Dexmedetomidine dose dependently decreases oral tissue blood flow during sevoflurane and propofol anesthesia in rabbits

Abstract

Purpose: The aim of the present study was to investigate the effect of dexmedetomidine (DEX) continuous infusion on blood flow in rabbit oral tissues during sevoflurane or propofol anesthesia.

Methods: A total of 24 male tracheotomized Japanese white rabbits were anesthetized with sevoflurane or propofol under mechanical ventilation. An initial loading dose of 6.0 μg/kg/hr DEX was administered for 10 minutes. DEX was then maintained at 0.2, 0.4, and 0.6 μg/kg/hr for 1 hour, respectively. The observed variables were systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, common carotid artery blood flow, tongue mucosal blood flow (TBF), mandibular bone marrow blood flow (BBF), masseter muscle blood flow (MBF), upper alveolar tissue blood flow (UBF), lower alveolar tissue blood flow (LBF), and vascular resistance for each tissue (tongue mucosal vascular resistance, mandibular bone marrow vascular resistance, masseter muscle vascular resistance, upper alveolar tissue vascular resistance, and lower alveolar tissue vascular resistance).

Results: The heart rate, systolic blood pressure, mean arterial pressure, common carotid artery blood flow, TBF, BBF, MBF, UBF, and LBF showed dose-dependent decreases during DEX infusion during both sevoflurane and propofol anesthesia. The decreasing ratios in TBF, BBF, MBF, UBF, and LBF were greater than those in heart rate, systolic blood pressure, mean arterial pressure, and common carotid artery blood flow. The vascular resistance of the oral tissues was increased in a dose-dependent manner during DEX infusion in both sevoflurane and propofol anesthesia.

Conclusion: Our findings suggest that infusion of DEX decreases TBF, BBF, MBF, UBF, and LBF in a dose-dependent manner without significant changes in systemic hemodynamic variables during sevoflurane or propofol anesthesia.