Effect of body position on the arterial partial pressures of oxygen and carbon dioxide in spontaneously breathing,conscious dogs in an intensive care unit

Objective – To evaluate the effect of body position on the arterial partial pressures of oxygen and carbon dioxide (PaO₂, PaCO₂), and the efficiency of pulmonary oxygen uptake as estimated by alveolar‐arterial oxygen difference (A‐a difference). Design – Prospective, randomized, crossover study. Setting – University teaching hospital, intensive care unit. Animals – Twenty‐one spontaneously breathing, conscious, canine patients with arterial catheters placed as part of their management strategy. Interventions – Patients were placed randomly into lateral or sternal recumbency. PaO₂ and PaCO₂ were measured after 15 minutes in this position. Patients were then repositioned into the opposite position and after 15 minutes the parameters were remeasured. Measurements and Main Results – Results presented as median (interquartile range). PaO₂ was significantly higher (P=0.001) when patients were positioned in sternal, 91.2 mm Hg (86.0–96.1 mm Hg), compared with lateral recumbency, 86.4 mm Hg (73.9–90.9 mm Hg). The median change was 5.4 mm Hg (1.1–17.9 mm Hg). All 7 dogs with a PaO₂<80 mm Hg in lateral recumbency had improved arterial oxygenation in sternal recumbency, median increase 17.4 mm Hg with a range of 3.8–29.7 mm Hg. PaCO₂ levels when patients were in sternal recumbency, 30.5 mm Hg (27.3–32.7 mm Hg) were not significantly different from those in lateral recumbency, 32.2 mm Hg (28.3–36.0 mm Hg) (P=0.07). The median change was ?1.9 mm Hg (?3.6–0.77 mm Hg). A‐a differences were significantly lower (P=0.005) when patients were positioned in sternal recumbency, 21.7 mm Hg (17.3–27.7 mm Hg), compared with lateral recumbency, 24.6 mm Hg (20.4–36.3 mm Hg). The median change was ?3.1 mm Hg (?14.6–0.9 mm Hg). Conclusions – PaO₂ was significantly higher when animals were positioned in sternal recumbency compared with lateral recumbency, predominantly due to improved pulmonary oxygen uptake (decreased A‐a difference) rather than increased alveolar ventilation (decreased PaCO₂). Patients with hypoxemia (defined as PaO₂<80 mm Hg) in lateral recumbency may benefit from being placed in sternal recumbency. Sternal recumbency is recommended to improve oxygenation in hypoxemic patients.     

Localised Mycobacterium ulcerans infection in four dogs

Localised infection caused by Mycobacterium ulcerans is described in two Kelpies, a Whippet and a Koolie domiciled on the Bellarine Peninsula, Victoria, Australia. The diagnosis was confirmed using real-time polymerase chain reaction (PCR) targeting the M. ulcerans-specific insertion sequence (IS2404) in DNA extracted from swabs of ulcerated lesions in all cases. Where available, molecular typing confirmed that three of the dogs were infected with a strain of M. ulcerans that was indistinguishable from a disease-causing strain in people and other animals in Victoria. One dog was still undergoing treatment at the time of writing, but the remaining three dogs were successfully treated with a combination of surgical debridement and medical therapy in one case, and medical therapy alone in the other two. Investigation of the home environs of three of the dogs using real-time PCR revealed low amounts of M. ulcerans DNA in various environmental samples. Mycobacterium ulcerans infection should be included in the differential diagnoses of any ulcerated skin lesions in dogs that live in or visit endemic areas of Victoria and Queensland.     

FLUOROSCOPICALLY GUIDED PERCUTANEOUS FINE-NEEDLE ASPIRATION BIOPSY OF THORACIC LESIONS IN DOGS AND CATS

Forty-eight fine-needle aspiration biopsy specimens of intrathoracic lesions were obtained with a Westcott needle by localizing needle placement using TV-monitored, image-amplified fluoroscopy and by detecting changes in tactile sensation. Thiryt-five lesions were pulmonary in origin and 13 were within the mediastinum. Most biospy specimens were obtained with the patients sedated, however, general anesthesia was used in one patient to prevent movement that could have resulted in puncture of a critical structure. The only clinical and radiographic complication from this procedure was pneumothorax, occurring in eight dogs and resulting in one death. Definitive diagnoses were made from tissue obtained from 37 of the 48 lesions sampled for a sensitivity rate of 77.1%. Fine-needle aspiration biopsy was found to be a simple, safe, and accurate diagnostic technique.     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.

     

The relationship among current management systems, production, disease and drug usage on Ontario dairy farms

The study involved 110 randomly selected dairy farms located in the Ontario, Canada counties of Bruce, Grey, Huron, Oxford, Perth, Waterloo and Wellington. Herds were classified as "intensive" and "extensive". On extensive farms, data were collected at the herd level only, while on intensive farms, data were recorded at both the individual animal and herd level. Data collection continued for approximately two and one-half years. At each visit, technicians collected production data from the most recent production recording scheme report and from the "daily log" maintained by each producer. As well as the ongoing data collection procedures, a number of supplementary data collections were made. The average 305 day milk production increased gradually during the three calendar years from 6224.6 kg in 1981 to 6443.7 kg in 1983. The average calving interval was stable at 13.2 months for all three years. The majority of cows removed from the herds were culled for beef (0.243 per animal year). The next highest removal rate was for domestic sale, followed by death, export sale and destroyed. The highest disease rate, for those conditions whose rates were based on calving, was for retained placenta (0.09 per calving), while clinical mastitis was highest for those conditions whose rates were based on animal years (0.37 per animal year). The overall crude antimicrobial dosage rate, that is, including any antimicrobial used for either prophylactic or therapeutic purposes, was 3.85 doses per animal year. The rate for therapeutic purposes only was 3.6 doses per animal year. Penicillin/streptomycin was used most often with a rate of 1.45 doses per animal year.