Intubation Techniques

Endotracheal intubation is the placement of a tube into the trachea to maintain a patent airway in those who are unconscious or unable to breathe independently.
Oxygen, anaesthesia and other drugs can be delivered via the endotracheal tube (ETT). Compared to the use of pharyngeal airways (oropharyngeal or nasopharyngeal), an endotracheal airway provides protection against aspiration, enables more effective ventilation and oxygenation, facilitates suctioning, and prevents gastric insufflation.

Previously restricted to the anaesthetic and operating rooms, advances such as rapid sequence induction(RSI) have meant that intubation is often performed in emergency or pre-hospital settings.¹ These situations are by their nature high-risk and there is some evidence that pre-hospital endotracheal intubation in adult major trauma patients with head injury actually increases mortality.² Many confounding variables exist - experience levels, lack of monitoring equipment, difficulties pre-oxygenating patients etc - and the studies are retrospective but benefit should not be assumed.

Intubation is a technique that requires training, experience and regular updating to maintain competence. Anyone attempting it, should also be capable of managing any complications that arise. GPs will vary in their ability: some will have developed a special interest during hospital training, gained postgraduate qualifications and may even perform regular anaesthetic lists; others will have an interest in pre-hospital and emergency care and may be involved in BASICS or ATLS to maintain relevant skills. The key principle is not to act beyond your personal level of competence.

Alternatives?³

• Laryngeal mask airway (LMA) - widely used in UK in more than 50% of surgical patients. Consists of an inflatable silicone ring attached diagonally to a flexible tissue which forms an oval cushion filling the space around and behind the larynx, creating a low pressure seal between the tube and trachea without insertion into the larynx.
  It can be used in an emergency setting by providers not trained in tracheal intubation and is an option in the management of a difficult airway where intubation has been unsuccessful. However, it is not a definitive airway and provides limited protection only from gastric aspiration.
• Oesophageal Tracheal Combitube© (ETC) - double lumen tube combining an oesophageal tube with closed distal end linked by a short connection to a conventional tracheal tube. Designed for blind insertion and placement is determined by examination and auscultation and cuffs can be adjusted according to whether the trachea or oesophagus has been intubated. It has been used amongst first responders in the US successfully.
• Tracheostomy.

• Inability to oxygenate patient (SO₂<90%, PaO₂<55).
• Inability to ventilate patient (rising PaCO₂, respiratory acidosis, mental status change).
• Patient unable to protect airway.

• Neck immobility or increased risk of neck trauma (for example, rheumatoid arthritis or suspected cervical spine injury) - consider fibreoptic intubation if available.
• Inability to open mouth (for example, scleroderma or surgical wiring) - consider nasal intubation or surgical airway.

Equipment

Ensure all in working order.

• Monitoring equipment - pulse oximeter, BP gauge, cardiac monitor
• Oxygenation equipment - oxygen source and tubing, face mask, anaesthesia bag or ambu-bag
• Suction equipment
• Premedication and induction equipment - IV access, draw up and label premedication agents, induction agents and paralytic agents
• Intubation equipment - laryngoscope with handles and blades of different sizes and shapes (curved/straight), endotracheal tubes of different sizes, means of securing tube in place. To estimate laryngoscope blade size - with blade held next to patient's face, the blade should reach between lips and larynx .
• Equipment for checking tube position - stethoscope, CO₂ detector or end-tidal CO₂ monitor, CXR.

Preparation

• Preoxygenate with 100% oxygen via well-fitting mask.
• Consider premedications.
• If conscious, consider RSI.

Patient position

• Patient aligned without lateral deviation of head or neck
• Head extended on neck with pillow under occiput. If cervical spine trauma is suspected, have assistant hold neck in neutral position.
• Neck flexed to approximately 15 degrees on chest.

(In infants under 2, the occiput naturally extends the head and the chin alone needs lifting into the 'sniffing' position.)

Inspect mouth for loose teeth or dentures and remove. Suction any secretions or vomitus.

Intubation

Intubation attempts should not last longer than 30 seconds.

• Hold laryngoscope in left hand and ETT in right and introduce laryngoscope over right side of tongue, sweeping the tongue to the midline
• Position the tip of the blade in the valecula (between the epiglottis and base of tongue) and lift upwards and away from yourself until the glottis is visualized
• Exert traction along the axis of the handle - do not use the teeth or gums as a fulcrum as this will result in damage to teeth and/or gums
• Introduce the endotracheal tube into the right corner of the mouth, passing it through the vocal cords with the cuff positioned and inflated just beyond the cords
• Ventilate with high concentration oxygen and secure endotracheal tube
• To assess tube position:
  • Look for symmetrical chest movement
  • Listen over apices and base of lungs and stomach for equal breath sounds and no gastric breath sounds
  • End-tidal carbon dioxide monitor attached to ETT

Trouble shooting⁴

Consider:

• Dislodged tube
• Obstructed tube
• Pneumothorax
• Equipment failure

• Failed intubation and hypoxaemia
  • Can ventilate with mask - seek senior help, defer intubation or consider alternative
  • Can't ventilate - call for urgent assistance; if bag and mask ventilation maintaining oxygen saturations above 90% and there is adequate time, consider other options such as the use of a bougie to guide ETT placement or alternatives such as the use of LMA or Combitube© or fibreoptic induction or if not, cricothryoidectomy. See "failed airway" algorithm.⁵
• Aspiration
• Trauma from laryngoscope
  • Teeth & soft tissues - avoidable with good technique
  • Oedema - usually due to repeated attempts
• oesophageal intubation - fatal if unrecognised
• Hypertension and arrhythmias

Avoiding problems

Potential problems in maintaining airway or performing intubation as suggested by presence of:

• Physical signs, eg short immobile neck, receding jaw, limited mouth opening, protruding or unhealthy teeth, large tongue, facial trauma.
• Injuries to cervical spine limiting movement
• Possible airway obstruction, for example as result of severe facial trauma or burns to airway
• Stridor at rest

Seek experienced assistance in advance of intubation attempt if possible.