Guidelines for physician training in transesophageal echocardiography: recommendations of the American Society of Echocardiography Committee for Physician Training in Echocardiography

Transesophageal echocardiography (TEE) in congenital heart disease with focus on the adult

Remarkable innovations in medical and surgical approaches over the past several decades now allow for correction of major cardiac defects in children, even in early infancy. These advances have provided for survival of many pediatric patients with congenital heart disease into adulthood. Although transthoracic echocardiography remains the primary imaging technique for the characterization of simple and complex congenital cardiovascular malformations in the pediatric and adult age groups, high-resolution transesophageal imaging has markedly expanded the anatomic and hemodynamic assessment in these patients. The benefits of this imaging approach apply particularly to those with challenging or limited transthoracic examinations or poorly characterized congenital cardiovascular malformations. The utility of TEE in defining the anatomy of the usual spectrum of congenital cardiac malformations is well established. The transesophageal approach has been shown to provide additional diagnostic information over conventional transthoracic imaging for specific structural cardiac anomalies and in the perioperative setting, the opportunity for confirmation of preoperative diagnoses, and modification of the surgical plan if new or different pathology is identified. This imaging modality also may reliably provide for immediate detection of suboptimal surgical repairs and significant postoperative residua, potentially improving the efficacy of the surgical intervention. This accounts for the vital role of this technology in perioperative management and integration into the standard of care in many congenital heart centers. The usefulness of TEE also has been documented during diagnostic and therapeutic cardiac catheterizations of patients with structural cardiac anomalies, allowing for safer and more effective application of these technologies. The experience supports the use of TEE as a useful approach in the surveillance of the adult with operated and unoperated congenital heart disease.

Introduction to transesophageal echocardiography (TEE) with a historical perspective

Since its introduction in the early 1980s, TEE has become an important standard clinical tool with greatly expanded applications. The technique continues to develop. We can expect the future to bring reliable imaging of myocardial perfusion and user-friendly three-dimensional applications.

Field-by-field evaluation of intraoperative transoesophageal echocardiography interpretative skills

A quality assurance system is essential for the credibility and structured growth of anaesthesiology-based transoesophageal echocardiography (TEE) programmes. We have developed software (Q/A Kappa), involving a 400-line source code, capable of directly reporting kappa correlation coefficient values, using external reviewer interpretations as the 'gold standard', and thereby allowing systematic assessment of the validity of intraoperative echocardiographic interpretation. This paper presents assessment of the validity of 240 intraoperative anaesthesiologists' echocardiographic interpretations, and, in addition, the results of field testing of this prototypical software. Data, derived from consecutive cardiac surgery patients, consisted of standardized two-dimensional transoesophageal echocardiographic, colour flow and Doppler imaging sequences. Intraoperative and off-line 'gold standard' TEE interpretations were compared for 19 fields or variables using the Q/A Kappa program. The kappa correlation coefficients were highly variable and dependent on the examination field, ranging from 0.08 for apical regional wall motion scores to 1.00 for tricuspid regurgitation grade, left atrial measurement, aortic valve anatomy and left ventricular long axis and short axis global function. The correlation coefficients were also operator dependent. These data (480 interpretations) were also manually integrated into the equation required for calculation of values of the variable kappa correlation coefficient. The relationship between Q/A Kappa-derived values and manually calculated values was highly significant (p < 0.001; r = 1.0). The implications and possible explanations of the results for particular examination fields are discussed. This study also demonstrates successful seamless functioning of this software program from data entry, segmentation into tables and valid statistical analysis. These findings suggest that it is practical to provide sophisticated continuous quality improvement TEE data on a routine basis.

