MILITARY MEDICINE, 180, 4:153, 2015
Successful Strategies for Integrating Bedside Ultrasound Into Undergraduate Medical Education CDR James K. Palma, MC USN
A BSTRA CT Nearly all physician specialties currently utilize bedside ultrasound, and its applications continue to expand. Bedside ultrasound is becoming a core skill for physicians; as such, it should be taught during undergraduate medical education. When ultrasound is integrated in a longitudinal m anner beginning in the preclerkship phase of medical school, it not only enhances teaching the basic science topics of anatomy, physiology, and pathology but also ties those skills and knowledge to the clerkship phase and medical decision-making. Bedside ultrasound is a natural bridge from basic science to clinical science. The Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine is currently in its fourth year of implementing an integrated ultrasound curriculum in the school of medicine. In our experience, successful integration of a bedside ultrasound curriculum should: align with unique focuses of a medical schools' mission, simplify complex anatomy through multimodal teaching, correlate to teaching of the physical examination, solidify understanding o f physiology and pathology, directly link to other con current content, narrow differential diagnoses, enhance medical decision-making, improve procedural skills, match to year-group skillsets, develop teaching and leadership abilities, and have elective experiences for advanced topics.
INTRODUCTION Ultrasound is frequently described as the “stethoscope of the 21st century.” Much like Laennec’s invention, ultrasound is becoming almost as ubiquitous in medical practice as the stethoscope.1 Bedside ultrasound is used in almost every specialty of medicine.2 Ultrasound is particularly applicable to the military physician who will frequently practice in an austere environment where other diagnostic and monitoring devices may not be readily available. Bedside ultrasound can guide triage, diagnosis, monitoring of therapeutics, and evac uation decisions. The majority of medical schools recognize the utility of ultrasound and are beginning training programs of their own,3 but only a handful of schools have completely integrated bedside ultrasound into all 4 years of undergradu ate medical education.4-6 The preclerkship timeframe poses challenges to implementation that most medical schools have not yet overcome, but ultrasound is particularly suited to integrate teaching of anatomy, physiology, pathology, and medical decision-making. Bedside ultrasound is not only a teaching tool but also a clinical tool that can be integrated into daily practice. The clinician, rather than a technologist, performs bedside ultrasound; this will typically be the same provider who has already obtained a history and physical examination before performing the bedside ultrasound. Bedside ultrasound is more than just an extension of the physical examination, though: it is also a focused diagnostic test to answer a specific clinical question (i.e., does this patient have an abdominal Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road. Bethesda, MD 20814. The views expressed in this article are those of the author and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the U.S. Government, doi: 10.7205/MILMED-D-14-00573
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aortic aneurysm or not?). The bedside ultrasound is per formed at the bedside of the patient in the clinic, emergency department, or hospital ward, rather than transporting the patient to another location in the hospital or to an imaging center. The ultrasound findings are immediately applied to guide patient care. Much more than just image interpretation, an integrated bedside ultrasound curriculum teaches medical students to recognize the indications for and limitations of ultrasound, then simultaneously obtain and interpret ultra sound images, and finally integrate this data into their diag nosis and treatment plan. APPROACH The Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine has an integrated, organsystems-based curriculum during the preclerkship period (the first 18 months of medical school), followed by 12 months of core clinical rotations, then a 2-month period for U.S. Medi cal Licensing Examination preparation, 6 weeks of advanced didactics, and finally 12 months of advanced clinical rota tions. During each of the seven preclerkship modules, organ systems are studied through the entire spectrum from the molecular level to diagnosis and treatment. Bedside ultrasound sessions are integrated throughout the curriculum (Table I) to re-enforce and expand upon the teaching of normal anatomy, structure, and function, as well as providing specific exam ples of pathology and how ultrasound can guide the medical decision-making process. There are short readings assigned before each ultrasound session, and each ultrasound lab begins with a brief sum mary lecture. The majority of each ultrasound session is then devoted to hands-on image acquisition by the medical stu dents. There are no more than five students per ultrasound machine, and there is typically one faculty per five students to guide both image acquisition and discuss clinical application.
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Integrating Bedside Ultrasound Into Undergraduate Medical Education TABLE I.
