Successful management of persistent tachycardia using esmolol in 2 dogs with septic shock.

OBJECTIVE: To describe the successful management of 2 dogs with septic shock and persistent tachycardia using norepinephrine and esmolol, a short-acting beta receptor antagonist. SERIES SUMMARY: Two cases are reviewed. In the first case, septic shock with ventricular tachycardia was diagnosed in a 4-year-old neutered female Great Dane that underwent jejunoileal resection and anastomosis for a partial mesenteric torsion. The patient's tachyarrhythmias failed to respond to lidocaine, and an esmolol infusion was used for heart rate control. The condition of the dog improved and she was discharged after 4 days of hospitalization. The second case was a 7-year-old neutered female Cavalier King Charles Spaniel with septic peritonitis. Following surgery for intestinal resection and anastomosis, supraventricular tachycardia developed that was not responsive to volume resuscitation and was treated with an esmolol infusion. The condition of the dog improved and she was discharged after 6 days of hospitalization. Both patients were doing well at the time of long-term follow-up. NEW OR UNIQUE INFORMATION PROVIDED: This case series highlights a novel method of managing dogs in septic shock with persistent tachycardia based on recently published data in the human literature. The use of esmolol may be considered in certain veterinary patients with septic shock to improve persistent tachycardia not related to hypovolemia.

Suspected Compartment Syndrome, Consumptive Thrombocytopenia, and Anemia Secondary to a Ruptured Arterial Aneurysm or Pseudoaneurysm Following Multiple Stifle Surgeries.

A 12 yr old male neutered beagle was presented on transfer to the intensive care unit with severe anemia, thrombocytopenia, and bruising detected 1 day after undergoing tibial plateau leveling osteotomy surgery. The patient had undergone extra-capsular stifle stabilization surgery 14 wk prior to treat ligament disease in the same knee. Laboratory testing and treatment for anemia, presumptive immune-mediated thrombocytopenia, and possible hemostatic disorder was initiated. A persistent anemia, progressive thrombocytopenia, and the development of a firm swelling and neurologic impairment in the limb raised concerns for compartment syndrome (CS). A musculoskeletal ultrasound revealed a large aneurysm in the caudal thigh surrounded by abnormal muscle tissue. The patient underwent amputation of the limb and recovered without further complication. Pathology findings were consistent with the development of femoral CS secondary to a ruptured peripheral arterial aneurysm or a pseudoaneurysm. A consumptive thrombocytopenia and regenerative anemia were attributed to periodic or progressive thrombosis of the vessel and regional hemorrhage. Postoperative CS can develop in combination with peripheral arterial aneurysm or pseudoaneurysm, and screening for vascular abnormalities as well as CS should be considered in complicated recovery from orthopedic surgery with compatible clinical signs including progressive soft tissue swelling, persistent anemia, and thrombocytopenia.

Suspected drug-induced infiltrative lung disease culminating in acute respiratory failure in a dog treated with cytarabine and prednisone.

OBJECTIVE: To describe a case of suspected drug-induced infiltrative lung disease (ILD) and acute respiratory failure associated with the administration of cytarabine and prednisone in a dog requiring mechanical ventilation. CASE SUMMARY: A 4.5-year-old, female spayed Yorkshire Terrier presented to the ICU with acute onset of respiratory distress following a 24-hour cytarabine infusion. The patient was previously diagnosed with meningoencephalitis of unknown etiology (MUO), caudal occipital malformation, and syringohydromyelia, and was being treated with oral prednisone and levetiracetam, and cytarabine infusions. The patient developed tachypnea and dyspnea, and had diffuse crackles on auscultation of all lung fields, and hypoxemia 6 hours following completion of the fourth cytarabine infusion (300 mg/m2 ). Thoracic radiographs revealed diffuse, bilateral infiltrates consistent with noncardiogenic pulmonary edema or acute respiratory distress syndrome. Respiratory distress and hypoxemia persisted despite oxygen supplementation and furosemide therapy and led to initiation of mechanical ventilation. Approximately 12 hours later, the dog became progressively hypoxemic with worsening pulmonary edema. The owners elected euthanasia. Postmortem examination revealed pulmonary edema and diffuse interstitial pneumonia. Histopathologic evaluation revealed pulmonary edema, severe acute neutrophilic and histiocytic pneumonia, and multifocal interstitial fibrosis. Bacterial culture yielded no growth. NEW OR UNIQUE INFORMATION PROVIDED: Drug-induced ILD is rarely reported in the veterinary literature, and has not previously been reported in dogs receiving cytarabine. As with administration of any medication, adverse events may occur. While ILD is unlikely to be commonly recognized, it may be considered in veterinary patients receiving chemotherapy that acutely become dyspneic.

The activity and inhibition of poly(ADP-ribose) polymerase-1 in equine peripheral blood mononuclear cells in vitro.

