BRONCHOALVEOLAR LAVAGE AND EVALUATION OF OBTAINED BAL FLUID IN HEALTHY DOGS

Jolanta Spużak, Józef Nicpoń, Krzysztof Kubiak, Marcin Jankowski

ABSTRACT

Bronchoalveolar lavage – BAL serves for taking material from bronchi and alveoli. The examination was carried out in 10 clinically healthy dogs, of different breed, size and sex aged from 1 to 16 years of age. Bronchoalveolar lavage was conducted during bronchoscopy. On the basis of the cytological examination it was found that alveolar macrophages prevailed – from 64% to 92% (on average 77.1 ą 9.42 %). Apart from them, lymphocytes occurred – from 2% to 28% (on average 16.4 ą 8.8 %), neutrophiles – from 0% to 8% (on average 5.3 ą 2.24%) and eosinophils – from 0% to 4% (on average 1.2 ą 1.33%). In the microbiological examination of bronchoalveolar fluid, the occurrence of bacteria or mycetes was not found.

Key words: dog, bronchoscopy, bronchoalveolar lavage..

INTRODUCTION

Bronchoalveolar lavage (BAL) serves for collecting BAL fluid from bronchi and alveoli and enables to conduct their analysis, among others: cytological, microbiological, biochemical and immunological [7, 14, 15].

BAL is performed both in human and veterinary medicine. In veterinary medicine, bronchoalveolar lavage has been described with regard to dogs, cats, horses, cattle and pigs. It was conducted in healthy animals as well as in ones with respiratory system diseases [1, 2, 3, 5, 13, 18, 21, 22].

In case of dogs, BAL can be conducted: during bronchoscopy, directly through the biopsy channel of the endoscope or by means of cannula [1, 3, 6, 11, 19], “blindly” – with a catheter introduced through the endotracheal tube (when a physician has no endoscope) [1, 19] or with a catheter inserted directly to the larynx or trachea, through the wall of these organs after previous local anesthesia (in cases when the patient’s condition does not allow applying general anesthesia) [11].

Sterile and heated up to body temperature 0.9% NaCl, usually administered twice or three times in the doses of 5 up to 25 ml, depending on the animal size, is used for bronchoalveolar lavage in dogs. From 40 up to 79% of the fluid administered into bronchoalveolar space should be recovered during a correctly performed BAL. The obtained BAL fluid is usually subject to cytological and microbiological evaluation [1, 3, 6, 12, 16, 19].

THE GOAL OF THE RESEARCH

This goal of the research was to conduct bronchoalveolar lavage during bronchoscopy as well as cytological and microbiological evaluating of the collected BAL fluid in healthy dogs.

MATERIAL AND METHODS

Bronchoalveolar lavage (BAL) was performed in 10 clinically healthy dogs, of various breed, size and sex at the age of 1 up to 16 years. The procedure was preceded by: history taking, clinical examination, hematological and biochemical blood tests as well as chest RTG. In the clinical examination, special attention was paid to respiratory and circulatory systems. The hematological test considered: leucocyte (L) count, erythrocyte (E) count, hemoglobin level (Hb), hematocrit number (Ht) as well as blood smear, while the biochemical test considered: alanine aminotransferase activity (ALT), aspartate aminotransferase activity (AST), urea and creatinine levels. The chest radiological examination was conducted in two projections: lateral and dorsoventral.

Bronchoalveolar lavage was performed during bronchoscopy (Fig. 1): in small dogs – with Super Vision bronchofiberoscope with working length of 60 cm and a diameter of 5 mm; while in medium and big dogs – with pediatric bronchofiberoscope Olympus XQ 20, with working length of 100 cm and a diameter of 9.8 mm. The examination was conducted under general anesthesia after a 24-hour fasting and a 6-hour break in fluid consumption, directly before endoscopy. Xylasine in the dose of 1 – 2 mg/kg and atropin in the dose of 0.05 mg/kg of body mass (i.m.) were used for premedication. Thiopental was administered after 10-15 minutes in the initial dose of 5 mg/kg of body mass (i.v.), and later according to its effects. 2% lignocaine was used for local anesthesia of the throat, larynx and bronchial tree mucous membranes. The shape of the elements forming the structure of the larynx, trachea and bronchi as well as the appearance of the mucosa (color, blood vessel markings, secretion presence) were evaluated during the the endoscopic examination. The tip of the fiberoscope was placed in the selected bronchus and “wedged” in order to collect BAL fluid. Then, through the biopsy channel, 2% lignocaine was administered in the amount of 1 – 2 ml and 0.9% NaCl, three times, in the amount depending on the animal size, and the following criterion was assumed: dogs with 7.6 kg up to 12.5 kg of body mass – 3 x 10 ml, from 12.6 kg up to 20 kg – 3 x 15 ml, from 20.1 kg up to 30 kg – 3 x 20 ml, over 30 kg – 3 x 25 ml. The administered fluid doses were aspired into syringes. Then, the amount and appearance of the recovered fluid were evaluated. The number of cells in 1 ľl of the BAL fluid was calculated in Thom’s chamber and their vitality was evaluated using staining with trypan blue. Part of the material (1.5 – 2 ml) was sent for microbiological test, while the remaining part was centrifuged. Microscopic specimens for cytological evaluation were prepared from the obtained sediment, fixed with Cytofix and stain ed with the following methods: May-Grünwald-Giemsa, hematoxyline and eosin as well as Hemacolor. Then, percentage cellular composition was calculated assuming the following rule: 200 cells were subject to evaluation, and macrophage as well as leucocytes were counted. Epithelia and erythrocytes were noted but not considered in the percentage composition.

