Synergism Between Sevoflurane and Intravenous Fentanyl on A delta and C Somatosympathetic Reflexes in Dogs

Abstract

Although fentanyl caused a greater depression of C than of A delta reflexes to the point of abolition, the maximal depression of spontaneous sympathetic activity, heart rate, and arterial pressure occurred at smaller doses. The combined depressant effects of sevoflurane and fentanyl were synergistic on somatosympathetic reflexes but were less than additive on spontaneous sympathetic activity, heart rate, and arterial pressure.