A. Introduction to Endotracheal Intubation

Endotracheal intubation is a critical medical procedure that involves inserting a tube into the trachea to establish and maintain a patent airway. This lesson provides a comprehensive overview of endotracheal intubation, covering oral and nasal techniques, indications, contraindications, equipment, step-by-step procedures, advanced considerations, and resources.

B. Understanding Endotracheal Intubation

Endotracheal intubation is the placement of a flexible tube (endotracheal tube or ETT) into the trachea (windpipe) to maintain an open airway. The tube is inserted either through the mouth (orotracheal) or the nose (nasotracheal). Once the tube is in place, it can be connected to a mechanical ventilator to assist or control the patient’s breathing.

C. Indications for Endotracheal Intubation

Endotracheal intubation is performed in various clinical scenarios where a patient is unable to maintain an adequate airway or requires mechanical ventilation. Key indications include:

• Respiratory Failure:
  • Inability to maintain adequate oxygenation (hypoxemia)
  • Inability to eliminate carbon dioxide (hypercapnia)
• Airway Protection:
  • To prevent aspiration in patients with decreased level of consciousness
  • To protect the airway from obstruction (e.g., swelling, foreign body)
• Need for Mechanical Ventilation:
  • To provide ventilatory support during surgery
  • To manage patients with conditions such as ARDS, pneumonia, or severe asthma
• Other:
  • Facilitation of pulmonary hygiene (e.g., suctioning)
  • Administration of certain medications

D. Contraindications to Endotracheal Intubation

While endotracheal intubation is often life-saving, there are some situations where it may be contraindicated or require special considerations:

• Absolute Contraindications:
  • Patient refusal (if the patient is competent)
  • Some cases of epiglottitis (though intubation may be necessary in advanced cases)
• Relative Contraindications/Precautions:
  • Severe facial trauma
  • Significant upper airway obstruction (e.g., tumor, foreign body) – may require alternative techniques like cricothyroidotomy or tracheostomy
  • Cervical spine instability – requires special precautions to avoid exacerbating the injury
  • Limited mouth opening
  • Laryngeal or pharyngeal abscess

The decision to intubate must always be based on a careful assessment of the patient’s condition and the potential risks and benefits of the procedure.

E. Equipment for Endotracheal Intubation

Successful endotracheal intubation requires a variety of specialized equipment. It is critical to gather and check all equipment before initiating the procedure.

• Laryngoscope:
  • Used to visualize the vocal cords.
  • Consists of a handle and a blade.
  • Blades can be curved (Macintosh) or straight (Miller).
  • Video laryngoscopes are increasingly common.
• Endotracheal Tube (ETT):
  • A flexible tube inserted into the trachea.
  • Available in various sizes (internal diameter).
  • Cuffed (to seal the airway) or uncuffed.
• Stylet: A malleable wire inserted into the ETT to provide rigidity and shape.
• Syringe: To inflate the ETT cuff.
• Bag-Valve-Mask (BVM): For manual ventilation before and after intubation.
• Oxygen Source: To pre-oxygenate and ventilate the patient.
• Suction Equipment: To clear secretions or vomitus from the airway.
• Monitoring Equipment:
  • Pulse oximetry
  • Capnography (to confirm ETT placement)
  • Cardiac monitor
• Medications: Sedatives and neuromuscular blocking agents (paralytics) as indicated.
• Other:
  • Tape or securing device
  • Lubricant (for nasotracheal intubation)
  • Magill forceps (for nasotracheal intubation)

F. Step-by-Step Procedure: Orotracheal Intubation

Orotracheal intubation involves inserting the endotracheal tube through the mouth. Here’s a step-by-step guide:

