tracheal wash vs balraleigh, north carolina, usa 1. introduction: tracheal wash vs bal 2. focus on...

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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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• 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.



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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

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Tracheal Wash

• Indications• Bronchial and alveolar disease

• CHRONIC COUGH (BRONCHITIS)• BRONCHOPNEUMONIA / ASPIRATION PNEUMONIA

• Majority of dogs and cats requiring airway sampling!!

Bronchoalveolar Lavage

• Indications• Primarily: Interstitial / deep lung disease

• Neoplasia• Systemic fungal infection

• Eosinophilic lung disease

• Bronchoscopic collection• Directed sampling

TRACHEAL WASH vs BAL – WHICH IS BETTER?1. Is bronchoscopy indicated?

2. Where is the disease within the lung?

3. What are the top differential diagnoses?

4. How stable is the patient?

5. How risk‐averse are the clients?

6. What are the financial constraints?

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TRACHEAL WASH vs BAL – WHICH IS BETTER?3. What are the top differential diagnoses

• If neoplasia or systemic fungal disease, BAL more likely to provide diagnostic specimen

• Unsure for other infectious agents such as parasites

• Aelurostrongylus best found on fecal Baermannexam!

TRACHEAL WASH vs BAL – WHICH IS BETTER?

1. Is bronchoscopy indicated

2. Where is the disease within the lung?

3. What are the top differential diagnoses

4. How stable is the patient

5. How risk‐averse are the clients

6. What are the financial constraints

Tracheal Wash: Bronchial and/or alveolar disease

• Signs of bronchitis – usually cough, consistent radiographs (bronchial pattern or unremarkable)

• Confirm inflammation• Characterize inflammation• Identify organisms (cytology, bacterial culture, +/‐ mycoplasma culture and/or PCR)

• Culture and antibiotic sensitivity information

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Tracheal Wash: Bronchial and/or alveolar disease

• Signs of bacterial bronchopneumonia

• Confirm septic inflammation

• Culture and antibiotic sensitivity information

TRANS‐TRACHEAL WASH (TTW) vsENDOTRACHEAL (ETW)

By‐passing the oral cavity

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

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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





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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





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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





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





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!

Considerations





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Now What?

•Cytologic Examination•Aerobic culture•Mycoplasma?

•PCR•Culture

•Anaerobes?•Actinomycetes?•Nocardia?

CYTOLOGIC EXAMINATION

• CLASSIFICATION OF CELL POPULATION

• QUALITATIVE EVALUATION OF CELLS• MACROPHAGE ACTIVATION

• NEUTROPHIL DEGENERATION

• CRITERIA OF MALIGNANCY

• ETIOLOGIC AGENTS• BACTERIA

• PROTOZOA

• FUNGI

• PARASITES

Cytospin or Sediment Prep

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PRACTICE TIP: MAKE SLIDES OF MUCUS

•May find trapped organisms!

PRACTICE TIP: MAKE SLIDES OF MUCUS

•May concentrate organisms

•Saline likely to disperse over time

•Make the slides yourself•Poor for cellular characteristics

Need BOTH cytospinAND mucus squash

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Not happening for you?

Picture the Anatomy and Change Something!

•Position of catheter•Position of patient•Volume of saline

•Size of catheter

THE END

tracheal wash vs balraleigh, north carolina, usa 1. introduction: tracheal wash vs bal 2. focus on...

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