Bronchoalveolar lavage is a minimally invasive technique used to obtain luminal cells from terminal bronchi, bronchioles, and alveoli for investigating pulmonary disease.1 In human, canine, and equine medicine, certain aspects of BAL techniques can affect the quality of BALF samples and therefore the diagnostic and clinical use of those samples.2,3
Two common techniques for performing BAL in cats have been described.1,4–6 One involves a sterile catheter that is blindly wedged into a terminal bronchus (NB-BAL),4,5 and the other technique consists of a flexible bronchoscope wedged into a bronchus in the lung lobe of interest (B-BAL).1,6 Nonbronchoscopic BAL can be performed without a bronchoscope, which may be useful when such equipment is unavailable. However, blindly wedging the catheter in NB-BAL precludes visual examination of the airways and restricts the ability of clinicians to collect samples from multiple lung lobes or focal lesions, which may reduce the diagnostic value of the procedure for cats with focal small airway or pulmonary parenchymal disease.7 In contrast, B-BAL allows for examination of the airways, including visual examination of airway collapse, determination of the amount of mucus and erythema, and retrieval of foreign bodies.8 Samples may be collected from multiple lung lobes or focal lesions during B-BAL; however, depending on the diameter of the bronchoscope, extubation may be required, which can cause respiratory compromise and anesthetic complications.1,6,9 The purpose of the study reported here was to compare the quality of BALF samples obtained by use of NB-BAL and B-BAL techniques in healthy cats. We hypothesized that NB-BAL would be noninferior to B-BAL for procedural variables, anesthetic complications, and cytologic quality of samples.
This manuscript represents a portion of a thesis submitted by Dr. Hooi to the Department of Clinical Studies at the University of Guelph as partial fulfillment of the requirements for a Doctor of Veterinary Science Degree.
Supported by the Pet Trust Foundation at the University of Guelph.
Presented in abstract form at the 2016 American College of Veterinary Internal Medicine Forum, Denver, June 2016.
The authors thank Drs. Lynne O'Sullivan and Shari Raheb for assistance with cardiac evaluation of cats and Dr. Alex zur Linden for assistance with CT imaging of cats.
Bronchoalveolar lavage fluid
Bronchoscopic bronchoalveolar lavage
Nonbronchoscopic bronchoalveolar lavage
N-terminal pro B–type natriuretic protein
Oxygen saturation measured by pulse oximetry
Chiron Compounding Pharmacy, Guelph, ON, Canada.
Dexdomitor, Zoetis Canada Inc, Kirkland, QC, Canada.
Torbugesic, Zoetis Canada Inc, Kirkland, QC, Canada.
Fresenius Kabi Canada Ltd, Richmond Hill, ON, Canada.
Lidodan Endotracheal, Odan Laboratories, Point-Claire, QC, Canada.
Sheridan/CF endotracheal tube, Teleflex Medical Canada Inc, Markham, ON, Canada.
Kangaroo polyvinyl chloride feeding tube with radioopaque line, Covidien, Saint Laurent, QC, Canada.
Sizing catheter, Infiniti Medical, Menlo Park, Calif.
Rusch soft rubber bladder catheter, Teleflex Medical Canada Inc, Markham, ON, Canada.
Weasel Wire, Infiniti Medical, Menlo Park, Calif.
BV Endura Mobile C-arm, Philips Healthcare, Markham, ON, Canada.
Flex X, Karl Storz Endoscopy Ltd, Mississauga, ON, Canada.
Monoject 20-mL syringe with Leur-lock tip, Covidien, Mansfield, Mass.
Plastic multipurpose tubing adapter, Cook Inc, Bloomington, Ind.
Animal Health Laboratory, University of Guelph, Guelph, ON, Canada.
Universal mycoplasma detection kit (ATCC 30–1012K), ATCC, Manassas, Va.
Z2 Coulter counter, Beckman Coulter, Mississauga, ON, Canada.
Shandon Cytospin 4, Thermo Fisher Scientific Inc, Waltham, Mass.
GE Bright Speed, General Electric Healthcare, Milwaukee, Wis.
Heska Solo Step FH, Heska, Barrie, ON, Canada.
Cardiopet proBNP test–feline, IDEXX Laboratories Inc, Markham, ON, Canada.
SAS, version 9.3, SAS Institute Inc, Cary, NC.
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Description of scoring system used to assess anesthetic recovery of cats after BAL.
|1||Very calm, smooth, and no excitement; no additional sedation required; and no oxygen supplementation required > 10 min after extubation to maintain Spo2 ≥ 95%.|
|2||Mild excitement; no additional sedation required; and oxygen supplementation needed for 10 to 30 min after extubation to maintain Spo2 ≥ 95%.|
|3||Severe excitement; additional sedation required; and oxygen supplementation needed for 30 to 60 min after extubation to maintain Spo2 ≥ 95%.|
|4||Airway complication requiring reintubation; additional sedation required; cardiac arrest followed by successful resuscitation or oxygen supplementation needed for > 60 min after extubation to maintain Spo2 ≥ 95%; and cat transferred to intensive care unit.|
|5||Cardiac arrest without successful resuscitation (death or euthanasia).|
Criteria for microscopic assessment of cytocentrifuge preparations of BALF obtained from 12 cats by use of B-BAL and NB-BAL.
|(No. of leukocytes/slide)||1||10–100|
|Cell preservation||0||< 10|
|(% of well-preserved cells/slide)||1||10–25|
|Epithelial cells (No. of cells/slide)||0||Absent|
|RBCs (percentage/slide)||0||≤ 1|
|Bacteria (No. of organisms/slide)||0||Absent|
|Hemosiderophages (No. of cells/slide)||0||Absent|
|Mucus (No. of strands/slide)||0||Absent|
Scoring system was created by use of criteria described elsewhere2,10 (Adapted from Woods KS, Defarges AM, Abrams-Ogg AC, et al. Comparison between manual aspiration via polyethylene tubing and aspiration via a suction pump with a suction trap connection for performing bronchoalveolar lavage in healthy dogs. Am J Vet Res 2013;74:523–529. Reprinted with permission).