Relationship of sedation level with hemodynamics and heart rate variability

Abstract

Introduction and aim. Bispectral index (BIS) and heart rate variability (HRV) can be monitored in real time, along with the standard hemodynamic parameters: blood pressure (BP) and heart rate (HR). It is interesting to assess the interrelationship between these parameters during anesthesia. In this work, the objective was to evaluate the changes of HRV, depending on the level of sedation for outpatient endoscopic procedures and to develop a mathematical model of their relationship. Materials and methods. In the first phase of the study, comparative and staged assessment of hemodynamic parameters, BIS and HRV was performed in 26 patients, including 11 men and 15 women aged from 18 to 74 (46±14) years. In the second stage, in order to test the operability of the model, the study was conducted in 12 patients aged from 20 to 72 (44±15) years. All patients were subjected to endoscopic surgery (colonoscopy). The assessment of HRV, hemodynamic profile, and the BIS was carried out in three stages of the study. Depending on the BIS values, all patients were allocated to three levels of sedation. Results and discussion. As a result, the models for HRV-based BIS determination were obtained, giving a high degree of objectivity in determining the status of anesthesia in patients based on HRV-derived BIS. Conclusions. The results of the study revealed the parameters that together reflect the level of sedation. Suggested mathematical model based on discriminant analysis allows to assess the level of light sedation with accuracy of 85.7 %, and the level of adequate sedation with accuracy of 93.3 %. The accuracy of a classification matrix was 89.1 %. The developed software allows to visually assess the level of sedation.