Integrated Ultrasound Curriculum
Fundamentals Module (During Medical Field Practicum): 2.5 Hours O Introduction to Physics/Knobology (0.5 Hours) O Extended Focused Assessment With Sonography in Trauma (eFAST): Free Intraperitoneal Fluid. Pericardial Effusion, Hemothorax, Pneumothorax (2 Hours) Skin and Musculoskeletal Module: 2 Hours O Basic Musculoskeletal: Long-Bone Fracture, Tendon Rupture, Foreign Body, Cellulitis Versus Abscess, Rotator Cuff (1.5 Hours) O “Integration of Bedside Ultrasound Into the Physical Exam” Review (0.5 Hours) Cardiopulmonary-Renal Module: 4.75 Hours O Basic Cardiac (Parasternal Short and Long, Subxiphoid, and Apical Four-Chamber Views): Identify Chambers and Valves; Pericardial Effusion; Estimate of Ejection Fraction; Tricuspid and Mitral Valve Regurgitation (1.5 Hours) O Renal: Hydronephrosis, Urolithiasis, Bladder Volume (1.25 Hours) O Pulmonary: Pneumothorax (Part of Thoracic Trauma Lab) (0.5 Hour) O Deep Venous Thrombosis and Introduction to Pulmonary Embolism (0.5 Hour) O Ultrasound-Guided Peripheral Venous Access (1 Hour) Neuroscience and Psychiatry Module: 1 Hour O Ocular: Retinal Detachment, Vitreous Detachment, and Optic Nerve Sheath Diameter as a Marker of Increased Intracranial Pressure (1 Hour) Gastrointestinal, Hepatobiliary, Metabolism, and Nutrition Module: 2.5 Hours O Gallbladder: Gallstones, Cholecystitis, Obstructive Jaundice (1.5 Hours) o Aorta: Abdominal Aortic Aneurysm and Dissection (1 Hour) Reproduction and Endocrinology Module: 2.5 Hours O Thyroid: Nodules (Differentiation of Benign Versus Malignant); FNA (1 Hour) O Female Genitourinary: Intrauterine and Ectopic Pregnancy (1.5 Hours) Complex and Multi-System Diseases Module: 1.5 Hours O Rapid Ultrasound in Shock Protocol: Free Intraperitoneal Fluid. Pericardial Effusion/Tamponade, Hemothorax, Pleural Effusion, Pneumothorax, Pulmonary Edema/Consolidation, Right Heart Strain/Pulmonary Embolism, Inferior Vena Cava for Volume Status, Abdominal Aortic Aneurysm, and Deep Venous Thrombosis (1.5 Hours) Clerkships and Electives (Clinical Rotations): O Various Ultrasound Topics During Core Clinical Rotations O Emergency Ultrasound Elective Rotation Advanced Didactics (Between 3rd and 4th Year of Medical School): 3.5 Hours O Ultrasound-Guided Central Venous Access (2 Hours) O Ultrasound-Guided Advanced Cardiac Life Support (1.5 Hours) Every topic includes normal anatomy and physiology, as well as the pathology noted. “Modules” are in the preclerkship phase during first 18 months of medical school.
Each opening lecture is also available as an online articulated “e-learning” module. Each session has an associated online quiz due within one week of the session. The quiz is openresource (but individual effort), so most students take this opportunity to review the online module and solidify their knowledge base. Some of the sessions have associated ultra sound simulators or phantoms, such as female pelvic and vascular access. For most sessions, students serve as models for their classmates, which not only introduces a patient context but also helps them better understand some of the finer points of image acquisition (e.g., respiratory variation, transducer pressure). K E Y P R IN C IP L E S
Our ultrasound curriculum embraces several key principles. Ultrasound is always taught with a military context in mind— directly supporting the core mission of our school. Our ultra sound education also strives to simplify complex anatomy, correlate to physical examination teaching, solidify under standing of physiology and pathology, directly link to other concurrent content, narrow differential diagnoses, enhance medical decision-m aking, improve procedural skills, match to year-group skillsets, develop teaching and leadership skills,
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and provide elective experiences for advanced topics. The following are select examples of each principle.
Emphasize Military Utility The first ultrasound topic taught in our curriculum is the extended Focused Assessment with Sonography in Trauma (eFAST) examination, which has the most military-specific relevance of any ultrasound application. Emergent life threats are rapidly diagnosed, including intraperitoneal hem or rhage, cardiac tam ponade, pneum othorax, and hemothorax. The eFAST can guide triage decisions: a positive examination leads to a higher triage category. When surgical services are available, the eFAST guides management: a positive FAST in a hypotensive patient leads directly to laparotomy, whereas a negative FAST requires additional diagnostic evaluation. When surgical services are not available, eFAST guides evac uation priority: in patients with similar injury severity, those with a positive examination are evacuated before those with a negative examination. Diagnosis of a pneumothorax also has immediate impact on aeromedical evacuation and should be addressed before flying at altitude. After the eFAST exami nation, forward-deployed practitioners have noted musculo skeletal ultrasound to be the most useful military ultrasound
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Integrating Bedside Ultrasound Into Undergraduate Medical Education application in the operational environment.7 Considering the depth and breadth of combat operations and humanitarian assistance missions, nearly every bedside ultrasound topic has direct application to military medicine.
immediately confirm their physical examination findings, which has also been shown to significantly improve their self-confidence.11
Directly Link to Other Concurrent Topics Simplify Complex Anatomy M usculoskeletal ultrasound is perhaps the most straight forward example of “living anatom y.” Students can literally look through the skin to visualize muscles, tendons, ligaments, arteries, veins, nerves, and bones. Musculoskeletal ultrasound can be either simple or complex, depending on the body part being imaged. The rotator cuff is a complex structure to under stand, but ultrasound can help simplify it by complementing both the visual images of anatomic drawings, as well as the tactile experiences of cadaveric dissection and physical exami nation teaching. Ultrasound thereby reaches a broader range of learning styles, allowing students to explore and reinforce anatomy while engaging both visual and tactile learners.
Solidify Understanding of Physiology and Pathology The cardiac cycle can be difficult to teach and learn. Normal physiology is classically depicted with the Wiggers diagram ot the cardiac cycle: variations in pressure and volume are correlated with electrocardiogram (ECG) activity, arterial flow, and heart sounds. This is much easier to understand when combined with direct ultrasound visualization of the chambers contracting/relaxing and valves opening/closing. Most ultrasound applications also inherently teach patho physiology. Cardiac tamponade cannot be truly understood without being able to identify right atrial and ventricular diastolic collapse and dilation of the inferior vena cava. As another example, ureteral jets are normal physiologic findings of ureteral smooth muscle contraction. They are visualized with ultrasound as areas of flow in the urinary bladder; their absence corresponds with obstruction and hydronephrosis.