Development and Costs of an Intraoperative Echocardiography Service

Intraoperative echocardiography (IOE) has become an important part of cardiovascular anesthesiology. An IOE service should provide the equipment and personnel needed to acquire and interpret echocardiographic images during surgery and communicate findings to the medical record. It also should archive images and reports, provide training in echocardiography skills, arrange for continuous quality improvement, and develop a means to bill for echocardiography services. Although the costs of providing IOE services can be estimated, the financial impact of starting such a service will vary greatly between institutions depending on the availability and use of existing resources and expertise. IOE is not a trivial skill and requires considerable training and experience to perform competently. Reimbursement for IOE services provided by anesthesiologists is highly dependent on local policies and will require continued vigilance and effort to be made fair and reasonable for all providers. The primary motivation for anesthesiologists to become involved in IOE is improved patient care.

The surgeon's use of transesophageal echocardiography

Transesophageal echocardiography has become an instrumental diagnostic modality for the accurate evaluation of cardiac and aortic anatomy and function. Multiplanar technology has facilitated improved visualization of structures and enhanced TEE over TTE in many situations. Care of the trauma patient and critically ill patient is improved with the appropriate and timely performance of TEE. Education, certification, credentialing, and determination of competency are areas that need to be addressed continually in the future.

Analysis of left ventricular systolic function

Images

Validation of a test of competence in transesophageal echocardiography

OBJECTIVE

A test was developed that is based on intraoperative findings to evaluate knowledge of intraoperative echocardiography. This study examines the performance of attending anesthesiologists and residents at various levels of training in order to validate the test's ability to measure physician competence in intraoperative echocardiographic diagnosis.

DESIGN

This study was a prospective evaluation of a test of competence in transesophageal echocardiography.

SETTING

Two university medical centers.

PARTICIPANTS

Volunteer anesthesia faculty and residents.

INTERVENTIONS

The participants took an echocardiographic examination that consisted of 34 "K"-type multiple-choice questions and a 45-second video-loop sequence for each question. The video sequences were chosen for their high quality and unambiguous representation of both normal and pathologic images obtained by transverse transesophageal echocardiographic imaging. The questions were written by experienced echocardiographers. The test was administered to 25 individuals at two academic institutions: 11 residents with minimal transesophageal echocardiography exposure and 14 faculty who were relatively experienced with transesophageal echocardiography. All of the residents repeated the examination at the end of their third clinical anesthesia year, which included transesophageal echocardiography training. The differences between the groups' scores were analyzed using the Kruskal-Wallis test and Wilcoxon's rank-sum test. To correct for the multiple comparisons, p < 0.025 was deemed significant. MEASUREMENTS AND MAIN RESULTS. Before their transesophageal echocardiography training, the residents scored significantly lower than the faculty (p < 0.002). After 1 year of training, their scores significantly increased (p = 0.021), and their scores were not significantly different from the faculty level (p = 0.052).

CONCLUSIONS

Test performance differed according to level of experience. This suggests that the test is a valid measure of intraoperative transesophageal echocardiography competence.

Transesophageal echocardiographic assessment of mitral valve position and pulmonary venous flow during cardiopulmonary resuscitation in humans

BACKGROUND

The mechanisms of blood flow during closed-chest cardiopulmonary resuscitation (CPR) in humans have been debated since the technique was first described in 1960. Two competing models, the cardiac pump theory and the thoracic pump theory, have been proposed, and some investigators have used mitral valve position during the downstroke of chest compression to distinguish between them. Previous studies using either transthoracic or transesophageal echocardiography have yielded conflicting results, and there have been few, if any, hemodynamic or echocardiographic studies on pulmonary venous flow (PVF) during CPR.

METHODS AND RESULTS

In this study, transesophageal two-dimensional and pulsed Doppler echocardiography were used to study mitral valve position and flow, together with PVF, in 20 adult patients undergoing manual CPR. In the 17 patients who could be analyzed, the mitral valve closed in 5 patients (group 1) during chest compression but stayed open or opened further in the remaining 12 patients (group 2). Peak forward mitral flow occurred during the release phase in group 1 but during the compression phase in group 2. During chest compression, PVF occurred in the forward direction (from the pulmonary vein to the left atrium) in 8 of the group 2 patients (group 2a) and in the backward direction (from the left atrium to the pulmonary vein) in all group 1 patients and the remaining 4 patients in group 2 (group 2b). The downtime (time from collapse to CPR) was significantly shorter (P < .05) for those in group 1 (7.0 +/- 4.4 minutes) than in groups 2a (19.8 +/- 7.7 minutes) and 2b (17.8 +/- 6.8 minutes).