1. Preparation:
   • Gather and check all equipment.
   • Position the patient (sniffing position, if possible).
   • Pre-oxygenate the patient with 100% oxygen using a BVM or non-rebreather mask.
   • Administer medications (sedatives and neuromuscular blocking agents) as indicated.
2. Laryngoscopy:
   • Hold the laryngoscope in your left hand.
   • Open the patient’s mouth and insert the blade along the right side of the tongue.
   • Advance the blade until the tip of the blade is in the vallecula (for a curved blade) or lifts the epiglottis (for a straight blade).
   • Lift the laryngoscope upwards and forward (along the axis of the handle) to visualize the vocal cords. Do not rock the wrist.
3. Tube Insertion:
   • Hold the ETT in your right hand.
   • Insert the ETT through the vocal cords, advancing it until the cuff is just beyond the cords.
   • The depth of insertion is typically 21-23 cm at the teeth for an average adult.
4. Cuff Inflation:
   • Inflate the ETT cuff with an appropriate amount of air (usually 5-10 mL) using a syringe.
5. Confirmation of Tube Placement: This is the most critical step.
   • Primary Methods:
     • Direct Visualization: Seeing the ETT pass through the vocal cords.
     • Capnography: The most reliable method. A sustained EtCO2 waveform confirms tracheal intubation.
   • Secondary Methods:
     • Auscultation: Listen for bilateral breath sounds and the absence of epigastric sounds.
     • Chest X-ray: To confirm ETT position and depth.
6. Securing the Tube:
   • Secure the ETT with tape or a commercial securing device.
7. Ventilation and Further Management:
   • Connect the ETT to a mechanical ventilator or continue manual ventilation with a BVM.
   • Obtain a chest X-ray to confirm ETT position.
   • Monitor the patient closely.

G. Step-by-Step Procedure: Nasotracheal Intubation

Nasotracheal intubation involves inserting the endotracheal tube through the nose. It is less commonly performed in emergency situations but may be used in certain scenarios.

1. Preparation:
   • Gather and check all equipment.
   • Assess the patient for nasal patency and choose the larger nostril.
   • Pre-oxygenate the patient.
   • Administer medications (sedatives, topical vasoconstrictors, and local anesthetics) as indicated.
2. Tube Preparation:
   • Select an appropriately sized ETT (usually smaller than for oral intubation).
   • Lubricate the ETT.
   • Insert a stylet into the ETT.
3. Nasal Insertion:
   • Gently insert the ETT into the chosen nostril, advancing it along the floor of the nasal cavity.
   • Advance the tube until it reaches the nasopharynx.
4. Laryngoscopy and Tube Advancement:
   • Perform direct laryngoscopy as in orotracheal intubation.
   • Use Magill forceps to direct the ETT through the vocal cords.
   • Advance the ETT until the cuff is just beyond the cords.
5. Cuff Inflation:
   • Inflate the ETT cuff with an appropriate amount of air.
6. Confirmation of Tube Placement:
   • Use the same methods as for orotracheal intubation (direct visualization, capnography, auscultation, chest X-ray). Capnography is crucial.
7. Securing the Tube:
   • Secure the ETT with tape or a commercial securing device.
8. Ventilation and Further Management:
   • Connect the ETT to a mechanical ventilator.
   • Obtain a chest X-ray.
   • Monitor the patient closely.

H. Confirming Endotracheal Tube Placement

Accurate confirmation of ETT placement is paramount to avoid serious complications such as esophageal intubation.

• Direct Visualization:
  • Seeing the ETT pass through the vocal cords is the most specific sign.
  • However, it can be challenging in some situations.
• Capnography:
  • The gold standard for confirming ETT placement.
  • Detects the presence of carbon dioxide (CO2) in exhaled air.
  • A sustained EtCO2 waveform indicates tracheal intubation.
  • Colorimetric capnometers are less reliable but can be used as a secondary confirmation tool.
• Auscultation:
  • Listen for bilateral breath sounds in the lungs.
  • Listen over the epigastrium (stomach) to rule out esophageal intubation (absence of breath sounds).
  • Auscultation can be unreliable, especially in noisy environments or in patients with significant lung disease.
• Chest X-ray:
  • Confirms the position of the ETT in the trachea.
  • Should be obtained after initial confirmation methods.
  • Ideally, the ETT tip should be positioned 3-5 cm above the carina.
• Other Methods:
  • Observation of chest rise: Can be misleading.
  • Esophageal detector device: Less reliable than capnography.

