FIELD : medicine.SUBSTANCE : invention relates to medicine, in particular to anesthesiology – resuscitation, and can be used in predicting the level of sedation during anesthesia. To do this, determine the indicators of the electrophysiological activity of the brain of the patient by the method of omegametry with the registration of ultralow brain biopotentials. Heart rate variability and hemodynamic parameters are analyzed to form a visual demonstration. Statistically significant factors are assigned numerical values, after which the prognostic factors F1, F2 and F3 are determined by the original calculation formulas. If value F1 is more than F2 and F3, a high probability of the first level of sedation is predicted, if F2 is more then F1 and F3, a high probability of the second level of sedation is predicted, and if F3 is more then F1 and F2, a high probability of the third level of sedation is predicted.EFFECT : method provides the possibility of timely registration of the development of a painful reaction to surgical aggression during anesthesia before the onset of its clinical manifestations and thus allows for adequate sedation and analgesia.1 cl, 4 dwg, 1 ex, 2 tbl