Thoracotomy and Pericardiotomy for Access to the Heart in Horses: Surgical Procedure and Effects on Anesthetic Variables.
Authors: Adler Ditte Marie Top, Hopster Klaus, Hopster-Iversen Charlotte, Fenner Merle, Buhl Rikke, Jacobsen Stine
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Thoracotomy remains a rare but critical intervention in equine practice for managing conditions ranging from pleuropneumonia and pericarditis to diaphragmatic herniation, yet the procedural details and physiological impacts have been poorly characterised in the literature. Danish researchers developed a standardised surgical approach using fifth rib resection with pericardiotomy in 11 Standardbred horses (experimentally fitted with atrial fibrillation) whilst measuring arterial blood gases before, 5 minutes and 30 minutes after pleural puncture, comparing findings against six control horses undergoing routine anaesthesia. Fifth rib resection alone provided complete circumferential cardiac exposure in all but one horse, with total surgical time under 45 minutes; importantly, whilst arterial oxygen tension (PaO₂) dropped significantly from 291.8 to 165.2 mmHg following thoracotomy, this decline was within expected parameters for anaesthetised horses and carbon dioxide elimination remained uncompromised. For equine surgeons and anaesthetists, these findings provide practical reassurance that thoracotomy using this approach is physiologically manageable under standard isoflurane anaesthesia with intermittent positive pressure ventilation, though the arterial oxygen decrease warrants vigilant intraoperative monitoring and reinforces the importance of optimised ventilatory support during thoracic procedures.
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Practical Takeaways
- •Fifth rib resection provides reliable access to the entire circumference of the heart in horses and can be completed within 45 minutes, making this approach suitable for cardiac emergencies and experimental procedures
- •Expect a significant drop in PaO2 during thoracotomy even with 100% oxygen and positive pressure ventilation; this is a normal physiologic response and does not indicate inadequate anesthesia management
- •This surgical approach enables complete visualization of the heart for procedures addressing pericarditis, thoracic trauma, and other cardiac pathologies in cases where medical management has failed
Key Findings
- •Fifth rib resection was adequate for complete cardiac exposure in 10 of 11 horses undergoing thoracotomy and pericardiotomy
- •Thoracotomy and pericardiotomy procedure duration was less than 45 minutes
- •PaO2 decreased significantly during thoracotomy from 291.8 ± 82.8 mmHg to 165.2 ± 73.5 mmHg but remained comparable to anesthetized controls
- •PaCO2 remained within normal limits during thoracotomy with IPPV ventilation and no PEEP