrating injury is less common than blunt injury. In America, gunshot wounds are the most frequently encountered cause of penetrating injury. Fetal mortality rates in penetrating trauma are as high as 70%.
Complications peculiar to the pregnant patient as a result of trauma include preterm labor, placental abruption, fetal-maternal hemorrhage and fetal demise.
Q. A frequently asked question by pregnant patients is 'Should I wear my seat belt, doctor?' What is your response?
A. Your answer should be "YES." Unfortunately, up to one-half of all pregnant women do not wear their seat belt, or wear it incorrectly. Unbelted pregnant women are 4 times more likely to have a fetal demise and about 2.5 times more likely to give birth within 2 days of the injury, when compared with belted pregnant females. Correct placement of the belt is to wear the lap portion of the belt across the pelvis, below the pregnant abdomen, with the shoulder belt placed over the mid point of the clavicle, between the breasts, and to the side of the pregnant abdomen. Instruction by health care workers in the wearing and the correct positioning of belts will result in a significant increase in the correct wearing of seat belts by patients (83% vs. 65% for those not instructed).(6)
Let us discuss another case to illustrate some of the key concepts in managing the pregnant trauma patient. In general, in patients who are 24 weeks pregnant or less, the immediate focus of the resuscitation should be on the mother, though gaining some information about the fetus (for example, fetal heart tones) is useful. This does NOT mean that the fetus can be completely ignored, and I will discuss this later, but for the initial management, concentrate wholly on the mother as this will afford the fetus the best chance of survival. So, on to our next case.
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Second Case. The patient is a 27-year-old female who states that she is 28 weeks pregnant with her second child. While driving to work, she has been involved in a road crash where she was struck head-on by a truck that crossed the mid-line. Because her primary care health worker had counseled her, she was wearing her seatbelt correctly. However, there was significant damage to the patient's vehicle and she describes a momentary loss of consciousness. |
The patient is currently complaining of shortness of breath and has a cramping abdominal pain. She feels a little light headed. She is lying flat on a stretcher immobilized in a neck collar. She has one intravenous line in place and has oxygen running via a facemask. She is able to protect her airway. Her respiratory rate is 24 and shallow. Her blood pressure is 100/60 mm Hg and the oxygen saturation is 99%.
Q. Given that her airway is protected and her breathing probably adequate currently, what ONE measure could immediately help her and why?
A.The one immediate step that should be taken is that a wedge of some kind -- a rolled towel or other object -- should be placed under the right hip, moving the uterus over to the left side slightly. An angle of about 15° is usually recommended. This removes the uterus from the inferior vena cava and facilitates venous return. Compression of the vena cava can result in a significant reduction in venous return, enough to appear that the patient is hypovolemic. The result of this movement is that the blood pressure is now 118/68 mm Hg.
Q. Is this blood pressure 'normal'? And if it is normal, does this indicate we don't have to worry about occult blood loss here?
A. During pregnancy, a number of physiological changes occur. Among them, the blood pressure initially falls in the first trimester, rises slightly in the second, then rises again in the third trimester almost back to pre-pregnancy levels. The pulse rate gradually rises through pregnancy, with a baseline of 85 by the third trimester. The blood pressure recorded on our patient could be considered 'normal'. However, the presence of a normal blood pressure does not preclude the possibility of a significant bleed. Blood volume gradually increases through pregnancy, to levels about 50% or more above pre-pregnancy levels. The result of this is that clinical signs of significant hypovolemia may be delayed because of the increased reserve. Pregnant women suffering significant trauma should have two large bore IV lines established as a routine, even if they appear hemodynamically stable.
Q. What fluid should be run through these lines, and why?
A. In the pregnant patient, the use of lactated Ringer's solution is preferred. This is because the fluid is more physiologic and less acidotic that normal saline. Saline appears more likely to cause a significant acidosis and should be avoided. As is usual in the management of trauma victims, consideration should be given to warming the fluids.
