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Emergency medicine physicians saving time with ultrasound
Diagnostics
Emergency Medicine Physicians Saving Time With Ultrasound BRITT DURHAM, MD In an attempt to provide comprehensive and timely patient care, emergency physicians have begun to use ultrasonography to perform and interpret goal-oriented examinations. Reducing time to diagnosis can potentially have a major impact on the treatment of patients with ruptured ectopic pregnancy, leaking aortic aneurysm, and cardiac tamponade, who require time-sensitive surgical intervention. A review of three cases reveals how ultrasonography performed by emergency physicians can rapidly provide valuable diagnostic information and expedite patient care in three different clinical scenarios. (Am J Emerg Meal 1996;14:309-313. Copyright © 1996 by W.B. Saunders Company) Emergency physicians may have to accept delays during weekend and night shifts for t h e arrival of the ultrasound technician, the performance of the examination, and the radiologist's interpretation. The need to improve patient care through timely diagnostic imaging in patients whose conditions are potentially unstable has fueled the growing interest in bedside ultrasonography performed by emergency physicians. Ultrasonography has been shown to be a safe, accurate, and rapid method for diagnosing many conditions in the emergency department (ED), such as ruptured ectopic pregnancy, aortic aneurysm, and cardiac tamponade. 1 Despite the success of rapid surgical intervention, these conditions are associated with high mortality, in part because of misdiagnosis and delays in diagnostic workup. 2,3 Bedside ultrasonography is an ideal medium for use by trained emergency medicine physicians for the early detection of these life-threatening conditions.
CASE1 A 34-year-old woman presented to the ED complaining of diffuse abdominal pain with vaginal bleeding for 1 day. She denied fever, vomiting, or risk factors for ectopic pregnancy. On physical examination, her blood pressure was 110/70 mm Hg, pulse was 90 beats/rain, respirations were 16 breaths/min, and her temperature was .37.4°C. She was awake and alert in moderate distress. Her From the Department of Emergency Medicine, Martin Luther King Trauma and Medical Center, Los Angeles, CA. Manuscript received February 22, 1995, returned March 25, 1995; revision received June 9, 1995, accepted June 10, 1995. Address reprint requests to Dr Durham, Department of Emergency Medicine, Martin Luther King Trauma and Medical Center, 12021 S. Wilmington Ave, Los Angeles, CA 90059. Key Words: Ectopic pregnancy, culdocentesis, endovaginal ultrasound, transabdominal ultrasound, abdominal aortic aneurysm, echocardiography, cardiac tamponade. Copyright © 1996 by W.B. Saunders Company 0735-6757/96/1403-002055.00/0
lungs were clear to auscultation and percussion. Heart sounds were normal without cardiac murmur or rubs. Abdominal examination revealed bilateral lower abdominal tenderness with involuntary guarding. There were no masses or rebound tenderness appreciated. Her pelvic examination revealed small amounts of dark blood in the vaginal vault. The uterus was slightly enlarged with bilateral adnexal tenderness, and no adnexal masses were palpated. The urine pregnancy test result was positive, and the hematocrit level was 34 mL/dL. Ten minutes after arrival, transabdominal and endovaginal ultrasonography was performed by emergency physicians. A right adnexal mass and fluid in the cul-de-sac were visualized. No intrauterine contents were detected (Figures 1 and 2). Immediate gynecology consultation was requested. The operating staff was called within 20 minutes after the first patient contact. The patient was transferred to the operating room where she underwent an exploratory laparotomy. A right tubal pregnancy and 900-cc hemoperitoneum was discovered intraoperatively. The patient recovered from surgery with no postoperative complications.
CASE 2 A 77-year-old man presented to the ED complaining of sudden onset of weakness and diffuse abdominal pain, associated with nausea and diaphoresis. He denied back pain, vomiting, or previous medical illness. On physical examination, his blood pressure was 96/60 mm Hg, his pulse was 110 beats/min, his respirations were 24 breaths/min, and his temperature was 36.8°C. He was pale, diaphoretic, and in moderate distress. His lungs were clear to auscultation and percussion. Heart sounds revealed a rapid regular rhythm without murmur or rubs. An abdominal examination revealed a distended abdomen with diffuse tenderness, increased over the right upper quadrant on palpation. Involuntary guarding was present with rebound tenderness, but no masses or hepatosplenomegaly were appreciated. Bowel sounds were decreased. A rectal exam revealed guiac negative stool. The initial workup results showed a hemoglobin level of 11 g/dL and hematocrit level of 33 mL/dL. Decubitus, flat, and cross-table lateral radiographs of the abdomen showed normal images. Ten minutes after arrival, abdominal ultrasound performed by emergency physicians showed an abdominal aortic aneurysm (AAA) measuring 7.5 cm in diameter (Figure 3). Vascular consultation was immediately requested and the operating room staff was notified within 20 minutes after the patient's arrival at the ED. The patient was transferred to the operating room and underwent infrarenal aortic graft replacement for ruptured aortic aneurysm. He survived despite massive intraoperative and postoperative blood replacement.
CASE 3 A 33-year-old man was brought to the ED by paramedics after sustaining a penetrating gunshot wound to the left anterior chest 309
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FIGURE I. Endovaginal image of the right adnexa shows a tubal gestational sac (arrow). wall. Paramedics noted a significant amount of blood loss at the scene. On physical examination, his blood pressure was 90/50 mm Hg, his pulse was 140 beats/min, his respirations were 36 breaths/min, and his temperature was 36.4°C, The patient was warm, diaphoretic, and in moderate respiratory distress. No distended neck veins or tracheal deviation was noted on examination of the neck. Auscultation of the lung fields revealed decreased breath sounds over the left chest. No murmurs, rubs, or muffled heart sounds were present on auscultation of the heart. The patient received aggressive infusion of lactated Ringer's solution, and auto-transfusion from left chest tube thoracotomy. Despite these efforts, he remained hypotensive with signs of hypovolemic shock. Within 10 minutes after his arrival, emergency medicine physicians performed echocardiography, which revealed a pericardial effusion, using 2D and M-mode parasternal long axis and subcostal views (Figure 4). The patient was immediately transferred to the operating room where open thoracotomy and pericardiotomy confirmed the presence of a cardiac tamponade. He survived surgery and had no postoperative complications.
