Clamp Size and Clamp Pressure

When choosing the right size of clamp for your work, clamp pressure is an important consideration. Clamp pressure is determined by the closing force of the clamp (in grams), divided by the area of the vessel wall that is compressed between the jaws (in square millimeters). Thus, the smaller the area, the higher the pressure is, inversely proportional to the vessel size. Each size of clamp has its own different and carefully calibrated closing force.

Each clamp size is designed for a specific range of vessel diameters.

Despite the wide range of closing forces, the pressure exerted by each clamp, large or small, remains consistent throughout the series. Each size of clamp exerts a pressure of 5gm/mm 2 when used on the largest vessel in its range, and 15gm/mm 2 when used on the smallest vessel. Even at the higher range, S&T's clinical micro clamps have the gentlest working pressure of any small vessel clamp available.

The table summarizes the relationship between clamp size,
recommended vessel diameter and clamp pressure.

'Vessel diameter' refers to the external diameter of the vessel in its natural state of full dilation.

There is a 50% overlap in the recommended vessel diameter range, between each clamp size and the next larger or smaller size. Thus, for every vessel diameter, with the exception of those at the extreme ends of the range, there will always be two suitable clamps. Whenever a choice arises, the smaller clamp should be selected to ensure a gentler handling of the vessel.