Correlate to Physical Examination Thyroid nodules can be difficult to “appreciate” on physical examination, and abdominal palpation has been shown to be insensitive for abdominal aortic aneurysm .8 The frequent poor sensitivity of physical examination is worsened in obese patients. Certain physical examinations are inherently complex to both teach and perform; for example, the uterus and ovaries can be difficult to examine when first learning the pelvic examination. Ultrasound allows learners to “see” what they are actually palpating, and this has been shown to improve medical students’ accuracy. For example, echo cardiography performed by medical students significantly improves their accuracy in bedside diagnosis of cardiac pathology,1’ and one study of liver size estim ation found that medical students with ultrasound are vastly superior to physical examination performed by physicians.10 U ltra sound allows direct visualization of structures and enhances learning and teaching of physical examination. Students can
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Whenever possible, our ultrasound sessions are linked to simi lar or complementary topics. For example, the echocardiogra phy ultrasound session is one of three stations in an afternoon lab; the other two stations are auscultation of heart sounds and interpretation of the ECG. During the same afternoon, students listen to murmurs with their stethoscope, then “see” murmurs with red/blue color flow on echocardiography. They study the P, QRS, and T waves on ECG, then “see” an overlay of this on the ultrasound screen correlated with the physical contraction of chambers. This multimodal approach enhances learning.
Narrow Differential Diagnosis After initial history and physical examination, the initial differential diagnosis may be broad. For example, a brief dif ferential of right flank pain may include the gallbladder (gallstones, cholecystitis), kidney (urolithiasis, pyelonephritis), aorta (aneurysm, dissection), intestine (appendicitis, obstruc tion, intussecption), or ovary (cyst, torsion). Bedside ultra sound can rapidly confirm or exclude most of these, which rapidly narrows the differential diagnosis and guides not only further diagnostic testing but also therapeutic intervention.
Enhance Medical Decision-Making Different ultrasound examinations have varying sensitivity and specificity. For example, if the entire abdominal aorta is adequately visualized, then the sensitivity for aneurysm is nearly 100%. However, the sensitivity for aortic dissection is much lower. Medical students learn how to integrate bedside ultrasound into their medical decision-making process, linking with biostatistics to develop pre- and post-test probability. They also recognize that sometimes a positive bedside ultrasound finding is much more useful than a negative examination.
Improve Procedural Guidance Ultrasound can safely guide needles to their target in numerous procedures, including peripheral and central venous access,12 lumbar puncture, arthrocentesis, paracentesis, thoracentesis, pericardiocentesis, foreign body localization, fine needle aspiration (FNA), and regional anesthesia. The same basic skillset of ultrasound needle guidance applies to all of these procedures and is emphasized during our curriculum three times: during the first year of medical school with periph eral IV insertion, during second year with FNA of thyroid nodules, and between third and fourth years with central venous catheter insertion.
Match to Year-Group Skillsets Our ultrasound curriculum begins with relatively simple appli cations; difficulty progresses as students advance into the later
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Integrating Bedside Ultrasound Into Undergraduate Medical Education
years of medical school. At the beginning of medical school, the eFAST examination provides a useful survey of abdominal and thoracic anatomy, and identification of free fluid is rela tively straightforward. As the curriculum progresses, more advanced applications are introduced, such as hepatobiliary ultrasound. This examination is technically more difficult to obtain images, and the integration of ultrasound data into the overall clinical picture has many subtle considerations. At the end of the preclerkship period, the Rapid Ultrasound in Shock protocol11 integrates several ultrasound applications to diagnose and manage undifferentiated shock or dyspnea. Central venous access is covered between the third and fourth year of medical school, when students may have already observed a central line being placed and will hopefully have the opportunity to do so themselves shortly thereafter. Develop Teaching and Leadership Skills Learning to teach and relay knowledge is an important phy sician skillset to develop, and teaching also solidifies the students’ knowledge of ultrasound. One never truly under stands a topic until they have taught it. Certain students volunteer for additional ultrasound training early in their first year of medical school; when deemed competent, they are invited to serve as “teaching assistants” to students in their own year-group. Select second-year medical students are invited to serve as “teaching assistants” for first-year medical student ultrasound sessions, as well. Some students have even joined university faculty for international teaching events, leading hands-on sessions for ultrasound-novice foreign phy sicians being trained during humanitarian missions. After medical school graduation, physicians will be expected to supervise a variety of health care personnel. A host of nonphysician military medical providers perform bedside ultrasound, ranging from medics and corpsmen, to nurses, to physician assistants and nurse practitioners. Physicians will be expected to supervise their training, provide quality-assurance reviews, and provide real-time medical oversight through telemedicine. Given the wide dissemination of ultrasound technology and practice, all physicians must have basic com petency in the range of bedside ultrasound applications. Elective Experiences for Review or Advanced Topics The topics mentioned above are all part of the mandatory curricular content for all of our medical students, and the assessments contribute to their grades. Although not a struc tured part of the curriculum, ultrasound is also available at many of the physical examination teaching sessions for faculty to use as they desire. Periodic voluntary review ses sions are provided for additional practice with topics already covered. There are also optional extra sessions correlated with the curricular content, such as carotid, breast, or tes ticular ultrasound. Students with heightened interest may elect to participate in a one-week (36 hour) summer elective course
