Propofol Dose-Dependently Increases Bite Force During Sedation

Abstract

The purpose of this study was to investigate the dose-dependent effects of propofol on cognitive function and muscle power as well as vital functions. Twenty volunteers participated in this study. Each subject underwent 2 experiments in a randomized crossover manner (propofol group and control group). After control data were obtained, propofol at predicted effect site concentrations of 0.4, 0.8, 1.2, 1.6, and 2.0 μg/mL was infused in the propofol group using a target controlled infusion system. Heart rate, noninvasive blood pressure, arterial oxygen saturation, respiratory rate, and bispectral index value were monitored. Observer's assessment of alertness/sedation and the correct answer rate of the Stroop color word test were assessed. Muscle power, grip strength and bite force were measured. In the propofol group, the bispectral index value and observer's assessment of alertness/sedation scale dose-dependently reduced. At the predicted effect site propofol concentration of 2.0 μg/mL, 6 subjects became unconscious. The correct answer rate of Stroop color word test reduced at the predicted effect site propofol concentration of 1.6 and 2.0 μg/mL. Grip strength slightly increased at the predicted effect site propofol concentration of 1.2 μg/mL or less, and bite force dose-dependently increased. At the predicted effect site propofol concentration of 2.0 μg/mL, both muscle powers began to decrease. Bite force dose-dependently increased and reached the maximum at the predicted effect site propofol concentration of 1.6 μg/mL. Although the detailed mechanisms are unknown, propofol dose-dependently increases bite force during minimal and moderate sedation.