Q. The patient is now complaining of a cramping feeling in her abdomen. What complication is a possibility now?
A. The presence of a cramping sensation should raise the possibility of the development of a placental abruption. This is a feared complication of trauma in pregnancy. It results from the relatively inelastic placenta separating from the elastic uterine wall when the latter is distorted because of trauma. It can occur after relatively minor trauma. It is the reason why careful observation is required for pregnant women after trauma. Unfortunately, ultrasound is not always reliable at spotting this problem.
Q. What monitoring modality is useful?
A. Patients need to have at least four hours of external fetal monitoring if they are beyond 20 weeks gestation. The absence of any uterine activity over the four-hour period immediately following the trauma virtually excludes the possibility of an abruption. The presence of 8 or more contractions in an hour is highly suggestive of the diagnosis of abruption. Management then should be by an experienced obstetrician and will depend upon fetal gestational age. Between 3 and 7 contractions in an hour require further observation and many would recommend 24 hours of continuous monitoring. Assessment of the fetal heart tones are also vital and should be performed regularly while in the emergency department. .
Q. What is the normal fetal heart rate? What is the fetal response to stress?
A. The normal fetal heart rate is between 120 and 160 beats per minute. The normal fetal response to stress is bradycardia and the commonest cause of this is hypoxia. If correction of maternal hypoperfusion, hypoventilation or hypothermia does not improve the heart rate, then abruption or another uterine abnormality is likely.
Q. You are very suspicious that your patient has an abruption. From what complication of the abruption is the mother at risk? You also find out that the mother is Rh negative. The patient has no vaginal bleeding, so does this matter?
A. Abruption is a risk factor for the development of disseminated intravascular coagulation, secondary to the passage of placental products into the maternal circulation. We are also told that the patient is Rh negative. The patient has abruption, and there is up to a 30% rate of fetal maternal hemorrhage, and she must be given Rh immune globulin. The usual dose is 300 micrograms intramuscularly. As little as 0.5 ml of fetal blood is required to sensitize 70% of Rh negative women. Some authorities use the Kleihauer-Betke test to estimate the degree of fetal blood loss into the maternal circulation. This test is, however, not always available in the emergency department and is, thus, rarely useful in the emergency management of patients.
Patients who have an abruption have fetal distress obvious in at least 60% of cases on arrival in the emergency department. In these cases, immediate intervention is required. In the remainder, the abruption may be small enough to allow continuation of the pregnancy, but the mother must be observed very closely. If there is a significant abruption, and the fetus is over 32 weeks, many authorities would proceed to delivery.
Q. Let us assume that examination of the abdomen in our patient now revealed a boggy-feeling uterus and you are sure you can easily palpate a foot through the abdominal wall. What devastating complication has now arisen?
A. The presence of a boggy uterus and easily palpable fetal parts are signs of a uterine rupture. Although this complication is very rare, it is devastating in that there is profuse bleeding and rapid deterioration of mother and fetus. Immediate delivery is paramount to save either life.
The technique of emergency department caesarian section is a little beyond this Cyberounds®, but it is indicated if there are signs of fetal life and resuscitative efforts on the mother have been unsuccessful, with no pulse or blood pressure, for four minutes. The technique involves a midline incision from the pubis to the umbilicus. This incision is extended down through all layers to the uterus. The uterus is opened in the lower section with a small vertical incision from a scalpel. A scissors is then inserted into the incision and, using the fingers as a guide so as to keep the points away from the fetus, extended up to the top of the uterus. The baby is delivered through the incision and the cord clamped. If the placenta is encountered on the anterior wall, it is cut through.
The management of pregnant trauma victims can be challenging and stressful for the staff. The immediate resuscitation should follow well-established advanced trauma life support (ATLS) guidelines. An organized approach, using the skills of the emergency department personnel, together with obstetric, pediatric and trauma surgical colleagues will result in the best outcome for our patient.