DISCUSSION Ectopic pregnancy is a common disorder seen in the ED, and remains the leading cause of death in the first trimester
FIGURE 2. Sagittal endovaginal scanning of the uterus shows no intrauterine contents (A) and blood can be visualized in the cul-de-sac (B).
FIGURE 3. An aortic aneurysm is seen on cross-sectional transabdominal image. of pregnancy. The incidence of this illness has tripled over the past 15 years? Fifty percent of cases are misdiagnosed on first medical visit, suggesting that this is often a difficult diagnosis to make. Pelvic ultrasonography is the diagnostic adjunct of choice for use in these patients because accurate diagnosis is often impossible by clinical examination alone. In Case 1, the patient underwent transabdominal and endovaginal ultrasonography using 3.5 MHz transducer and vaginal probe. Images were recorded on video for review, and photocopies were placed in medical records. Transabdominal ultrasound images are performed in longitudinal and transverse sections with the goal of visualizing products of conception within the uterus. Endovaginal ultrasound images are performed in longitudinal and coronal sections and allows visualization of intrauterine pregnancy (IUP) 1 week earlier than does transabdominal scanning. 4 This technique can be performed with an empty bladder, and provides more reliable data, especially in obese patients. The gestational sac is the earliest finding of IUE It can be seen between 4 to 5 weeks of gestation from the last menstrual period using endovaginal scanning. 4 This may appear similar to a psuedogestational sac, which may be present with ectopic pregnancy. Presence of fetal pole and cardiac activity are detectable at approximately 6 and 7
FIGURE 4. Ventricular wall (A) and pericardial effusion (B) can be seen on subcostal view.
BRITT DURHAM • EMERGENCY PHYSICIANS SAVING TIME WITH ULTRASOUND
weeks, respectively.4 The identification of an IUP virtually excludes the diagnosis of ectopic pregnancy, as a simultaneous intrauterine and extrauterine gestation occurs in less than 1 in 40,000 patients. 5 The absence of intrauterine contents suggests the possibility of early on IUP of less than 4 weeks' gestation, complete abortion, or extrauterine gestation. Endovaginal scanning consistently identifies 4-week gestational sacs at human chorionic gonadotropin (hCG) levels of 1,000 to 2,000 IU/L. 5 The absence of an IUP on endovaginal examination in symptomatic patients with hGC levels of >2,000 IU/L should be considered to diagnose ectopic pregnancy until proven otherwise. 3 The visualization of an extrauterine embryo with cardiac activity confirms the diagnosis of ectopic pregnancy. This finding is present in approximately 20% of cases. 6 Adnexal embryo, gestational sac, complex mass, fluid in the cul-desac, and intrauterine pseudogestational sac are all consistent with ectopic pregnancy. Although endovaginal scanning showed an adnexal gestational sac in this patient, evidence of extrauterine gestation may not be visualized in more than a third of cases. 6 Ultrasound evaluation of adnexal structures may require additional experience; however, as in case 1, the absence of intrauterine contents in a pregnant patient with fluid in the cul-de-sac is easily visualized and has a high predictive value for ruptured ectopic pregnancy in clinically suspicious patients. 6,7 Endovaginal scanning is sensitive in detecting small amounts of blood in the cul-de-sac and is replacing traditional culdocentesis as a noninvasive test for the diagnosis of ruptured ectopic pregnancy. 3,8This painful procedure, which is limited by false-negative or nondiagnostic findings, is being surpassed by improving ultrasonographic technology that can detect as little as 150 mL of fluid in the cul-de-sac) Emergency physicians detected blood in the cul-de-sac using ultrasonography in case 1, and delays of a painful culdocentesis were avoided. The limitations of initial vital signs and routine laboratory studies for the detection of potentially unstable ruptured ectopic pregnancies are well documented in the literature) The initial vital signs and the hematocrit level were within normal limits in case 1; however, this patient was noted to be actively hemorrhaging at the time of surgery. Poor detection of hypovolemia and lack of appropriate resuscitation in the radiology department during examination may result in a poor outcome. This unstable patient never left the care of the ED, delays were avoided, and she had no complications associated with hypovolemic shock. A ruptured AAA is a catastrophic event. The prevalence of AAA in the general population is 3% in people older than the age of 50 years, 9% in men older than 60 years of age with hypertension or coronary artery disease. 9 The most common presenting complaint is abdominal and/or back pain, both common and nonspecific symptoms in the middle-aged and elderly patient. AAA is misdiagnosed in 30% to 50% of cases, suggesting that ruptured aneurysm is frequently a difficult diagnosis. 9 The presence of an abdominal pulsating mass or enlarged calcified aorta on X-rays are helpful, but may be detectable in only half of cases. Ultrasonography has been used as a rapid method for diagnosing this condition in
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the ED, demonstrating the presence of AAA in 98% of cases in one study, l° Ultrasonography of the aorta is a relatively straightforward procedure. The aorta can be identified on transabdominal scanning as a thick-walled, pulsating, noncompressible structure lying next to the inferior vena cava. The diagnosis of aorta aneurysm can be excluded if the aorta is well visualized and is of normal diameter. A combination of scanning evidence of AAA in patients with abdominal pain and alterations in hemodynamic condition has a high predictive value for ruptured or leaking aortic aneurysm. 