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Current Issue: July 2016
Survey of Intraoperative Bacterial Contamination in Dogs Undergoing Elective Orthopedic Surgery
Andrade, N., Schmiedt, C. W., Cornell, K., Radlinsky, M. G., Heidingsfelder, L., Clarke, K., Hurley, D. J. and Hinson, W. D. (2016) Veterinary Surgery, 45: 214–22
Peri-operative infections are a major cause of morbidity in orthopaedic surgery. This prospective study aimed to investigate bacterial contamination of surgeon and patient during clean orthopaedic surgeries, and to assess the impact of contamination on surgical site infection (SSI). 100 dogs undergoing stifle surgery were included in the study. Intraoperatives swabs were taken for culture from surgical foot wrap, skin at the time of incision, surgical gloves and the hands of the surgical team. Samples were also taken from the operating room environment every 5 months. Gloves were tested for perforations after each operation. 81% of procedures yielded positive bacterial cultures from at least one source, including positive cultures from hands in 58% of cases, from gloves in 46% of cases and from patient skin in 23% of cases. 18% of gloves were perforated. The most common bacteria isolated were Staphylocci. However, a correlation between intra-operative contamination and SSI was not found.
Bottom line: The authors note that although bacterial contamination in orthopaedic procedures is common, it does not appear to be clinically important.
Differentiation of Cardiac from Noncardiac Pleural Effusions in Cats using Second-Generation Quantitative and Point-of-Care NT-proBNP Measurements
Hezzell, M.J., Rush, J.E., Humm, K., Rozanski, E.A., Sargent, J., Connolly, D.J., Boswood, A. and Oyama, M.A. (2016) Journal of Veterinary Internal Medicine, 30: 536–542
The dyspnoeic cat with pleural effusion is a common presentation in practice, and assessing whether the cause is cardiac or not is important in the therapeutic decision making process. This prospective cohort study aimed to assess whether second generation ELISA tests to assess N-terminal pro-B-type natriuretic peptite (NT-proBNP) values in plasma and pleural fluid could be used to distinguish cardiac and non-cardiac causes of pleural effusion. The results were compared with a point of care (POC) test. 78 cats were included in the study, with 43 classified as having a cardiac and 35 having a non-cardiac pleural effusion. The diagnostic accuracy of the second generation NT-proBNP ELISA was good for both plasma and pleural fluid, but for the POC test, although accuracy was good for plasma, and sensitivity was very high for pleural fluid, specificity for pleural fluid was low.
Bottom line: A second generation ELISA and a POC test for NT-proBNP were both accurate in distinguishing cardiac from non-cardiac causes of pleural effusion when testing plasma, but the POC test was less accurate for testing on the effusion
Evaluation of capsule endoscopy to detect mucosal lesions associated with gastrointestinal bleeding in dogs
Davignon, D. L., Lee, A. C. Y., Johnston, A. N., Bowman, D. D. and Simpson, K. W. (2016) Journal of Small Animal Practice, 57: 148–158
Capsule endoscopy involves swallowing a small pill-sized camera in order to image the intestines. This study aimed to assess the utility of the technique to visualise mucusal abnormalities in dogs with gastrointestinal haemorrhage. 2 healthy controls and 8 dogs with gastrointestinal haemorrhage were included in the study, with weights ranging from 7.7 to 58kg. No adverse effects were noted. In 5 out of 8 patient dogs, the capsule traversed the whole intestinal tract and gave high quality images of the stomach and small intestine. In 3 patients, the capsule remained in the stomach despite giving pro-kinetic medication. 2 of these patients had gastric lesions. Other lesions identified included a healing duodenal ulcer, ileal ulceration and colonic bleeding. In 4 dogs the lesions identified were considered to be a significant source of haemorrhage.
Bottom line: Capsule endoscopy is a non-invasive investigative technique that has utility for identification of lesions causing gastro-intestinal haemorrhage.
Clinical data, clinicopathologic findings and outcome in dogs with amegakaryocytic thrombocytopenia and primary immune-mediated thrombocytopenia
Cooper, S. A., Huang, A. A., Raskin, R. E., Weng, H.-Y. and Scott-Moncrieff, J. C. (2016) Journal of Small Animal Practice, 57: 142–147
Primary immune-mediated thrombocytopenia (ITP) is seen regularly in clinical practice, and is caused by immune destruction of the platelets. Amegakaryocytic thrombocytopenia is rarer, and is due to a reduction of megakaryocytes in the bone marrow, the causes of which include infections, drug reactions and immune-mediated disease. This retrospective study aimed to compare the characteristics of primary ITP with amegakaryocytic thrombocytopenia. 7 dogs with amegakaryocytic thrombocytopenia and 34 with primary peripheral ITP were included. All dogs with amegakaryocytic thrombocytopenia were anaemic on presentation wiht a median haematocrit of 23% compared to a median haematocrit of 35% in the dogs with ITP. Dogs with amegakaryocytic thrombocytopenia had more clinical signs of bleeding than ITP dogs and 86% of them required a blood transfusion compared to 41% of the ITP dogs. 6 out of 7 amegakaryocytic thrombocytopenia cases did not survive to discharge, compared to 5 out of 34 ITP dogs.
