Hemostasis in blood vessels after ligation.

The length of time required to achieve hemostasis after ligation of blood vessels with a diameter of 1.0 to 3.5 mm was studied. Canine limb vessels were ligated with stainless steel clips. These were removed at 48, 60, 72, 84, or 96 hours after ligation, and the degree of hemostasis was evaluated by observing the effect of varying amounts of trauma applied to the vessels. The vessels were first observed for 1 minute. In the second phase the vessels were stroked for 15 seconds and then observed for 1 minute. In the second phase the vessels were stroked for 15 seconds and then observed for any bleeding. An additional 15 seconds of stroking followed by observation completed the evaluation. All blood vessels achieved hemostasis after 96 hours of secure ligation despite the trauma. All ligating devices must provide secure ligation to achieve hemostasis for at least 96 hours. The presence of disease processes or medications interfering with clotting would necessitate a longer period of secure ligation to achieve hemostasis.