1° Symptomatic aneurysms of greater than 5 cm in diameter are at risk for rupture; this risk increases with size. 5 In Case 2, ultrasonography performed by the emergency physicians diagnosed the presence of an AAA that was not palpable on physical examination or evident on X-rays. Experienced ultrasound operators can estimate the proximal and distal extent of the aneurysm and occasionally detect retroperitoneal hemorrhage. Emergency scanning in this case showed no obvious bleeding and suggested that the aneurysm was infrarenal in location. A diagnosis of a symptomatic aortic aneurysm was made in a decisive manner that was not possible on clinical examination alone, resulting in a timely disposition. Patients with AAA undergo diagnostic evaluations in the ED of 5 to 6 hours on average. Patients whose ED evaluation lasted longer than 5 hours have a significant increase in mortality, u An abbreviated sonographic examination in the ED can provide accurate information about the presence of aneurysm, avoid potential delays, and prevent unstable patients from decompensating while undergoing computed tomography (CT) examinations. CT can provide more detailed information regarding the anatomic extent of the aneurysm and is more sensitive in detecting small hemorrhages. One major advantage of ultrasound is that it can be performed at the bedside within minutes, without interruptions in resuscitation efforts. The presence of shock precludes contrast studies, as these patients are too unstable to be transferred to the radiology department. Cardiac tamponade is most commonly associated with penetrating trauma to the thorax. Restriction of cardiac activity and cardiac filling occur as a result of a traumatic hemopericardium, which is fatal if not treated rapidly. This important diagnosis may be difficult to make in patients who often present without the classic findings of Beck's triad. These findings may be difficult to detect in a noisy ED, they may be absent, or they may confused with other conditions. Ultrasonography is a safe and accurate method for the detection of pericardial fluid at the bedside. 12 In addition, resuscitation efforts do not have to be interrupted while this procedure is being performed. The immediate life-threatening nature of this condition usually precludes the time required to arrange ultrasonography through the radiology department. Multidimensional sections of the heart can be performed through subcostal, apical, and parasternal echocardiographic windows. Interpretation of ventricular function and valvular structures may require some experience, but the presence or absence of pericardial effusion is easily identified. Although a pericardial effusion itself is not pathopneumonic for cardiac tamponade, it has a high predictive value in penetrat-
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ing chest trauma patients who are hypotensive. 13A4 The compression of the right atrium or ventricle may be visualized as the intrapericardial pressure exceeds the right atrial pressure. This finding is specific for hemodynamic compromise found with cardiac tamponade.15 A negative examination virtually excludes the diagnosis of cardiac tamponade and may prevent complications associated with pericardiocentesis in patient with false-positive signs or inaccurate central venus pressure readings. Pericardiocentesis is a rapid invasive diagnostic procedure which is potentially dangerous and unreliable, resulting in unnecessary surgery and prolonged hospitalization.12 Because of the growth and availability of ultrasound technology, its use has spread from traditional radiology into the fields of internal medicine, obstetrics, trauma, and emergency medicine. This rapid noninvasive tool has many applications for emergency physicians who are called on to treat and perform procedures under time-sensitive urgent or emergency conditions. Patients arriving at the ED with ruptured ectopic pregnancy, leaking aortic aneurysm, or cardiac tamponade require rapid intervention. During night and weekend hours, radiology may not arrive with sufficient speed to perform ultrasound examinations and interpret images. 16 Valuable time is lost in facilities where an ultrasound staff is not immediately available or when the emergency physician is hesitant in initiating a costly ultrasound workup during inconvenient hours. Waiting until a patient has obvious clinical signs of a life-threatening condition is a c o m m o n e r r o r . 2,3J2 Emergency physicians interpret radiographs, CT scans, and electrocardiograms and perform advanced airway management and slit lamp examinations in patients who are not subject to delays in the ED. Although these readings and procedures are performed by specialists, they have become incorporated into routine emergency physician practice. In the resolution of boundary issues between emergency and radiology departments, the benefit of ultrasonography in patients who should not be subject to diagnostic delays should be an important consideration. This use of ultrasonography has an important impact on optimizing patient care. Surgical consultation and preparation for time-sensitive definitive surgical intervention was initiated within 20 minutes of first patient contact in all three cases reviewed. This represents hours of time saved during night and weekend shifts. Although considerable controversy exists regarding the future role of ultrasonography in the ED, emergency physicians are taking an increasingly active position in establishing standards of training and practice. The Society for Academic Emergency Medicine proposed a model curriculum which includes 40 hours of instruction and 150 ultrasound examinations. 17The American College of Emergency Physicians supports the immediate availability of ultrasound technology for ED patients by appropriately trained physicians, and has developed its own diagnostic ultrasound c o u r s e . 18
No absolute guidelines or training criteria exists for many specialties that routinely use diagnostic ultrasonography) 9 The American Institute of Ultrasound Medicine has endorsed a completion of fellowship training or extensive clinical experience involving more than 500 cases and
completion of 100 hours of continuing medical education. 2° Currently there are many medical centers in which emergency physicians are actively utilizing diagnostic ultrasound in their EDs. Many residency programs have begun to include training in ultrasonography as part of their curricula with favorable results. 21 Ultrasonography in the cases reviewed in this article was performed by emergency medicine residents under the supervision of an attending physician who had approximately 100 cases of experience and 12 hours of formal education. Simple goal-directed ultrasound examinations by emergency physicians are not required to be as detailed as a formal comprehensive scanning by the radiology department to diagnose or exclude medical illness. A simple goal-oriented examination can provide definitive information. A selective pelvic scanning for the presence of an intrauterine pregnancy is easily learned and can rule out the diagnosis of ectopic pregnancy in the majority of cases. The aorta is easily identified on transabominal ultrasound. A normal diameter virtually excludes the diagnosis of aortic aneurysm. A simple single-view subcostal echocardiogram revealing no pericardial effusion excludes the presence of cardiac tarnponade. These simple techniques are easily learned and do not require skillful interpretation. The incidence of false-negative ultrasound examinations by emergency physicians has been reported to correlate well with the incidences reported in the standard ultrasound imaging literature. 