Continuous measurement of intracardiac and pulmonary blood flow velocities with transesophageal pulsed Doppler echocardiography: technique and initial clinical experience.

Pulsed Doppler techniques have become well established adjuncts to conventional echocardiography in the noninvasive diagnosis of various cardiac malfunctions. Disadvantages of the transthoracic approach, such as inaccessibility and instability of the probe position, limit the continuous application of pulsed Doppler echocardiography during surgery. This study presents a new technique using the transesophageal approach that combines pulsed Doppler measurements with two-dimensional echocardiographic imaging (TDE). The first intraoperative experience with this new enhancement to two-dimensional transesophageal echocardiography (TEE) showed that this relatively noninvasive technique is a safe method allowing constant monitoring of cardiac and pulmonary blood flow velocities. The simultaneous high-resolution two-dimensional imaging facilitates spatial orientation and placement of the sample volume, as well as continued control of the sampling location. The typical flow velocity patterns in standard TEE views are described. The mitral valve and pulmonary artery offer particularly favorable conditions for continuous high-quality TDE measurements. It is concluded that the new technique may further increase the value of TEE to clinicians in the perioperative period.