Educational Program for Intraoperative Transesophageal Echocardiography

Although both disciplines have cooperated for many years, cardiovascular anesthesiology and echocardiography have recently grown and merged in part. Intraoperative echocardiography has demonstrated its usefulness in many aspects of cardiovascular surgery, including valvular repair and replacement, myocardial function, aortic aneurysm repair, congenital heart disease, pericardial disease, complications of surgery, endocarditis, myocardial ischemia, and many others. Given the enlarging scope of cardiovascular surgery, echocardiography can address the compelling need for precise and accurate intraoperative diagnostic and monitoring capabilities. With the rapid development and clinical application of this technology, little attention has been focused on the necessary skills, training, and means of confirming competency for physicians performing intraoperative echocardiography. This article will not address all the questions surrounding this subject, but will explore some of the relevant issues regarding the training of physicians in intraoperative echocardiography and describe the training program developed for anesthesiologists at the Cleveland Clinic. We present our program in the hope of stimulating further discussion and research. The ultimate objective in developing an organized training program in intraoperative echocardiography is to enhance patient care at our institution through the proficient use of echocardiography in the operating arena by physicians from varying specialties and practice backgrounds. The Importance of Intraoperative Echocardiography for the Cardiac Anesthesiologist Intraoperative echocardiography, consisting of transesophageal and epicardial echocardiography with color flow mapping [1], has emerged as a technique with application in many aspects of cardiovascular surgery. Ultrasound provides a window for visualizing both structural and flow characteristics of the functioning anatomy inside the heart. Previously, clinicians have striven to obtain objective measurements of intravascular volume, and thereby characterize the cardiac filling, by using pulmonary artery catheters and other hemodynamic monitors that give volume information only indirectly. Now, echocardiography can directly assess left ventricular size and function as well as a patient's intraoperative response to pharmacologic, volume, or clinical intervention. Objectives of Education in Intraoperative Echocardiography A number of cognitive and technical requirements are necessary for the physician to proficiently perform intraoperative echocardiography Table 1 and Table 2[2]. Deficiencies in any of these cognitive or technical skills may potentially interfere with the accuracy and efficiency of reaching a diagnosis and managing the patient. The echocardiography skills must be developed to a level at which one may function efficiently in the accelerated pace of the operating room. Having an "experience-derived" working knowledge of the normal and abnormal echocardiographic findings is essential for recognizing the spectrum of cardiovascular disorders. Developing such skills may best be accomplished in an environment, such as the echocardiography laboratory, where the urgency of arriving at an immediate diagnosis is usually not as pressing. Although it is important for any physician performing intraoperative echocardiography to have the necessary echocardiography skills, it is absolutely essential that one possess a thorough understanding of the intraoperative environment in order to function competently in this setting.Table 1: Cognitive Skills Needed to Perform Intraoperative EchocardiographyTable 2: Technical Skills Needed to Perform Intraoperative EchocardiographyIn an initial effort to define training guidelines in echocardiography, the American Society of Echocardiography defined three levels of training in echocardiography on the basis of the opinion of experts in the field [3]. In a subsequent document, the American Society of Echocardiography stated that, as a background before the initiation of training in transesophageal echocardiography (TEE), a physician should reach Level II of training, defined as experience in performing and interpreting 300 supervised transthoracic echocardiography studies [2]. This represents six months of full-time training in echocardiography followed by the performance of 50 TEE studies under direct supervision. Regardless of any suggested numerical guidelines, the end product of individual competency in intraoperative echocardiography is more important than the numerical milestones along the way. We believe that a substantial amount of hands-on exposure to echocardiography is necessary to obtain the background necessary for competency in the clinical setting. The question is often raised whether a practitioner should strive for echocardiographic competence in a focused area of intraoperative diagnosis, such as evaluation of left ventricular size and function, without being responsible for other expected or unexpected abnormalities and diagnoses. We have found that, in a significant number of our intraoperative echocardiograms, the information most influential in