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that covers a wide variety of advanced ultrasound topics; this course is also attended by other learners, such as ultrasoundnovice physicians, nurse practitioners, and medics, which creates a truly interprofessional learning environment. During the third and fourth year clinical rotations, bedside ultrasound is routinely used when clinically indicated, and it is formally taught in several of the clerkships. An optional four-week emergency ultrasound elective is offered during the fourth year of medical school. This capstone event solidifies image acqui sition, interpretation, and integration into patient care, and it also touches on teaching and research. LESSONS LEARNED AND FUTURE DIRECTIONS Before instituting mandatory ultrasound instruction during the preclerkship phase of medical school, a one-year volun tary curriculum was administered to approximately 15% of both the first- and second-year medical student classes. This allowed refinement of the curricular content, faculty train-up and buy-in, and gathering of student feedback. The trial curriculum was immensely popular with students, as well as both junior and senior faculty, which helped justify both the significant cost of equipment and the commitment for student contact time in an already-crowded curriculum. Key factors included low student to faculty ratio (5:1 is optimal), emphasis of hands-on scanning time, close inte gration with concurrent coursework, longitudinal integra tion (repeated small contacts), involvement of the local teaching hospital and simulation center, and support from the medical school dean. Bedside ultrasound cannot be taught effectively without expert faculty, and the optimal mix includes both junior and senior faculty from multiple specialties and multiple institu tions. Recruiting these faculty has strengthened ties between our university and our associated teaching hospitals, as well as with several other local hospital systems as we invite guest faculty. The ultrasound curriculum has also fostered intradepartmental collaboration. For example, echocardiogra phy is taught by faculty from cardiology, emergency medicine, critical care, and radiology. Pelvic ultrasound faculty include obstetricians, family medicine, radiologists, and emergency physicians. There is also an important role played by resi dent physicians, and sonographers are especially effective teachers. The core ultrasound faculty are primarily from emergency medicine and radiology. The synergy generated by multidepartmental participation enhances the quality of medical student teaching. Several departments at our main teaching hospital have requested that our medical school faculty provide them addi tional ultrasound training for their residents and faculty. This not only builds their skillset and improves their patient care at the hospital but also expands the faculty pool for the medi cal school. The medical school’s ultrasound curriculum has also expanded to include our University’s graduate school of nursing, which provides interprofessional exchange between both students and faculty from each school. The medical
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Integrating Bedside Ultrasound Into Undergraduate Medical Education students serve as teaching assistants for the graduate school of nursing student courses. An integrated ultrasound program not only improves stu dent satisfaction but also separates a medical school from its competition when candidates are applying for admission. An ultrasound curriculum also brings opportunity for medical research and grants, and it is very attractive to potential donors. Additionally, there is opportunity for continuing medical education courses as a service to local faculty or as a source of revenue. Nearly all specialties are using bedside ultrasound already and its use is constantly expanding; it is becoming a core skill for physicians. There is significant face validity for this “common sense” reason for teaching ultrasound, and medical student feedback about ultrasound training has been over whelmingly positive. The current evidence base for ultra sound in undergraduate medical education consists mainly of descriptions of curricula and experiences, but studies are beginning to emerge that demonstrate the measurable effects of the training. Further investigation is required to delineate the best content and extent of bedside ultrasound education during undergraduate medical education. When ultrasound is integrated in a longitudinal manner beginning in the preclerkship phase of medical school, it not only enhances teaching of basic science topics like anat omy, physiology, and pathology but also ties those skills and knowledge to the clerkship phase and medical decision making. Bedside ultrasound is a natural bridge from basic science to clinical science. Ultrasound is not only a teaching tool but also a clinical tool that can be integrated into daily practice. Rather than teaching fundamentals of ultrasound during residency, early training during medical school allows residency programs to focus more on pathology and timesensitive information that directly guides clinical management and improves patient care, cost, and safety. Medical schools
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are realizing that they either need to teach bedside ultrasound, or be left behind.
REFERENCES 1. Wittenberg M: Will ultrasound scanners replace the stethoscope? BMJ 2014; 348: g3463. 2. Moore CL, Copel JA: Point of care ultrasonography. N Engl J Med 2011;364:749-57. 3. Bahner DP, Goldman E, Way D. Royall NA, Liu YT: The state of ultrasound education in U.S. medical schools: results of a national survey. Acad Med 2014; 89: 1681-6. 4. Rao S. van Holsbeeck L, Musial JL. et al: A pilot study of compre hensive ultrasound education at the Wayne State University School of Medicine. J Ultrasound Med 2008; 27: 745-9. 5. Hoppmann RA, Rao VV, Poston MB. et al: An integrated ultrasound curriculum (iUSC) for medical students: 4-year experience. Crit Ultra sound J 2011; 3: 1-12. 6. Bahner DP. Adkins EJ, Hughes D, Barrie M, Boulger CT, Royall NA: Integrated medical school ultrasound: development of an ultrasound vertical curriculum. Crit Ultrasound J 2013; 5: 6. 7. Morgan AR, Vasios WN, Hubler DA. Benson PJ: Special operator level clinical ultrasound: an experience in application and training. J Spec Oper Med 2010; 10: 16-21. 8. Lederle FA, Simel DL: The rational clinical examination. Does this patient have abdominal aortic aneurysm? JAMA 1999; 281: 77-82. 9. Decara JM, Kirkpatrick JN, Spencer KT, et al: Use of hand-carried ultrasound devices to augment the accuracy of medical student bedside cardiac diagnoses. J Am Soc Echocardiogr 2005: 18: 257-63. 10. Mouratev G, Howe D. Hoppmann R, et al: Teaching medical students ultrasound to measure liver size: comparison with experienced clinicians using physical examination alone. Teach Learn Med 2013; 25: 84-8. 11. Fodor D. Badea R, Poanta L, Dumitrascu DL, Buzoianu AD, Mircea PA: The use of ultrasonography in learning clinical examination—a pilot study involving third year medical students. Med Ultrason 2012; 14: 177-81. 12. Wu SY, Ling Q. Cao LH, Wang J, Xu MX, Zeng WA: Real-time two-dimensional ultrasound guidance for central venous cannulation: a meta-analysis. Anesthesiology 2013; 118: 361-75. 13. Perera P, Mailhot T, Riley D, Mandavia D: The RUSH exam: rapid ultrasound in shock in the evaluation of the critically ill. Emerg Med Clin North Am 2010; 28: 29-56.
