Laryngoscopy and Endotracheal Intubation

Laryngoscopy is the technique of exposing the laryngeal inlet so that a tracheal tube can be passed under vision, and endotracheal intubation is the placement of a cuffed tube into the trachea to secure and isolate the airway. Together they are the reference method for definitive airway control during general anaesthesia.

Definition

Endotracheal intubation is the insertion of a cuffed tube through the larynx into the trachea, usually under laryngoscopic vision, to maintain a patent airway and permit controlled ventilation.

Scope

This topic covers direct and video laryngoscopy, the grading of the laryngoscopic view, the steps and confirmation of tracheal intubation, and the comparative role of videolaryngoscopy. It is a reference description of the techniques and their evidence base, not a procedural manual or device-selection instruction.

Core questions

• How does laryngoscopy expose the larynx for tube placement?
• How is the laryngoscopic view graded and related to difficulty?
• How does videolaryngoscopy compare with direct laryngoscopy?

Key concepts

• Direct laryngoscopy
• Videolaryngoscopy
• Cormack-Lehane grade
• Cuffed tracheal tube
• Confirmation by capnography
• Axis alignment and sniffing position
• First-pass success

Mechanisms

During direct laryngoscopy the operator uses a laryngoscope blade to displace the tongue and align the oral, pharyngeal, and laryngeal axes so the glottis can be seen and a tube advanced between the vocal cords. The resulting view is described by the Cormack-Lehane grade, which links visualisation to anticipated difficulty (Cormack-Lehane, 1984). Videolaryngoscopy uses a camera at the blade tip to provide an indirect view that does not require the same line-of-sight axis alignment, often improving glottic visualisation. Correct tracheal placement is confirmed objectively, principally by sustained end-tidal carbon dioxide (Apfelbaum, 2022).

Clinical relevance

Tracheal intubation provides a secured, isolated airway and is central to general anaesthesia for many procedures; technique choice and confirmation of placement are addressed in difficult-airway guidance (Apfelbaum, 2022; Frerk, 2015). This entry is descriptive and not individualised clinical advice.

Epidemiology

A Cochrane systematic review found that videolaryngoscopy, compared with direct laryngoscopy in adults, is associated with improved glottic view and reductions in failed and difficult intubations (Hansel, 2022).

Evidence & guidelines

The Difficult Airway Society and ASA guidelines structure intubation around planned attempts, limiting repeated traumatic tries and confirming placement; systematic-review evidence supports a beneficial role for videolaryngoscopy in many settings (Frerk, 2015; Apfelbaum, 2022; Hansel, 2022).

History

Laryngoscopy and tracheal intubation were established through the twentieth century as anaesthesia matured; the Cormack-Lehane grading of the laryngeal view (1984) standardised description of difficulty, and the later introduction of videolaryngoscopy expanded the available techniques (Cormack-Lehane, 1984; Hansel, 2022).

Debates

Should videolaryngoscopy replace direct laryngoscopy as the default?

Systematic-review evidence shows videolaryngoscopy improves the view and reduces failed intubation, but questions of routine use, training, cost, and the best device remain under discussion.

Seminal works

• cormack-lehane-1984
• frerk-2015
• hansel-2022

Frequently asked questions

How is correct tracheal tube placement confirmed?

Sustained end-tidal carbon dioxide on capnography is the principal objective confirmation that a tube is in the trachea, alongside clinical signs; this is emphasised in difficult-airway guidance (Apfelbaum, 2022).

Does videolaryngoscopy improve intubation outcomes?

A Cochrane systematic review reports that videolaryngoscopy improves glottic visualisation and reduces failed and difficult intubations in adults compared with direct laryngoscopy (Hansel, 2022).