BRONCHIAL WASH & BRONCHO ALVEOLAR LAVAGE
CHRIS BELFORD BVSc MRCVS DVSc FACVSc
This article covers the techniques for obtaining a bronchial wash and broncho alveolar lavage from
small animals. These techniques are relatively simple and can provide more information on lower airway
Unless there is overt evidence of upper airway disease, a Bronchial Wash or a Broncho-Alveolar
Lavage (BAL) will help establish a definitive diagnosis in lower airway respiratory conditions. When an
endoscope is available BALs are superior.
(1) WITHOUT ENDOSCOPE- Bronchial Wash Technique,
Use a cuffed endotracheal tube. Intubate dog/cat as aseptically as possible under a short acting, light,
general anaesthetic and inflate the cuff. Measure the distance from the anterior tip of the endotracheal
tube to the carina. Using this as a guide , pass a urinary catheter gently via the endotracheal tube, taking
care not to use excess force and damage bronchi. Use sterile saline or lactated Ringers as the flush
solution. As a rule of thumb 0.5ml of solution per kg bodyweight divided into 2-3 flushes can be safely
used. Using an appropriately- sized syringe, flush the liquid into the lungs and recover immediately after
each flush, by sucking back on the syringe. Commonly only 10-15% of the solution is recovered. It is best
to keep the animal anaesthetised lightly enough to have a cough reflex as this helps recovery of sample
(2) WITH ENDOSCOPE- Broncho Alveolar Lavage
Pass the scope . A sterile endoscopic catheter is the threaded down the endoscope and visualised as
the endoscope occludes the selected airway. Flush fluid and recover as above, commonly 20-30% of
the volume flushed is retrieved.
SAMPLE PREPARATION AND STORAGE/TRANSPORT
Make direct smears in clinic. If you have a centrifuge , spin down and also make smears from the
sediment. Take samples for cultures before contaminating with non-sterile laboratory equipment.
Smears from samples which contain a lot of mucus are best made by the horizontal/pull apart method
and rapidly waving to help drying. Lie a slide on top of a second slide onto which a "glob" of mucus has
been pipetted, let the mucus spread out and the pull apart horizontally. Submit left-over material to the
labaratory as a liquid in EDTA.
Chris Belford is a RCVS specialist in clinical pathology. Chris has recently established Cytopath, a new
veterinary laboratory providing a quality service to vets in the UK.
Chris can be contacted; by phone; +44 (0)1352 840 888 or via the editor of Vet On-Line.
Chris welcomes enquiries from vets worldwide.
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