Superior vena cava collapsibility as a gauge of volume status in ventilated septic patients

Excerpt

Sir: We read the article of Vieillard-Baron and colleagues [1] with great interest. In this article superior vena cava (SVC) collapsibility during tidal ventilation was found to be an excellent indicator of fluid responsiveness. The diameter of the SVC was measured in a long-axis view using transoesophageal echocardiography. The authors even reported occasional total collapse of the SVC during the ventilation cycle. Like Vieillard-Baron and colleagues [2], we also examined the SVC in the short- and in the long-axis views. However, while examining the SVC in the short-axis view we occasionally observed a left-right shift of the SVC during tidal ventilation. This motion of the SVC is sometimes as great as the radius of the SVC. Vieillard-Baron and colleagues [2] also examined the SVC from the short axis, but did not mention motion of the SVC. However, it is conceivable that this motion of the SVC could mimic collapse of the SVC during tidal ventilation when assessed in the long-axis view. Therefore, it would seem to be advisable to exclude motion of the SVC during tidal ventilation in the short-axis view before measuring the diameter of the SVC in the long-axis view. We would appreciate a response from the authors as to their experience in this regard. …