The use of electrical impedance tomography (EIT) to evaluate pulse rate in anaesthetised horses.

Electrical impedance tomography (EIT) provides clinically useful lung images; however, it would be an advantage to extract additional cardiovascular information from the data. The aim of this study was to evaluate if cardiac-related changes measured by EIT can be used to measure pulse rate (PR) under physiological as well as high and low blood pressure states in anaesthetised horses. Electrical impedance tomography data and PR from seven horses anaesthetised in dorsal recumbency were recorded over 1 min during mechanical ventilation and 1 min of apnoea. Data were collected at four measurement time points; before and during intravenous administration of nitroprusside and phenylephrine, respectively. Nine pixels, estimated to represent the heart, were chosen from the EIT image. A novel algorithm detected peaks of impedance change for these pixels over 10 s intervals. Concurrent PR measured using an invasive blood pressure trace, was recorded every 10 s. EIT- and pulse-rate data were compared using Bland-Altman assessment for multiple measurements on each horse. Overall, 288 paired datasets from six of seven horses were available for analysis. There was excellent agreement for baseline measurements, as well as during hypertension and hypotension, with a bias of -0.26 and lower and upper limit of agreement at -2.22 (95% confidence intervals [CI], -2.89 to -1.86) and 1.69 (95% CI, 1.34-2.36) beats per min, respectively. EIT can be used to evaluate PR using cardiac-related impedance changes. More work is required to determine bias that might occur in anaesthetised horses in other recumbencies or clinical situations.

Surgical management of refractory nasal aspergillosis using iodine cadexomer dressings in three dogs.

BACKGROUND: This case series describes surgical management of nasal aspergillosis refractory to conventional medical management or with evidence of cribriform plate osteolysis in three dogs. METHODS: All dogs had surgical debridement of mucosa, nasal turbinates and necrotic debris via dorsal sinusotomy/rhinotomy. Sinuses were packed with iodine cadexomer-impregnated bandages for several weeks and affixed with tie-over bandages. Bandage changes were performed under sedation in 2/3 cases. Once mature granulation tissue covered all exposed bone, the tie-over bandages were removed and the sinusotomy/rhinotomy closed by apposing the skin edges. CONCLUSION: This technique was well tolerated, effective and afforded a cure in all three patients. It should be considered in cases of cribriform lysis or lack of clinical response to conventional medical management.

Prevalence of bacteriuria in dogs without clinical signs of urinary tract infection presenting for elective surgical procedures.

OBJECTIVES: To determine the frequency of bacteriuria in dogs presenting for elective surgery, to compare the frequency of bacteriuria in dogs presenting for orthopaedic (non-neurological) procedures to that of dogs presenting for soft tissue procedures and to measure the agreement of microscopic visualisation of bacteria in urine sediment with the occurrence of bacterial growth on culture. METHODS: Prospective cohort study of 140 client-owned dogs. Urine was collected via prepubic cystocentesis prior to or immediately after induction of anaesthesia. Urine was submitted for quantitative bacteriological culture and urinalysis. The dogs' age, sex, weight and breed were recorded, as well as the surgical procedure performed. RESULTS: In total, 80 orthopaedic and 60 soft tissue surgical cases were included in the study; 3 dogs (2.1%) returned bacterial growth on culture (positive urine culture) and 19 (13.6%) recorded urine sediment with pyuria and/or bacteriuria on urinalysis (positive urinalysis). All dogs with positive urine culture were female and two of them underwent orthopaedic procedures. Each bitch had growth of Escherichia coli >10(5) CFU/mL. The agreement between positive urinalysis and positive urine culture was poor (κ = 0.15). CONCLUSIONS: The prevalence of bacteriuria in dogs without clinical signs of urinary tract infection in this population was low (2.1%). An at-risk population could not be identified because of the small number of positive outcomes. A positive urinalysis showed poor agreement with urine culture results and therefore the decision to treat without performing a urine culture is not advised.

Transdermal methimazole treatment in cats with hyperthyroidism.

The objectives of this study were to assess serum thyroxine concentrations and clinical response in hyperthyroid cats to treatment with transdermal methimazole, and to determine if further investigation is indicated. Clinical and laboratory data from 13 cats with hyperthyroidism were retrospectively evaluated. Methimazole (Tapazole, Eli Lilly) was formulated in a pleuronic lecithin organogel (PLO)-based vehicle and was applied to the inner pinna of the ear at a dosage ranging from 2.5mg/cat q 24h to 10.0mg/cat q 12h. During the treatment period, cats were re-evaluated at a mean of 4.3 weeks (recheck-1), and again at a mean of 5.4 months (recheck-2). Clinical improvement was observed, and significant decreases in thyroxine concentrations were measured at recheck-1 (mean: 39.57nmol/L, SEM: 14.4, SD: 41.2) and recheck-2 (mean: 36.71nmol/L, SEM: 13.9, SD: 45.56) compared to pretreatment concentrations (mean: 97.5nmol/L, SEM: 11.42, SD: 39.5). No adverse effects were reported.

Plasma and bronchoalveolar fluid concentrations of nitric oxide and localization of nitric oxide synthesis in the lungs of horses with summer pasture-associated obstructive pulmonary disease.

OBJECTIVE: To determine concentrations of nitric oxide (NO) in plasma and bronchoalveolar lavage fluid (BALF) and localize nitric oxide synthesis in the lungs of horses with summer pasture-associated obstructive pulmonary disease (SPAOPD). ANIMALS: 7 adult horses with SPAOPD and 6 clinically normal adult horses. PROCEDURE: Severity of SPAOPD was determined by use of clinical scores, change in intrapleural pressure (APpl) during tidal breathing, cytologic analysis of BALF, and histologic evaluation of lung specimens obtained during necropsy. Nitric oxide concentrations in plasma, BALF and epithelial lining fluid (ELF) were determined by use of a chemiluminescent method. Inducible nitric oxide synthase (iNOS) and nitrotyrosine (NT) were localized in formalin-fixed lung specimens by use of immunohistochemical staining, and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) activity was localized in cryopreserved specimens by use of histochemical staining. RESULTS: Plasma concentration of NO in affected horses was slightly but not significantly greater than concentration in nonaffected horses. Nitric oxide concentrations in BALF or ELF did not differ between groups. Immunoreactivity of iNOS in bronchial epithelial cells of 3 of 5 lung lobes was greater in horses with SPAOPD, compared with nonaffected horses. However, staining for NT and NADPHd activity did not differ between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Expression of iNOS was greater in bronchial epithelial cells of horses with SPAOPD, compared with nonaffected horses, suggesting that NO may play a role in amplifying the inflammatory process in the airways of horses with this disease.

Management of the patient with generalized peritonitis.

Peritonitis is a serious disease requiring aggressive therapy in the hope of effecting a cure. Stabilization of the patient's condition is important; immediate fluid therapy and systemic antibiotics are essential. Surgery is indicated, not only to locate and correct the causative lesion, but to mechanically cleanse the peritoneal cavity by debridement and copious irrigation. Establishment of drainage is also necessary. The drainage method chosen is dictated by the source and the extent of peritoneal contamination, the patient's condition, and the experience of the surgeon.

Pathophysiology and pathogenesis of generalized peritonitis.

Peritonitis is a complex disease state that results in many pathophysiologic alterations that affect multiple organs. The clinician must possess a thorough understanding of the pathophysiology and pathogenesis of the disease so that effective treatment can be instituted. Treatment should be directed at eliminating the cause of peritonitis and preventing or reversing the resulting pathophysiologic alterations.