Alexandra Gougnard

ULTRASONOGRAPHIC FINDINGS IN 13 HORSES WITH LYMPHOMA.

Ultrasonography and radiography are commonly used for staging of lymphoma in horses, however there is little published information on imaging characteristics for horses with confirmed disease. The purpose of this retrospective, case series study was to describe ultrasonographic and radiographic findings for a group of horses with a confirmed diagnosis of lymphoma. A total of 13 horses were sampled. Lymphadenopathy (8/13), peritoneal effusion (6/13), splenic (6/13), and hepatic (5/13) lesions were the most frequently identified. The predominant splenic and hepatic ultrasonographic lesions were hypoechoic nodules, organomegaly, and changes in echogenicity. Digestive tract lesions were detected in three horses and these included focal thickening and decreased echogenicity of the small (2/13) and large intestinal (2/13) wall. Thoracic lesions were predominantly pleural effusion (4/13), lymphadenopathy (4/13), and lung parenchymal changes (3/13). Enlarged lymph nodes were detected radiographically (4/13) and/or ultrasonographically (2/13) in the thorax and ultrasonographically in the abdomen (7/13) and in the caudal cervical region (4/13). Findings supported the use of abdominal and thoracic ultrasonography for lymphoma staging in horses. Ultrasound landmarks for localizing cecal and caudal deep cervical lymph nodes were also provided.

Effect of High Pressure-Volume and Low Pressure-Volume Mechanical Ventilation on Plasma Concentrations of Inflammatory Markers in Horses during General Anesthesia

Systemic changes of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), neutrophil elastase (ELT) and myeloperoxidase (MPO) during mechanical ventilation (MV) in horses anaesthetized for surgery are evaluated. Thirty-four client-owned ASA I-II horses randomly received mechanical ventilation (MV) with either a peak inspiratory pressure (PIP) of 30 cm H2O and tidal volume (VT)>10 mL kg-1 (high pressure-volume MV) or PIP of 15 cm H2O and VT ≤ 10 mL kg-1 (low pressure-volume MV) in dorsal or lateral recumbency. Horses were premedicated with acepromazine (0.1 mg kg-1 IM) and xylazine (0.6 mg kg-1 IV), induced with midazolam (0.06 mg kg-1 IV) and ketamine (2.2 mg kg-1 IV) and maintained with isoflurane in oxygen 70% plus ketamine-midazolam infusion (1 and 0.02 mg kg-1 h-1, respectively). Anti-inflammatory drug and antibiotics were administered before surgery. Plasmatic proinflammatory mediator concentrations were estimated by ELISA at the beginning (T0) and after 60 minutes (T1) of MV. Mean plasmatic TNF-α, MPO, and ELT concentrations at T1 were significantly (p<0.05) lower than T0. Mean plasmatic concentration of IL-6 did not significantly change with time. The reduction in plasmatic concentration of proinflammatory mediators at T1 was not linked to ventilation strategy or recumbency. None of the ventilation protocols enhanced systemic inflammatory response during surgery after 1 hour of MV. The anti-inflammatory properties of drugs included in the anaesthesia protocol may have contributed to the overall decreased systemic inflammatory mediator concentrations, despite MV and surgery.

Use of Nasotracheal Intubation during General Anesthesia in Two Ponies with Tracheal Collapse

Ponies with tracheal collapse may have an increased anesthetic risk due to airway obstruction during induction and recovery. To our knowledge, there are no anesthetic descriptions of these patients, despite a reported 5.6% incidence and 77% mortality rate. Two Shetland ponies with tracheal collapse, a 12-year-old male (pony 1) and a 27-year-old female (pony 2), were referred for right eye enucleation due to a perforating corneal ulcer and severe recurrent uveitis, respectively. Pony 1 was stressed, had lung stridor and hyperthermia, and developed inspiratory dyspnea with handling. Radiography confirmed collapse of the entire trachea as well as inflammation of the lower airways. Corticosteroids and bronchodilators were administered by nebulization for 1 week before surgery. Pony 2 had a grade III/VI mitral murmur and a clinical history of esophageal obstructions and tracheal collapse requiring tracheostomy. Both ponies were premedicated with acepromazine and xylazine; anesthesia was induced with midazolam and ketamine. Nasotracheal intubation was performed in left lateral recumbency with extension of the neck and head and was guided by capnography. The nasotracheal tube consisted of two endotracheal tubes attached end-to-end to create a tube of adequate length and diameter. Pony 2 was orotracheally intubated during surgery and later reintubated with a nasotracheal tube. Anesthesia was maintained with isoflurane using volume-controlled ventilation. Analgesia was provided by a retrobulbar blockade with mepivacaine and lidocaine. Cardiovascular support consisted of lactated Ringer’s solution and dobutamine. After surgery, the ponies were administered xylazine and supplemented with oxygen through the nasotracheal tube. Recovery was assisted by manual support of the head and tail. Successful extubation was achieved following butorphanol administration after approximately 1 h in standing position. Both ponies were discharged from the clinic a few days after surgery.