21Furthermore, studies have shown initial real-time ultrasound interpretations to be at least as accurate as later hard-copy readings. 16,22 Well-trained emergency medicine physicians are in a unique position to integrate the patient's history and physical examination to best interpret ultrasound findings. Patients are at risk of morbidity or death in the event of an incorrect ultrasound diagnosis. For example, an inexperienced ultrasonographer can easily misidentify a psuedogestational sac for an early intrauterine pregnancy.4 Quality assurance, therefore, will require continued education, clear definitions of proposed applications, with their indications and limitations, proper documentation, and a well-constructed monitoring program. All inconclusive exams should be followed by formal imaging studies or appropriate diagnostic procedures, and all discharged patients must be followed up closely. Collaborating efforts between the emergency and radiology departments are also recommended. Outcomes for patients with ruptured ectopic pregnancy, leaking abdominal aneurysm, and cardiac tamponade depend on early recognition, resuscitation, and surgical intervention. 3,13,23 These conditions are often diagnosed late because patients present with nonspecific and nonsensitive findings. The immediate use of ultrasonography by emergency physicians in patients with cardiac tamponade was found to improve survival and patient outcomes in one study, and was attributed to a shorter time to diagnosis and disposition. ~3Although similar studies have not been undertaken for ruptured ectopic pregnancy and symptomatic abdominal aneurysm, a decrease in time to diagnosis in these time-dependent conditions would logically improve patient care.
BRITT DURHAM • EMERGENCY PHYSICIANS SAVING TIME WITH ULTRASOUND
CONCLUSION Ultrasonography properly used by emergency physicians is a helpful diagnostic tool that has great potential application in the ED. This imaging tool is the modality of choice for trained emergency physicians for the rapid assessment and early detection of ruptured ectopic pregnancy, leaking aortic aneurysm, and cardiac tamponade. REFERENCES 1. Plummer D, Hahn R: Diagnostic ultrasonography in the emergency department. Ann Emerg Med 1993;22:592-594 2. Walker EM: Unoperated aortic aneurysm: Presentation and natural history. Ann R Coil Surg Eng11983;65:311-313 3. Lawler HK, Rubin BJ: Early diagnosis of ectopic pregnancy. Western J Med 1993; 159:195-199 4. Pennell RG, Needleman L: Prospective comparison of vaginal and abdominal sonography in normal early pregnancy. J Ultrasound Med 1991 ;10:63-67 5. Heller MB, Verdile VP: Ultrasound in emergency medicine. Emerg Med Clin North Am 1992; 10:27-46 6. Kivikoski A, Martin CM: Transabdominal and transvaginal ultrasonography in the diagnosis of ectopic pregnancy: A comparative Study. Am J Obstet Gynecol 1990; 163:123-128 7. Bohm-Velez M, Mendelson EB: Transvaginal sonography in evaluating ectopic pregnancy. Semin Ultrasound CT MR 1990;11: 44-46 8. Vermosh M: Reevaluation of the role of culdocentesis in the management of ectopic pregnancy. Am J Obstet Gyneco11990;162: 411-413
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9. Lederle FA, Walker JM: Selective screening for abdominal aortic aneurysms with physical examination and ultrasound. Arch Intern Med 1988;148:1753-1756 10. Shuman WP, Hastrup W: Suspected leaking abdominal aortic aneurysm: Use of sonography in the emergency room. Radiology 1988;168:117-119 11. Borrero E: Symptomatic abdominal aneurysm misdiagnosed as nephroureterolithiasis. Ann Vasc Surg 1988;2:145-149 12. Turturro MA: Emergency echocardiography. Emerg Meal Clin North Am 1992; 10:47-57 14. Plummer D: Principles of emergency ultrasound and echocardiography. Ann Emerg Med 1989;18:1291-1297 15. Singh S, Wann LS: Usefulness of right ventricular diastoloic collapse in diagnosing cardiac tamponade, a combined echocardiographic and hemodynamic study. Am J Cardio11986;57:652-656 16. Deutchman ME, Hahn RG: Diagnostic ultrasound imaging by physicians of first contact: Extending the family medicine experience into emergency medicine. Ann Emerg Med 1993;22:594-596 17. Plummer D, Dick C: Model curriculum for physician training in emergency ultrasonography. Ann Emerg Med 1994;23:95-102 18. Johnson JC: Emergency physicians' new diagnostic tool: Ultrasound indications, implications explored. Am Coil Emerg Phys News 1990;8:4 19. Geyman JP: Toward the resolution of generalist-specialist boundary issues. J Fam Pract 1989;28:399-400 20. American Institute of Ultrasound Medicine: Guidelines for evaluation and interpreting diagnostic ultrasound examinations. AlUM Reporter 1993;May:1 21. Schlager D, LazzareschiG:Aprospectivestudy of ultrasonography in the ED by emergency physicians. Am J Emerg Med 1994;12:185-189 22. O'Leay MR, Smith MS: Applications of clinical indicators in the emergency department. JAMA 1989;262:3444-3447 23. Ottinger LW: Ruptured arteriosclerotic aneurysms of the abdominal aorta: Reducing mortality. JAMA 1975;223:147-150
Emergency Medicine Physicians Saving Time With Ultrasound BRITT DURHAM, MD In an attempt to provide comprehensive and timely patient care, emergency physicians have begun to use ultrasonography to perform and interpret goal-oriented examinations. Reducing time to diagnosis can potentially have a major impact on the treatment of patients with ruptured ectopic pregnancy, leaking aortic aneurysm, and cardiac tamponade, who require time-sensitive surgical intervention. A review of three cases reveals how ultrasonography performed by emergency physicians can rapidly provide valuable diagnostic information and expedite patient care in three different clinical scenarios. (Am J Emerg Meal 1996;14:309-313. Copyright © 1996 by W.B. Saunders Company) Emergency physicians may have to accept delays during weekend and night shifts for t h e arrival of the ultrasound technician, the performance of the examination, and the radiologist's interpretation. The need to improve patient care through timely diagnostic imaging in patients whose conditions are potentially unstable has fueled the growing interest in bedside ultrasonography performed by emergency physicians. Ultrasonography has been shown to be a safe, accurate, and rapid method for diagnosing many conditions in the emergency department (ED), such as ruptured ectopic pregnancy, aortic aneurysm, and cardiac tamponade. 1 Despite the success of rapid surgical intervention, these conditions are associated with high mortality, in part because of misdiagnosis and delays in diagnostic workup. 2,3 Bedside ultrasonography is an ideal medium for use by trained emergency medicine physicians for the early detection of these life-threatening conditions.
