[The autonomic nervous system and blood circulation system during different modes of anesthetic coinduction]

The autonomic nervous system (ANS) at the stage of induction was studied in 128 spinal surgical patients with chronic pain syndrome (CPS) (ASA 2-3). In all groups premedication was similar (diazepam 10 mg i.m.), intramuscular and intravenous atropine 0.5 was additionally injected in Groups 3 and 4, respectively. Introductory anesthesia used 4 coinduction modes: thiopental, fentanyl, and propofol (Group 1); propofol and fentanyl (Group 2); propofol, medazolam, and fentanyl (Groups 3 and 4). BIS monitoring was used to evaluate the impact of anesthesia and sedation on the central nervous system; autonomic screening and the Kerdo index were employed for the ANS. Intraoperative circulatory function was controlled by the values of blood pressure, heart rate, stroke index, cardiac index (CI), total peripheral resistance, and double product. Assessment of the time course of changes in ANS tone in patients with CPS indicated that after premedication, the number of parasympathotonics ranged up to 82% and that of normo- and sympathotonics was reduced to 13 and 5%, respectively. During induction with vagotonic agents, ignoring the baseline ANS tone was followed by a progression of the parasympathetic reaction of the circulatory system as a drop of CI to the low values of relevant dissadjustment in the hypokinetic hemodynamic type. There was a transition of ANS tone to physiological sympathicotonia and, accordingly, to the eukinetic circulatory type during coinduction mode 4 that suppressed vagus reflex.