Connection between the level of anesthesia and hemodynamic and heart rate variability
The work presents the analysis of changes of statistical parameters, hemodynamic and cardiac rhythm variability in dynamics depending on sedation level according to the bispectral index in patients undergone intravenous anaesthesia in painful endoscopic procedures. Heart rate variability is a reliable and sensitive method for evaluation of functions of the autonomic nervous system. Registration and interpretation of heart rate variability reflects the activity of the autonomic nervous system in such diseases as intracranial hypertension, stroke, and brain trauma. As a "gold standard" assessment of the level of anesthesia we used the original methodology for the evaluation of bioelectrical activity of the brain based on electroencephalogram - "Bispectral index" - BISPECTRAL INDEX (BIS], demonstrating the degree of sedation of the patient on a dynamic curve from 100 % to 0 %. Assessment of heart rate variability, hemodynamic profile, and the BIS was carried out in three phases of research: phase 1 - before the introduction of anaesthesia (baseline]; phase 2- after administration of drugs for anesthesia; phase 3 - the end of the procedure, recovery of consciousness (post anesthesia]. Depending on the BIS, values for all patients were allocated to three levels of sedation: the first level corresponded to the patient''s state of consciousness or light sedation, the second and third - to deep anesthesia. A mathematical model of light and deep levels of anesthesia based on the discriminant analysis contingency options.