RESULTS AND DISCUSSION

The results of hematological and biochemical blood tests of all 10 dogs were within the reference value limits. No pathological lesions were found during clinical or radiographic chest examination. Normal larynx, trachea as well as the inspected bronchi structure were found in the endoscopic picture. Mucous membrane of these organs was pink, moist, smooth and shiny.

The fluid recovery from bronchoalveolar lavage ranged from 60% up to 85% (with mean of 72.04 ą 8.20%) (table 1). Bronchoalveolar fluid was colorless, clear and did not contain any admixtures. The cell vitality was from 89% up to 95% (with mean of 92.2 ą 1.89%) (table 3). From 400 up to 630 cells/ľl (mean 508 ą 66.15 cells/ľl) were observed in the BAL fluid (table 2). Similar results were obtained by Vail et al. [20], who observed 434 cells/ľl on average, Hawkins et al. [9] and Rebar et al. [17] – from 400 up to 500 cells/ľl, while Sturgess [19] – approx. 500 cells/ľl. A smaller number of cells was observed by Andreasen [1] – mean of 200 ą 86 cells/ľl and Brown et al. [6] – mean of 57 cells/ľl.

It was determined, on the basis of the cytological tests, that bronchoalveolar fluid contained mainly alveaolar macrophage – from 64% up to 92% (mean 77.1 ą 9.42 %) (Fig. 2, Fig. 3). Apart from that, also lymphocytes – from 2% up to 28% (mean 16.4 ą 8.8 %), neutrophils – from 0% up to 8% (mean 5.3 ą 2.24%) as well as eosinophils – from 0% up to 4% (mean 1.2 ą 1.33%) were present (table 4). Similar results with regard to the percentage cellular composition were obtained by other authors, who observed from 70% up to 87% of alveolar macrophage, from 5% up to 13.4% of lymphocytes, from 0.6% up to 5% of neutrophils and from 3% up to 6% of eosinophils [1, 4, 16, 19, 20]. On the other hand, Brown et al. [6] and Mayer et al. [12] observed less macrophage, i.e. about 50%, and more leucocytes – from 30% up to 50%.

No micro-organisms were found in the microbiological examination of the BAL fluid in the discussed group of dogs. Similar observations were also made by other authors [8, 11]. King [10], on the other hand, found bacteria in 35% - 50% of cultures.

On the basis of the conducted tests it was determined that bronchoalveolar lavage conducted during bronchoscopy is safe for the patient, while microbiological and cytological examination of the BAL fluid supplements the evaluation of the lower respiratory tract in dogs.

REFERENCES

1. Andreasen C. B., 2003. Bronchoalveolar lavage. Vet. Clin. North. Am. Small Anim. Pract., 33, 69-88.

2. Andrews F. M., Schmeitzel L., 2000. Aktualne sposoby rozpoznawania i leczenia przewlekłej zaporowej choroby płuc u koni. [Present Ways of Diagnosis and Treatment of Chronic Obstructive Lung Disease in Horses.] Weterynaria po Dyplomie, 1, 65-71 [in Polish].

3. Baker R., Lumsden J. H., 2000. Color atlas of cytology of the dog and cat. Mosby Inc., St. Louis.

4. Baudendistel L. J., Vogler G. A., Frank P. A., 1992. Bronchoalveolar eosinophilia in random-source versus purpose-bred dogs. Lab. Anim. Sci., 42, 491-496.

5. Bednarek D., 2003. Badania nad modulacją odczynów zapalnych płuc w terapii cieląt chorych z objawami bronchopneumonii. [Research of Inflammatory Lung Reaction Modulation of Sick Calves with Bronchopneumonia Symptoms.] Rozprawa habilitacyjna, Puławy [in Polish].

