Unexpected internal jugular vein obstruction revealed by ultrasound surface scan before central venous catheter insertion.

transesophageal Doppler probe. At the tip of the probe the Doppler transducer emits a 4-MHz continuous wave signal at an angle of 45 degrees to the long axis of the probe. Emitting the Doppler signal at 45 degrees facilitates the interrogation by the Doppler beam of the PDA opening in the descending aorta (Fig. 1). After obtaining the best arterial waveform, the probe was withdrawn gradually and rotated anteriorly (so that esophagus is now posterior to aorta) until flow reversal in upper part of descending aorta appears. Then, the probe was further withdrawn until the characteristic high velocity flow pattern of PDA was obtained (Fig. 2). Surgery was performed with the patient in the right lateral decubitus position. Successful PDA ligation was confirmed in the eight patients by the disappearance of the high velocity pattern (Fig. 3) and the absence of diastolic flow reversal in the descending aorta. The higher sensitivity of TEE for detection of residual shunt may be related to color flow mapping guidance. Although EDM uses only spectral Doppler analysis, none of our patients had a residual ductal flow during postoperative TTE examination. Our report represents a new application of esophageal Doppler monitor during VATS PDA closure. Because of small number of the patients in this report, we cannot judge with confidence whether EDM can replace TEE as a monitor of VATS PDA ligation.