CASE1 A 34-year-old woman presented to the ED complaining of diffuse abdominal pain with vaginal bleeding for 1 day. She denied fever, vomiting, or risk factors for ectopic pregnancy. On physical examination, her blood pressure was 110/70 mm Hg, pulse was 90 beats/rain, respirations were 16 breaths/min, and her temperature was .37.4°C. She was awake and alert in moderate distress. Her From the Department of Emergency Medicine, Martin Luther King Trauma and Medical Center, Los Angeles, CA. Manuscript received February 22, 1995, returned March 25, 1995; revision received June 9, 1995, accepted June 10, 1995. Address reprint requests to Dr Durham, Department of Emergency Medicine, Martin Luther King Trauma and Medical Center, 12021 S. Wilmington Ave, Los Angeles, CA 90059. Key Words: Ectopic pregnancy, culdocentesis, endovaginal ultrasound, transabdominal ultrasound, abdominal aortic aneurysm, echocardiography, cardiac tamponade. Copyright © 1996 by W.B. Saunders Company 0735-6757/96/1403-002055.00/0
lungs were clear to auscultation and percussion. Heart sounds were normal without cardiac murmur or rubs. Abdominal examination revealed bilateral lower abdominal tenderness with involuntary guarding. There were no masses or rebound tenderness appreciated. Her pelvic examination revealed small amounts of dark blood in the vaginal vault. The uterus was slightly enlarged with bilateral adnexal tenderness, and no adnexal masses were palpated. The urine pregnancy test result was positive, and the hematocrit level was 34 mL/dL. Ten minutes after arrival, transabdominal and endovaginal ultrasonography was performed by emergency physicians. A right adnexal mass and fluid in the cul-de-sac were visualized. No intrauterine contents were detected (Figures 1 and 2). Immediate gynecology consultation was requested. The operating staff was called within 20 minutes after the first patient contact. The patient was transferred to the operating room where she underwent an exploratory laparotomy. A right tubal pregnancy and 900-cc hemoperitoneum was discovered intraoperatively. The patient recovered from surgery with no postoperative complications.
CASE 2 A 77-year-old man presented to the ED complaining of sudden onset of weakness and diffuse abdominal pain, associated with nausea and diaphoresis. He denied back pain, vomiting, or previous medical illness. On physical examination, his blood pressure was 96/60 mm Hg, his pulse was 110 beats/min, his respirations were 24 breaths/min, and his temperature was 36.8°C. He was pale, diaphoretic, and in moderate distress. His lungs were clear to auscultation and percussion. Heart sounds revealed a rapid regular rhythm without murmur or rubs. An abdominal examination revealed a distended abdomen with diffuse tenderness, increased over the right upper quadrant on palpation. Involuntary guarding was present with rebound tenderness, but no masses or hepatosplenomegaly were appreciated. Bowel sounds were decreased. A rectal exam revealed guiac negative stool. The initial workup results showed a hemoglobin level of 11 g/dL and hematocrit level of 33 mL/dL. Decubitus, flat, and cross-table lateral radiographs of the abdomen showed normal images. Ten minutes after arrival, abdominal ultrasound performed by emergency physicians showed an abdominal aortic aneurysm (AAA) measuring 7.5 cm in diameter (Figure 3). Vascular consultation was immediately requested and the operating room staff was notified within 20 minutes after the patient's arrival at the ED. The patient was transferred to the operating room and underwent infrarenal aortic graft replacement for ruptured aortic aneurysm. He survived despite massive intraoperative and postoperative blood replacement.
CASE 3 A 33-year-old man was brought to the ED by paramedics after sustaining a penetrating gunshot wound to the left anterior chest 309
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FIGURE I. Endovaginal image of the right adnexa shows a tubal gestational sac (arrow). wall. Paramedics noted a significant amount of blood loss at the scene. On physical examination, his blood pressure was 90/50 mm Hg, his pulse was 140 beats/min, his respirations were 36 breaths/min, and his temperature was 36.4°C, The patient was warm, diaphoretic, and in moderate respiratory distress. No distended neck veins or tracheal deviation was noted on examination of the neck. Auscultation of the lung fields revealed decreased breath sounds over the left chest. No murmurs, rubs, or muffled heart sounds were present on auscultation of the heart. The patient received aggressive infusion of lactated Ringer's solution, and auto-transfusion from left chest tube thoracotomy. Despite these efforts, he remained hypotensive with signs of hypovolemic shock. Within 10 minutes after his arrival, emergency medicine physicians performed echocardiography, which revealed a pericardial effusion, using 2D and M-mode parasternal long axis and subcostal views (Figure 4). The patient was immediately transferred to the operating room where open thoracotomy and pericardiotomy confirmed the presence of a cardiac tamponade. He survived surgery and had no postoperative complications.
