Transesophageal echocardiography (TEE) is a monitoring and diagnostic tool for the care of children undergoing cardiac surgery. We analyzed reports from 865 routine TEE examinations performed between January 1994 and March 2002 in patients younger than 17-yr-old who were undergoing surgery for congenital heart disease. Patients' median age was 36 mo (range, 1 day-16 yr). The primary end-point of the study was the incidence of surgical and medical management decisions changed as a result of TEE findings; secondary end-points were diagnostic impact (diagnostic exclusions and new diagnoses) and surgical outcome. Fifty percent of the examinations were performed by anesthesiologists with an advanced level of training in perioperative TEE; all of the examiners had an experience of >or=>500 TEE examinations. Supervision by an anesthesiologist with an advanced level of training was requested in 36.7% of cases; supervision by a cardiologist was requested in 3.8%. Surgical alterations of management were reported in 12.7% of cases and included the need for a repeat bypass run in 7.3%; medical alterations of management were required in 19.4% of cases. We observed a diagnostic impact of TEE in 18.5% of cases and a suboptimal but acceptable surgical outcome in 27.6%; TEE findings predicted postoperative difficulties in 4.0%. Our results confirm the utility of routine TEE to assess repair of congenital heart defects. Furthermore, this service was competently performed by a regular team of cardiac anesthesiologists appropriately trained in TEE. IMPLICATIONS: Transesophageal echocardiography (TEE) is an essential monitoring and diagnostic device for the care of children undergoing cardiac surgery. The surgical and medical impact of TEE is demonstrated in a large series of patients. This service can be performed by appropriately trained cardiac anesthesiologists.