Practice Guidelines for Perioperative Transesophageal Echocardiography

Developed by the Task Force on Perioperative Transesophageal Ecocardiography: Daniel M. Thys, MD (Chair), New York, New York; Martin Abel, M.B.B.Ch., Rochester, Minnesota; Bruce A. Bollen, MD, Missoula, Montana; Michael K. Cahalan, MD, San Francisco, California; Patrick Curling, MD, Houston, Texas; Robert J. Dean, D.O., Grand Rapids, Michigan; David Paulus, MD, Gainesville, Florida; Alan S. Pearlman, MD, Seattle, Washington (American Society of Echocardiography); Michael F. Roizen, MD, Chicago, Illinois; John Smith, MD, Las Vegas, Nevada; William J. Stewart, MD, Cleveland, Ohio (American College of Cardiology); and Steven H. Woolf, MD, M.P.H. (Methodologist), Fairfax, Virginia.Submitted for publication October 30, 1995. Accepted for publication October 30, 1995. Approved by the House of Delegates, October 25, 1995, and the SCA Board of Directors, October 23, 1995.Address reprint requests to the American Society of Anesthesiologists: 520 North Northwest Highway, Park Ridge, Illinois 60068-2573.Key words: Echocardiography: perioperative; transesophageal. Practice guidelines: transesophageal echocardiography.Echocardiography was introduced in the operating room in the 1970s, with its initial applications involving epicardial echocardiography (EE). The use of transesophageal echocardiography (TEE) during surgery was first described in 1980 and did not become commonplace until high-frequency transducers and color Doppler imaging became available in the mid-1980s. The improved quality of the acoustic image enabled anesthesiologists and surgeons to use TEE intraoperatively to diagnose myocardial ischemia, confirm the adequacy of valve reconstruction and other surgical repairs, determine the cause of hemodynamic disorders and other intraoperative complications, and provide diagnostic information that could not be obtained preoperatively. Real-time access to this information has enabled surgeons to correct inadequate repairs before patients leave the operating room, has reduced the need for reoperation, and has facilitated the prevention and early treatment of perioperative complications.Although other intraoperative monitoring devices can provide some of this information, TEE offers important advantages over other diagnostic monitoring techniques. For example, intraoperative echocardiograms can be obtained by transthoracic echocardiography (TTE) or, if the chest is open, by EE. However, the acoustic images of TTE are generally poorer than those of TEE, and monitoring must be discontinued if the chest is opened or if surgical equipment, drapes, or monitors block access to the chest. Epicardial echocardiographic images are equivalent and sometimes superior to TEE, but the probe must be placed in a sterile field, can disrupt surgical procedures, and must be removed once the chest is closed. In contrast, TEE can facilitate diagnosis, allow the institution of specific treatments, and monitor interventions throughout the operative course without disrupting surgical technique. Other devices, such as electrocardiography (ECG) and pulmonary artery catheters, can provide continuous monitoring of cardiac performance, but are often unable to provide important information (e.g., wall motion abnormalities, perivalvular leakage) that can be provided readily and rapidly by TEE.Anesthesiologists also have used TEE outside the operating room. Typical applications in this setting include the emergency assessment of patients preoperatively to determine whether surgery is indicated (e.g., thoracic aortic disruption after blunt chest trauma), as well as the postoperative assessment and treatment of patients in the hours and days after surgery. Even in nonoperative settings, anesthesiologists engaged in critical care medicine increasingly use TEE to evaluate and treat unstable patients in the intensive care unit (ICU).There are important limitations to TEE. Some regions of the heart and great vessels cannot be well visualized (although some of these limitations may be overcome by more advanced technology and new imaging planes). The procedure is generally safe, but insertion and manipulation of the TEE probe can produce pharyngeal and/or laryngeal trauma, dental injuries, esophageal trauma or bleeding, arrhythmias, respiratory distress, and hemodynamic effects. Case reports have attributed some perioperative deaths to TEE. The inaccurate interpretation of TEE images by inexperienced examiners can generate incorrect information, potentially resulting in improper clinical decisions by the anesthesiologist and surgeon and, hence, unnecessary perioperative complications. The performance of TEE can consume anesthesiologists' time and attention that they need to attend to other intraoperative responsibilities.In recent years, the publication of practice guidelines has become a useful, and often necessary, means of establishing the scientific support for clinical procedures and for justifying their use in patient care. Although practice guidelines on TEE have been issued by the American College of Cardiology, American Society of Echocardiography, and Society of Pediatric Echocardiography, they include only brief comments on the use of TEE in the operating room. In 1993, the American Society of Anesthesiologists and the Society of Cardiovascular Anesthesiologists established the Ad Hoc Task Force on Practice Parameters for Transesophageal Echocardiography to develop evidence-based guidelines on the proper indications for performing TEE in the operative setting. The 12-member task force included 9 anesthesiologists (6 of whom hold academic appointments and 3 of whom are private practitioners), 2 cardiologists, and 1 methodologist.Before developing its recommendations, the task force reviewed all evidence regarding the effectiveness of TEE in the perioperative setting. A computerized and manual literature search retrieved 1,844 studies, of which 558 were considered relevant to the perioperative setting. Evidence was considered relevant if it addressed the accuracy and reliability of perioperative TEE, its yield and predictive value, or the effect of perioperative TEE on therapeutic decisions or clinical outcomes. The role of TEE in the emergent preoperative assessment of potential surgical emergencies also was considered. Studies investigating TEE in nonoperative critical care patients were examined, but studies of TEE in the cardiac catheterization or echocardiography laboratory were not reviewed. Thus, a large body of indirect evidence of potential relevance to critical care and surgical patients is omitted from this report but is examined elsewhere. 1,2Further details about the literature review process are available on request.A detailed summary of the studies examined by the task force is published in a separate monograph. This Executive Summary provides an overview of the evidence for each of the topic categories examined by the task force. Each section includes a summary discussing the evidence obtained directly from studies of perioperative TEE, and an