[Visualization of the superior vena cava in the supraclavicular acoustic window].

BACKGROUND: The ultrasound-guided venipuncture of the internal jugular vein for placement of a central venous catheter is well established. For verification of the catheter tip position mostly intracardiac ECG or chest radiography are used. Previously, we established the right supraclavicular fossa view for ultrasound based verification of the catheter placement in the superior vena cava utilizing a microconvex probe. The microconvex probe has a small footprint. However, not all ultrasound systems used in the operating theater are equipped with a microconvex transducer.

AIM: Thus, we systematically compared the visibility of intrathoracic vessels obtained by a linear and a microconvex prone via the right supraclavicular view.

MATERIAL AND METHODS: We assessed the visibility of the junction of the brachiocephalic veins, the superior vena cava, the right pulmonary artery, the ascending aorta and the internal jugular vein, comparing a linear with a microconvex probe when using the right supraclavicular view in healthy volunteers. The superior vena cava also was identified using Doppler ultrasound.

RESULTS: With the microconvex probe the superior vena cava was visible in all 30 healthy volunteers, but with a linear transducer it was visible in only 53 %. The combined view of the superior vena cava and the right pulmonary artery was possible in all cases when using the microconvex probe, but in only 38 % when using the linear probe. The junction of the brachiocephalic veins was seen in 75 % of the volunteers with the microconvex probe and in 38 % with the linear one. The aorta was visible in 87 % of cases with the microconvex transducer, but only in 30 % with the linear probe. The internal jugular vein was always visible with either probe.

CONCLUSION: The microconvex transducer as compared to the linear probe is superior in visualizing the superior vena cava. Possible reasons are a smaller footprint, a better degree of freedom for angulation and a greater penetration depth of the microconvex probe.