operative management is not the same as the answer to the initial primary question asked. For example, although a focused answer such as the competency of the mitral valve is important immediately after valve repair, many others, such as the presence and severity of left ventricular outflow tract obstruction due to systolic anterior motion of the mitral valve leaflets, are equally important [4]. Called to perform an echocardiographic study to assess left ventricular function in a patient struggling to come off cardiopulmonary bypass, the impact of new or previously unrecognized valvular lesions is of great importance to the patient's operative course. Problems detected by TEE are easier to correct if they are found while the chest is open, as opposed to when they are later managed after discovery during overreading of a videotape [5]. Therefore, to provide optimal care, one should not limit competence in intraoperative echocardiography to a focused area. Experience Versus Accuracy in Echocardiography In areas outside the operating room, the learning curves for development of competence in echocardiography have been characterized [6-8]. Interpretation of exercise echocardiographic images for myocardial ischemia is similar in some ways to the intraoperative evaluation of ventricular function through characterization of segmental wall motion abnormalities. Picano et al. [6] found that newcomers to stress echocardiography, with experience of less than 20 studies, had an accuracy of 62%, compared to the 85% accuracy of experienced interpreters who had read more than 100 stress echoescardiograms, although both groups, presumably, had Level II training in echocardiography. Another group evaluated the learning curve of reading transthoracic echocardiograms from the Framingham study and found that individuals with five months of experience or less had a 28% accuracy, compared with an 81% accuracy in those with more than two years of experience [7]. Ungerleider et al. [8] found that 200 intraoperative echocardiographic studies were required in order to learn to interpret diagnostic information to enhance operative repair of congenital heart disease. There are enough similarities between the development of echocardiography skills examined in these studies and those necessary for intraoperative echocardiography to demonstrate that accuracy is related to experience. Technology Aids to Collaboration in Intraoperative Echo Several practices for introducing newcomers to intraoperative echocardiography are helpful but not sufficient for adequate training in the field. It is tempting to resort to a system wherein the newcomer to echocardiography makes intraoperative recordings as well as submits those tapes to be overread later by an expert. Unfortunately, this late interpretation is removed from a direct patient care environment where decisions have an immediate impact on management [1,4]. Once the patient is out of the operating room, the threshold for altering surgical management is far higher than when the problem is discovered before the incision is closed, or while the patient is still cannulated for cardiopulmonary bypass. Another collaboration practice is the use of a video communication system between the operating room and echocardiography laboratory to provide on-line overreading of intraoperative echocardiograms by experts to enhance the level of instruction and confidence as the physician in training becomes more independent. Although a video communication system from the operating room to the echocardiographic laboratory provides remote supervision and valuable tutelage, it does not solve all the problems of this situation. This collaboration assumes the availability of competent echocardiographic colleagues who have the time to consult with the operative team. Telephone contact, in addition to the video link between the novice and teacher, is important during performance of the study for communications regarding timing (on versus off cardiopulmonary bypass), loading conditions (preload and afterload), or additional hemodynamic perturbations (inflow occlusion or cardiac distortion). For this system to work, the cardiac anesthesiologist/echocardiographer must recognize when to call for on-line help. Furthermore, having a colleague view images from afar does not teach the nuances of image acquisition and proper attainment of image orientation that a hands-on teaching can provide. Ways to Obtain Education in Intraoperative Echocardiography The ultimate goal for developing training in intraoperative echocardiography is to expand the proficient use of this diagnostic and monitoring capability. Educational alternatives must not be exclusionary, and must accommodate the wide variety of specialty and practice backgrounds of those interested in becoming competent in its use. A variety of video and printed material is available to assist with home study. In addition, a variety of options for hands-on training are available that promote an optimal standard of clinical competency. Available training tracts are of two distinct types: 1) those incorporated as part of an organized postgraduate medical education program and 2) training for practitioners under the direction of