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Successful Strategies for Integrating Bedside Ultrasound Into Undergraduate Medical Education CDR James K. Palma, MC USN
A BSTRA CT Nearly all physician specialties currently utilize bedside ultrasound, and its applications continue to expand. Bedside ultrasound is becoming a core skill for physicians; as such, it should be taught during undergraduate medical education. When ultrasound is integrated in a longitudinal m anner beginning in the preclerkship phase of medical school, it not only enhances teaching the basic science topics of anatomy, physiology, and pathology but also ties those skills and knowledge to the clerkship phase and medical decision-making. Bedside ultrasound is a natural bridge from basic science to clinical science. The Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine is currently in its fourth year of implementing an integrated ultrasound curriculum in the school of medicine. In our experience, successful integration of a bedside ultrasound curriculum should: align with unique focuses of a medical schools' mission, simplify complex anatomy through multimodal teaching, correlate to teaching of the physical examination, solidify understanding o f physiology and pathology, directly link to other con current content, narrow differential diagnoses, enhance medical decision-making, improve procedural skills, match to year-group skillsets, develop teaching and leadership abilities, and have elective experiences for advanced topics.
INTRODUCTION Ultrasound is frequently described as the “stethoscope of the 21st century.” Much like Laennec’s invention, ultrasound is becoming almost as ubiquitous in medical practice as the stethoscope.1 Bedside ultrasound is used in almost every specialty of medicine.2 Ultrasound is particularly applicable to the military physician who will frequently practice in an austere environment where other diagnostic and monitoring devices may not be readily available. Bedside ultrasound can guide triage, diagnosis, monitoring of therapeutics, and evac uation decisions. The majority of medical schools recognize the utility of ultrasound and are beginning training programs of their own,3 but only a handful of schools have completely integrated bedside ultrasound into all 4 years of undergradu ate medical education.4-6 The preclerkship timeframe poses challenges to implementation that most medical schools have not yet overcome, but ultrasound is particularly suited to integrate teaching of anatomy, physiology, pathology, and medical decision-making. Bedside ultrasound is not only a teaching tool but also a clinical tool that can be integrated into daily practice. The clinician, rather than a technologist, performs bedside ultrasound; this will typically be the same provider who has already obtained a history and physical examination before performing the bedside ultrasound. Bedside ultrasound is more than just an extension of the physical examination, though: it is also a focused diagnostic test to answer a specific clinical question (i.e., does this patient have an abdominal Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road. Bethesda, MD 20814. The views expressed in this article are those of the author and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the U.S. Government, doi: 10.7205/MILMED-D-14-00573
M IL IT A R Y M E D IC IN E , Vol. 180, April Supplement 2015
aortic aneurysm or not?). The bedside ultrasound is per formed at the bedside of the patient in the clinic, emergency department, or hospital ward, rather than transporting the patient to another location in the hospital or to an imaging center. The ultrasound findings are immediately applied to guide patient care. Much more than just image interpretation, an integrated bedside ultrasound curriculum teaches medical students to recognize the indications for and limitations of ultrasound, then simultaneously obtain and interpret ultra sound images, and finally integrate this data into their diag nosis and treatment plan. APPROACH The Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine has an integrated, organsystems-based curriculum during the preclerkship period (the first 18 months of medical school), followed by 12 months of core clinical rotations, then a 2-month period for U.S. Medi cal Licensing Examination preparation, 6 weeks of advanced didactics, and finally 12 months of advanced clinical rota tions. During each of the seven preclerkship modules, organ systems are studied through the entire spectrum from the molecular level to diagnosis and treatment. Bedside ultrasound sessions are integrated throughout the curriculum (Table I) to re-enforce and expand upon the teaching of normal anatomy, structure, and function, as well as providing specific exam ples of pathology and how ultrasound can guide the medical decision-making process. There are short readings assigned before each ultrasound session, and each ultrasound lab begins with a brief sum mary lecture. The majority of each ultrasound session is then devoted to hands-on image acquisition by the medical stu dents. There are no more than five students per ultrasound machine, and there is typically one faculty per five students to guide both image acquisition and discuss clinical application.
