Thoracoscopy in horses: comparison between two approach techniques

Abstract

Thoracoscopy has been used more frequently as an ancillary exam in the diagnosis of several thoracic diseases. In order to compare two approach techniques to inspect the pleural cavity, sixteen healthy animals underwent thoracoscopy. Ten horses received general anesthesia with selective orobronchial intubation and six were maintained in standing position under sedation associated with local anesthesia. The right and left hernithorax were approached with a fifteen-day interval between each procedure. It was possible to observe the following different structures of the thoracic cavity during the exam: the diaphragm muscle (muscular and tendinous portions), esophageal hiatus, mediastinum, aorta, dorsal and ventral branches of the vagus nerve, thoracic duct, azigus vein, intercostal vessels and muscles, ribs, sympathetic nerve trunk, thoracocervical vascular trunk, trachea, lung (cranial and caudallobes), esophagus, pericardium, caudal cava vein, phrenic nerve, aortic lymphnodes. A larger number of structures could be identified in standing animals. Thoracoscopy proved to be a very helpful exam, as it is easy to perform. In addition, it is not time-consuming and provides a wide inspection of the pleural cavity. The animal's position will depend on the organ or structure to be examined. Wben lateral recumbence is chosen, the use of mechanical ventilation with selective orobronchial intubation must be considered.