Prediction of outcome and severity of illness by analysis of the frequency distributions of cardiorespiratory variables.

Despite the wide variety of illnesses and operations, we observed a common cardiorespiratory pattern of shock that was differenf for the survivors and nonsurvivors, although no one variable was capable of predicting outcome. Differences between the patterns of survivors and nonsurvivors were defined by range criteria and by cut-points operationally obtained from the frequency distributions of cardiorespiratory variables. The values of each of the 33 variables obtained, at times remote from therapy during each successive stage in the postoperative course, were used to predict survival and death in a series of 113 patients by the range and cut-point methods. An average of 13.5% of all the available variables gave a correct prediction by the range cirteria and 35% by the cut-point method. The mean percentage of Right--Wrong classifications throughout all stages for range and cut-point methods was 80 and 85%, respectively. Using the last available stage, the outcome was correctly predicted by the range criteria in 80% and by the cut point method in 88% of the patients. The high percentage of correct predictions suggests that these methods may provide a measure of the severity of acute illness as well as early warning of impending death.