Abstract:
Background: Induction of general anesthesia with midazolam or thiopental is often associated with cardiovascular changes.
Material and methods: The study group involved 94 patients. The analysis of heart rate variability and the changes in cardiac vegetative tonus was
performed after premedication with fentanyl solution and after induction of general anesthesia with midazolam combined with fentanyl (midazolam
group) or thiopental combined with fentanyl (thiopental group).
Results: After administration of fentanyl in doses of 1.0 mkg/kg for premedication there were no significant changes of heart rate variability and vegetative
heart tonus in both groups. Administration of midazolam 0.2-0.3 mg/kg combined with fentanyl 1.0 mkg/kg for induction of general anesthesia leads to
a significant reduction of heart rate variability. The LFun (marker of sympathetic heart tonus) reduced by 24.2% (69.1 (95%CI 65.9-72.3) vs 52.4 (95%CI
42.9-70.0) (p=0,02), meantime the HFun (marker of parasympathetic cardiac tonus) enhanced by 34,9% (30,9 (95%CI 27.6-34.1) vs 47.5(95% CI 30.4-
57.4) (p=0.01). Administration of thiopental 6.0-7.0 mg/kg combined with fentanyl 1.0 mkg/kg for induction of general anesthesia leads to a significant
reduction of heart rate variability.
Conclusions: Administration of fentanyl solution in doses 1.0 mkg/kg for premedication is not associated with significant changes of vegetative tonus
of the heart. Administration of midazolam in combination with fentanyl for induction of general anesthesia leads to significant decrease of heart rate
variability and enhanced parasympathetic cardiac tonus. Induction of general anesthesia with thiopental and fentanyl leads to enhanced sympathetic
tonus of the heart and reduced parasympathetic tonus of the heart.
Key words: heart rate variability, sympathetic heart tonus, parasympathetic heart tonus.
Description:
Valeriu Ghereg Department of Anesthesiology and Intensive Care No 1, Department of Pathophysiology and Clinical Pathophysiology, Nicolae Testemitsanu State University of Medicine and Pharmacy, Chisinau, the Republic of Moldova, Institute of Emergency Medicine, Chisinau, the Republic of Moldova