Physiologic abnormalities and outcome from acute disease. Evidence for a predictable relationship.

Initial physiologic data from 1625 nonoperative patients with 18 acute life-threatening diseases treated in an intensive care unit suggest a uniform predictable relationship between acute changes in normal physiologic balance and a patient's risk of death. We found that incremental deviations from normal physiologic balance represent equivalent and predictable incremental risks to survival, regardless of the disease initiating the physiologic disturbance. The relative impact of these physiologic abnormalities on outcome may depend on our understanding of the disease's mechanism of action. Diseases for which there is good understanding of underlying pathophysiology and precise treatment appear to have lower death rates throughout the range of physiologic imbalance compared with those for which pathophysiologic knowledge is limited or unknown. These results document the importance of pathophysiologic understanding to improving survival from acute disease. More importantly, they suggest a predictable relationship between risk of death and physiologic abnormalities for a wide range of diseases. The existence of such a relationship could greatly expand our prognostic ability and permit improved evaluation of new therapeutic discoveries.