DISCUSSION Ectopic pregnancy is a common disorder seen in the ED, and remains the leading cause of death in the first trimester
FIGURE 2. Sagittal endovaginal scanning of the uterus shows no intrauterine contents (A) and blood can be visualized in the cul-de-sac (B).
FIGURE 3. An aortic aneurysm is seen on cross-sectional transabdominal image. of pregnancy. The incidence of this illness has tripled over the past 15 years? Fifty percent of cases are misdiagnosed on first medical visit, suggesting that this is often a difficult diagnosis to make. Pelvic ultrasonography is the diagnostic adjunct of choice for use in these patients because accurate diagnosis is often impossible by clinical examination alone. In Case 1, the patient underwent transabdominal and endovaginal ultrasonography using 3.5 MHz transducer and vaginal probe. Images were recorded on video for review, and photocopies were placed in medical records. Transabdominal ultrasound images are performed in longitudinal and transverse sections with the goal of visualizing products of conception within the uterus. Endovaginal ultrasound images are performed in longitudinal and coronal sections and allows visualization of intrauterine pregnancy (IUP) 1 week earlier than does transabdominal scanning. 4 This technique can be performed with an empty bladder, and provides more reliable data, especially in obese patients. The gestational sac is the earliest finding of IUE It can be seen between 4 to 5 weeks of gestation from the last menstrual period using endovaginal scanning. 4 This may appear similar to a psuedogestational sac, which may be present with ectopic pregnancy. Presence of fetal pole and cardiac activity are detectable at approximately 6 and 7
FIGURE 4. Ventricular wall (A) and pericardial effusion (B) can be seen on subcostal view.
BRITT DURHAM • EMERGENCY PHYSICIANS SAVING TIME WITH ULTRASOUND
weeks, respectively.4 The identification of an IUP virtually excludes the diagnosis of ectopic pregnancy, as a simultaneous intrauterine and extrauterine gestation occurs in less than 1 in 40,000 patients. 5 The absence of intrauterine contents suggests the possibility of early on IUP of less than 4 weeks' gestation, complete abortion, or extrauterine gestation. Endovaginal scanning consistently identifies 4-week gestational sacs at human chorionic gonadotropin (hCG) levels of 1,000 to 2,000 IU/L. 5 The absence of an IUP on endovaginal examination in symptomatic patients with hGC levels of >2,000 IU/L should be considered to diagnose ectopic pregnancy until proven otherwise. 3 The visualization of an extrauterine embryo with cardiac activity confirms the diagnosis of ectopic pregnancy. This finding is present in approximately 20% of cases. 6 Adnexal embryo, gestational sac, complex mass, fluid in the cul-desac, and intrauterine pseudogestational sac are all consistent with ectopic pregnancy. Although endovaginal scanning showed an adnexal gestational sac in this patient, evidence of extrauterine gestation may not be visualized in more than a third of cases. 6 Ultrasound evaluation of adnexal structures may require additional experience; however, as in case 1, the absence of intrauterine contents in a pregnant patient with fluid in the cul-de-sac is easily visualized and has a high predictive value for ruptured ectopic pregnancy in clinically suspicious patients. 6,7 Endovaginal scanning is sensitive in detecting small amounts of blood in the cul-de-sac and is replacing traditional culdocentesis as a noninvasive test for the diagnosis of ruptured ectopic pregnancy. 3,8This painful procedure, which is limited by false-negative or nondiagnostic findings, is being surpassed by improving ultrasonographic technology that can detect as little as 150 mL of fluid in the cul-de-sac) Emergency physicians detected blood in the cul-de-sac using ultrasonography in case 1, and delays of a painful culdocentesis were avoided. The limitations of initial vital signs and routine laboratory studies for the detection of potentially unstable ruptured ectopic pregnancies are well documented in the literature) The initial vital signs and the hematocrit level were within normal limits in case 1; however, this patient was noted to be actively hemorrhaging at the time of surgery. Poor detection of hypovolemia and lack of appropriate resuscitation in the radiology department during examination may result in a poor outcome. This unstable patient never left the care of the ED, delays were avoided, and she had no complications associated with hypovolemic shock. A ruptured AAA is a catastrophic event. The prevalence of AAA in the general population is 3% in people older than the age of 50 years, 9% in men older than 60 years of age with hypertension or coronary artery disease. 9 The most common presenting complaint is abdominal and/or back pain, both common and nonspecific symptoms in the middle-aged and elderly patient. AAA is misdiagnosed in 30% to 50% of cases, suggesting that ruptured aneurysm is frequently a difficult diagnosis. 9 The presence of an abdominal pulsating mass or enlarged calcified aorta on X-rays are helpful, but may be detectable in only half of cases. Ultrasonography has been used as a rapid method for diagnosing this condition in
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the ED, demonstrating the presence of AAA in 98% of cases in one study, l° Ultrasonography of the aorta is a relatively straightforward procedure. The aorta can be identified on transabdominal scanning as a thick-walled, pulsating, noncompressible structure lying next to the inferior vena cava. The diagnosis of aorta aneurysm can be excluded if the aorta is well visualized and is of normal diameter. A combination of scanning evidence of AAA in patients with abdominal pain and alterations in hemodynamic condition has a high predictive value for ruptured or leaking aortic aneurysm. 