Very heavy sedation or general anesthesia is necessary for bronchoscopy in small animal patients. Injectable anesthetic drugs are used so that it is not necessary to use an endotracheal tube for the inhalation of gas anesthesia during the procedure. Without such a tube, there is more room for the bronchoscope to be inserted into the trachea and the bronchi. Oxygen can be delivered during the procedure through a small catheter inserted down into the trachea or through the bronchoscope itself. In larger patients, gas anesthesia may be used, as the bronchoscope can pass through larger endotracheal tubes while still allowing for the delivery of oxygen and gas anesthetic agents to the patient. Patients are monitored with an electrocardiogram and with pulse oximetry during the procedure.
Once the patient is anesthetized, the bronchoscope is passed into the trachea from the oral cavity. In most cases, bronchoscopy is done with flexible fiberoptic endoscopes. Many times, these are attached to a small camera that can record findings during the procedure. Rigid bronchoscopes are also available, but they are not commonly used in small animal patients.
Bronchoscopy is used to visually inspect the airway for any evidence of collapse, compression, or dilation. Mass lesions can be seen if present within the lining of the trachea or bronchi. Abnormal discharges such as excessive mucus, blood, or pus may also be seen. If a foreign object has been inhaled, it may be seen if the scope can reach the point where it is lodged.
The procedure is useful not only for visualization of abnormalities, but also for obtaining samples. With bronchoscopy, biopsies can be taken if lesions requiring biopsy are seen, and samples of abnormal discharges can be collected and submitted for microscopic analysis and culture. Flushing sterile saline through the endoscope often facilitates sample collection. Special brushes may be passed through the endoscope for collecting samples as well. If airway foreign bodies are seen, special grasping forceps may allow for their removal without surgical intervention.
