Catecholamine responses to anesthetic induction with fentanyl and sufentanil

In a randomized study, the authors examined the changes in plasma epinephrine and norepinephrine concentrations associated with induction of anesthesia and surgery in 33 patients with good ventricular function undergoing elective coronary artery surgery. After premedication with morphine and scopolamine, patients received either fentanyl, 100 micrograms/kg (n = 16), or sufentanil, 15 micrograms/kg, (n = 17), intravenously (IV), over 10 minutes to induce anesthesia. Metocurine, 0.42 mg/kg, IV, produced muscle relaxation. Arterial blood for plasma catecholamine determinations was drawn prior to induction, every two minutes throughout induction, one minute following endotracheal intubation, and one minute after sternotomy. Plasma epinephrine concentration was unchanged with either induction agent. Plasma norepinephrine concentration increased significantly after administration of either narcotic, peaked between six and ten minutes into induction, and returned to the preinduction value after intubation. Induction-related changes in arterial pressure and pulmonary capillary wedge pressure were significantly correlated with changes in the logarithm of plasma norepinephrine concentration. Similar degrees of endogenous norepinephrine release appear to accompany induction with equipotent doses of fentanyl and sufentanil in patients premedicated with morphine and scopolamine. Norepinephrine release may influence the hemodynamic response to induction with narcotics.