The Role of Bronchoscopy in Foreign Body Removal in Dogs and Cats: 37 Cases (2000–2008)

Background: Foreign body aspiration is a differential diagnosis for acute or chronic cough that requires medical or surgical management in animals. Hypothesis: Success of bronchoscopy in airway foreign body removal is dependent on the size of the animal, duration of clinical signs, and location of the foreign body. Animals: Thirty‐two dogs and 5 cats with airway foreign bodies identified at the UC Davis Veterinary Medical Teaching Hospital. Methods: Retrospective case study evaluating the role of duration of clinical signs and body size in successful bronchoscopic removal of foreign bodies. In addition, radiographic localization of disease was compared with bronchoscopic identification. Bronchoalveolar lavage (BAL) culture and cytologic findings are reported. Results: Bronchoscopy was successful for removal of airway foreign bodies in 76% of animals (24/28 dogs and 2/5 cats), and in dogs was independent of duration of clinical signs or body size. One‐third of thoracic radiographs lacked distinctive features of an airway foreign body, and therefore radiography was unable to predict the affected site. BAL fluid at the site of the foreign body contained more neutrophils and more often had intracellular bacteria than lavage fluid from a separate site. Conclusions and Clinical Importance: Bronchoscopy was successful in removing airway foreign bodies regardless of animal size or long duration of clinical signs. Results of this study confirm the utility of bronchoscopy with lavage in management of suspected foreign bodies, even in the absence of localizing radiographic findings.     

Bronchoscopic findings in 48 cats with spontaneous lower respiratory tract disease (2002-2009)

Background: Diagnosis of lower respiratory disease requires collection of airway samples to confirm the etiology of disease. Bronchoscopic evaluation is commonly performed in dogs but less information is available in cats. Hypothesis: The presence and number of bronchoscopic abnormalities visualized during bronchoscopic evaluation of cats with lower respiratory disease will correlate with the type of disease and total and differential cell counts in bronchoalveolar lavage (BAL) fluid. Animals: Forty‐eight cats prospectively evaluated by a single bronchoscopist. Methods: Bronchoscopy was performed during clinical evaluation of cats presenting with cough, respiratory distress, or both. Cats were evaluated for airway hyperemia, stenosis, or collapse, mucus accumulation, bronchiectasis, and epithelial irregularities. Cats were placed into groups of bronchitis/“asthma,” pneumonia, or neoplasia based on BAL findings, histopathology, and response to appropriate medical therapy. Summation of bronchial abnormalities and total and differential cell counts were compared among groups. Results: Endobronchial abnormalities were common in cats with feline bronchitis/asthma, pneumonia, and neoplasia and no differentiating features were found. Excessive mucus accumulation was common (83%), followed by stenosis of bronchial openings and nodular epithelial irregularities (56%), airway hyperemia (54%), airway collapse (48%), and bronchiectasis (27%). Total bronchoscopic score and total cell count did not differ among groups, although differential cell counts were significantly different. A weak correlation (R²= 0.16, P= .006) between age and total bronchoscopic score was noted. Conclusions and Clinical Relevance: Bronchoscopic abnormalities are common in cats with lower respiratory tract disease, and visualization of the airways provides additional nonspecific clinical information in cats.     

Cytological Analysis of Bronchoalveolar Lavage Fluid in the Diagnosis of Spontaneous Respiratory Tract Disease in Dogs: A Retrospective Study

Results of cytological analysis of bronchoalveolar lavage (BAD fluid were compared with clinical diagnoses in dogs that presented with signs of respiratory disease to referral hospitals. Of 68 dogs in which a clinical diagnosis was possible, BAL cytological findings were considered definitive for the diagnosis in 17 cases (25%), supportive of the diagnosis in 34 cases (50%), and not helpful in 17 cases (25%). Findings were most often considered supportive of or definitive for the clinical diagnosis in dogs with alveolar or bronchial radiographic patterns, or the presence of pulmonary masses. BAL results among lung lobes differed in 23 of 63 dogs (37%) with diffuse radiographic patterns. Tracheal wash cytology differed from BAL fluid cytology in 45 of 66 dogs (68%). Bronchoalveolar lavage was a clinically useful procedure for the diagnostic evaluation of dogs with signs of respiratory disease.     