Bottom line: Amegakaryocytic thrombocytopenia is a rare cause of thrombocytopenia but is associated with a more severe clinical course and a poorer prognosis than primary peripheral immune-mediated thrombocytopenia.
Gastrointestinal dysmotility disorders in critically ill dogs and cats
Whitehead, K., Cortes, Y. and Eirmann, L. (2016) Journal of Veterinary Emergency and Critical Care, 26: 234–253
Gastrointestinal (GI) dysmotility can occur secondary to critically illness in both humans and veterinary patients. This paper reviewed the human and veterinary literature on GI dysmotility disorders, which include oesophageal dysmotility, delayed gastric emptying, ileus and colonic dysmotility. Conditions associated with a high risk of GI dysmotility include sepsis, shock and trauma. Persistent regurgitation, vomiting and abdominal pain can lead to a presumptive diagnosis of GI dysmotility in at-risk patients. Radioscintigraphy is required for definitive diagnosis which is not easily available in small animals. Treatment involves early enteral nutrition, improving GI motility with drugs such as ranitidine, metoclopramide and cisapride, as well as optimising GI perfusion. GI dysmotility is associated with an increased risk of mortality, and prophylactic therapy in high risk patients is recommended, although there is no evidence on timing, which treatment or for how long.
Bottom line: Gastrointestinal dysmotility is a signficant cause of mortality in critically ill patients.
Alfaxalone for total intravenous anaesthesia in bitches undergoing elective caesarean section and its effects on puppies: a randomized clinical trial
Conde Ruiz, C., Del Carro, A. P., Rosset, E., Guyot, E., Maroiller, L., Buff, S. and Portier, K. (2016) Veterinary Anaesthesia and Analgesia, 43: 281–290
Alfaxalone is an anaesthetic agent that is recommended for use in high-risk patients because of its minimal effects on cardiac output. This prospective, randomised and blinded study aimed to assess the use of alfaxalone as a constant rate infusion (CRI) to provide total intravenous anaesthesia in bitches undergoing elective caesarean section. 22 bitches with 94 puppies were included in the study, and the bitches were randomised to receive either alfaxalone CRI or 2% isoflurane for maintenance of anaesthesia. All dogs were induced with alfaxalone. Mechanical ventilation was performed. Further alfaxalone was given if the depth of anaesthesia was inadequate. Various physiological variables for the bitch were recorded, and modified Apgar scores for the puppies were also evaluated. The dose of alfaxalone required for rescue was higher, the bitch’s recovery times were longer and the Apgar score was lower in the alfaxalone CRI group compared to the isoflurane group. However, there was no significant difference in survival time.
Bottom line: Alfaxalone CRI can be used for elective caesarean sections, but bitches recovered more slowly and puppies had poorer Apgar scores with this method of anaesthesia compared to isoflurane maintenance.
Evaluation of adjuvant carboplatin chemotherapy in the management of surgically excised anal sac apocrine gland adenocarcinoma in dogs
Wouda, R. M., Borrego, J., Keuler, N. S. and Stein, T. (2016) Veterinary and Comparative Oncology, 14: 67–80
Anal sac apocrine gland adenocarcinoma (ASAGAC) can cause problems due to local disease, metastasis, particularly to the sublumbar lymph nodes, as well as paraneoplastic effects (hypercalcaemia). Surgery is the mainstay of treatment, but this may be insufficient to control the disease. However, the role of adjuvant chemotherapy is not known. This retrospective study aimed to assess the use of carboplatin in the post-operative management of ASAGAC. 74 dogs were included in the study, 44 of which received carboplatin. Median survival time was 703 days and median time to progression was 384 days. There was no significant difference between these figures between dogs that received carboplatin and those that didn’t. However, treatment of disease progression, which included chemotherapy and other treatments, did significantly prolong survival. The treatment was well-tolerated.