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Integrating Bedside Ultrasound Into Undergraduate Medical Education TABLE I.
Integrated Ultrasound Curriculum
Fundamentals Module (During Medical Field Practicum): 2.5 Hours O Introduction to Physics/Knobology (0.5 Hours) O Extended Focused Assessment With Sonography in Trauma (eFAST): Free Intraperitoneal Fluid. Pericardial Effusion, Hemothorax, Pneumothorax (2 Hours) Skin and Musculoskeletal Module: 2 Hours O Basic Musculoskeletal: Long-Bone Fracture, Tendon Rupture, Foreign Body, Cellulitis Versus Abscess, Rotator Cuff (1.5 Hours) O “Integration of Bedside Ultrasound Into the Physical Exam” Review (0.5 Hours) Cardiopulmonary-Renal Module: 4.75 Hours O Basic Cardiac (Parasternal Short and Long, Subxiphoid, and Apical Four-Chamber Views): Identify Chambers and Valves; Pericardial Effusion; Estimate of Ejection Fraction; Tricuspid and Mitral Valve Regurgitation (1.5 Hours) O Renal: Hydronephrosis, Urolithiasis, Bladder Volume (1.25 Hours) O Pulmonary: Pneumothorax (Part of Thoracic Trauma Lab) (0.5 Hour) O Deep Venous Thrombosis and Introduction to Pulmonary Embolism (0.5 Hour) O Ultrasound-Guided Peripheral Venous Access (1 Hour) Neuroscience and Psychiatry Module: 1 Hour O Ocular: Retinal Detachment, Vitreous Detachment, and Optic Nerve Sheath Diameter as a Marker of Increased Intracranial Pressure (1 Hour) Gastrointestinal, Hepatobiliary, Metabolism, and Nutrition Module: 2.5 Hours O Gallbladder: Gallstones, Cholecystitis, Obstructive Jaundice (1.5 Hours) o Aorta: Abdominal Aortic Aneurysm and Dissection (1 Hour) Reproduction and Endocrinology Module: 2.5 Hours O Thyroid: Nodules (Differentiation of Benign Versus Malignant); FNA (1 Hour) O Female Genitourinary: Intrauterine and Ectopic Pregnancy (1.5 Hours) Complex and Multi-System Diseases Module: 1.5 Hours O Rapid Ultrasound in Shock Protocol: Free Intraperitoneal Fluid. Pericardial Effusion/Tamponade, Hemothorax, Pleural Effusion, Pneumothorax, Pulmonary Edema/Consolidation, Right Heart Strain/Pulmonary Embolism, Inferior Vena Cava for Volume Status, Abdominal Aortic Aneurysm, and Deep Venous Thrombosis (1.5 Hours) Clerkships and Electives (Clinical Rotations): O Various Ultrasound Topics During Core Clinical Rotations O Emergency Ultrasound Elective Rotation Advanced Didactics (Between 3rd and 4th Year of Medical School): 3.5 Hours O Ultrasound-Guided Central Venous Access (2 Hours) O Ultrasound-Guided Advanced Cardiac Life Support (1.5 Hours) Every topic includes normal anatomy and physiology, as well as the pathology noted. “Modules” are in the preclerkship phase during first 18 months of medical school.
Each opening lecture is also available as an online articulated “e-learning” module. Each session has an associated online quiz due within one week of the session. The quiz is openresource (but individual effort), so most students take this opportunity to review the online module and solidify their knowledge base. Some of the sessions have associated ultra sound simulators or phantoms, such as female pelvic and vascular access. For most sessions, students serve as models for their classmates, which not only introduces a patient context but also helps them better understand some of the finer points of image acquisition (e.g., respiratory variation, transducer pressure). K E Y P R IN C IP L E S
Our ultrasound curriculum embraces several key principles. Ultrasound is always taught with a military context in mind— directly supporting the core mission of our school. Our ultra sound education also strives to simplify complex anatomy, correlate to physical examination teaching, solidify under standing of physiology and pathology, directly link to other concurrent content, narrow differential diagnoses, enhance medical decision-m aking, improve procedural skills, match to year-group skillsets, develop teaching and leadership skills,
154
and provide elective experiences for advanced topics. The following are select examples of each principle.
Emphasize Military Utility The first ultrasound topic taught in our curriculum is the extended Focused Assessment with Sonography in Trauma (eFAST) examination, which has the most military-specific relevance of any ultrasound application. Emergent life threats are rapidly diagnosed, including intraperitoneal hem or rhage, cardiac tam ponade, pneum othorax, and hemothorax. The eFAST can guide triage decisions: a positive examination leads to a higher triage category. When surgical services are available, the eFAST guides management: a positive FAST in a hypotensive patient leads directly to laparotomy, whereas a negative FAST requires additional diagnostic evaluation. When surgical services are not available, eFAST guides evac uation priority: in patients with similar injury severity, those with a positive examination are evacuated before those with a negative examination. Diagnosis of a pneumothorax also has immediate impact on aeromedical evacuation and should be addressed before flying at altitude. After the eFAST exami nation, forward-deployed practitioners have noted musculo skeletal ultrasound to be the most useful military ultrasound
MILITARY MEDICINE, Vol. 180, April Supplement 2015
Integrating Bedside Ultrasound Into Undergraduate Medical Education application in the operational environment.7 Considering the depth and breadth of combat operations and humanitarian assistance missions, nearly every bedside ultrasound topic has direct application to military medicine.
immediately confirm their physical examination findings, which has also been shown to significantly improve their self-confidence.11
Directly Link to Other Concurrent Topics Simplify Complex Anatomy M usculoskeletal ultrasound is perhaps the most straight forward example of “living anatom y.” Students can literally look through the skin to visualize muscles, tendons, ligaments, arteries, veins, nerves, and bones. Musculoskeletal ultrasound can be either simple or complex, depending on the body part being imaged. The rotator cuff is a complex structure to under stand, but ultrasound can help simplify it by complementing both the visual images of anatomic drawings, as well as the tactile experiences of cadaveric dissection and physical exami nation teaching. Ultrasound thereby reaches a broader range of learning styles, allowing students to explore and reinforce anatomy while engaging both visual and tactile learners.
