Lower airway ultrasonographic, endoscopic, and cytological changes in horses undergoing inhalation anesthesia with controlled ventilation for minor elective surgeries.
Authors: Laclaire Anne-Louise, Manguin Estelle, Tanquerel Ludovic
Journal: Journal of equine veterinary science
Summary
# Editorial Summary General anaesthesia with controlled ventilation triggers measurable respiratory tract changes in horses even when surgery itself is uncomplicated, though the clinical significance of these findings remains to be determined. Laclaire and colleagues conducted a prospective observational study on eleven client-owned horses, performing lung ultrasound imaging, tracheal endoscopy, tracheal wash cytology and haematological analysis before anaesthesia, immediately post-recovery and 24 hours later. Key findings included elevated blood neutrophil counts (P=0.004), increased ultrasonographic lung scores at recovery that partially resolved by 24 hours (particularly in dependent lung fields: P=0.026), markedly elevated tracheal mucus scores (P=0.001) with severe local inflammation at the endotracheal tube cuff site in several horses, and significantly increased neutrophil counts in tracheal wash fluid (P=0.016) without bacterial overgrowth. For practitioners managing post-operative horses, these results indicate that transient tracheal inflammation and pulmonary changes occur as direct consequences of intubation and positive-pressure ventilation rather than infectious processes, highlighting the importance of baseline respiratory assessment before anaesthesia when investigating post-operative respiratory concerns and suggesting careful consideration of intubation technique and cuff pressure management to minimise iatrogenic mucosal trauma.
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Practical Takeaways
- •Expect transient inflammatory changes in airways following routine elective surgery under general anesthesia in horses, even without complications or clinical signs of pneumonia
- •Tracheal inflammation from endotracheal tube cuff pressure is a predictable consequence of controlled ventilation anesthesia—monitor recovery carefully and consider post-operative respiratory assessment if indicated
- •Ultrasound imaging and tracheal wash can detect subclinical respiratory changes after anesthesia that may not be apparent from physical examination alone; use judiciously in high-risk cases
Key Findings
- •Blood neutrophil count significantly increased between pre- and post-anesthesia (P=0.004)
- •Lung ultrasonographic score increased at recovery, with dependent lung showing higher scores than independent lung (P=0.026)
- •Tracheal mucus score significantly higher after anesthesia (P=0.001) with severe local inflammation at endotracheal tube cuff sites in several horses
- •Tracheal wash cytology showed significantly elevated neutrophil counts post-anesthesia (P=0.016) without increased bacterial load, indicating sterile inflammation