Engelbert TA, Jr LPT, Malone D, et al.
Endoscopic tracheal lavage cytology was evaluated before and 24 hours after standing transendoscopic laser surgery of the upper airway in 18 horses (9 patients undergoing Neodymium:yttrium aluminum garnet [Nd:YAG] surgery and 9 non-patient horses undergoing argon surgery). Paired endoscopic tracheal lavages taken 24 hours apart were evaluated in six control horses to determine if the lavage technique influenced the cytology. After 24 hours, no inflammation was noted in three, mild inflammation was noted in six and suppurative inflammation in four surgically treated horses. Five of the surgically treated horses underwent general anesthesia prior to baseline tracheal lavage and had evidence of inflammation in pre-laser lavage samples; this made it difficult to assess the true incidence of laser-induced inflammation in horses in this report. Five of six control horses had a normal tracheal lavage at 24 hours. Six normal adult horses had baseline tracheal mucous clearance rates determined using scintigraphy followed one week later by tracheal mucous clearance rates two hours after either standing transendoscopic Nd:YAG ventriculectomy or standing transendoscopic argon cauterization of a 2 ◊ 2 cm area of dorsal pharynx. The horses were left in pasture for three weeks, followed by a second baseline and post-laser tracheal mucous clearance rate using the opposite laser technique. There was no significant difference between the first and second baseline measurements. The order of laser treatments had no effect on the results obtained. There was no significant difference between the baseline tracheal mucous clearance rates (mean 1.65 ± 0.65 cm/min) and tracheal mucous clearance rates post-laser surgery (mean 1.62 ± 1.21 cm/min). Neither laser technique altered tracheal mucous clearance rates significantly (argon mean 1.57 ± 0.59 cm/min and Nd:YAG mean 1.67 ± .68 cm/min.