Amrinone attenuates airway constriction during halothane anesthesia

Phosphodiesterase (PDE) inhibitors should, in theory, be useful in patients with both cardiac and reactive airway disease who require anesthesia. The effects of the PDE inhibitor, amrinone, on the release of endogenous catecholamines and on airway reactivity to aerosol methacholine challenge were evaluated during thiopental/fentanyl and halothane anesthesia in five mongrel dogs.

Responses to methacholine aerosol challenge (0.03, 0.075, 0.15, 0.30, 0.75, and 3.0 mg/ml) were measured during four conditions: thiopental/fentanyl anesthesia, thiopental/fentanyl anesthesia with amrinone infusion, halothane anesthesia, and halothane anesthesia with amrinone infusion. Increase in pulmonary resistance (RL) and decreases in dynamic compliances (Cdyn) were calculated for each methacholine dose. Plasma epinephrine and norepinephrine concentrations were measured during thiopental/fentanyl anesthesia with amrinone infusion.

Before aerosol challenge, baseline RL and Cdyn did not differ in the four groups. Amrinone significantly attenuated the pulmonary response to methacholine during both thiopental/fentanyl and halothane anesthesia. Plasma catecholamine concentrations did not increase during amrinone infusion.

Amrinone attenuates methacholine-induced airway responses even during halothane anesthesia. These data indicate that isozyme-selective PDE inhibitors hold promise for the perioperative treatment of bronchospasm.