6. Brown N. O., Noone K. E., Kurzman I. D., 1983. Alveolar lavage in dogs. Am. J. Vet. Res., 44, 335-337.

7. Domagała-Kulawik J., Marsan C., 1993. Opracowanie popłuczyn oskrzelowo-pęcherzykowych w pracowni patomorfologii. [Treatment of Bronchoalveolar BAL fluid in Pathomorphology Laboratory.] Sanmedia, Warszawa [in Polish].

8. Ettinger S. J., Feldman E. C., 2000. Textbook of veterinary internal medicine: diseases of the dog and cat. WB Saunders Company, Philadelphia.

9. Hawkins E. C., DeNicola D. B., 1990. Cytological analysis of tracheal wash specimens and bronchoalveolar lavage fluid in the diagnosis of mycotic infections in dogs. J. Am. Vet. Med. Assoc., 197, 79-83.

10. King L. G.: Zakażenia bakteryjne płuc u psów i kotów. [Bacterial Lung Infection in Dogs and Cats.] Magazyn Wet., 2004, 13, 4-6 [in Polish].

11. Martin M., Corcoran B., 2000. Choroby układu krążenia i oddechowego psów i kotów. [Circulatory and Respiratory System Diseases in Dogs and Cats.] SIMA WLW, Warszawa [in Polish].

12. Mayer P., Laber G., Walzl H., 1990. Bronchoalveolar Lavage in Dogs; Analysis of Proteins and Respiratory Cells. J. Vet. Med. A., 37, 392-399.

13. Padrid P. A., Feldman B. F., Funk K., Samitz E. M., Reil D., Cross C. E., 1991. Cytologic, microbiologic, and biochemical analysis of bronchoalveolar lavage fluid obtained from 24 healthy cats. Am. J. Vet. Res., 52, 1300-1307.

14. Pirożyński M., 1999. Bronchofiberoskopia. [Bronchofiberoscopy.] a – medica press, Bielsko-Biała.

15. Pirożyński M., 1993. Zastosowanie bronchofiberoskopii poszerzonej o własną modyfikację płukania oskrzelowo-pęcherzykowego w diagnostyce obwodowego cienia w płucu. [Use of Bronchofiberoscopy with Author’s Modification of Bronchoalveolar Lavage in Diagnosis of Peripheral Lung Shadow.] Rozprawa habilitacyjna, Warszawa [in Polish].

16. Rajamaki M. M., Jarvinen A. K., Saari S. A. M., Maisi P. S., 2001. Effect of repetitive bronchoalveolar lavage on cytologic findings in healthy dogs. Am. J. Vet. Res., 62, 13-16.

17. Rebar A. H., DeNicola D. B., Muggenburg B. A., 1980. Bronchopulmonary lavage cytology in the dog: normal findings. Vet. Pathol., 17, 294-304.

18. Reinhold P., Müller G., Kreutzer B., Gerischer A., Putsche R., 1992. Diagnostische Aussagefähigkeit biochemischer und zytologischer Parameter in der Lungenspülflüssigkeit gesunder und pneumoniekranker Kälber. J. Vet. Med. A., 39, 404-418.

19. Sturgess K., 2002. Kaszel przewlekły u psów. [Chronic cough in dogs.] Mat. z VI Symp. Waltham, Mikołajki, 28-29.09.2002, 23-29 [in Polish].

20. Vail D. M., Mahler P. A., Soergel S. A., 1995. Differential cell analysis and phenotypic subtyping of lymphocytes in bronchoalveolar lavage fluid from clinically normal dogs. Am. J. Vet. Res., 56, 282-285.

21. Venner M., 2003. Wypłuczyny oskrzelowo-pęcherzykowe (BAL). [Bronchoalveolar Fluid (BAL).] Mat. z Symp."Przewlekłe schorzenia układu oddechowego koni". Wrocław 14.02.2003, 18–21 [in Polish].

22. Whitney M. S., Roussel A. J., Cole D. J., 2001. Cytologia w diagnostyce chorób bydła: badanie mazi stawowej, płynu mózgowo-rdzeniowego oraz wypłuczyn z tchawicy i drzewa oskrzelowego. [Cytology in the diagnosis of Cattle Diseases: Examination of Synovial Fluid, Cerebrospinal Fluid and BAL fluid from the Larynx and Bronchial Tree.] Weterynaria po Dyplomie, 2, 67-74 [in Polish].

Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed ‘Discussions’ in each series and hyperlinked to the article.