Lower airway ultrasonographic, endoscopic, and cytological changes in horses undergoing inhalation anesthesia with controlled ventilation for minor elective surgeries.

Effects of general anesthesia with controlled ventilation on the respiratory system have had limited evaluation in horses. A prospective observational study was performed with eleven client-owned horses undergoing elective surgery. Physical examination, auscultation with a rebreathing bag, complete blood cell count, lung ultrasound imaging, tracheal endoscopy imaging and transendoscopic tracheal wash were conducted before and 24 hours after anesthesia. Lung ultrasound imaging was also repeated just after recovery. A significant increase in blood neutrophil count between pre- and post-anesthesia (P=0.004) was observed. There was an increase in ultrasonographic score of the lungs at recovery (left P=0.007, right P=0.017). The score of the dependent lung was higher than the independent lung at recovery time (P=0.026) but no difference was observed 24 hours after anesthesia. The tracheal mucus score was higher after anesthesia (P=0.001); severe local inflammation was present in several horses at the site of endotracheal tube cuff. Neutrophil count was significantly higher on tracheal wash fluid cytology after anesthesia (P=0.016), without any significant changes on bacterial load. Increased tracheal mucus score and neutrophil count in tracheal wash samples were observed after general anesthesia in healthy horses without clinical evidence of pneumonia (fever, cough). Tracheal inflammation secondary to endotracheal intubation and cuff inflation was, therefore, suspected. Elective surgery without complications can induce inflammation of the trachea and changes in ultrasound images of the lungs in healthy horses and should be considered when evaluating respiratory system after a general anesthesia.

Balloon catheter occlusion of the maxillary, internal, and external carotid arteries in standing horses.

OBJECTIVE: To assess the feasibility of balloon catheter occlusion of the internal carotid artery (ICA), external carotid artery (ECA), and maxillary artery (MA) in standing horses. STUDY DESIGN: Experimental and clinical cases series. ANIMALS: Eight healthy horses (phase 1) and 11 clinical cases (phase 2). METHODS: Occlusions were performed on standing horses under sedation and local anesthesia. In phase 1, four horses underwent bilateral ICA balloon catheter occlusion, and four horses underwent balloon catheter occlusion of the ECA and MA. In phase 2, horses were treated by occlusion of ICA (n = 7), ECA (n = 2), or ECA and ICA (n = 2). RESULTS: Internal carotid artery occlusion was successful in seven of eight and seven of nine arteries in phases 1 and 2, respectively. The procedures lasted 53 and 50 minutes, respectively, and catheters were inserted over 13 ± 0.7 cm (mean ± SD). External carotid artery occlusion was successful in seven of seven and four of four arteries in phases 1 and 2, respectively, with mean durations of 31 and 26 minutes, respectively, and a mean distance of catheter insertion of 11.9 cm. Maxillary artery occlusion was successful in five of seven arteries (phase 1), with a mean surgical duration of 47 minutes and a mean distance of catheter insertion of 42.8 cm. CONCLUSION: Balloon catheter occlusion of the ICA, ECA, and MA was achieved in most standing horses. CLINICAL SIGNIFICANCE: Balloon catheter occlusion in standing horses provides an alternative to prevent or treat hemorrhage related to guttural pouch mycosis, particularly in horses in which general anesthesia might pose a risk.