OBJECTIVES: To evaluate the poly (ADP-ribose) polymerase-1 (PARP1) enzyme and its inhibition in horses and explore its potential as a novel therapeutic target for equine intestinal ischemia-reperfusion injury by (1) identifying poly (ADP-ribose) (PAR) as an indication of PARP1 activation in equine cells using available immunoblot analytical techniques, (2) inducing PARP1 activation in an in vitro oxidative DNA damage model, (3) and demonstrating the inhibition of PARP1 in equine cells using commercially available PARP1 inhibitors. DESIGN: Experimental study. ANIMALS: Blood samples were collected from systemically healthy ponies (n = 3) and horses (n = 3). INTERVENTIONS: (1) Equine peripheral blood mononuclear cells were exposed to 3 different concentrations of hydrogen peroxide (H2 O2 ) and were lysed at specific time points. PARP1 activity was then assessed by using immunoblot analyses to determine PAR levels. (2) Equine peripheral blood mononuclear cells were preincubated with defined concentrations of PARP1 inhibitors prior to H2 O2 -mediated PARP1 stimulation. PAR levels reflecting PARP1 activity were determined using immunoblot analyses. MEASUREMENTS AND MAIN RESULTS: Commercially available anti-PAR antibodies were used successfully to identify equine PAR. There was a significant increase in PAR accumulation following treatment with H2 O2 . All of the tested PARP inhibitors significantly reduced PAR accumulation to or below basal levels following treatment with H2 O2 . CONCLUSIONS: This proof of principle study demonstrated that PAR, an indicator of PARP1 activity, can be identified in the equine species using immunoblot techniques, that equine PARP1 can be activated by H2 O2 -induced DNA damage, and that this activation can be inhibited by PARP1 enzyme inhibitors. The data suggest that the PARP1 pathway plays a role in the equine cellular response to oxidative DNA damage and supports its potential as a novel therapeutic target. Further research documenting an increase in PAR levels in vivo and the efficacy of PARP1 inhibitors in an equine intestinal ischemia-reperfusion model is needed.

Impact of colic surgery on return to function in racing Thoroughbreds: 59 cases (1996-2009).

OBJECTIVE: To determine the effect of colic surgery on return to function in Thoroughbred racehorses, identify clinical variables associated with successful return to racing, and compare racing performance between horses undergoing colic surgery and an untreated cohort. DESIGN: Retrospective cohort study. ANIMALS: 59 Thoroughbred racehorses 2 to 5 years of age that underwent colic surgery and survived to hospital discharge and 90 untreated Thoroughbred racehorses equivalent in class. PROCEDURES: Medical records of patients evaluated for colic between January 1996 and July 2009 were reviewed, and horses with a Jockey Club Information Systems record were included. Physical examination and laboratory findings on hospital admission, lesion location and type, duration of surgery, duration of hospitalization, and any postoperative complications were recorded. The untreated cohort comprised 2 untreated horses randomly selected from runners in each treated horse's last race immediately prior to the date of colic surgery. Records were obtained from the Jockey Club Information Systems in April 2011. Only horses that raced at least once before and after surgery were included in the performance analysis. Number of starts, earnings per start, and total earnings were determined from race records for all horses. Quarterly earnings and number of starts for 12 quarters following the date of surgery were compared between treated and untreated horses via a Wilcoxon rank sum test. Longevity of racing was assessed by means of survival analysis. Poisson regression was used to compare rates of return to racing and active quarters aggregated across the first 12 quarters after surgery and for the available follow-up period for treated and untreated horses. RESULTS: 45 of 59 (76%) horses that raced prior to surgery returned to racing. Return to racing was significantly associated with admission heart rate and blood lactate concentration. From quarters 3 to 12, treated and untreated horses had slight differences in the number of starts but no difference in earnings per quarter. Treated and untreated horses had no difference in total number of quarters raced, number of starts, or earnings after surgery. Treated horses had higher earnings per start, compared with untreated horses. CONCLUSIONS AND CLINICAL RELEVANCE: In the present study, racing Thoroughbreds that underwent colic surgery and successfully returned to racing had no differences in performance variables, compared with their untreated cohorts.

Diaphragmatic hernia in horses: 44 cases (1986-2006).

OBJECTIVES: To present a case series of horses diagnosed with diaphragmatic hernia, and to determine the significance of (1) historical information, examination findings, and laboratory data; and (2) exploratory laparotomy or necropsy findings on short- and long-term outcome. SETTING: University Referral Hospital. DESIGN: Retrospective study. ANIMALS: Forty-four horses/foals admitted between 1986 and 2006 with a diagnosis of diaphragmatic hernia made either at exploratory laparotomy or necropsy. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Information from the medical records included history, clinical examination findings at presentation, and findings of exploratory laparotomy or necropsy. Logistic regression or the Fisher exact test was used to determine factors associated with survival. Outcome was defined as survival to discharge (short-term survival), and long-term survival was defined as horses alive at least 1-year post surgery. Of the 44 horses, 18 died or were euthanized before surgery. Twenty-six were taken to surgery, 17 were euthanized. Nine horses recovered from anesthesia, 7 of which survived to hospital discharge. Of these, 5 were alive at long-term follow-up. Survival was significantly associated with the age of the horse (≤2 y old) at presentation, presence of normal peritoneal fluid at presentation, amount of compromised viscera at surgery (<50% small intestine), and the size (<10 cm) and location (ventral) of the diaphragmatic tear. CONCLUSION: This study confirms that size and location of the lesion do play a significant role in prognosis. And, although the prognosis for horses with diaphragmatic hernia is poor, if horses have operable lesions there is a fair prognosis for long-term survival.