Application of a Miniaturized Biplane Transesophageal Echocardiographic Probe in Adults

Background. Standard multiplane transesophageal echocardiographic probes have large transducer tips that could increase patient discomfort, especially during esophageal intubation. A miniaturized biplane probe has been developed for pediatric use; however, its utility for adult patients is unknown. Methods. The miniaturized biplane imaging was tested in 48 anesthetized, ventilated adult patients during cardiac surgery and was compared with the standard multiplane imaging. We evaluated the image quality of cardiac structures and thoracic aorta using a five-grade scoring system. We also measured the left ventricular end-diastolic dimension (LVEDD, mm) and the peak flow velocity (cm/s) of the left atrial appendage (LAA) by pulsed-wave Doppler. Results. Esophageal intubation with the multiplane probe was unsuccessful in 1 patient, although this patient was successfully intubated with the biplane probe. There were no complications with either probe. The image qualities of the left ventricle, mitral valve, aortic valve, and ascending aorta by the biplane probe were inferior to those by the multiplane one. On the other hand, left atrium (LA), LAA, interatrial septum, aortic arch, and descending aorta were as well visualized by the biplane probe as by the multiplane one. The values of LVEDD and peak flow velocity of LAA were not different between the probes. LAA thrombus in 2 of 47 patients and aortic dissection (Stanford type A) in 7 were also well detected by both methods. Conclusions. The resolution of the two-dimensional images in the near fields of the miniaturized biplane probe was as good as the standard multiplane one. The miniaturized biplane probe was found to be applicable to the detection of LA or LAA thrombus and assessment of LAA function in adults.