approved instructors who have obtained documented levels of competence. One method of training is for the individual anesthesiologist to spend a block of time in echocardiography during his or her formal postgraduate medical education or, alternatively, to return for further post-graduate training, although established in practice. This requires a mentor with experience in intraoperative echocardiography and an organized program that would teach all the necessary objectives of a cohesive experience. Incorporation of echocardiography into the training programs of cardiovascular anesthesia fellowships is an important element in the curriculum. Reves and Schell [9] have reported that cardiac anesthesia fellows at Duke University spend a total of eight weeks in the echocardiography laboratory focusing on the principles of transthoracic echocardiography and TEE as well as attending and performing TEEs. Developing echocardiographic training for a practitioner of anesthesiology is a much more difficult, but not impossible, task. Some practice groups have an anesthesiology colleague who is an experienced echocardiographer capable of training other practice members. The addition of a recent cardiac anesthesiologist graduate who has acquired the experience and competence necessary would also provide an appropriate resource to train other practice members. Another way to provide effective education for the anesthesiology practitioner is to develop a training relationship with a clinical colleague with the necessary experience. Forming a strong affiliation with an echocardiography laboratory may be the most available and effective alternative for the anesthesiologist already in practice. To satisfy the learning objectives, this must be a multidisciplinary effort that provides a substantive period of exposure. In many cases, this will include anesthesiologists doing hands-on outpatient transthoracic echocardiography, cardiologists coming regularly to the operating room, and the development of habits and technology that facilitate review for quality control of intraoperative echocardiographic studies. Although echocardiography laboratories are common, the practical experience of applying echocardiography to intraoperative use is not a routine skill of most cardiologists involved in outpatient transthoracic echocardiography and TEE. The proficient application of echocardiography in the intraoperative setting includes not only the cognitive skills associated with this technique but, of equal importance, a thorough understanding of the many concerns surrounding the operating room and the perioperative environment. Among these are the pharmacodynamic effects of medications used intraoperatively, the hemodynamic changes associated with cardiopulmonary bypass, and the consequences of the various surgical interventions. Benefits will be shared by the cardiologist learning the nuances of the operative environment in addition to the accelerated learning curve resulting from the immediate feedback gained by visualizing the pathology during surgery. Although it may be possible to learn TEE without having exposure to transthoracic echocardiographic technique, it is probably more difficult to do so. Such training provides a more relaxed atmosphere in which to develop the cognitive skills necessary for intraoperative echo. Transthoracic training is even more critical for performing epicardial imaging in those infrequent, but important, circumstances where it is not possible to obtain satisfactory imaging planes from which to visualize certain structures (e.g., ascending aorta) or to acquire optimal Doppler angulation for accurate gradient determination (e.g., aortic or subaortic stenosis). To provide the information necessary for patient management decisions in these circumstances, the intraoperative echocardiographer must resort to epicardial imaging [1]. Transthoracic echocardiographic training provides experience with many of the same imaging planes used in epicardial imaging. It is simply impossible to acquire the necessary intraoperative epicardial training "on the fly" due to the obvious surgical time constraints and infrequency with which epicardial imaging is performed. Another challenging problem is that of verifying competency in intraoperative echocardiography. In doing so, it will be important to accommodate diverse training backgrounds, variations in local practice characteristics, and equivalent training alternatives. The determination of competency would probably be best ascertained by a voluntary, yet formal, proficiency examination dealing with all the aspects of intraoperative echocardiography. Such an examination could conceivably be administered by a "neutral" multidisciplinary society committed to the encouragement of clinical expertise in echocardiography, and may represent the fairest alternative for documenting competency. The proficiency examination would most probably encompass the basic training objectives, the ability to recognize the important abnormalities, and reasonable options for their management. The Program for Training Anesthesiologists in Intraoperative Echocardiography at the Cleveland Clinic At our institution, we have established a one-year