Solidify Understanding of Physiology and Pathology The cardiac cycle can be difficult to teach and learn. Normal physiology is classically depicted with the Wiggers diagram ot the cardiac cycle: variations in pressure and volume are correlated with electrocardiogram (ECG) activity, arterial flow, and heart sounds. This is much easier to understand when combined with direct ultrasound visualization of the chambers contracting/relaxing and valves opening/closing. Most ultrasound applications also inherently teach patho physiology. Cardiac tamponade cannot be truly understood without being able to identify right atrial and ventricular diastolic collapse and dilation of the inferior vena cava. As another example, ureteral jets are normal physiologic findings of ureteral smooth muscle contraction. They are visualized with ultrasound as areas of flow in the urinary bladder; their absence corresponds with obstruction and hydronephrosis.
Correlate to Physical Examination Thyroid nodules can be difficult to “appreciate” on physical examination, and abdominal palpation has been shown to be insensitive for abdominal aortic aneurysm .8 The frequent poor sensitivity of physical examination is worsened in obese patients. Certain physical examinations are inherently complex to both teach and perform; for example, the uterus and ovaries can be difficult to examine when first learning the pelvic examination. Ultrasound allows learners to “see” what they are actually palpating, and this has been shown to improve medical students’ accuracy. For example, echo cardiography performed by medical students significantly improves their accuracy in bedside diagnosis of cardiac pathology,1’ and one study of liver size estim ation found that medical students with ultrasound are vastly superior to physical examination performed by physicians.10 U ltra sound allows direct visualization of structures and enhances learning and teaching of physical examination. Students can
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Whenever possible, our ultrasound sessions are linked to simi lar or complementary topics. For example, the echocardiogra phy ultrasound session is one of three stations in an afternoon lab; the other two stations are auscultation of heart sounds and interpretation of the ECG. During the same afternoon, students listen to murmurs with their stethoscope, then “see” murmurs with red/blue color flow on echocardiography. They study the P, QRS, and T waves on ECG, then “see” an overlay of this on the ultrasound screen correlated with the physical contraction of chambers. This multimodal approach enhances learning.
Narrow Differential Diagnosis After initial history and physical examination, the initial differential diagnosis may be broad. For example, a brief dif ferential of right flank pain may include the gallbladder (gallstones, cholecystitis), kidney (urolithiasis, pyelonephritis), aorta (aneurysm, dissection), intestine (appendicitis, obstruc tion, intussecption), or ovary (cyst, torsion). Bedside ultra sound can rapidly confirm or exclude most of these, which rapidly narrows the differential diagnosis and guides not only further diagnostic testing but also therapeutic intervention.
Enhance Medical Decision-Making Different ultrasound examinations have varying sensitivity and specificity. For example, if the entire abdominal aorta is adequately visualized, then the sensitivity for aneurysm is nearly 100%. However, the sensitivity for aortic dissection is much lower. Medical students learn how to integrate bedside ultrasound into their medical decision-making process, linking with biostatistics to develop pre- and post-test probability. They also recognize that sometimes a positive bedside ultrasound finding is much more useful than a negative examination.
Improve Procedural Guidance Ultrasound can safely guide needles to their target in numerous procedures, including peripheral and central venous access,12 lumbar puncture, arthrocentesis, paracentesis, thoracentesis, pericardiocentesis, foreign body localization, fine needle aspiration (FNA), and regional anesthesia. The same basic skillset of ultrasound needle guidance applies to all of these procedures and is emphasized during our curriculum three times: during the first year of medical school with periph eral IV insertion, during second year with FNA of thyroid nodules, and between third and fourth years with central venous catheter insertion.
