 To take into account the parallel conductance, GP, the most common method involves injection of hypertonic saline into the subject—enough to temporarily reduce blood resistance, and therefore increase preload, but not so much as to alter haemodynamics.The minimum and maximum volumes (Vmax and Vmin) from each loop in the series of loops are plotted on a graph.Vmax and Vmin lines are extrapolated and at their point of intersection, where Vmax is equal to Vmin, must be zero—conductance is parallel conductance only.