Cellular composition of bronchial brushings obtained from healthy dogs and dogs with chronic cough and cytologic composition of bronchoalveolar lavage fluid obtained from dogs with chronic cough

OBJECTIVE: To determine whether bronchial brushings from dogs with chronic cough have increased numbers of goblet cells and WBCs, compared with numbers for healthy dogs, or have differing WBC populations, compared with populations in bronchoalveolar lavage (BAL) fluid obtained from dogs with chronic cough. ANIMALS: 9 healthy dogs and 10 dogs with chronic cough. PROCEDURE: Specimens were collected by use of bronchoscopy. Cellular composition was determined for brushings, and results from dogs with chronic cough were compared with those from healthy dogs. Cellular composition of brushings was compared with composition of BAL obtained from dogs with chronic cough. RESULTS: Brushings from healthy dogs contained a median of 2.9 x 10(6) epithelial cells, comprising 100% epithelial cells (96% ciliated, 3% goblet, and 1% other) and no WBCs. Brushings from dogs with chronic cough had 4.5 x 10(6) epithelial cells, comprising 93% epithelial cells (86% ciliated, 2% goblet, and 12% other). Dogs with chronic cough had significantly greater percentages of WBCs (7%) and neutrophils (6%), compared with values for healthy dogs. Five dogs with chronic cough had no neutrophilic inflammation evident in BAL, but 4 of these had evidence of neutrophilic inflammation in brushings. CONCLUSIONS AND CLINICAL RELEVANCE: Neutrophils, but not goblet cells, were increased in brushings from dogs with chronic cough. Analysis of bronchial brushings provides information about airway inflammation that differs from that found by examination of BAL in some dogs with chronic cough and is a more sensitive indicator of airway inflammation than cytologic examination of BAL in these dogs.     

Specific enzyme activities in bronchoalveolar lavage fluid as an aid to diagnosis of tracheobronchitis and bronchopneumonia in dogs

Lactate dehydrogenase (LDH), alkaline phosphatase (ALP), alanine aminotransferase and gamma-glutamyl transferase enzyme activities, and total protein (TP), calcium, inorganic phosphate, urea nitrogen (UN) and creatinine concentrations in bronchoalveolar lavage fluid were investigated for their relative importance in the diagnosis of respiratory diseases in dogs. Bronchoalveolar lavage (BAL) fluid was obtained from 26 dogs (20 with respiratory diseases and six controls) following anaesthesia with sodium pentothal. Enzyme activities and biochemical parameters were measured in BAL fluid. LDH and ALP levels were significantly increased in 12 dogs with bronchopneumonia, but not in eight dogs with tracheobronchitis. Insignificant and variable levels of TP and UN concentrations were found in both groups. It was concluded that LDH and ALP enzyme activities could be considered as pointers to pulmonary inflammation and/or damage while TP and UN measurements in BAL fluid may have a place in the identification of changes in respiratory and vascular permeability.     

Clinical findings,bronchoalveolar lavage fluid cytology and matrix metalloproteinase-2 and -9 in canine pulmonary eosinophilia

We characterized clinical and clinicopathological features, and the involvement of gelatinolytic matrix metalloproteinases (MMP-2 and -9) in canine pulmonary eosinophilia (PE). Study material consisted of 20 PE dogs and 16 healthy beagles. All dogs underwent a similar clinical examination and bronchoalveolar lavage (BAL). Analysis for cell count and differential cell count of BAL fluid (BALF), arterial blood gas analysis before and after BAL, and thoracic radiographs before BAL and after treatment were obtained. Twelve dogs were re-evaluated and six relavaged. MMP-2 and MMP-9 in BALF were analysed by zymography, Western immunoblotting and immunocytochemistry.In the PE dogs, BALF, cell count, number and percentage of eosinophils, and numbers of macrophages, lymphocytes, neutrophils, mast cells and epithelial cells were all significantly elevated. Blood eosinophilia was detected in half of the PE dogs. Three PE dogs had mild hypoxaemia. The BAL procedure had an equal effect on PE and healthy dogs' arterial blood gas values. Bronchointerstitial densities were seen in PE dogs' radiographs. Treatment of PE decreased BALF cell count, eosinophil count and percentage and diminished radiographic changes. Gelatinolytic activity was higher in PE dogs' BALF. BALF macrophages and epithelial cells were the principal sources of the MMP-9.     

