Twenty years later: a single-centre, repeat retrospective analysis of equine perioperative mortality and investigation of recovery quality.

OBJECTIVES: To determine the mortality rates associated with equine anaesthesia for elective and emergency (colic and non-colic) cases in one equine, university teaching hospital and to investigate the effect of several horse- and anaesthetic-related variables on anaesthetic recovery quality. STUDY DESIGN: Retrospective data analysis. ANIMALS OR ANIMAL POPULATION: In total, 1416 horses undergoing anaesthesia between May 2010 and December 2013. METHODS: Patient information and details of the anaesthetic, recovery period and immediate complications were extracted from an archiving database. Statistical evaluation of factors affecting mortality included chi-squared tests and binary logistic regression. Factors affecting recovery quality were investigated using univariable and multivariable ordinal logistic regression. Statistical significance was set at p < 0.05. RESULTS: Anaesthesia/recovery-related mortality was 1.1% for all cases, 0.9% for elective cases, 1.6% for colics and 0% for non-colic emergencies. Fractures and dislocations accounted for the majority (71.4%) of deaths. No intra-operative deaths occurred during the study period. Risk factors for mortality included increasing age and American Society of Anesthesiologist's (ASA) status but these and other factors were confounded by 'colic'. Non-fatal complications in the immediate recovery period included postanaesthetic myopathy/neuropathy and postanaesthetic respiratory obstruction. Recovery quality was associated with body mass (p = 0.016), ASA status 3 and 4 (p = 0.020 and 0.002, respectively), duration of anaesthesia (p < 0.001) and out-of-hours anaesthesia (p = 0.013). Although recovery quality was also influenced by age and breed-type, these factors were removed from the final model as age was highly associated with both ASA status (p < 0.001) and colic surgery (p < 0.001), and breed-type was a determinant of body mass. CONCLUSION AND CLINICAL RELEVANCE: Anaesthetic/recovery-associated mortality was comparable to previously reported figures except intra-operative deaths were not reported. Fractures remained responsible for the largest proportion of recovery-associated deaths. Improvements to the recovery process that can reduce fracture occurrence are still required.

Comparison of a chlorambucil-prednisolone combination with an azathioprine-prednisolone combination for treatment of chronic enteropathy with concurrent protein-losing enteropathy in dogs: 27 cases (2007-2010).

OBJECTIVE: To compare treatment protocols for chronic enteropathy and concurrent protein-losing enteropathy that used prednisolone in conjunction with either azathioprine or chlorambucil in dogs. DESIGN: Retrospective case series. ANIMALS: 27 dogs. PROCEDURES: All dogs had hypoalbuminemia (serum albumin concentration, < 18.0 g/L) and chronic enteropathy as diagnosed via complete gastrointestinal tract investigations including intestinal biopsy. Dogs received either an azathioprine-prednisolone combination (group A; n = 13) or a chlorambucil-prednisolone combination (group C; 14). Response to treatment was assessed by evaluation of body weight gain, serum albumin concentration, and duration of primary treatment. RESULTS: No significant pretreatment differences were detected between groups for any baseline variable (signalment and weight), clinicopathologic variable (albumin, cobalamin, and folate concentrations), or histopathologic findings. After treatment, serum albumin concentration and weight gain were significantly greater in group C. Median survival time for group A dogs was 30 days (95% confidence interval, 15 to 45 days) and was not reached for group C dogs. Duration of primary treatment was positively associated with the histopathologic presence of mild lacteal dilatation and use of a chlorambucil-prednisolone combination. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that a chlorambucil-prednisolone protocol is more efficacious for treatment of chronic enteropathy and concurrent protein-losing enteropathy, compared with an azathioprine-prednisolone combination. Given these findings, a prospective randomized clinical trial is warranted.

Study to assess in vitro antimicrobial activity of nine ear cleaners against 50 Malassezia pachydermatis isolates.

