ATTENUATION OF HISTAMINE-INDUCED AIRWAY CONSTRICTION BY ALBUTEROL DURING HALOTHANE ANESTHESIA

The effects of albuterol (a β2 specific adrenergic agonist) on airway reactivity to histamine aerosol challenge was evaluated during halothane anesthesia and thiopental-fentanyl anesthesia in five Basenji Greyhound dogs. Responses to histamine aerosol challenges (0.01, 0.03, 0.1, 0.3, 1.0, and 3.0 mg/ml) were measured during thiopental-fentanyl anesthesia and during halothane anesthesia in the presence and absence of iv albuterol (2.5 μg/kg). Prior to aerosol challenges, baseline pulmonary resistance (R(L)) and dynamic compliance (C(dyn)) did not differ in the four conditions. Albuterol significantly attenuated the pulmonary response to histamine during thiopental-fentanyl anesthesia. Although halothane itself significantly attenuated the pulmonary response to histamine, this response was further attenuated by the addition of albuterol. This study suggests that albuterol is effective in attenuating bronchoconstriction during both thiopental-fentanyl and halothane anesthesia. As the effects of albuterol and halothane on the airways are additive, β-adrenergic agonists such as albuterol are the agents of choice to treat bronchospasm in patients anesthetized with inhalational anesthetics.