Test #2: Intubation in Dogs and Cats:

Intubation Definition:

• placement of flexible plastic tube into trachea to maintain an open airway or to serve as a conduit through which to administer certain drugs

Benefits of Intubation:

• assist in maintaining open airways

• prevents aspiration of saliva or regurgitated gastic contents

• seals respiratory system and breathing circuit

Indication of Intubation:

• respiratory and cardiac arrest

• general anesthesia

• heavy sedation

• any procedure or disease that compromises the airway

• endotracheal washes

• decreased level of consciousness

• periodontal therapy

• upper airway obstructions

Intubation Equipment:

• 3-12 mL syringe to inflate cuff

• endotracheal tubes in varying sizes

• gauze squares

• laryngoscope

• oxygen

• sterile lubricant

• supplies to secure endotracheal tube

Types of Endotracheal Tubes:

• Material:

  • Silicone

  • Red Rubber

  • Polyvinyl Chloride (PVC)

• Types:

  • Plain/uncuffed

  • Cuffed

Types of Endotracheal Tubes: Plain: Cole

• cuffed ET tube <3.0mm

• besst choice: avians, pediatric animals or exotic pets

• birds must complete tracheal rings— cuffed ET can lead to pressure necrosis if cuff is inflated too much

• excellent pressure flow, provides less resistance

• shoulders form an airtight seal at the entrace to larynx

Types of Endotracheal Tubes: Cuffed:

• used in all species

• 2 purposes:

  • prevent gas leaks around the tube'

  • to reduce risk of aspiration of gastric and oral secretions

• 2 types:

  • high pressure, low volume

  • high volume, low pressure: less damage to tracheal mucosa

Cuffed ET Tubes: Murphy

• most common

• oval opening (murphy eye) across from bevel of tube

• Murphy Eye: emergency opening if the distal end of lumen of tube becomes clogged

Cuffed ET Tubes: Magill

• does NOT have the murphy eye but similar otherwise

Selecting Tube Size:

• rapid intubation

• minimize tracheal trauma

• ensure that airway is appropriately protexted

  • too large: airway trauma

  • too small: leaks around the cuff/airway protection be compromised

• always choose 3 tubes

Selecting Tube Size: Correlating Body Weight tp Tracheal Size

• brachycephalic breeds have smaller tracheal diameter, narrower and smaller upper airways than other breeds

Selecting Tube Size: Evaulating Width of Nasal Septum:

• ET tube should be held up to narrowest point between the nares

• 21% effective

Selecting Tube Size: Palpation of the Width of Extra Thoracic Trachea Just Above Thoracic Inlet

• 46% effective

Selecting Tube Size: Proximal End & Distal End

• proximal end: not extend past the incisor teeth

• distal end": not extend past point of shoulder

Stylets:

• in cases of smaller or extremely flexible ET tubes

  • provides support to faciliate intubation

• cats with laryngospasm

• ensure tip of stylet does not protrude beyond tip pf ET tube to minimize injury to the larynx and trachea

Patient Positioning:

Procedure in Cats:

• same as dogs

• laryngospasm: arytenoids to remain closed

• use 1 drop of 2% lidocaine into each arytenoid

  • cats sensitive to lidocaine

Techniques to Confirm Tracheal Intubation:

1. Visual Confirmation: ET tube passing between arytenoids only definitibe way of confirming correct placement

2. Cough: ET tube is advanced into trachea

3. Condensation: clear tube on exhalation— air movement

4. Palpation of the Ventral Cervical Region: should reveal one rigid structure

Monitoring Under Anesthesia:

• Circulation

  • electrocardiography (ECG)

  • oscillometric blood pressure measurement

• Ventilation:

  • Capnography: measurement of CO2 in patient’s exhaled breath

• Oxygenation:

  • pulse oximetry

• Body Temperature:

  • thermometer

• Depth of Anesthesia:

  • anesthetic gas analyzer

Extubation:

• ONLY after confirmation that the pharyngeal reflex is reestablished

• Before:

  • Check—- excessice secretions; aspirate

  • Cuff should be fully deflated

• After:

  • Monitored

  • Head: be kept elevated to avoid aspiration from regurgitation

  • Flow-by O2 should be administered

  • Respiration and oxygenation should be monitored until animal fully awake

Types of Injections:

• Injections can be delivered into:

  • Muscle (IM)

  • Tissue under skin (SQ)

  • Veins (IV)

  • Skin (Intradermal)

  • Body Cavities: abdominal cavity or thoracic cavity

  • Bone (intraosseous)

• Most Common:

  • SQ

  • IM

  • IV