Effects of a single intravenous bolus of fentanyl on the minimum anesthetic concentration of isoflurane in chickens (Gallus gallus domesticus)

Administration of a single fentanyl bolus induced a dose-dependent and short-lasting reduction in isoflurane MAC. The higher dose induced no significant cardiopulmonary depression in isoflurane-anesthetized chickens during spontaneous ventilation. In chickens anesthetized with isoflurane, the clinical usefulness of a single fentanyl bolus is limited by its short duration of effect.