interdisciplinary training program for cardiac anesthesiologists involving clinical experience in the standard echocardiography laboratory and the operating room. The definable components include exposure to outpatient echocardiography, early concentration on the fundamentals of ultrasound technology, a supervised hands-on participation in outpatient and intraoperative TEE studies, and a program of ongoing quality control and supervision. It is difficult for an anesthesiologist to concentrate on educational objectives if he or she is simultaneously providing direct anesthetic care of complex patients, even if the individual is an experienced anesthesiologist. This is the basis for our choice of a discrete six-month period of echocardiography training that does not include daytime responsibilities for anesthetic management. Each anesthesiologist entering our training program in intraoperative echocardiography begins with an intensive two-month full-time exposure to the basic principles of ultrasound and outpatient transthoracic echocardiography, similar to the exposure of a first-year fellow in cardiology training. We believe that immersion in this environment is the most effective way to provide the anesthesiologist with a broad understanding of ultrasound physics, signal processing, tomographic anatomy, and the spectrum of cardiovascular disease as diagnosed by standard equipment. This experience includes exposure to echocardiography artifacts, variations of normal, and the intricacies of machine control adjustment, as well as the advantages and limitations of echocardiographic diagnosis compared to other relevant imaging modalities. In the third month of the full time spent in the echocardiography laboratory, the anesthesiologist begins involvement in outpatient TEE in conscious patients or those in the intensive care unit. The experience with outpatient TEE has advantages for education in terms of the speed and number of studies done, as well as their relative hemodynamic stability. Months four through six of training are spent half-time in the outpatient echocardiography laboratory, including transthoracic echocardiography and TEE, and half-time in intraoperative echocardiography under the aegis of a cardiologist or anesthesiologist with extensive experience in intraoperative echocardiography. During this time, it is important to concentrate solely on echocardiography learning objectives, as opposed to mixing responsibilities of patient care. If intraoperative echoes can be performed on patients whose anesthesiology care is managed by another experienced physician, the case load and magnitude of the experience can be much better. After six months devoted to echocardiography education, the training continues with a minimum of six more months of supervised echocardiography integrated into clinical anesthesiology responsibilities. Case material that will require intraoperative echocardiography is preferentially selected for the training anesthesiologist during this time. Direct supervision by an experienced cardiology or anesthesiology staff with experience in echocardiography is readily available. In addition, attendance at echocardiography teaching conferences is encouraged. Physicians completing this program have participated in a minimum of 300 transthoracic echocardiographic examinations, 60 outpatient transesophageal studies under supervision, and 75 intraoperative studies using either transesophageal or epicardial technique. Upon completion of the one-year program, however, the education process continues through a weekly intraoperative echocardiography quality assurance conference as well as interdisciplinary consultation and incorporation into the formal echocardiography teaching faculty. Our program provides an optimal level of training for full participation in intraoperative echocardiography that meets the needs of our institution. The goal of our intraoperative echocardiography training program is to train physicians to be full-fledged, independently functioning members of our imaging service. Our institutional needs are somewhat unique with a high volume of valve surgery requiring intraoperative echocardiography. To date, our intraoperative TEE practice has been used less for noncardiac surgery. Although the general principles employed in the development of this educational program may apply to other institutions, each institution will have unique needs that will guide the local development of their training curriculum. Consequently, the substitution of training equivalencies is likely to be the rule rather than the exception. The American Society of Anesthesiology and the Society of Cardiovascular Anesthesiologists have appointed an ad hoc task force to develop practice parameters for TEE. The findings of the task force will be published in the future. The purpose of the present manuscript is to present the approach of the Cleveland Clinic to our particular clinical environment. This may not be a global solution to the problem of educational training in TEE that would apply to other institutional environments. We would like to thank Solomon Aronson, MD, Michael K. Cahalan, MD, Alan S. Pearlman, MD, and Daniel M. Thys, MD, for reviewing the manuscript.