Kirsten Verryken

Effects of a constant rate infusion of detomidine on cardiovascular function, isoflurane requirements and recovery quality in horses

OBJECTIVE To examine the influence of a detomidine constant rate infusion (CRI) on cardiovascular function, isoflurane requirements and recovery quality in horses undergoing elective surgery. STUDY DESIGN Prospective, randomized, blinded, clinical trial. ANIMALS Twenty adult healthy horses. METHODS After sedation (detomidine, 10 μg kg(-1) intravenously [IV]) and induction of anaesthesia (midazolam 0.06 mg kg(-1) , ketamine 2.2 mg kg(-1) IV), anaesthesia was maintained with isoflurane in oxygen/air (inspiratory oxygen fraction 55%). When indicated, the lungs were mechanically ventilated. Dobutamine was administered when MAP<70 mmHg. The horses were randomly allocated to one of two groups and throughout anaesthesia, received either a detomidine (5 μg kg(-1)  hour(-1) ) (D) or saline (S) CRI, with the anaesthetist unaware of the treatment. Monitoring included end-tidal isoflurane concentration, arterial pH, PaCO(2) , PaO(2) , dobutamine administration rate, heart rate (HR), arterial pressure, cardiac index (CI), systemic vascular resistance (SVR), stroke index and oxygen delivery index (ḊO(2) I). For recovery from anaesthesia, all horses received 2.5 μg kg(-1) detomidine IV. Recovery quality and duration were recorded in each horse. For statistical analysis, anova, Pearson chi-square and Wilcoxon rank sum tests were used as relevant. RESULTS Heart rate (p=0.0176) and ḊO(2) I (p= 0.0084) were lower and SVR higher (p=0.0126) in group D, compared to group S. Heart rate (p=0.0011) and pH (p=0.0187) increased over time. Significant differences in isoflurane requirements were not detected. Recovery quality and duration were comparable between treatments. CONCLUSIONS AND CLINICAL RELEVANCE A detomidine CRI produced cardiovascular effects typical for α(2) -agonists, without affecting isoflurane requirements, recovery duration or recovery quality.

Equine multisystemic eosinophilic epitheliotropic disease: A case report and review of literature

CASE HISTORY: A 2-year-old Standardbred gelding presented with a history of fever over 1 week, anorexia and skin lesions on all four legs. The lesions were associated with severe pruritus and oedema, and there was no response to therapy. CLINICAL FINDINGS: The horse was in poor body condition, was lethargic and severely pruritic. Skin lesions consisted of diffuse alopecia and crusting of the distal extremities. Initially it was slightly febrile, but subsequently its temperature increased up to 40°C. Ten days after admission it developed profuse watery diarrhoea and the skin lesions progressed. Skin biopsies revealed superficial and deep perivascular dermatitis with lymphoplasmacytic and eosinophilic predominance. Based on the poor prognosis the horse was subject to euthanasia. PATHOLOGICAL FINDINGS: The most notable lesions included ulcerative gastritis, typhlitis and colitis with prominent oedema of the intestines, marked subcutaneous oedema and severe thickening of the large bile ducts. Histopathology showed marked eosinophilic and lymphoplasmacytic infiltration of various tissues including the skin, gastrointestinal tract, mesenteric lymph nodes, large bile ducts, pancreatic duct and kidney. Immunohistochemistry revealed a clear predominance of CD3-positive cells in the lymphocytic infiltrations. DIAGNOSIS: Based on the clinical findings and histopathology a diagnosis of multisystemic eosinophilic epitheliotropic disease (MEED) was made. CLINICAL RELEVANCE: Multisystemic eosinophilic epitheliotropic disease is rare in horses, and usually chronic. In the current case the horse showed an apparently acute onset with high fever and rapid clinical deterioration. A diagnosis of MEED should be considered in horses presenting with weight loss and skin lesions with or without fever. A final diagnosis is based on histological results of biopsy specimens from affected organs.

Motor evoked potentials in standing and recumbent calves induced by magnetic stimulation at the foramen magnum

The aims of this study were to determine reference values for magnetic motor evoked potentials (mMEPs) in calves and the influence of position during examination (standing or lateral recumbency). Reference values were determined using 41 healthy Holstein Friesian bull calves aged 1-10 months; standing and lateral recumbency were examined in 11 calves. Maximal magnetic stimulation was performed at the level of the foramen magnum with a magnetic field of 4 T at the coil surface. In standing position, distinct, reproducible mMEPs were obtained in all calves. Onset latency (LAT) (mean ± standard deviation) was significantly shorter in the thoracic limbs (34.4 ± 3.1 ms) than in the pelvic limbs (44.6 ± 3.0 ms). Amplitude (AMPL) was significantly higher in the thoracic limbs (3.7 ± 1.7 mV) than in the pelvic limbs (3.3 ± 1.7 mV) and significantly increased with body length. Age, body weight, height at the withers and rectal temperature had no significant association with LAT or AMPL, and no differences between left and right were noted. In the lateral position, only 64% of the calves showed responses in the four limbs; in these calves, LAT (29.7 ± 4.7 ms) and AMPL (3.0 ± 1.8 mV) in the thoracic limbs were significantly different from AMPL (47.0 ± 7.4 ms) and LAT (2.1 ± 2.1 mV) in the pelvic limbs. In conclusion, mMEPs in limb muscles can be evoked in calves by stimulation at the level of the foramen magnum. mMEPs are more difficult to obtain in lateral recumbency than in standing calves.