A vascular tourniquet or snare for use in a surgical procedure where it is desired to limit or restrict flow through a body vessel or to secure a tube within such vessel. The tourniquet or snare consists of an elongate sheath through which a rigid retractor extends. A tape or cord wrapped about the vessel is withdrawn through the sheath by the retractor and secured thereto by a plug inserted in the proximal end of the sheath. Superior and inferior vena cava via the right atrium is the most accepted method presently used for venous drainage is conjunction with extracorporeal circulation. Bleeding around the cannula is usually prevented by a purse-string suture secured by a rubber tourniquet. When an additional cotton ligature is used to hold the venous cannula in place, the procedure time is lenghtened and there is less room in the operative field.