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

Background: Orotracheal intubation is commonly performed for inhalation
anesthesia in horses to ensure safe and reliable administration of
volatile anesthetics 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 prevalemce and severity of tracheal lesions
following endotracheal intubation associated with general anesthesia in
equine patients. Study design: Prospective, clinical study Methods: Forty
adult warmblood horses, weighing 400-600 kg, presented for elective
surgery under general anesthesia were included. For orotracheal intubation
a silicone tube was used and inflated until a cuff pressure of 40 cmH2O
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 anesthesia.
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 anesthesia was 6
(2-12) and increased significantly to 11 (4-15) after one 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.  Duration of intubation correlated with degree of
tracheal damage (r2 =0.67, p < 0.001). Main Limitations: Clinical,
non-randomized study without control group. Conclusion: Although
orotracheal intubation was accompanied by focal inflammation of the
trachea, in the present study no horse showed clinical signs and lesions
healed within a week.