Evaluation of a device scoring classes of hemorrhagic shock

In order to evaluate the feasibility of a device scoring classes of hemorrhagic shock, a multivariate analysis of physiological data collected on swine enduring continuous blood loss was conducted. Raw data sampled at up to 500 Hz were first preprocessed and used for features extraction over period of 1 mm. An expert scored all these physiological features, into one of the four classes of hemorrhagic shock: none, compensated, uncompensated and irreversible. A supervised learning of various classifiers was then evaluated over these data. The percentage of misclassification obtained when using a realistic way of estimating error (a leave one -animal- out validation) is about 20% when mean arterial pressure is used, and about 40% when only non invasive features are used. The results are about the same whatever the classifiers used. This evaluation is discussed and a visualization is proposed in order to assess the temporal supervision given by the classifiers.