Estimating thrombin generation in subject 1 during cardiopulmonary bypass (CPB) using F1.2 and thrombin-antithrombin (TAT) levels. The left column of graphs shows the measured levels (filled circles) and predicted levels (lines) from the circulatory model for each activation marker. The right column of graphs shows the resulting predicted thrombin generation rate from the circulatory model. In model A, the thrombin generation rate in the circulatory model was held constant at the baseline level. The fit with measured F1.2 levels is poor; the predicted F1.2 levels show the effect of hemodilution if thrombin generation was constant. In model B, the thrombin generation rate in the model was adjusted to produce the best fit between measured and predicted levels of F1.2 only. In model C, the thrombin generation rate in the model was adjusted to produce the best fit between measured and predicted levels of TAT only. In model D, the thrombin generation rate in the model was adjusted to produce the best fit between measured and predicted levels of both F1.2 and TAT simultaneously. The solid black box at the top of each graph indicates the period of CPB.