Baseline heart parasympathicotonia – a risk factor for cardiovascular instability in anesthesia induction with propofol or midazolam

Abstract

Background: Aim of the study. Evaluation of relationship between baseline parasympathetic heart tonus and the frequency of adverse cardiovascular reactions in anesthesia induction with propofol or midasolam. Material and methods: The study was performed within Institute of Emergency Medicine and was approved by the Ethic Committee of the USMF ”N. Testemițanu”. In the study groups were involved 94 patients scheduled for elective general surgery with age 38,6±11,4 years and BMI 27,6±3,7 kg/m2. Heart rate variability was registered with Holter TLC 5000 device: 5 minutes in baseline, 5 minutes after intravenous administration of fentanyl 1,0 mkg/kg and 5 minutes after intravenous administration of 2,5 mg/kg propofol with 2,0 mkg/kg fentanyl or 0,2-0,3 mkg/kg midasolam with 2,0 mkg/kg fentanyl. Results: Baseline heart parasympathicotonia enhances the risk of sinus bradycardia (relative risk-7,7(95%CI 1,9-29,7), Odds Ratio–21,0 (95%CI 3,9-112,8) (p<0,0002), as well as the risk of sinus bradycardia associated with arterial hypotension (relative risk-6,2 (95%CI 2,1 -18,6), Odds Ratio-19,2(95%CI 4,1–88,6) (p<0,0001), after administration of propofol for induction of general anesthesia. Baseline heart parasympathicotonia enhances the risk of sinus bradycardia: (relative risk-4,5 (95%CI 1,7- 11,4), Odds Ratio–13,1(95%CI 3,1-54,7) (p=0,0002), the risk of arterial hypotension: (relative risk-4,8(95%CI 1,6-14,5), Odds Ratio-12,7(95%CI 2,9-55,9) (p=0,0003), as well as the risk of sinus bradycardia associated with arterial hypotension: (relative risk-3,5(95%CI 1,8-7,1), Odds Ratio-13,7(95%CI 3,0–62,7) (p=0,0003), after administration of midasolam for induction of general anesthesia. Conclusions: Baseline heart parasympathicotonia is a risk factor for development of sinus bradycardia and arterial hypotension after administration of midasolam or propofol for induction of general anesthesia.