Isogravimetric

We regulate the arterial inflow line and the venous outflow line back and forth until we have an isogravimetric or constant weight system.

Source: wiktionary

In an isogravimetric (not losing or gaining weight) isolated perfused lung, pulmonary arterial and venous pressures, and pulmonary blood flow are measured.

Source: wiktionary

The basic assumption made in determining an isogravimetric microvascular pressure is that the organ is in an isogravimetric state, neither gaining nor losing weight.

Source: wiktionary