Cytological and parasitological analysis of bronchoalveolar lavage fluid for the diagnosis of Angiostrongylus vasorum infection in dogs

Bronchoalveolar lavage (BAL) is a procedure that retrieves cells and other elements from the lungs for evaluation, which helps in the diagnosis of many pulmonary diseases. The aims of this work were to perform this procedure in dogs in the acute and chronic phases of an Angiostrongylus vasorum infection for cytological analysis and to evaluate the potential of this technique as a diagnostic method for this lung-heart worm. The BAL procedure was performed through the use of an endotracheal tube on seven A. vasorum infected dogs and on five non-infected dogs lined as a control group. Sixty days post-infection (dpi) active and live larvae were retrieved from the bronchoalveolar fluid (BALF) of all infected dogs. Furthermore, in one animal it was possible to retrieve larvae in its BALF before the pre-patent period. This work reports that the A. vasorum infection resulted in an increase of relative neutrophils and eosinophils counts. In contrast, there was a significant decrease in the alveolar macrophage relative count in infected animals from 60 to 330 dpi. This study shows that the BAL is an accurate technique for the diagnosis of canine angiostrongylosis. Moreover, the technique allows us to retrieve cells and other elements that line the lung surface for cytological evaluation, which provides information about inflammatory diseases, and the diagnosis and prognosis of pulmonary parasites such as A. vasorum.     

Effects of lung site and fluid volume on results of bronchoalveolar lavage fluid analysis in horses.

Bronchoalveolar lavage (BAL) fluid was analyzed in healthy horses, using different lavage fluid volumes and lung sites. The only significant difference in the cellular composition of BAL fluid between the right and left lungs was the mast cell numbers, which were significantly higher in the left lung. Total cell count ranged from 34 to 330 cells/microliter for the right lung and 43 to 330 cells/microliter for the left lung. Percentage of neutrophils ranged from 1 to 7% in the right lung and 1 to 5% in the left lung. The small-volume (50 ml) lavage had a greater percentage of neutrophils and a lesser percentage of mast cells in the large-volume (350 ml) lavage. Statistical difference in the composition of BAL fluid recovered was not detected between the 3 sequential 100-ml lavages and a single 300-ml lavage, except that macrophages were significantly higher in the 3 sequential 100-ml lavages. Values for BAL fluid analysis in healthy horses have varied considerably and this variation is from a failure to adhere to any standard technique for volume of fluid infused.     

Quantitative bacterial cultures and cytological examination of bronchoalveolar lavage specimens in dogs

Cytology and quantitative bacterial cultures of lower respiratory tract secretions are widely used in human medicine to differentiate airway infection from simple bacterial colonization. A retrospective study was conducted to determine the usefulness of quantitative aerobic cultures and Gram stain intracellular bacteria counts from bronchoalveolar lavage (BAL) specimens in dogs in diagnosing lower respiratory tract infection (LRTI) and to determine whether chronic bronchitis is associated with marked bacterial growth in dogs. The threshold determined to define clinically relevant bacterial growth was 1.7 x 10(3) colony-forming units per milliliter of BAL fluid. We used this threshold and found that diagnostic sensitivity and specificity were 86% and 100%, respectively. With a threshold for infection of >2 intracellular bacteria observed in any of 50 fields, microscopic examination of Gram stain BAL preparations had a sensitivity of 71% and a specificity of 97% in establishing LRTI. There was a high correlation between bacterial morphology on BAL Gram stain and bacterial cultures. Combining the results of intracellular bacteria counts from the BAL Gram stain with those from the quantitative cultures, the sensitivity in diagnosing LRTI was 87% and the specificity was 97%. BAL quantitative cultures as well as quantitating intracellular bacteria on Gram stain BAL cytology were revealed to be useful in identifying LRTI in dogs. Chronic bronchitis does not appear to be associated with marked bacterial growth in dogs.     

