Venous pressure meters are intended for the approximate determination of the patient's central venous pressure (CVP). The value of the patient's central venous pressure indirectly informs about the level of hydration and the size of the venous return and is therefore only indicative. This is not a treatment procedure but a way of monitoring the trend of CVP. The scale on the manometric branch is only indicative and is not used as a gauge, it only serves to determine the approximate value of CVP. A central venous catheter is used to accurately measure the CVP value.