A collection of sterile devices intended as an alternative to vascular clamping to interrupt local blood flow through transient intraluminal obstruction during surgery, suturing of blood vessels, or interventional vascular procedures. It includes a liquid polymer (e.g., poloxamer) that is injected into a vein/artery, and devices to contain/administer the solution (e.g., pouch, syringe, injection cannula or catheter). The solution typically has reverse thermal characteristics (i.e., liquid at room temperature and gelled at body temperature) enabling the formation of an in vivo plug that occludes the vessel; it eventually dissolves or is purposely dissolved. This is a single-use device.