Alveolar clearance in horses with chronic obstructive pulmonary disease

OBJECTIVE: To assess sensitivity of scintigraphic alveolar clearance rate as an indicator of alveolar epithelium damage in horses. ANIMALS: 5 healthy horses (group A) and 5 with chronic obstructive pulmonary disease (COPD; group B). PROCEDURE: Horses underwent clearance rate (k [%/min]) determination. Clearance rate of group-B horses was determined after remission of the disease following 2 months at pasture (remission 1), stabling in a controlled environment (remission 2), and during crisis induced by exposure to moldy hay and straw. Methacholine challenge test was performed at each investigation period to determine nonspecific pulmonary airway hyperresponsiveness. Pulmonary function tests (PFT) also were performed, and cell populations in bronchoalveolar lavage (BAL) fluid were determined on another occasion. RESULTS: Group-B horses had significantly faster mean clearance rate during crisis (k = 4.30+/-0.95%/min), compared with that for remission 1(k = 1.98+/-0.55%/min), which did not differ from the rate in group-A horses (k = 1.95+/-0.33%/min). Despite lack of clinical signs of COPD during remission when stabled in a controlled environment, an intermediate value was found (k = 3.20+/-0.72%/min). CONCLUSIONS: This technique allowed grading of lung damage induced by COPD, whereas use of PFT and determination of BAL fluid cell populations failed to differentiate between remission 1 and remission 2. CLINICAL RELEVANCE: Determination of alveolar clearance rate by use of scintigraphy is a sensitive indicator of lung damage. A modified clearance rate was found despite the lack of clinical and functional changes.     

Comparison of results of thoracic radiography, cytologic evaluation of bronchoalveolar lavage fluid, and histologic evaluation of lung specimens in dogs with respiratory tract disease: 16 cases (1996-2000)

OBJECTIVE: To compare results of thoracic radiography, cytologic evaluation of bronchoalveolar lavage (BAL) fluid, and histologic evaluation of biopsy and necropsy specimens in dogs with respiratory tract disease and to determine whether histologic evaluation provides important diagnostic information not attainable by the other methods. DESIGN: Retrospective study. ANIMALS: 16 dogs. PROCEDURE: BAL fluid was classified as normal, neutrophilic, eosinophilic, mononuclear, mixed, neoplastic, or nondiagnostic. Radiographic abnormalities were classified as interstitial, bronchial, bronchointerstitial, or alveolar. Histologic lesions were classified as inflammatory, fibrotic, or neoplastic, and the predominant site of histologic lesions was classified as the alveoli, interstitium, or airway. RESULTS: The predominant radiographic location of lesions correlated with the histologic location in 8 dogs. Of 11 dogs with histologic evidence of inflammatory disease, 8 had inflammatory BAL fluid. Of the 2 dogs with histologic evidence of neoplasia, 1 had BAL fluid suggestive of neoplasia, and the other had BAL fluid consistent with septic purulent inflammation. Two dogs without any histologic abnormalities had mononuclear or nondiagnostic BAL fluid. Two dogs with histologic evidence of fibrosis had mononuclear or mixed inflammatory BAL fluid. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that although thoracic radiography, cytologic evaluation of BAL fluid, and histologic evaluation of lung specimens are complementary, each method has limitations in regard to how well results reflect the underlying disease process in dogs with respiratory tract disease. Lung biopsy should be considered in cases where results of radiography and cytology are nondiagnostic.     

Flexible bronchoscopy and bronchoalveolar lavage in 68 cats (2001-2006)

