Objectives: To evaluate the factors influencing the short-term (<14 days) outcome of thoracic surgery in dogs.

Methods: A retrospective review of 98 dogs undergoing thoracotomy over a five-year period was undertaken.

Results: A pre-operative diagnosis was achieved in 69 per cent of cases. Intrathoraic neoplasia had the lowest pre-operative diagnosis rate (5·5 per cent). Mortality rates of 21 per cent were recorded and were significantly higher for intrathoracic neoplasia (50 per cent) and significantly lower for persistent ductus arteriosus (7·4 per cent) and vascular ring anomaly (0 per cent). Median sternotomy was the preferred approach for pyothorax (85 per cent) and penetrating thoracic injuries (66 per cent). Intercostal thoracotomy was the preferred approach for all other diseases. Postoperative complications occurred in 39 per cent of cases. Wound complications were more common for pyothorax (45 per cent) and following median sternotomy (71 per cent). Thoracic drains were placed in 77 per cent of cases and complications were recorded in 23 per cent. Pyothorax and chylothorax had thoracic drains maintained for significantly longer periods of time. Longer thoracic drain duration was correlated significantly with increased complication rates.

Clinical Significance: The short-term outcome following thoracic surgery is influenced by diagnosis. The thoracic approach is determined by intrathoracic disease, but may influence outcome by affecting the incidence of postoperative wound complications. The risk of thoracic drain complications increases with drain duration, which is influenced by the underlying disease. Drains should be maintained for the minimal amount of time possible.