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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the degree of fluctuation in tracheal dimensions between forced inspiration and passive expiration in healthy dogs of various sizes.

Animals—10 client-owned dogs with no evidence of respiratory disease or tracheal collapse.

Procedures—Anesthetized dogs underwent a computed tomographic examination during forced inspiration and induced but passive expiration to assess tracheal dimensions. Tracheal height, width, and cross-sectional area were measured at inspiration and expiration, and percentage change in dimension was calculated for each variable.

Results—Measurements were acquired in 10 dogs that ranged in body weight from 3.5 to 47.8 kg. Tracheal cross-sectional area at inspiration and expiration was associated with body weight at all 3 tracheal regions. The percentage change in tracheal height and cross-sectional area was associated with body weight in the cervical but not the thoracic-inlet or thoracic regions. The tracheal cross-sectional area changed by as much as 24.2% (mean, 5.5%), 20.0% (mean, 6.0%), and 18.6% (mean, 6.0%) in the cervical, thoracic-inlet, and thoracic regions, respectively.

Conclusions and Clinical Relevance—The change in tracheal cross-sectional area from inspiration to expiration was as great as 24% in healthy dogs, and the area was associated with body weight. Respiratory fluctuations appeared to result in changes in tracheal dimension during respiration similar to those reported for humans.

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in American Journal of Veterinary Research

Abstract

Objective—To compare the use of radiography and fluoroscopy for detection and grading of tracheal collapse in dogs.

Design—Retrospective case series.

Animals—62 dogs with tracheal collapse.

Procedures—For each dog, tracheal collapse was confirmed fluoroscopically and lateral cervical and thoracic radiographic views were reviewed. A board-certified radiologist (who was unaware of the dogs' clinical history) evaluated the cervical, thoracic inlet, thoracic, carinal, and main stem bronchial regions in all fluoroscopic videos and radiographic images for evidence of collapse. Cervical, thoracic inlet, thoracic, and carinal regions in both radio-graphic and fluoroscopic studies were graded for collapse (0%, 25%, 50%, 75%, or 100% decrease in diameter).

Results—Lateral cervical and thoracic radiographic images were available for 54 dogs, and inspiratory and expiratory lateral cervical and thoracic radiographic images were available for 8 dogs. For detection of tracheal collapse, assessment of radiographic views was sensitive and had the best negative predictive value in the cervical and thoracic inlet regions. Assessment of radiographic views was most specific and had the best positive predictive value in the thoracic inlet, thoracic, carina, and main stem bronchial regions. Radiography underestimated the degree of collapse in all areas. Review of inspiratory and expiratory views improved the accuracy of radiography for tracheal collapse diagnosis only slightly.

Conclusions and Clinical Relevance—Compared with fluoroscopy, radiography underestimated the frequency and degree of tracheal collapse. However, radiography appears to be useful for screening dogs with potential tracheal collapse.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare detomidine hydrochloride and romifidine as premedicants in horses undergoing elective surgery.

Animals—100 client-owned horses.

Procedure—After administration of acepromazine (0.03 mg/kg, IV), 50 horses received detomidine hydrochloride (0.02 mg/kg of body weight, IV) and 50 received romifidine (0.1 mg/kg, IV) before induction and maintenance of anesthesia with ketamine hydrochloride (2 mg/kg) and halothane, respectively. Arterial blood pressure and blood gases, ECG, and heart and respiratory rates were recorded. Induction and recovery were timed and graded.

Results—Mean (± SD) duration of anesthesia for all horses was 104 ± 28 minutes. Significant differences in induction and recovery times or grades were not detected between groups. Mean arterial blood pressure (MABP) decreased in both groups 30 minutes after induction, compared with values at 10 minutes. From 40 to 70 minutes after induction, MABP was significantly higher in detomidine-treated horses, compared with romifidine-treated horses, although more romifidine-treated horses received dobutamine infusions. In all horses, mean respiratory rate ranged from 9 to 11 breaths/min, PaO2 from 200 to 300 mm Hg, PaCO2 from 59 to 67 mm Hg, arterial pH from 7.33 to 7.29, and heart rate from 30 to 33 beats/min, with no significant differences between groups.

Conclusions and Clinical Relevance—Detomidine and romifidine were both satisfactory premedicants. Romifidine led to more severe hypotension than detomidine, despite administration of dobutamine to more romifidine-treated horses. Both detomidine and romifidine are acceptable α2-adrenoceptor agonists for use as premedicants before general anesthesia in horses; however, detomidine may be preferable when maintenance of blood pressure is particularly important. (Am J Vet Res 2001;62:359–363)

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate clinical, clinicopathologic, and radiographic findings in dogs with aspiration pneumonia.

Design—Retrospective case series.

Animals—88 dogs with aspiration pneumonia.

Procedures—History, physical examination findings, and clinicopathologic data were obtained from medical records and analyzed for all 88 dogs. Thoracic radiographic findings for all dogs were reviewed to determine the type and location of pulmonary infiltrates.

Results—Aspiration pneumonia was evident at admission to the hospital in 65 (74%) dogs and developed during hospitalization in 23 (26%) dogs. Less than half of these affected dogs had high values for rectal temperature, heart rate, or respiratory rate; however, most (68%) affected dogs had increased, decreased, or adventitious lung sounds. Neutrophilia with a left shift was a common finding. Hypoalbuminemia was detected in 31 of 58 (53%) dogs. Hypoxemia and a high alveolar-arterial gradient in partial pressure of oxygen were detected in 22 of 28 (79%) dogs and 27 of 28 (96%) dogs, respectively. Among the 88 dogs, thoracic radiography revealed a predominantly alveolar infiltrate in 65 (74%) dogs and an interstitial pattern in 23 (26%) dogs; a single lung lobe was affected in 46 (52%) dogs, most commonly the right middle lung lobe (21/46 [46%] dogs).

Conclusions and Clinical Relevance—In dogs, aspiration pneumonia was often associated with abnormalities in pulmonary auscultation in the absence of objective changes in physical examination findings. However, neutrophilia, hypoalbuminemia, and hypoxemia were frequently detected, and radiographic evidence of infiltrates in the right middle lung lobe was common.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate the number and types of underlying disorders detected in dogs with aspiration pneumonia and determine the survival rate among affected dogs.

Design—Retrospective case series.

Animals—88 dogs with aspiration pneumonia.

Procedures—Medical records were reviewed to identify disease processes that could result in aspiration pneumonia. To assess outcome (ie, survival to discharge from the hospital or nonsurvival), dogs were grouped by the type and number of underlying disease processes. Duration of hospitalization and radiographic severity of disease were evaluated with regard to case outcome.

Results—As the cause of aspiration pneumonia, a single underlying disorder was identified in 60 of the 88 dogs; 2 or more diseases were identified in the remaining dogs. Esophageal disease (n = 35), vomiting (34), neurologic disorders (24), laryngeal disease (16), and postanesthetic aspiration (12) were identified most commonly. Overall, 68 dogs survived to discharge from the hospital (survival rate, 77%). Survival rates were comparable among dogs regardless of the underlying cause of aspiration pneumonia. Radiographic severity of disease and duration of hospitalization did not influence survival.

Conclusions and Clinical Relevance—Among these study dogs, aspiration pneumonia was associated with a high survival rate. The presence of more than 1 underlying disease associated with aspiration pneumonia did not adversely impact survival rate. Interestingly, radiographic severity of disease and duration of hospitalization were not associated with overall survival rate.

Full access
in Journal of the American Veterinary Medical Association