BACKGROUND: Bronchoscopy is an important tool for identifying an underlying etiology for respiratory disease in cats. However, the procedure is challenging, because feline airways are small and prone to bronchoconstriction. HYPOTHESIS: Bronchoscopy and bronchoalveolar lavage (BAL) are appropriate and safe diagnostic procedures in the cat. ANIMALS: Sixty-eight cats. METHODS: Flexible bronchoscopy was performed in all cats with the cats under propofol infusion with jet ventilation. The procedures were reviewed for BAL volumes instilled and recovered and for the number and type of complications with the use of 3 flexible endoscopes < 5.0-mm outer diameter. The BAL procedure was compared among scopes by using a one-way analysis of variance. Complication rates were compared by using chi-square analysis. Significance was set at P < .05. RESULTS: Clinical diagnoses included inflammatory airway disease in 46 of 68 cats, pneumonia in 10 of 68, neoplastic disease in 8 of 68, and other conditions in 4 of 68 cats. Mean lavage volumes instilled for the 3 scopes were 2.62-5.05 mL/kg (range, 0.77-9.38 mL/kg). Mean percent fluid recovered for the 3 scopes was 51-73%, (range, 0-140%). BAL cell counts were adequate for cytologic assessment (> 300 cells/microL) in 61 of 64 cats (97%), and in 107 of 120 samples (89%) collected. Complications occurred in 38% of procedures; however, these were mild in 24% of cats; 6% of cats died or were euthanized after the procedure. Complications were not associated with fluid volume instilled or recovered, and could not be related to the underlying disease process. CONCLUSIONS AND CLINICAL IMPORTANCE: Flexible bronchoscopy with BAL was well tolerated in most cats examined.     

Clinical Tolerance and Bronchoscopic Changes Associated With Transtracheal High-Frequency jet Ventilation in Dogs and Cats

Eleven awake dogs and two cats received high-frequency jet ventilation (HFJV) via a transtracheal catheter for 6 hours to evaluate their clinical tolerance to the technique. A bronchoscopic examination was performed in all animals prior to and the morning of the day after the procedure to determine the gross effects of the technique on the tracheal epithelium.
All animals tolerated the technique well, exhibiting no discomfort and only a minimal amount of coughing. Only one dog exhibited coughing on the day following the procedure. No bronchoscopic changes were noted after HFJV in one dog. In one dog and one cat, the only observed change was an increase in the prominence of the vascularity compared to that observed prior to HFJV. The remaining animals exhibited more severe tracheal changes that included: an accumulation of mucus (seven dogs, one cat), focal spots of hemorrhage (two dogs), linear stretches of epithelial denuding (two dogs), and diffuse reddening and epithelial denuding (four dogs).
High-frequency jet ventilation by a transtracheal intravenous catheter is well tolerated for short-term ventilatory support in dogs and cats, but the magnitude of the tracheal damage observed in the present report may preclude long-term ventilatory support by this tecnique.     

Results of cytologic and microbiologic analysis of bronchoalveolar lavage fluid in New Zealand White rabbits

OBJECTIVE: To determine cytologic and microbiologic findings in bronchoalveolar lavage (BAL) fluid and SpO(2) values obtained during BAL in healthy rabbits. ANIMALS: 9 rabbits. PROCEDURES: Bronchoscopic BAL of left and right caudal lobar bronchi (LB2 and RB4) was performed with 3 mL of sterile saline (0.9% NaCl) solution; SpO(2) was measured before, during, and after BAL. Percentage fluid recovered, total leukocyte counts, and differential cell counts were determined. Aerobic and anaerobic bacterial, mycoplasmal, and fungal cultures were performed from combined LB2 and RB4 samples. RESULTS: Mean +/- SD percentage fluid volumes recovered from LB2 and RB4 were 53 +/- 13% and 63 +/- 13%, respectively. Mean +/- SD total leukocyte counts from LB2 and RB4 were 422 +/- 199 cells/microL and 378 +/- 97 cells/microL, respectively. Macrophages were most frequently identified. There were no significant differences in volumes retrieved, total leukocyte counts, or differential cell percentages between LB2 and RB4. Microbial culture results were negative for 3 rabbits and positive for mixed aerobic and anaerobic bacterial growth in 6 and 2 rabbits, respectively. The SpO(2) was > or = 95% in 7 of 9 rabbits after anesthetic induction, < 95% in 5 of 6 rabbits 1 minute after BAL, and > or = 95% in 5 of 9 rabbits and > 90% in 4 of 9 rabbits 3 minutes after BAL. CONCLUSIONS AND CLINICAL RELEVANCE: Bronchoscopic BAL with 3 mL of saline solution provided adequate fluid recovery for microbiologic and cytologic examination from the caudal lung lobes. Transient low SpO(2) was detected immediately after BAL.     