CONCLUSIONS

Transesophageal echocardiography performed during manual CPR in humans disclosed three different patterns of mitral valve position and PVF during chest compression. The presence of an opened mitral valve with forward mitral flow and backward pulmonary venous flow during chest compression in a small number of subjects underscores this heterogeneity in blood flow and suggests the possible existence of a "left atrium pump" in addition to the currently known "left ventricle pump" and "chest pump" mechanisms.

Echocardiography in the evaluation of thoracic trauma

Echocardiography has become a useful diagnostic modality in the evaluation of cardiovascular injury after thoracic trauma. Valuable information about cardiac wall motion, valvular function, pericardial effusions, and ventricular volume status can be obtained without significant risk. More recent application for the diagnosis of traumatic aortic disruption provides a safer, easier, less expensive, and more accurate method for detecting these injuries. Cardiac evaluation with TTE is unsuccessful in approximately 20% of examinations and is unable to provide the image resolution of the more invasive transesophageal approach.

Who uses transesophageal echocardiography in the operating room?

A survey was made of 155 anesthesiology residency programs in the United States to determine the patterns of use, responsibility for interpretation, and training of those responsible for intraoperative transesophageal echocardiography (TEE). Survey questions included numbers and types of cases for which TEE is used, who interprets TEE data and how they are trained, the extent of resident training in TEE, and beliefs about the utility of TEE. One hundred eight completed surveys were returned (70% response). Of those responding, 98 (91%) use intraoperative TEE. In 53 of those 98 institutions (54%), an anesthesiologist was primarily responsible for the interpretation of TEE data, whereas a cardiologist was responsible in the remainder. Approximately 35% of anesthesiologists using TEE had training in its use during residency or fellowship; the remainder were trained after finishing residency or fellowship. Forty-two percent of anesthesiologists who use TEE leave a formal interpretation on the chart apart from the anesthesia record, and 43% bill specifically for performing TEE. Although 69% of those responding thought that formal credentials should be required for anesthesiologists to use intraoperative TEE, only 32% reported that their institutions actually mandated this. 38% of those responding stated that they offer a dedicated TEE rotation to their residents, and 13% thought that their graduating residents were trained well enough to use TEE on their own. Among academic institutions responding, the use of intraoperative TEE is nearly universal, responsibility for its interpretation is split almost evenly between cardiologists and anesthesiologists, and there is a disparity between opinions and reality with regard to TEE credentialing for anesthesiologists.

Cost-benefit analysis of transesophageal echocardiography in cardiac surgery

This article evaluates the costs and outcomes associated with TEE during and after cardiac surgery. The costs include the direct and indirect costs--the complications of TEE. The outcomes include the positive consequences or the benefits: money and lives saved. The article uses liberal (high) estimates of the direct and indirect costs of TEE and conservative (low) estimates of the benefits. The exact cost or benefit depends on the number of cases performed. The analysis shows that patients having surgery for congenital heart disease derive the greatest overall benefit: around $600 per case studied. Patients having valvular repair surgery derive the next greatest benefit: around $450 per case studied. In contrast patients having valve replacement have an overall cost of around $150 per case studied. Patients having surgery for coronary artery disease also derive an overall benefit: around $100-$300 per case studied, depending upon assumptions regarding TEE's role in prevention of intraoperative strokes. This analysis indicates that the financial benefits of TEE are substantial and frequently outweigh costs in patients requiring cardiac surgery.

