CHAPTER 69 Thoracoscopically Guided Pulmonary Biopsy
Thoracoscopy can be used to provide a more accurate diagnosis and prognosis in horses with thoracic disease when less invasive diagnostic tools fail to yield an accurate assessment. Common indications for thoracoscopy include (1) exploration of the thorax when neoplasia is suspected or there is pleural effusion of unknown origin, (2) drain placement for relief of pleural effusion or management of abscesses, (3) transection of pleural adhesions, (4) pulmonary biopsy, and (5) window pericardectomy. Thoracoscopy in the standing horse has proven to be safe, well tolerated, and associated with minimal detrimental effects to cardiovascular and pulmonary function of healthy horses and those with chronic lung disease.
TECHNIQUE FOR LUNG BIOPSY
The instruments used for thoracoscopically guided lung biopsy are the same as those used for laparoscopic surgery and include a 30-degree, 10-mm × 58-cm rigid laparoscope,∗ videocamera,∗ and a 300W xenon light source. Endoscopic forceps† are used to manipulate the lung, and an endoscopic stapler† (EZ endoscopic linear cutter, 45 mm) is used to perform the lung biopsy. The procedure is performed with the horse standing under chemical restraint with xylazine (0.5 to 1.1 mg/kg, intravenous [IV] administration), or detomidine (0.02-0.04 mg/kg, IV), or a continuous IV drip infusion of detomidine (6 μm/kg loading dose followed by an administration rate of 0.8 mcg/kg per minute until the desired effect is observed).