BACKGROUND: Ear cleaning is an important part of the successful therapy of otitis externa. HYPOTHESIS/OBJECTIVES: To evaluate the in vitro activity of nine commercially available ear cleaners (Cerumaural(®), CleanAural Dog(®), Epi-Otic(®), MalAcetic Aural(®), Otoclean(®), Otodine(®), Sancerum(®), Surosolve(®) and TrizUltra™ + Keto) against 50 Malassezia pachydermatis isolates from clinical cases of canine otitis externa. To the authors' knowledge, this is the first study to analyse the in vitro susceptibility of a large number of M. pachydermatis isolates to a variety of ear cleaner products. ANIMALS: Forty-nine hospital population dogs diagnosed with otitis externa with Malassezia spp. present on cytological examination of ear swabs and culture. METHODS: The antimicrobial activity of nine ear cleaners was tested against 50 M. pachydermatis isolates from 49 clinical cases of canine otitis externa using an in vitro agar diffusion test. RESULTS: There were statistically significant differences in activity between ear cleaners, with five showing excellent in vitro anti-Malassezia activity (CleanAural Dog(®), Epi-Otic(®), MalAcetic Aural(®), Sancerum(®) and TrizUltra™ + Keto), two moderate activity (Otodine(®) and Surosolve(®)), one variable activity (Otoclean(®)) and one no activity (Cerumaural(®)). There was a significant overall difference in susceptibility between M. pachydermatis isolates tested (P < 0.001). CONCLUSIONS AND CLINICAL IMPORTANCE: Ear cleaners with activity against Malassezia may help to reduce the unnecessary use of antibiotic-containing polypharmaceutical ear medications. This study shows that the use of a large number of isolates may provide a more accurate account of the in vitro activity of a product.

Acid-base and electrolyte balance following administration of three crystalloid solutions in dogs undergoing elective orthopaedic surgery.

OBJECTIVE: To compare acid-base balance and incidence of hyperchloraemic metabolic acidosis following administration of three crystalloid solutions to dogs undergoing anaesthesia for orthopaedic surgery. STUDY DESIGN: Prospective, randomised, clinical study. ANIMALS: Sixty dogs. METHODS: During a non-standardised anaesthetic, 0.9% saline (S), Hartmann's solution (H) or a polyionic glucose-free maintenance solution (M) was administered IV at 10 mL kg(-1)  hour(-1) . Venous blood pH, PCO2 , PCV, total protein, urea, sodium, potassium and chloride concentrations were measured at induction of anaesthesia (T0) and after 2 hours of fluid therapy (T2). Base excess (BE), bicarbonate, corrected chloride concentration (corrCl), osmolality, change in plasma volume (PV) and strong ion gap (SIG) were calculated. Changes in variables within groups (1-sample Student's t-test/Wilcoxon signed rank test) and between groups (1-way anova/Kruskal-Wallis) were assessed. Data are presented as median (interquartile range). Significance was set at p < 0.05. RESULTS: No significant differences existed between groups for pH, PCO2 , PCV, total protein, urea, potassium, corrCl, PV and SIG. Potassium significantly increased in all groups. Significant differences existed between groups S and M for BE, sodium, chloride, bicarbonate and osmolality, and between groups H and M for sodium and osmolality. Chloride concentration significantly changed from 116 (114-117) to 117 (116-119) mmol L(-1) in group S, 116 (115-118) to 115 (113-117) mmol L(-1) in group H and 116 (115-118) to 114 (113-118)  mmol L(-1) in group M. In groups H and M, sodium and osmolality decreased, and BE and bicarbonate concentration increased significantly. Plasma volume increased by 28 (14-44)%, 25 (5-40)% and 24 (13-33)% in groups S, H and M, respectively. CONCLUSION AND CLINICAL RELEVANCE: Hyperchloraemic metabolic acidosis did not develop after intraoperative 0.9% saline, Hartmann's solution or maintenance solution at 10 mL kg(-1)  hour(-1) for 2 hours in dogs undergoing elective orthopaedic surgery. Bicarbonate and BE increased after Hartmann's and maintenance solutions. Increases in potassium concentration were unexplained.

Parotid duct transposition in dogs: a retrospective review of 92 eyes from 1999 to 2009.