Match to Year-Group Skillsets Our ultrasound curriculum begins with relatively simple appli cations; difficulty progresses as students advance into the later
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years of medical school. At the beginning of medical school, the eFAST examination provides a useful survey of abdominal and thoracic anatomy, and identification of free fluid is rela tively straightforward. As the curriculum progresses, more advanced applications are introduced, such as hepatobiliary ultrasound. This examination is technically more difficult to obtain images, and the integration of ultrasound data into the overall clinical picture has many subtle considerations. At the end of the preclerkship period, the Rapid Ultrasound in Shock protocol11 integrates several ultrasound applications to diagnose and manage undifferentiated shock or dyspnea. Central venous access is covered between the third and fourth year of medical school, when students may have already observed a central line being placed and will hopefully have the opportunity to do so themselves shortly thereafter. Develop Teaching and Leadership Skills Learning to teach and relay knowledge is an important phy sician skillset to develop, and teaching also solidifies the students’ knowledge of ultrasound. One never truly under stands a topic until they have taught it. Certain students volunteer for additional ultrasound training early in their first year of medical school; when deemed competent, they are invited to serve as “teaching assistants” to students in their own year-group. Select second-year medical students are invited to serve as “teaching assistants” for first-year medical student ultrasound sessions, as well. Some students have even joined university faculty for international teaching events, leading hands-on sessions for ultrasound-novice foreign phy sicians being trained during humanitarian missions. After medical school graduation, physicians will be expected to supervise a variety of health care personnel. A host of nonphysician military medical providers perform bedside ultrasound, ranging from medics and corpsmen, to nurses, to physician assistants and nurse practitioners. Physicians will be expected to supervise their training, provide quality-assurance reviews, and provide real-time medical oversight through telemedicine. Given the wide dissemination of ultrasound technology and practice, all physicians must have basic com petency in the range of bedside ultrasound applications. Elective Experiences for Review or Advanced Topics The topics mentioned above are all part of the mandatory curricular content for all of our medical students, and the assessments contribute to their grades. Although not a struc tured part of the curriculum, ultrasound is also available at many of the physical examination teaching sessions for faculty to use as they desire. Periodic voluntary review ses sions are provided for additional practice with topics already covered. There are also optional extra sessions correlated with the curricular content, such as carotid, breast, or tes ticular ultrasound. Students with heightened interest may elect to participate in a one-week (36 hour) summer elective course
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that covers a wide variety of advanced ultrasound topics; this course is also attended by other learners, such as ultrasoundnovice physicians, nurse practitioners, and medics, which creates a truly interprofessional learning environment. During the third and fourth year clinical rotations, bedside ultrasound is routinely used when clinically indicated, and it is formally taught in several of the clerkships. An optional four-week emergency ultrasound elective is offered during the fourth year of medical school. This capstone event solidifies image acqui sition, interpretation, and integration into patient care, and it also touches on teaching and research. LESSONS LEARNED AND FUTURE DIRECTIONS Before instituting mandatory ultrasound instruction during the preclerkship phase of medical school, a one-year volun tary curriculum was administered to approximately 15% of both the first- and second-year medical student classes. This allowed refinement of the curricular content, faculty train-up and buy-in, and gathering of student feedback. The trial curriculum was immensely popular with students, as well as both junior and senior faculty, which helped justify both the significant cost of equipment and the commitment for student contact time in an already-crowded curriculum. Key factors included low student to faculty ratio (5:1 is optimal), emphasis of hands-on scanning time, close inte gration with concurrent coursework, longitudinal integra tion (repeated small contacts), involvement of the local teaching hospital and simulation center, and support from the medical school dean. Bedside ultrasound cannot be taught effectively without expert faculty, and the optimal mix includes both junior and senior faculty from multiple specialties and multiple institu tions. Recruiting these faculty has strengthened ties between our university and our associated teaching hospitals, as well as with several other local hospital systems as we invite guest faculty. The ultrasound curriculum has also fostered intradepartmental collaboration. For example, echocardiogra phy is taught by faculty from cardiology, emergency medicine, critical care, and radiology. Pelvic ultrasound faculty include obstetricians, family medicine, radiologists, and emergency physicians. There is also an important role played by resi dent physicians, and sonographers are especially effective teachers. The core ultrasound faculty are primarily from emergency medicine and radiology. The synergy generated by multidepartmental participation enhances the quality of medical student teaching. Several departments at our main teaching hospital have requested that our medical school faculty provide them addi tional ultrasound training for their residents and faculty. This not only builds their skillset and improves their patient care at the hospital but also expands the faculty pool for the medi cal school. The medical school’s ultrasound curriculum has also expanded to include our University’s graduate school of nursing, which provides interprofessional exchange between both students and faculty from each school. The medical
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Integrating Bedside Ultrasound Into Undergraduate Medical Education students serve as teaching assistants for the graduate school of nursing student courses. An integrated ultrasound program not only improves stu dent satisfaction but also separates a medical school from its competition when candidates are applying for admission. An ultrasound curriculum also brings opportunity for medical research and grants, and it is very attractive to potential donors. Additionally, there is opportunity for continuing medical education courses as a service to local faculty or as a source of revenue. Nearly all specialties are using bedside ultrasound already and its use is constantly expanding; it is becoming a core skill for physicians. There is significant face validity for this “common sense” reason for teaching ultrasound, and medical student feedback about ultrasound training has been over whelmingly positive. The current evidence base for ultra sound in undergraduate medical education consists mainly of descriptions of curricula and experiences, but studies are beginning to emerge that demonstrate the measurable effects of the training. Further investigation is required to delineate the best content and extent of bedside ultrasound education during undergraduate medical education. When ultrasound is integrated in a longitudinal manner beginning in the preclerkship phase of medical school, it not only enhances teaching of basic science topics like anat omy, physiology, and pathology but also ties those skills and knowledge to the clerkship phase and medical decision making. Bedside ultrasound is a natural bridge from basic science to clinical science. Ultrasound is not only a teaching tool but also a clinical tool that can be integrated into daily practice. Rather than teaching fundamentals of ultrasound during residency, early training during medical school allows residency programs to focus more on pathology and timesensitive information that directly guides clinical management and improves patient care, cost, and safety. Medical schools
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are realizing that they either need to teach bedside ultrasound, or be left behind.
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