Treatment of Low Arterial Oxygen Tension in Anesthetized Horses with Clenbuterol

Clenbuterol (0.8 4mUg/kg intravenously) was administered to 10 anesthetized horses with an abnormally low Pao₂ (<90 mm Hg) despite controlled ventilation with an oxygen‐rich gas mixture. Results were compared with those from 10 controls to which no clenbuterol was given and in which conventional methods to increase Pao₂ were ongoing. Horses treated with clenbuterol had higher Pao₂ values for at least 90 minutes. Clenbuterol was associated with increased heart rate and profuse sweating. Clenbuterol can be administered intravenously to increase the Pao₂ of mechanically ventilated horses that have low arterial oxygen tension while under inhalation anesthesia. Further studies are warranted to define more precisely the circumstances under which clenbuterol may be used safely.