I. Potential Complications of Endotracheal Intubation

Endotracheal intubation is an invasive procedure with potential complications. It is important to be aware of these risks and take steps to minimize them.

• Immediate Complications:
  • Hypoxia: Due to prolonged intubation attempts or failure to establish a patent airway.
  • Esophageal Intubation: Placement of the ETT into the esophagus instead of the trachea. Leads to inadequate ventilation and hypoxia.
  • Aspiration: Inhalation of gastric contents into the lungs.
  • Trauma:
    • Dental trauma (chipped or broken teeth)
    • Laceration of the lips, tongue, or pharynx
    • Tracheal injury (e.g., perforation, rupture) – rare but life-threatening
  • Arrhythmias: Due to vagal stimulation or hypoxia.
  • Bronchospasm: Especially in patients with asthma or COPD.
  • Pneumothorax: Rare, but can occur due to barotrauma from positive pressure ventilation.
  • Hypertension/Hypotension: Transient changes in blood pressure.
• Delayed Complications:
  • Ventilator-Associated Pneumonia (VAP): Infection of the lungs that can occur in patients on mechanical ventilation.
  • Tracheal Stenosis: Narrowing of the trachea due to scar tissue formation.
  • Laryngeal Edema/Ulceration: Swelling or sores in the larynx.
  • Subglottic Stenosis: Narrowing of the airway below the vocal cords.
  • Granuloma Formation: Tissue growth in the airway.
  • Sinusitis (with nasotracheal intubation): Inflammation of the sinuses.

J. Special Considerations and Advanced Techniques

In some situations, standard endotracheal intubation techniques may be challenging or contraindicated. Advanced techniques and special considerations are crucial in these cases:

• Difficult Airway:
  • A situation where a skilled intubator has difficulty visualizing the vocal cords or inserting the ETT.
  • Assessment: Use tools like the LEMON score (Look, Evaluate, Mallampati, Obstruction, Neck mobility) to predict difficult airways.
  • Management:
    • Alternative Laryngoscopes: Video laryngoscopes (e.g., Glidescope, McGrath) provide an indirect view of the larynx and can improve success rates in difficult airways.
    • Supraglottic Airway Devices (SADs): Devices like the laryngeal mask airway (LMA) or King LT can be used as a rescue device or as an alternative to ETT in certain situations.
    • Flexible Bronchoscopy: A fiberoptic scope can be used to visualize the airway and guide ETT placement, especially in patients with known or suspected difficult airways.
    • Intubating Stylets/Bougies: A bougie is a thin, flexible device that can be inserted through the vocal cords, and the ETT is then railroaded over it.
    • Awake Intubation: Performed in a patient who is spontaneously breathing, using topical anesthesia and sedation. Useful for patients with known difficult airways or cervical spine instability.
• Rapid Sequence Intubation (RSI):
  • A technique used to achieve rapid and optimal intubating conditions, especially in emergency situations.
  • Involves the simultaneous administration of a sedative and a neuromuscular blocking agent (paralytic) to induce unconsciousness and muscle relaxation.
  • Indications: Patients at high risk of aspiration, patients requiring urgent airway control.
  • Key Steps:
    • Preparation and equipment check
    • Pre-oxygenation
    • Administration of sedative (e.g., etomidate, ketamine)
    • Administration of neuromuscular blocking agent (e.g., succinylcholine, rocuronium)
    • Application of cricoid pressure (Sellick maneuver) – its use is controversial
    • Laryngoscopy and intubation
    • Confirmation of ETT placement
• Pediatric Intubation:
  • Intubation in children requires special considerations due to anatomical and physiological differences.
  • Key Differences:
    • Smaller airway diameter
    • Shorter trachea
    • Larger occiput
    • More anterior larynx
    • Increased risk of hypoxia
  • Equipment: Use appropriately sized ETTs and laryngoscope blades.
  • Technique: Gentle technique, avoid excessive force.
  • Cuffed vs. Uncuffed Tubes: Cuffed tubes are increasingly used in children of all ages.
• Intubation in Pregnancy:
  • Pregnant patients have physiological changes that can make intubation more challenging.
  • Changes:
    • Increased risk of aspiration
    • Difficult mask ventilation
    • Decreased functional residual capacity
    • Hormonal changes leading to airway edema
  • Management:
    • Left lateral tilt to displace the uterus
    • RSI is often indicated
    • Smaller ETT size may be needed

