Experimentally Induced Open Pneumothorax in Horses.
Authors: Canola Paulo A, Valadão Carlos A A, Canola Júlio C, Flôres Fabíola N, Lopes Maristela C S
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Experimentally Induced Open Pneumothorax in Horses Researchers created a controlled unilateral pneumothorax in seven healthy horses to examine how this life-threatening condition affects cardiopulmonary function and intrathoracic pressures over time. The team measured pleural and oesophageal pressures, arterial blood gases, left ventricular function, and pneumothorax resolution via ultrasonography at multiple timepoints during the 60-minute injury period and throughout a seven-day recovery phase. Whilst arterial oxygen levels declined significantly until day three before normalising, the horses demonstrated remarkable cardiovascular stability with no meaningful changes in carbon dioxide tensions, blood pH, or cardiac function—suggesting innate physiological compensation mechanisms are robust even in this acute scenario. Oesophageal pressure proved a useful proxy for pleural pressure and remained elevated until day five, providing a practical clinical marker that, when combined with blood gas analysis and ultrasound assessment, could aid pneumothorax diagnosis in field or clinical settings without requiring invasive pleural pressure monitoring. These findings indicate that equine patients tolerate penetrating thoracic trauma with spontaneous air leakage better than traditionally assumed, which has important implications for triage decisions and expectations regarding clinical outcome in horses presenting with open chest wounds.
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Practical Takeaways
- •Esophageal pressure measurement combined with blood gas analysis and thoracic ultrasonography can aid in diagnosing pneumothorax in clinical cases
- •Horses demonstrate remarkable physiological tolerance to open pneumothorax with maintained cardiovascular stability, even without immediate therapeutic air removal
- •Monitor arterial oxygen levels as they may remain depressed for 3 days post-injury; respiratory function typically recovers without intervention
Key Findings
- •Esophageal pressure showed moderate correlation with pleural pressure (rs = 0.404) and increased significantly until day 5 post-thoracotomy
- •Partial pressure of oxygen in arterial blood decreased until day 3 postoperatively then returned to baseline; no significant changes in PaCO2 or arterial pH
- •Left ventricular function showed no significant variations throughout the study period
- •Horses tolerated 60-minute open pneumothorax with minimal cardiovascular impairment without air aspiration from pleural space