Figure 5. A nomogram showing the relation between the infusion rate and the infusion time (left) and the infusion rate required to maintain a steady state dilution 30 min later (right) when male volunteers given Ringer's solution by intravenous infusion were normovolemic (top) and when 450 ml (middle) and 900 ml (bottom) blood had just been withdrawn. The (%) isobars show the predicted dilution of V1(i.e., (v1-V1)/V1), of which the plasma in the cubital vein is a part. The dilution required to obtain normovolemia is indicated by a thick irregular line in the middle and bottom graphs. The graphs are based on mean parameter values of the two-volume model as shown in Table 1. The baseline blood volume was calculated from the weight and height of the volunteers using Nadler's regression equation. [11]Directions for using the nomogram: 1. Choose a desired dilution of the plasma (expressed as a percentage). 2. Using the left graph, start infusing Ringer's solution at any combination of rate (y axis) and time (x axis) that meets the (%) isobar corresponding to the chosen dilution. To restore normal blood volume, choose the target dilution represented by the thick irregular line. 3. When the target dilution is found, take the horizontal to the right graph, along the same infusion rate line, to the line corresponding to the infusion time used. The steady state infusion rate is indicated by the vertical correlation (x axis).