Using urea dilution to standardise components of pleural and bronchoalveolar lavage fluids in the dog

AIM: To develop a technique to estimate the volume of epithelial lining fluid (ELF) obtained during bronchoalveolar lavage (BAL) and pleural lavage (PL) in the dog, using the urea dilution method. METHODS: BAL and PL fluids were obtained by saline lavage of pulmonary and pleural cavities of nine clinically healthy mixed-breed dogs immediately after euthanasia. Cell counts in the BAL and PL fluids were measured using standard techniques. The concentration of ELF in each lavage fluid was calculated from the relative concentration of urea in plasma and in each type of lavage fluid. Cell counts in ELF were then calculated. RESULTS: There were substantially higher cell counts in ELF compared to BAL or PF fluid. However, nucleated cell counts in ELF could not be predicted from cell counts in BAL or PL fluid. CONCLUSIONS AND CLINICAL RELEVANCE: These results suggest that accurate assessment of cellular or non-cellular components in lavage fluids should include a calculation of the proportion of ELF recovered, using a method such as urea dilution.     

Using urea dilution to standardise components of pleural and bronchoalveolar lavage fluids in the dog

AIM: To develop a technique to estimate the volume of epithelial lining fluid (ELF) obtained during bronchoalveolar lavage (BAL) and pleural lavage (PL) in the dog, using the urea dilution method.

METHODS: BAL and PL fluids were obtained by saline lavage of pulmonary and pleural cavities of nine clinically healthy mixed-breed dogs immediately after euthanasia. Cell counts in the BAL and PL fluids were measured using standard techniques. The concentration of ELF in each lavage fluid was calculated from the relative concentration of urea in plasma and in each type of lavage fluid. Cell counts in ELF were then calculated.

RESULTS: There were substantially higher cell counts in ELF compared to BAL or PF fluid. However, nucleated cell counts in ELF could not be predicted from cell counts in BAL or PL fluid.

CONCLUSIONS AND CLINICAL RELEVANCE: These results suggest that accurate assessment of cellular or non-cellular components in lavage fluids should include a calculation of the proportion of ELF recovered, using a method such as urea dilution.     

Bronchoalveolar lavage cytology in cynomolgus monkeys and identification of cytologic alterations following sequential saline lavage

Total and differential cell counts were determined on cytolytic specimens obtained by fiberoptic bronchoscopy and bronchoalveolar lavage (BAL) of five normal cynomolgus monkeys. Total nucleated cell counts ranged from 100 to 430 cells/microliters. Macrophages were approximately 91% of total nucleated cells, while lymphocytes were 3%, neutrophils 4%, and eosinophils 2% of the initial BAL from each monkey. Less than 1% of the cells were mast cells and ciliated or nonciliated epithelial cells. The effects of repeated saline BAL on pulmonary cell populations were evaluated. Saline lavage of individual lung lobes resulted in a marked rise in circulating blood neutrophils at 4 hr after BAL; there was a similar rise in neutrophils in lavage fluids 24 hr after the initial lavage. Differential and total cell counts of both blood and lavage fluid returned to normal if subsequent lavages were spaced at 48-hr intervals. Lymphocytes were not present in saline-lavaged lung lobes, and protein levels of lavage fluids did not rise significantly. BAL produced a transient, reversible, intra-alveolar influx of neutrophils which was preceded by mobilization of bone marrow-stored neutrophils. Neutrophilia in the lavage fluid and blood was not detectable if lavage and blood sampling procedures were done at 48-hr intervals (which did not alter Ia antigen expression among BAL cells). These observations indicate that BAL is a valid method for sampling and assessing pulmonary cellular and fluid constituents if the procedures are done at intervals of at least 48 hr.     

