Prevalence and degree of orotracheal intubation-related tracheal lesions in horses.

Background: Orotracheal intubation is commonly performed for inhalation anaesthesia in horses to ensure safe and reliable administration of volatile anaesthetics and to secure the airways. In human and equine medicine, the occurrence of intubation-associated complications has been described, which can range from mild mucosal irritation to severe necrosis. However, there are only sparse descriptions of mucosal alterations and the course of healing after elective surgery in horses.
Objective: To investigate the prevalence and severity of tracheal lesions following endotracheal intubation associated with general anaesthesia in equine patients.
Study Design: Prospective, clinical study.
Methods: Forty adult Warmblood horses, weighing 400-600 kg, presented for elective surgery under general anaesthesia were included. For orotracheal intubation, a silicone tube was used and inflated until a cuff pressure of 40 cmH ₂ O was confirmed. In all horses, endoscopic examination of the trachea with video documentation was performed prior to intubation and immediately after extubation, as well as 1, 3, 5 and 7 days after general anaesthesia. The type (redness, secretion, bleeding, erosions) and degree (0 = non-existent to 4 = severe) of corresponding lesions were assessed and scored. The occurrences of clinical signs were recorded. Statistical evaluation was performed using Friedman's test and Pearson correlation.
Results: The median score immediately after recovery from anaesthesia was 6 (2-12) and increased significantly to 11 (4-15) after 1 day (p = 0.021). At day 7, the median score was 0 (0-2) with only four horses showing signs of mild tracheitis, and clinical signs were not observed throughout this time period. The duration of intubation correlated with the degree of tracheal damage (r ²  = 0.67, p < 0.001).
Main Limitations: Clinical, non-randomised study without a control group.
Conclusion: Although orotracheal intubation was accompanied by focal inflammation of the trachea, in the present study no horses showed clinical signs and lesions healed within a week.
(© 2025 The Author(s). Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.)