Endotracheal intubation

Indications

An artifi cial airway is necessary in the following circumstances:

• Apnoea: provision of mechanical ventilation, e.g. unconsciousness, severe respiratory muscle weakness, self-poisoning.

• Respiratory failure: provision of mechanical ventilation, e.g. ARDS, pneumonia.

• Airway protection: GCS <8, trauma, aspiration risk, poisoning. Airway obstruction: maintain airway patency, e.g. trauma, laryngeal oedema, tumour, burns.

• Haemodynamic instability: facilitate mechanical ventilation, e.g. shock, cardiac arrest.

Choice of endotracheal tube

Most adults require a standard high volume, low pressure, cuffed endotracheal tube. Average sized adults require a size 8.0–9.0mm id tube (size

7.5–8.0mm id for females), cut to a length of 23cm (21cm for females). Particular problems with the upper airway, e.g. trauma, oedema, may require a smaller tube. In specifi c situations, non-standard tubes may be used, e.g. armoured tubes to avoid external compression or double lumen tubes to isolate the right or left lung.

Route of intubation

The usual routes are orotracheal and nasotracheal. Orotracheal intubation is generally preferred. The nasotracheal route has the advantages of increased patient comfort, easier blind placement, and easier to secure the tube. However, there are several disadvantages. The tube is usually smaller, there is a risk of sinusitis and otitis media, and is generally contraindicated in coagulopathy, CSF leak, and nasal/base-of-skull fractures.

Difficult intubation

If predicted, this should not be attempted by an inexperienced, unaccompanied operator except in life-threatening situations. Difficulty may be predicted in patients with a small mouth, high arched palate, large upper incisors, hypognathia, large tongue, anterior larynx, short neck, immobile temporomandibular joints, immobile cervical joints, or morbid obesity. If a difficult intubation presents unexpectedly, the use of a stylet, a straight bladed laryngoscope, a laryngeal mask airway, or a fibreoptic laryngoscope may help. It is important not to persist for too long; revert to bag-andmask ventilation to ensure adequate oxygenation.

Choice of endotracheal tube

Most adults require a standard high volume, low pressure, cuffed endotracheal tube. Average sized adults require a size 8.0–9.0mm id tube (size

7.5–8.0mm id for females), cut to a length of 23cm (21cm for females). Particular problems with the upper airway, e.g. trauma, oedema, may require a smaller tube. In specific situations, non-standard tubes may be used, e.g. armoured tubes to avoid external compression or double lumen tubes to isolate the right or left lung.

Route of intubation

The usual routes are orotracheal and nasotracheal. Orotracheal intubation is generally preferred. The nasotracheal route has the advantages of increased patient comfort, easier blind placement, and easier to secure the tube. However, there are several disadvantages. The tube is usually smaller, there is a risk of sinusitis and otitis media, and is generally contraindicated in coagulopathy, CSF leak, and nasal/base-of-skull fractures.

Difficult intubation

If predicted, this should not be attempted by an inexperienced, unaccompanied operator except in life-threatening situations. Diffi culty may be predicted in patients with a small mouth, high arched palate, large upper incisors, hypognathia, large tongue, anterior larynx, short neck, immobile temporomandibular joints, immobile cervical joints, or morbid obesity. If a difficult intubation presents unexpectedly, the use of a stylet, a straight bladed laryngoscope, a laryngeal mask airway, or a fibreoptic laryngoscope may help. It is important not to persist for too long; revert to bag-andmask ventilation to ensure adequate oxygenation.

Complications of intubation

Early complications

• Trauma, e.g. haemorrhage, mediastinal perforation.

• Haemodynamic collapse, e.g. positive pressure ventilation,

vasodilatation, arrhythmias, or rapid correction of hypercapnia.

• Tube malposition, e.g. failed intubation or endobronchial intubation.

Later complications

•Infection, including maxillary sinusitis if nasally intubated.

• Cuff pressure trauma (avoid by maintaining cuff pressure <25cmH2O).

• Mouth/lip or pharyngeal trauma.

Equipment required

• Suction (Yankauer tip).

• O2 supply, rebreathing bag, and mask.

• Laryngoscope (two curved blades and straight blade).

• Stylet/bougie.

• Endotracheal tubes (preferred size and smaller).

• Water-based gel to lubricate tube.

• Magill forceps.

• Drugs (Induction agent, muscle relaxant, sedative).

• Syringe for cuff inflation.

• Tape to secure tube.

• Capnograph.