Bottom line: The authors of this study believe that carboplatin may have a role in the management of ASAGAC
Prior antibacterial drug exposure in dogs with meticillin-resistant Staphylococcus pseudintermedius (MRSP) pyoderma
Hensel, N., Zabel, S. and Hensel, P. (2016) Veterinary Dermatology, 27: 72–e20
Antibiotic resistance is a growing crisis in human healthcare, and an increasing problem in veterinary medicine. This retrospective study aimed to identify factors associated with prior antibacterial drug exposure and pyoderma caused by meticillin-resistant Staphyloccus pseudintermedius (MRSP). 53 dogs with pyoderma associated with MRSP and 45 dogs with pyoderma associated with meticillin-sensitive Staphylococcus pseudintermedius (MSSP) were included in the study. 98% of MRSP cases and 93% of MSSP cases had had at least one course of antibiotics prior to diagnosis. However, the total number of antibiotic prescriptions and the variety of antibacterial classes used was higher in the MRSP cases than the MSSP cases. MRSP cases were more likely to have received beta-lactam drugs previously. Concurrent immunomodulatory therapy also increased the risk for acquisition of MRSP.
Bottom line: This study identifies risk factors for development of antibiotic resistance in cases of pyoderma.
Factors associated with outcome in 94 hospitalised foals diagnosed with neonatal encephalopathy
Lyle-Dugas J, Giguere S, Mallicote M.F, Mackay R.J and Sanchez L.C Equine Veterinary Journal
This retrospective cross-sectional study aimed to determine the factors involved in outcome of foals hospitalised for neonatal encephalopathy (aka neonatal maladjustment syndrome and dummy foals). The clinical records of 94 foals (less than 14 days old at admission) were included in the study. Clinical information was subjected to statistical analysis, including signalment, vital signs at admission, clinical signs throughout hospitalisation including signs of neurological dysfunction, laboratory variables and the duration of clinical events. The diagnosis of neonatal encephalopathy was made on a clinical basis.
Of the 94 foals, 75 (79.8%) survived to discharge from the hospital. The most commonly recorded clinical signs were abnormal udder seeking, abnormal suckling, inability to stand, abnormal gastrointestinal motility, abnormal consciousness and seizures. In 14 foals, neonatal encephalopathy was the sole diagnosis. In the others, concurrent conditions reported were sepsis, pneumonia, prematurity/dysmaturity, patent urachus, limb deformity, colic and uroperitoneum.
Of the 19 non-survivors, 4 died and 15 were euthanased. Post-mortem reports were available for 17 of which 11 had severe pneumonia, disseminated sepsis or sepsis-related complications. Microscopic examination of brain sections were available in 11 cases and 10 showed neuronal necrosis or degeneration consistent with ischaemia. Factors which were significantly associated with non-survival in the multivariable logistic regression model were high total calcium concentration, low alkaline phosphatase activity, an increased number of co-morbidities, recumbency and the requirement for vasopressor therapy.
Bottom line: The prognosis for foals with neonatal encephalopathy in this study was good. No single therapy was shown to improve survival. High calcium and low alkaline phosphatase concentrations found in non-survivors. Recumbency, multiple co- morbidities and use of vasopressors to treat hypotension are significantly associated with non- survival.
Double plate fixation for the management of proximal interphalangeal joint instability in 30 horses (1987–2015)
McCormick J.D, Watkins J.P Equine Veterinary Journal
This retrospective case series evaluated 30 cases (13 forelimbs and 18 hindlimbs) of double plate fixation in treating axial instability of the proximal interphalangeal joint. Trauma sustained during paddock turnout, cattle work and arena work were the most common causes of injury. One case developed gradual plantar luxation following intra-articular injection with alcohol to promote ankylosis. Pastern instability had been confirmed radiographically in each case. Prior to surgery, the affected limb was stabilised in a bandage cast with a dorsal splint. Fracture repair was carried out 1-28 days following injury. The delay before surgery did not negatively affect outcome.
The aim was to reconstruct the proximal articular surface and engage the palmar/plantar eminences to re-establish tensile strength. Two dynamic compression plates or locking compression plates were applied to the dorsomedial and dorsolateral aspects of the proximal and middle phalanges. Abaxial plates with a single lag screw engaged the proximal aspect of the middle phalanx. A half-limb cast was left on until 2-3 weeks post-operatively. The cast was then replaced, or a bandage cast used and bandaging was continued for 3 weeks following cast removal. Horses were kept on box rest for 2 months prior to 2 months of in-hand walking. If no complications were apparent at this point horses were reintroduced to paddock turnout for 2 months before returning to an exercise regime. Following this repair 29/30 (97%) of horses were discharged (compared to 67- 70% with other methods in previous reports); 6 returned to their intended use, 9 horses were able to be ridden in less demanding activity, 7 horses were sound for pasture and/or breeding, 3 were subjected to euthanasia and 5 horses were unavailable for follow up.
Bottom line: Use of a double fixation technique for injuries involving axial pastern instability results in a high survival rate and allows some horses to return to work at a similar or reduced level.