Effects of increases in carboxyhemoglobin percent saturation and tissue hypoxia on carbon monoxide binding to skeletal and heart extravascular tissues

The major goal of this article was to quantify relationships of the carboxyhemoglobin % saturation, a calculated tissue PCO and tissue hypoxia to the binding of carbon monoxide (CO) to canine skeletal and heart ventricular muscle extravascular (EV) tissue under normal conditions and during CO poisoning scenarios. These data are relevant to CO poisoning because CO bound to EV cellular hemoproteins evoke metabolic changes that produce toxic effects. Skeletal and heart muscle EV CO contents were calculated from data obtained from biopsies performed on living anesthetized dogs reported in previous publications (4, 6). Results include normal values of EV CO contents of resting skeletal muscle and heart ventricular muscle, effects of increasing COHb% saturation and a calculated mean tissue PCO on skeletal muscle EV CO binding, and effects of tissue hypoxia evoked by arterial hypoxemia on EV CO binding in both of these tissues. This study is the first that shows that tissue hypoxia-induced CO shifts out of blood resulting in increased EV CO binding are a mechanism that causes CO toxicity. Projections of results to tissue PCO levels occurring during different severe CO toxicity scenarios predict that skeletal muscle EV CO contents could increase as much as 100 to 300 fold.

Gape Angle in Asymptomatic Dogs with Normal Occlusion

This study reports the gape angle (vertical temporomandibular joint range of motion for mouth opening) in conscious and anesthetized dogs. Mouth opening was reported as an angle in this study. Additionally, conscious and anesthetized measurements were compared to see if the state of anesthesia affected this measurement in asymptomatic patients. This prospective study evaluated 165 anesthetized dogs. Patients were placed in 1 of 2 groups: dental patients or non-dental patients. Only patients who were reported by owners to be asymptomatic for oral pain were included in the study. All dogs that met inclusion criteria had the maxillary length and interincisal distance measured. There was no difference (p = 0.590) between the mean (+/-SD) gape angle of conscious 44.0o (+/- 4.1+o) and anesthetized patients 43.9o (+/- 3.9o). No difference was seen in the gape angle between dental (44.2o) and non-dental patients (43.2o) (p = 0.183), or between conscious (43.8o) and anesthetized patients (43.7o) (p = 0.610). This study suggests that a consistent gape angle of 44o exists in dogs not exhibiting overt signs of oral pain and the gape angle is easy to measure in conscious patients and may be a useful tool during routine physical examination to identify patients with restricted range of motion. Immediate clinical application of this information can be used to monitor progress of treated patients affected by disorders that cause a decreased gape angle.

B-Mode and Contrast Enhanced Ultrasonography Features of Gastric Inflammatory and Neoplastic Diseases in Dogs

Canine gastric disorders are common in veterinary clinical practice and among these neoplasms require rapid identification and characterization. Standard ultrasound (US) is the imaging modality of choice for gastric wall assessment. The aim of this prospective study is to describe the specific B-mode and contrast enhanced US (CEUS) features of normal, inflammatory, and neoplastic gastric wall in dogs. B-mode US and CEUS of the stomach were performed in anesthetized dogs with or without gastric disorders. Gastric wall qualitative and quantitative parameters were evaluated on B-mode US and CEUS examination. A total of 41 dogs were included: 6 healthy (HEA) as the control group; 9 gastritis (INF); 8 adenocarcinoma (AC); 8 alimentary lymphoma (AL); 4 leiomyosarcoma (LEIS); 2 gastrointestinal stromal tumor (GIST); 2 leiomyoma; 1 undifferentiated sarcoma; 1 metastatic gastric hemangiosarcoma. Gastric tumors appear as a marked wall thickness with absent layers definition and possible regional lymphadenopathy (AC and AL) and steatitis (AC) while gastritis generally shows no/mild thickening and no other alterations on B-mode US. On CEUS, neoplasm shows a higher and faster wash in if compared to that of gastritis. B-mode and CEUS assessment may be useful in the evaluation of canine gastric disorders in the distinction between gastritis and gastric neoplasms, even if there are no specific features able to discriminate between the different tumor histotypes.