Echocardiography practice issues: reimbursement, quality control, training, and credentialing

With the major changes in the delivery of medical care brought about by "health care reform," the American Society of Echocardiography has become active in dealing with a variety of issues related to reimbursement, continuing quality improvement, training, examination, and certification outcomes research, and strengthening of relations with local societies. These efforts will undoubtedly continue to occupy a major role in the Society's agenda. The importance of cooperation among echocardiographers, sonographers, and other cardiac ultrasound professionals in ensuring the proper role of echocardiography in the practice of medicine cannot be overemphasized.

Monitoring during paediatric cardiac anaesthesia

Monitoring of paediatric anaesthesia has become increasingly more complex in recent years and this is particularly true of cardiac anaesthesia. The purpose of this review is to give a comprehensive update of published material related to both routine and specialized cardiac monitoring. Routine monitoring can be particularly affected by the alterations of cardiac rhythm, blood flow, cardiac output and oxygenation which result from the congenital heart abnormalities themselves, the type of surgery undertaken and the effects of cardiopulmonary bypass. The use of specialized monitoring is becoming more widespread, particularly in the areas of cerebral function, mixed venous oxygenation, cardiac output measurement and coagulation. In the last five years, with the development of smaller probes, a great deal has been published on transoesophageal echocardiography. The use of the current monitors of cerebral function still remains controversial despite the need for a monitor of adequate brain perfusion, reflecting the need for a great deal of further research in this area. This review will concentrate on particular areas which have seen the most profound changes and on monitoring that may form the standards of tomorrow. Finally, amongst all the technology, it should not be forgotten that the most important clinical monitor is the bedside clinical monitoring of the physicians themselves.

Transesophageal echocardiography

To describe the role of transesophageal echocardiography (TEE) in the diagnosis of various cardiac pathologic conditions, we reviewed the currently accepted clinical applications, the contraindications to the procedure, and the potential complications. The Mayo Clinic experience with 7,134 TEE examinations during a 6-year period (1988 through 1993) was summarized, and TEE results reported in the literature were reviewed. TEE has a substantially higher yield than transthoracic echocardiography (TTE) for diagnosis of direct and indirect sources of cardioembolism. Moreover, TEE is highly sensitive for detecting abnormalities of mitral prostheses and endocarditis-related complications of aortic prostheses. TEE is superior to TTE for localization and characterization of cardiac and paracardiac masses. In addition to establishing the diagnosis of aortic dissection, TEE can readily show the site, type, and extent of the tear. Ventilated, critically ill patients can safely undergo TEE. TEE has a limited role in the assessment of neonates, infants, and children with congenital heart disease because TTE can provide almost all the necessary information in such patients. Intraoperatively, TEE is useful for managing patients undergoing mitral valve repair and for monitoring for air and fat embolism in those undergoing neurosurgical procedures or hip replacement. Absolute contraindications to the performance of TEE include a history of dysphagia, current pathologic conditions of the esophagus, and recent esophageal operations. In patients with relative contraindications, such as esophageal varices or active upper gastrointestinal bleeding, the risk-to-benefit ratio must be assessed before TEE is performed. Complications associated with TEE can be related to the probe, to the procedure, or to drugs used during the examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Levels of Involvement by Sonographers in Transesophageal Echocardiographic Examinations

A survey of hospital-based echocardiography laboratories in California, Oregon, and Washington was conducted to determine the level of sonographer involvement in transesophageal echocardiographic examinations. For the 113 sites included in the study, the levels of involvement were ranked in the following descending order: preparation and cleanup for the procedure (94%), manipulation of the ultrasound controls (94%), explanation of the procedure to the patient (58%), manipulation of the probe (13%), and insertion of the probe (2%). Sonographer education and registry was also studied to determine whether it was related to level of involvement, but no correlation was found.

