1 TRACHEAL WASHES IN DOGS AND CATS: WHY, WHAT, WHEN, AND HOW Eleanor C. Hawkins, DVM, Dipl ACVIM (SAIM) Professor, Small Animal Internal Medicine North Carolina State University Raleigh, North Carolina, USA 1. Introduction: Tracheal Wash vs BAL 2. Focus on Tracheal Wash TRACHEAL WASH vs BAL
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TRACHEAL WASH vs BALRaleigh, North Carolina, USA 1. Introduction: Tracheal Wash vs BAL 2. Focus on Tracheal Wash TRACHEAL WASH vs BAL ... MAKE SLIDES OF MUCUS •May find trapped organisms!
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TRACHEAL WASHES IN DOGS AND CATS: WHY, WHAT, WHEN, AND HOW
Eleanor C. Hawkins, DVM, Dipl ACVIM (SAIM)Professor, Small Animal Internal Medicine
North Carolina State UniversityRaleigh, North Carolina, USA
1. Introduction: Tracheal Wash vs BAL2. Focus on Tracheal Wash
TRACHEAL WASH vs BAL
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TRACHEAL WASH vs BAL
• Exudate from airways and alveoli to the trachea via mucociliaryclearance +/‐ cough.
• Good representation for most diffuse bronchial disease and aspiration or bronchopneumonia.
• Samples all alveoli dependent on the bronchus where scope or catheter is lodged.
• Primarily a deep lung sample: small airways, alveoli, and sometimes the interstitium.
TRACHEAL WASH vs BAL
TRACHEAL WASH vs BAL
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DEFINITIONS – Slippery slope• TW becomes BAL
• Catheter into small airways
• Relatively large volumes of fluid used
• BAL becomes TW• Single bolus
• Relatively small volume
Regardless of method• Tracheal wash (TW) and bronchoalveolar lavage (BAL) result in sufficient material for:CytologyCulturesPCRFlow cytometry
Special stains / markers
Cell function testing
• BAL: greater volume, more cells than TW
TW and BAL Cytology
• Similar benefits› Less invasive than getting tissue
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TW and BAL Cytology
• Similar limitations › No architecture› Cells must exfoliate
• E.g. not pulmonary fibrosis
• E.g. not sarcoma
›Organisms must be present in large numbers
› Secondary processes must not “hide” primary
• Infection vs non‐infectious disease
• Inflammation vs neoplasia
TW and BAL
• MOST USEFUL FOR• Ruling IN infectious disease
• Ruling IN neoplasia
• CAN HELP PRIORITIZE DIFFERENTIAL DIAGNOSES
Tracheal Wash
• Indications• Bronchial and alveolar disease• Because of safety, may consider for any lung disease
• Less likely to be representative of interstitial or local processes
• Quite challenging in small dogs and cats due to size of target
• Only requires sedation and local anesthesia
• Coughing may improve yield
ENDOTRACHEAL WASH
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TRANSTRACHEAL WASH
• Moderately difficult to perform
• Quite challenging in small dogs and cats due to size of target
• Only requires sedation and local anesthesia
• Coughing may improve yield
ENDOTRACHEAL WASH
• Technically easy• Safer for small dogs and cats
• Requires general anesthesia
• Greater ability to adjust positioning of catheter
Endotracheal wash: Great if needs anesthesia for other reason!
Getting the best TW results
1. DO THEM!
2. Select appropriate patient at the appropriate time
3. Practice tips for maximizing results
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Getting the best TW results: Review steps if it has been awhile
3rd edition due out Sept 2020
6th edition available now
Be prepared in advance
•Patient Prep•Catheter diameter
•Catheter length•Avoiding contamination
•Volume of saline / number of boluses
•Handling of fluid
Considerations: ET then TTW for each
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Endo‐tracheal wash – Eezy Peezy
• Patient under light anesthesia
• e.g. butorphanol / propofolin small dogs
• e.g. ketamine / midazolam in cats
• See anesthesiology
• Generally cats and small dogs
• Can collect from patient already under anesthesia
Bronchodilators:PRE‐MED CATS!