K. Post-Intubation Management

After successful intubation, proper post-intubation management is crucial for the patient’s ongoing care.

• Mechanical Ventilation:
  • Connect the ETT to a mechanical ventilator.
  • Set appropriate ventilator settings (e.g., tidal volume, respiratory rate, FiO2, PEEP).
  • Monitor the patient’s response to ventilation.
• Sedation and Analgesia:
  • Administer medications to ensure patient comfort and tolerance of the ETT and mechanical ventilation.
  • Regularly assess the patient’s level of sedation and pain.
• ETT Cuff Management:
  • Maintain appropriate cuff pressure (20-30 cm H2O) to prevent air leaks and tracheal injury.
  • Check cuff pressure regularly.
• Suctioning:
  • Regularly suction secretions from the ETT to maintain airway patency and prevent VAP.
  • Use sterile technique.
  • Avoid excessive suctioning.
• Humidification:
  • Provide adequate humidification to prevent drying of airway secretions.
• Positioning:
  • Elevate the head of the bed to 30-45 degrees to reduce the risk of aspiration and VAP.
• Monitoring:
  • Continuously monitor vital signs, oxygen saturation, and respiratory parameters.
  • Regularly assess lung sounds.
  • Obtain regular chest X-rays.
  • Monitor for complications.
• Nutrition:
  • Provide adequate nutrition (enteral or parenteral).
• Communication:
  • Establish a method of communication with the patient (if they are conscious).
• Weaning:
  • Assess the patient’s readiness for weaning from mechanical ventilation regularly.
  • Follow a weaning protocol.

L. Documentation

Accurate and timely documentation of the intubation procedure and post-intubation management is essential. Key elements to document include:

• Indications for intubation
• Patient assessment before intubation
• Informed consent (if possible)
• Equipment used (ETT size, laryngoscope blade)
• Medications administered
• Intubation technique (oral, nasal)
• Number of intubation attempts
• Confirmation of ETT placement methods used (EtCO2, auscultation, etc.)
• ETT depth
• Cuff pressure
• Patient’s response to the procedure
• Complications encountered
• Post-intubation ventilator settings
• Ongoing monitoring and assessment

M. Resources and Further Learning

Here are some resources for further learning about endotracheal intubation:

• Textbooks:
  • Textbooks of critical care medicine
  • Emergency medicine textbooks
  • Anesthesia textbooks
• Guidelines:
  • Society of Critical Care Medicine (SCCM)
  • American Heart Association (AHA)
  • American Society of Anesthesiologists (ASA)
• Journals:
  • • Critical Care Medicine
    • Anesthesiology
    • Respiratory Care
    • Journal of the American Medical Association (JAMA)
  • Websites:
    • PubMed
    • Google Scholar
    • Professional organization websites (e.g., SCCM, ASA)
  • Simulation and Training:
    • Use of mannequins and simulation labs for hands-on practice.
    • Video demonstrations of intubation techniques.
    • Continuing medical education courses.