Guidelines for physician training in advanced cardiac procedures: the importance of case mix

In recent years, guidelines have been issued for the standardization of physician training in various advanced cardiac procedures. One area that is often neglected by guidelines committees is the need for an adequate case mix during physician training. Case mix refers to the variety of patients and diseases that the trainee is exposed to during the course of learning a new procedure. Although physicians may perform the requisite number of procedures during their training, if the case mix is inadequate, the physician's competence in performing the procedure and interpreting its results may be inadequate as well.

Setting up a transoesophageal echocardiography service

Images

Southwestern Internal Medicine Conference: clinical applications of transesophageal echocardiography

Transesophageal echocardiography has emerged recently as a powerful cardiac imaging tool. The strengths and limitations of transesophageal echocardiography are reviewed. The clinical use of transesophageal echocardiography in aortic dissection, endocarditis, mitral valve disease, prosthetic heart valves, stroke, and miscellaneous other conditions is discussed.

An integrated software system for quality assurance-related kappa coefficient analysis of intraoperative transesophageal echocardiography interpretive skills

This report describes the development of a quality assurance-oriented integrated software system designed for an anesthesiology-based intraoperative transesophageal echocardiography service. Entry data include patient and operation demographics, two-dimensional echocardiographic, saline-contrast, and color flow/pulsed Doppler assessments of the heart and great vessels, presented in a defined sequence. A statistical analysis component (kappa coefficient analysis) allows for comparison of intraoperative real-time interpretations with laboratory interpretations made by experienced full-time echocardiographers on a field-by-field basis. This provides a means of quantifying expertise in each individual aspect of the patient examination sequence. We believe that such self-appraisal data are essential for delineating the status and tracking the progress of service being provided.

Physiology of blood flow during cardiopulmonary resuscitation. A transesophageal echocardiographic study

BACKGROUND

There are two competing theories of the mechanism of blood flow during cardiopulmonary resuscitation. The "cardiac pump" theory postulates that blood flows because the heart is squeezed between the sternum and the spine. The "thoracic pump" theory postulates that blood flows from the thorax because intrathoracic pressure exceeds extrathoracic vascular pressure and that flow is restricted to the venous-to-arterial direction because of venous valves that prevent retrograde flow at the thoracic inlet. To determine which mechanism is operative during actual cardiopulmonary resuscitation, 20 patients were imaged with transesophageal echocardiography during resuscitation.

METHODS AND RESULTS

Transesophageal two-dimensional and pulse Doppler echocardiography was begun within 7 minutes of initiation of cardiopulmonary resuscitation. In the 18 patients who could be analyzed, the mitral valve opened during the release phase (diastole) and closed during the compression phase (systole) of cardiopulmonary resuscitation. Mitral velocity-time integral measured 8 +/- 3 cm during diastole. There was compression of right and left ventricular cavities with significant reduction in measured left ventricular volume during cardiopulmonary resuscitation. In five patients, mitral regurgitation was present.

CONCLUSIONS

Transesophageal echocardiography performed during actual cardiopulmonary resuscitation showing mitral valve opening during cardiac release, reduction of ventricular cavity size with compression, and atrioventricular regurgitation support the cardiac pump theory of cardiopulmonary resuscitation. This study demonstrates the feasibility and usefulness of transesophageal echocardiography during cardiopulmonary resuscitation.

Transesophageal echocardiography: state-of-the art and future directions

Transesophageal echocardiography complements transthoracic examination in 5-10% of patients referred to the echocardiographic laboratory. Clinical indications for performing this procedure are continually evolving. The semi-invasive nature of this procedure necessitates that it be judiciously used and that trained personnel undertake the procedure. Complications of the procedure need to be kept in mind. Future directions in the development of this technology involve newer, multiplanar, multifrequency transducers, digital archiving and retrieval, wide-field imaging, and 3-dimensional reconstruction. For the present, transthoracic echocardiography must remain the primary echocardiographic window imaging the heart, with defined clinical applications for transesophageal echocardiography.