Effects of prolonged transesophageal echocardiographic imaging and probe manipulation on the esophagus--an echocardiographic-pathologic study.

Transesophageal echocardiography is being increasingly utilized in the operating room and intensive care and ambulatory settings. However, to date no data are available concerning possible trauma of the transesophageal echocardiographic technique to the esophagus due to probe insertion, manipulation or direct ultrasound energy transmission. To test the hypothesis that transesophageal manipulations caused no traumatic or thermal injury to the esophageal mucosa, 12 animals were studied with continuous transesophageal echocardiography for a period of variable duration (mean 4.6 h +/- 51 min). The study group consisted of four monkeys (mean weight 5.7 +/- 0.6 kg and eight mongrel dogs (mean weight 29.8 +/- 1.4 kg). The eight dogs were studied during right heart bypass with full heparinization for 6.6 +/- 0.2 h, whereas the four monkeys were studied for 60 to 90 min in the absence of cardiopulmonary bypass and anticoagulation. Immediately after completion of transesophageal echocardiography in each case, the esophagus was entirely excised. Detailed macroscopic and microscopic examination of the esophagus revealed no significant mucosal or thermal injury. This preliminary animal study suggests that transesophageal echocardiography is safe for the esophageal mucosa in animals as small as 5 kg in weight, despite prolonged use and in the presence of systemic anticoagulation.