Differential cell counts in canine cytocentrifuged bronchoalveolar lavage fluid: a study on reliable enumeration of each cell type

Background: Bronchoalveolar lavage (BAL) allows cell recovery from the lower respiratory tract; differential cell counts of BAL fluid gives important information in the assessment of various bronchial and pulmonary diseases. To the best of our knowledge no study has investigated the relation between the number of cells counted and the reproducibility of BAL fluid differential cell counts. Objective: The purpose of this study was to investigate using statistical methods how many cells should be counted in cytocentrifuged BAL fluid preparations in order to obtain a reliable enumeration of each cell type. Methods: BAL fluid samples from dogs with suspected bronchopulmonary disease were obtained during fiberoptic bronchoscopy with a standardized protocol. Differential cell counts were performed on May–Grünwald–Giemsa‐stained cytocentrifuged preparations by 2 independent observers. Reproducibility for the enumeration of each cell type was expressed as the intraclass correlation coefficient. We considered a threshold level of ≥0.90 to be high and a threshold level of ≥0.85 to be adequate. Results: Forty BAL fluid samples were included in the study. For neutrophils, alveolar macrophages, and eosinophils high reproducibility was reached by counting 200 cells; adequate reproducibility was reached for lymphocytes and bronchial epithelial cells by counting 500 cells. Conclusions: A 500‐cell differential count is required for all types of cells to be quantified with adequate reproducibility in canine cytocentrifuged BAL fluid samples.     

Pharmacokinetics of clarithromycin and concentrations in body fluids and bronchoalveolar cells of foals

OBJECTIVE: To determine pharmacokinetics of clarithromycin and concentrations in body fluids and bronchoalveolar (BAL) cells of foals. ANIMALS: 6 healthy 2-to 3-week-old foals. PROCEDURES: In a crossover design, clarithromycin (7.5 mg/kg) was administered to each foal via IV and intragastric (IG) routes. After the initial IG administration, 5 additional doses were administered IG at 12-hour intervals. Concentrations of clarithromycin and its 14-hydroxy metabolite were measured in serum by use of high-performance liquid chromatography. A microbiologic assay was used to measure clarithromycin activity in serum, urine, peritoneal fluid, synovial fluid, CSF, pulmonary epithelial lining fluid (PELF), and BAL cells. RESULTS: After IV administration, elimination half-life (5.4 hours) and mean +/- SD body clearance (1.27 +/- 0.25 L/h/kg) and apparent volume of distribution at steady state (10.4 +/- 2.1 L/kg) were determined for clarithromycin. The metabolite was detected in all 6 foals by 1 hour after clarithromycin administration. Oral bioavailability of clarithromycin was 57.3 +/- 12.0%. Maximum serum concentration of clarithromycin after multiple IG administrations was 0.88 +/- 0.19 microg/mL. After IG administration of multiple doses, clarithromycin concentrations in peritoneal fluid, CSF, and synovial fluid were similar to or lower than concentrations in serum, whereas concentrations in urine, PELF, and BAL cells were significantly higher than concentrations in serum. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of clarithromycin at 7.5 mg/kg every 12 hours maintains concentrations in serum, PELF, and BAL cells that are higher than the minimum inhibitory concentration (0.12 microg/mL) for Rhodococcus equiisolates for the entire 12-hour dosing interval.     

Effect of an external nasal dilator strip on cytologic characteristics of bronchoalveolar lavage fluid in Thoroughbred racehorses

OBJECTIVE: To determine the effects of an external nasal dilator strip on cytologic characteristics of bronchoalveolar lavage (BAL) fluid in racing Thoroughbreds. DESIGN: Clinical trial. ANIMALS: 23 Thoroughbred racehorses in active training. PROCEDURE: Each horse raced on 2 occasions: once while wearing an external nasal dilator strip and once while not. Bronchoalveolar lavage was performed 12 to 18 hours after each race, and BAL fluid was analyzed for RBC and leukocyte counts and hemosiderin content. RESULTS: Mean +/- SEM count of RBCs in BAL fluid when horses raced without the nasal dilator strip (84.6 +/- 275 cells/microL) was not significantly different from count when they raced with it (41.7 +/- 12.2 cells/microL). Horses were grouped as having mild or severe bleeding on the basis of RBC count in BAL fluid after horses raced without the nasal dilator strip. Mean count when horses with severe bleeding raced without the nasal dilator strip (271.0 +/- 63.7 cells/microL) was significantly higher than mean count when these horses raced with the strip (93.8 +/- 376 cells/microL). Mean count of lymphocytes in BAL fluid was significantly lower after horses raced with the external nasal dilator strip. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that use of an external nasal dilator strip in Thoroughbred racehorses may decrease pulmonary bleeding, particularly in horses with severe exercise-induced pulmonary hemorrhage.