1° Symptomatic aneurysms of greater than 5 cm in diameter are at risk for rupture; this risk increases with size. 5 In Case 2, ultrasonography performed by the emergency physicians diagnosed the presence of an AAA that was not palpable on physical examination or evident on X-rays. Experienced ultrasound operators can estimate the proximal and distal extent of the aneurysm and occasionally detect retroperitoneal hemorrhage. Emergency scanning in this case showed no obvious bleeding and suggested that the aneurysm was infrarenal in location. A diagnosis of a symptomatic aortic aneurysm was made in a decisive manner that was not possible on clinical examination alone, resulting in a timely disposition. Patients with AAA undergo diagnostic evaluations in the ED of 5 to 6 hours on average. Patients whose ED evaluation lasted longer than 5 hours have a significant increase in mortality, u An abbreviated sonographic examination in the ED can provide accurate information about the presence of aneurysm, avoid potential delays, and prevent unstable patients from decompensating while undergoing computed tomography (CT) examinations. CT can provide more detailed information regarding the anatomic extent of the aneurysm and is more sensitive in detecting small hemorrhages. One major advantage of ultrasound is that it can be performed at the bedside within minutes, without interruptions in resuscitation efforts. The presence of shock precludes contrast studies, as these patients are too unstable to be transferred to the radiology department. Cardiac tamponade is most commonly associated with penetrating trauma to the thorax. Restriction of cardiac activity and cardiac filling occur as a result of a traumatic hemopericardium, which is fatal if not treated rapidly. This important diagnosis may be difficult to make in patients who often present without the classic findings of Beck's triad. These findings may be difficult to detect in a noisy ED, they may be absent, or they may confused with other conditions. Ultrasonography is a safe and accurate method for the detection of pericardial fluid at the bedside. 12 In addition, resuscitation efforts do not have to be interrupted while this procedure is being performed. The immediate life-threatening nature of this condition usually precludes the time required to arrange ultrasonography through the radiology department. Multidimensional sections of the heart can be performed through subcostal, apical, and parasternal echocardiographic windows. Interpretation of ventricular function and valvular structures may require some experience, but the presence or absence of pericardial effusion is easily identified. Although a pericardial effusion itself is not pathopneumonic for cardiac tamponade, it has a high predictive value in penetrat-
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AMERICAN JOURNAL OF EMERGENCY MEDICINE • Volume 14, Number 3 • May 1996
ing chest trauma patients who are hypotensive. 13A4 The compression of the right atrium or ventricle may be visualized as the intrapericardial pressure exceeds the right atrial pressure. This finding is specific for hemodynamic compromise found with cardiac tamponade.15 A negative examination virtually excludes the diagnosis of cardiac tamponade and may prevent complications associated with pericardiocentesis in patient with false-positive signs or inaccurate central venus pressure readings. Pericardiocentesis is a rapid invasive diagnostic procedure which is potentially dangerous and unreliable, resulting in unnecessary surgery and prolonged hospitalization.12 Because of the growth and availability of ultrasound technology, its use has spread from traditional radiology into the fields of internal medicine, obstetrics, trauma, and emergency medicine. This rapid noninvasive tool has many applications for emergency physicians who are called on to treat and perform procedures under time-sensitive urgent or emergency conditions. Patients arriving at the ED with ruptured ectopic pregnancy, leaking aortic aneurysm, or cardiac tamponade require rapid intervention. During night and weekend hours, radiology may not arrive with sufficient speed to perform ultrasound examinations and interpret images. 16 Valuable time is lost in facilities where an ultrasound staff is not immediately available or when the emergency physician is hesitant in initiating a costly ultrasound workup during inconvenient hours. Waiting until a patient has obvious clinical signs of a life-threatening condition is a c o m m o n e r r o r . 2,3J2 Emergency physicians interpret radiographs, CT scans, and electrocardiograms and perform advanced airway management and slit lamp examinations in patients who are not subject to delays in the ED. Although these readings and procedures are performed by specialists, they have become incorporated into routine emergency physician practice. In the resolution of boundary issues between emergency and radiology departments, the benefit of ultrasonography in patients who should not be subject to diagnostic delays should be an important consideration. This use of ultrasonography has an important impact on optimizing patient care. Surgical consultation and preparation for time-sensitive definitive surgical intervention was initiated within 20 minutes of first patient contact in all three cases reviewed. This represents hours of time saved during night and weekend shifts. Although considerable controversy exists regarding the future role of ultrasonography in the ED, emergency physicians are taking an increasingly active position in establishing standards of training and practice. The Society for Academic Emergency Medicine proposed a model curriculum which includes 40 hours of instruction and 150 ultrasound examinations. 17The American College of Emergency Physicians supports the immediate availability of ultrasound technology for ED patients by appropriately trained physicians, and has developed its own diagnostic ultrasound c o u r s e . 18
No absolute guidelines or training criteria exists for many specialties that routinely use diagnostic ultrasonography) 9 The American Institute of Ultrasound Medicine has endorsed a completion of fellowship training or extensive clinical experience involving more than 500 cases and