OBJECTIVE: The aim of this study was to perform a retrospective review of parotid duct transposition (PDT) in the dog to determine the rate and nature of complications, the success and failure rates and to evaluate owner satisfaction. METHODS: Medical records of 56 dogs (92 eyes) that underwent PDT and subsequent follow-up by a veterinary ophthalmologist were reviewed. Forty owners (40 dogs/66 eyes) were contacted by telephone and 37 owners (37 dogs/60 eyes) also completed a visual analog scale questionnaire. Statistical evaluation included Wilcoxon Signed Rank tests, one-way analysis of variance and Kaplan-Meier survival analysis with Wilcoxon and Log-rank tests. RESULTS: The mean follow-up was 38.7 months (range 1-109 months). The surgical success rate was 92% (85/92 eyes). Total failures (8%, 7/92 eyes) were because of severe saliva intolerance (n = 5 eyes) and PDT failure (n = 2 eyes). The complication rate was 50% (46/92 eyes) of which 61% (28/46 eyes) were managed medically and 39% (18/46 eyes) required further surgery. Ninety percent (36/40) of owners indicated that they would proceed with surgery again. Statistically significant improvements in owner perception of ocular comfort, number of daily topical treatments, ocular wetness, and postoperative vision were identified. CONCLUSIONS: This study shows that PDT is a successful procedure based on clinical findings and in terms of owner perception. It has also demonstrated that PDT improves ocular comfort and vision in medically refractive cases of keratoconjunctivitis sicca, and that a low level of on-going management is required in 33% of cases.

Sonographic pleural fluid volume estimation in cats.

The aims of this study were to evaluate whether a recently published study used to objectively monitor pleural fluid volumes in dogs could be successfully employed in cats and secondly to assess its accuracy. Eleven feline cadavers were selected. Using the trans-sternal view employed in dogs, linear measurements from the pleural surface of the midline of the sternebra at the centre of the heart to the furthest ventro-lateral point of both right and left lung edges were recorded. Isotonic saline was injected using ultrasound guidance into both right and left pleural spaces and the measurements were repeated using standard increments until 400 ml total volume was reached. The mean measurement increased in a linear relationship with the cube root of fluid volume for all cats individually. An equation was produced to predict the volume of fluid from the mean linear measurement for all cats combined: Volume=[-3.75+2.41(mean)](3)(P<0.001) but variability in the slope of the curve for individual cats limited the accuracy of the combined equation. Equations were derived to predict the constant and slope of the curve for individual cats using the thoracic measurements made, but the residual diagnostic graphs demonstrated considerable variability. As in dogs, good correlation was found between the ultrasonographic measurement and fluid volume within individual cats. An accurate equation to predict absolute pleural fluid volume was not identified. Further analysis with reference to thoracic measurements did not increase accuracy. In conclusion, this study does provide a method of estimating absolute pleural fluid volume in cats, which may be clinical useful for pleural fluid volume monitoring but this is yet to be validated in live cats.

Teat disorders predispose ewes to clinical mastitis after challenge with Mannheimia haemolytica.

In order to study the effects of sheep teat disorders on the protection of the mammary gland, we used a Mannheimia haemolytica isolate, which did not cause clinical mastitis when deposited into intact teats. In the first experiment, this was deposited into the duct of teats with orf (Group A, n=5) or papilloma (Group B, n=3). In the second, teats were chapped and then, the organism was deposited into the duct (Group C, n=7) or on the skin (Group D, n=4). Ewes with healthy teats were controls (Group E, deposition into duct, n=5; Group F, deposition on skin, n=2). The ewes in Groups A, B or C developed clinical mastitis 5 h later, whilst the ewes in Group D developed it 2 d later; no control ewe developed clinical mastitis. In ewes with teat lesions, the organism was isolated from secretion samples and the California Mastitis Test became positive 5 h after challenge; neutrophils and lymphocytes were seen in Giemsa-stained secretion films from Group A or B ewes, whilst macrophages, neutrophils and lymphocytes in films from Group C or D ewes; neutrophils were predominating in films from Group E or F ewes. Inside the teats of Group A, B, C or D ewes, folds, hyperaemia and mucosal thickness were seen; histologically, subepithelial leucocytic infiltration was seen. In Group A or B ewes, no evidence of lymphoid tissue at the teat duct-cistern border was found. In Group C or D ewes, intense erosion and ulceration of the teat skin and conspicuous lymphoid tissue at the teat duct-cistern border, were evident; lesions characteristic of haemorrhagic mastitis were in the mammary parenchyma. In control ewes, subepithelial leucocytic infiltration in the teat duct and lymphoid tissue as above, were evident. We postulate that teat lesions can be predisposing factor to mastitis, by adversely affecting defences and speeding the process of infection and making it more severe.