• Usual dose of theophylline
• Oral aminophylline 30‐60 min prior to procedure
‐ OR ‐• SQ terbutaline 10 min prior to procedure
‐ AND/OR ‐
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TTW: Prevent Movement Without Suppressing Cough (if possible)
• Need to avoid movement• Tracheal laceration
• “Walk off” catheter
• Avoid narcotics if possible (cough suppressant)
• Acepromazine• 0.05 – 0.1 mg/kg IV or SQ
• Wait 10‐15 min
(OR ‐ low dose of butorphanol; dexmedetomidine)
• Lidocaine locally
TTW: Prevent Movement Without Suppressing Cough (if possible)• Need to avoid movement
• Tracheal laceration
• “Walk off” catheter
• Avoid narcotics if possible (cough suppressant)
• Acepromazine• 0.05 – 0.1 mg/kg IV or SQ
• Wait 10‐15 min
(OR ‐ low dose of butorphanol; dexmedetomidine)
• Lidocaine locally
• Ideally 5 people!• 1 to hold head
• 1 to hold body
• 1 to pass cannula and hold in position
• 1 to pass flushing catheter and perform lavage
• 1 to pass and cap syringes
Considerations
•Patient Prep•Catheter diameter
•Catheter length•Avoiding contamination
•Volume of saline / number of boluses
•Handling of fluid
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Size of catheter
• SMALLER is generally BETTER!
• Start with 3.5 – 5 Fr
Tracheal wash: Size of catheter
• SMALLER is generally BETTER!
•Want fluid and mucus, not air
• Start with 3.5 – 5 Fr
Transtracheal wash catheters: thru the needle
8 or 12”
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MILA® Canula with flush catheterTTW with ability to control insertion length
MILA® Canula with flush catheter
Considerations
•Patient Prep•Catheter diameter
•Catheter length•Avoiding contamination
•Volume of saline / number of boluses
•Handling of fluid
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Tracheal wash: Length is important!
Size tube: 4.0 I.D.Size catheter: 5 Fr red rubber
Size tube: 10.0 I.D.Size catheter: 5 Fr red rubber
Needs to extend several cm beyond end of ET tube
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Longer catheters
• Small diameter nasogastric tubes
• Polypropylene male dog urinary catheters
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VISUALIZE ANATOMY FULLY
1. Where is the carina? –Aiming for just proximal
2. How far should I pass the ET tube? ‐ Just past the larynx
3. How far should I pass the wash catheter? – Beyond the ET tube but before the carina
Length of catheter
• Relative to length of ET tube
• ALSO relative to depth into the lung• Aim for just in front of the carina
• Carina is at about the 4th intercostal space
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Visualize Anatomy Fully for TTW, too!
•Do I have the right length catheter?•With Mila‐type system, can adjust the length during the procedureMore versatilityRequires similar anatomical considerations as for ETW
Carina ≈ 4th ICS
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Considerations
•Patient Prep•Catheter diameter
•Catheter length•Avoiding contamination
•Volume of saline / number of boluses
•Handling of fluid
Intubation –Minimize Contamination
•Use sterile endotracheal tube•Do not touch either end• Put lidocaine on larynx•Use a laryngoscope
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GLOVES3‐WAY STOPCOCK
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Minimize Contamination
• Glycopyrrolate or Atropine?
• Surgical prep
• Care with hands• Gloves don’t stay sterile
• Touch neck
• Touch syringes
Non‐Dominant Hand:Hold larynx well
• Size of airway
• Prevent rolling of trachea or slipping off side
• Once catheter in place, maintain contact between catheter and neck
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BEVEL OF NEEDLE “DOWN”
Considerations
•Patient Prep•Catheter diameter
•Catheter length•Avoiding contamination
•Volume of saline / number of boluses
•Handling of fluid
Instillation Volume?
Number of Boluses?
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Instillation Volume?
Volume and bolus numbers
• Generally start with 3‐5 ml boluses to find “sweet spot”
• Adapt if needed to improve return
• BASE ON RESULTS• Visibly turbid fluid• Sufficient volume
Endo‐tracheal wash – VIDEO
NOTE: Suction or drain excess fluid from endotracheal tube when finished so that fluid does not obstruct ventilation through the endotracheal tube!