completion of 100 hours of continuing medical education. 2° Currently there are many medical centers in which emergency physicians are actively utilizing diagnostic ultrasound in their EDs. Many residency programs have begun to include training in ultrasonography as part of their curricula with favorable results. 21 Ultrasonography in the cases reviewed in this article was performed by emergency medicine residents under the supervision of an attending physician who had approximately 100 cases of experience and 12 hours of formal education. Simple goal-directed ultrasound examinations by emergency physicians are not required to be as detailed as a formal comprehensive scanning by the radiology department to diagnose or exclude medical illness. A simple goal-oriented examination can provide definitive information. A selective pelvic scanning for the presence of an intrauterine pregnancy is easily learned and can rule out the diagnosis of ectopic pregnancy in the majority of cases. The aorta is easily identified on transabominal ultrasound. A normal diameter virtually excludes the diagnosis of aortic aneurysm. A simple single-view subcostal echocardiogram revealing no pericardial effusion excludes the presence of cardiac tarnponade. These simple techniques are easily learned and do not require skillful interpretation. The incidence of false-negative ultrasound examinations by emergency physicians has been reported to correlate well with the incidences reported in the standard ultrasound imaging literature. 21Furthermore, studies have shown initial real-time ultrasound interpretations to be at least as accurate as later hard-copy readings. 16,22 Well-trained emergency medicine physicians are in a unique position to integrate the patient's history and physical examination to best interpret ultrasound findings. Patients are at risk of morbidity or death in the event of an incorrect ultrasound diagnosis. For example, an inexperienced ultrasonographer can easily misidentify a psuedogestational sac for an early intrauterine pregnancy.4 Quality assurance, therefore, will require continued education, clear definitions of proposed applications, with their indications and limitations, proper documentation, and a well-constructed monitoring program. All inconclusive exams should be followed by formal imaging studies or appropriate diagnostic procedures, and all discharged patients must be followed up closely. Collaborating efforts between the emergency and radiology departments are also recommended. Outcomes for patients with ruptured ectopic pregnancy, leaking abdominal aneurysm, and cardiac tamponade depend on early recognition, resuscitation, and surgical intervention. 3,13,23 These conditions are often diagnosed late because patients present with nonspecific and nonsensitive findings. The immediate use of ultrasonography by emergency physicians in patients with cardiac tamponade was found to improve survival and patient outcomes in one study, and was attributed to a shorter time to diagnosis and disposition. ~3Although similar studies have not been undertaken for ruptured ectopic pregnancy and symptomatic abdominal aneurysm, a decrease in time to diagnosis in these time-dependent conditions would logically improve patient care.
BRITT DURHAM • EMERGENCY PHYSICIANS SAVING TIME WITH ULTRASOUND
CONCLUSION Ultrasonography properly used by emergency physicians is a helpful diagnostic tool that has great potential application in the ED. This imaging tool is the modality of choice for trained emergency physicians for the rapid assessment and early detection of ruptured ectopic pregnancy, leaking aortic aneurysm, and cardiac tamponade. REFERENCES 1. Plummer D, Hahn R: Diagnostic ultrasonography in the emergency department. Ann Emerg Med 1993;22:592-594 2. Walker EM: Unoperated aortic aneurysm: Presentation and natural history. Ann R Coil Surg Eng11983;65:311-313 3. Lawler HK, Rubin BJ: Early diagnosis of ectopic pregnancy. Western J Med 1993; 159:195-199 4. Pennell RG, Needleman L: Prospective comparison of vaginal and abdominal sonography in normal early pregnancy. J Ultrasound Med 1991 ;10:63-67 5. Heller MB, Verdile VP: Ultrasound in emergency medicine. Emerg Med Clin North Am 1992; 10:27-46 6. Kivikoski A, Martin CM: Transabdominal and transvaginal ultrasonography in the diagnosis of ectopic pregnancy: A comparative Study. Am J Obstet Gynecol 1990; 163:123-128 7. Bohm-Velez M, Mendelson EB: Transvaginal sonography in evaluating ectopic pregnancy. Semin Ultrasound CT MR 1990;11: 44-46 8. Vermosh M: Reevaluation of the role of culdocentesis in the management of ectopic pregnancy. Am J Obstet Gyneco11990;162: 411-413
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9. Lederle FA, Walker JM: Selective screening for abdominal aortic aneurysms with physical examination and ultrasound. Arch Intern Med 1988;148:1753-1756 10. Shuman WP, Hastrup W: Suspected leaking abdominal aortic aneurysm: Use of sonography in the emergency room. Radiology 1988;168:117-119 11. Borrero E: Symptomatic abdominal aneurysm misdiagnosed as nephroureterolithiasis. Ann Vasc Surg 1988;2:145-149 12. Turturro MA: Emergency echocardiography. Emerg Meal Clin North Am 1992; 10:47-57 14. Plummer D: Principles of emergency ultrasound and echocardiography. Ann Emerg Med 1989;18:1291-1297 15. Singh S, Wann LS: Usefulness of right ventricular diastoloic collapse in diagnosing cardiac tamponade, a combined echocardiographic and hemodynamic study. Am J Cardio11986;57:652-656 16. Deutchman ME, Hahn RG: Diagnostic ultrasound imaging by physicians of first contact: Extending the family medicine experience into emergency medicine. Ann Emerg Med 1993;22:594-596 17. Plummer D, Dick C: Model curriculum for physician training in emergency ultrasonography. Ann Emerg Med 1994;23:95-102 18. Johnson JC: Emergency physicians' new diagnostic tool: Ultrasound indications, implications explored. Am Coil Emerg Phys News 1990;8:4 19. Geyman JP: Toward the resolution of generalist-specialist boundary issues. J Fam Pract 1989;28:399-400 20. American Institute of Ultrasound Medicine: Guidelines for evaluation and interpreting diagnostic ultrasound examinations. AlUM Reporter 1993;May:1 21. Schlager D, LazzareschiG:Aprospectivestudy of ultrasonography in the ED by emergency physicians. Am J Emerg Med 1994;12:185-189 22. O'Leay MR, Smith MS: Applications of clinical indicators in the emergency department. JAMA 1989;262:3444-3447 23. Ottinger LW: Ruptured arteriosclerotic aneurysms of the abdominal aorta: Reducing mortality. JAMA 1975;223:147-150