Evaluation of a thoracoscopic technique using ligating loops to obtain large lung biopsies in standing healthy and heaves-affected horses

Objective - To evaluate use of pre-tied ligating loop to perform thoracoscopic, large lung biopsy in normal and heaves-affected horses. Study Design - Prospective clinical study. Animals - Normal (n=5) and heaves-affected (n=6) horses. Methods - Lung biopsies, 1 from each hemithorax, were collected thoracoscopically using a pre-tied ligating loop. Horses were either normal (C) or heaves-affected with the latter being in remission (Ha) for the initial biopsy and in exacerbation (Hs) for the 2nd biopsy. Clinical variables, PaO2, and PaCO2 were used to determine the effect of surgical biopsy. Postoperative pneumothorax was monitored by serial thoracic radiographic examinations. Results - Thoracoscopic lung biopsy (n=29, 22 procedures) was well tolerated by all horses. Complication rate was 31%, including 8 ligature slippage and 1 pulmonary hemorrhage. Intranasal oxygen was administered intraoperatively to 6 horses (2 C, 1 Ha, 3 Hs) with severe hypoxemia or labored breathing. There was a significant decrease in PaO2 during surgery in horses not supplemented with oxygen. Postoperative pneumothorax (21/22 procedures) detected radiographically resolved within 3 weeks. Conclusion - Thoracoscopic lung biopsy using pre-tied ligating loops was minimally invasive, relatively inexpensive, and fairly efficient. Heaves-affected horses tolerated the surgery well, even when in exacerbation; however, the technique was associated with non life-threatening complications in 31% of the biopsies, most of which required correction with additional ligating loops or more sophisticated instrumentation. Clinical Relevance - Using laparoscopic pre-tied ligating loop for thoracoscopically-assisted lung biopsy can be considered in horses with normal and impaired lung function but alternative instrumentation and access to intranasal oxygen must be available to the surgeon in case of complications. (c) Copyright 2008 by The American College of Veterinary Surgeons.