Videolaryngoscopy Guidelines for Airway Management

Device Selection and Characteristics

The American Society of Anesthesiologists recommends using hyperangulated blade videolaryngoscopes for anticipated difficult airways, as they provide superior glottic visualization and higher first-attempt success rates 1
Macintosh-style (normal geometry) blades are equally effective for routine intubations without predicted difficulty and may be preferred due to easier tube delivery 2, 3
Channelled devices, such as Airtraq, KingVision, and Pentax, have guide channels for the endotracheal tube and are categorized as a separate type of videolaryngoscope 4, 5

Hyperangulated videolaryngoscopes should be the primary choice when difficult intubation is predicted, particularly in patients with at least two predictive factors 1
Reduced cervical spine mobility is a scenario where hyperangulated devices are particularly beneficial, as the acute blade angle requires less neck extension 6, 7

For patients without predicted difficulty, Macintosh-style videolaryngoscopes should be used as the second-attempt device after failed direct laryngoscopy 6, 7, 1
Unanticipated difficult intubation can be managed with Macintosh-style VL as a rescue device, especially when direct laryngoscopy reveals Cormack-Lehane Grade III or IV and mask ventilation is possible 6, 7

When using hyperangulated blades, a 60° curve on the stylet is required to match the blade curvature and navigate the pharyngo-glotto-tracheal angle 6, 7
Withdrawing the blade slightly from a perfect Grade 1 view may paradoxically facilitate tube passage by reducing the acute angle for tube delivery 6, 7
Normal geometry blades require less technical modification, and standard stylet shaping with gentle curvature is adequate 2, 3

Videolaryngoscopy should not be used in patients with mouth opening < 2.5 cm, as there is insufficient space for blade insertion 6, 7
Cervical spine fixed in flexion is a contraindication, as it cannot accommodate blade geometry 6, 7

For intensive care intubations, first-line VL use is recommended when the MACOCHA score ≥3 predicts difficulty, and either type of videolaryngoscope can be used initially 2, 3
McGrath Mac validation has demonstrated superiority in MACOCHA ≥3 patients, with increased first-attempt success from 55% to 79% in ICU patients 2, 3

Anticipated difficult airway (≥2 predictive factors): first choice is hyperangulated blade VL, with a 60° stylet available 1
Unanticipated difficult airway (failed direct laryngoscopy): Macintosh-style VL can be used as a rescue device, especially when Cormack-Lehane III/IV and mask ventilation is possible 6, 7

Video laryngoscopes function differently from direct laryngoscopes, changing the relationship between optimal view and successful intubation 8
With video laryngoscopes, especially those with hyperangulated blades, the best glottic view may not correspond with the best chance of passing the tracheal tube easily 8
When the blade is inserted too deeply to achieve a perfect Grade 1 view, the angle for tube insertion becomes more acute and difficult to navigate 9

Traditional direct laryngoscopy relies on aligning oral, pharyngeal, and tracheal axes, whereas video laryngoscopy works differently, considering two curves (oro-pharyngeal and pharyngo-glotto-tracheal) with video laryngoscopes serving to move the eye along the primary curve 10
With video laryngoscopes, particularly those with hyper-angulated blades, a 60° curve is often needed on the stylet to navigate these curves 10

Withdrawing the blade slightly from a Grade 1 view may be beneficial for tube passage when using video laryngoscopes 8
Operators should adopt a "patient-screen-patient" approach rather than fixating solely on the screen 8
The stylet should be shaped to match the curvature of the specific video laryngoscope blade being used 10

Video laryngoscopes optimize laryngoscopic view and have their place either initially or after failure of direct laryngoscopy in difficult intubation algorithms, according to the British Journal of Anaesthesia 11, 12
The C-Mac video laryngoscope performed significantly better than Macintosh direct laryngoscopy, increasing first-attempt success from 55% to 79% 11
The McGrath Mac appears to be the best validated video laryngoscope, showing superiority to Macintosh in laryngoscopy quality and success rates 11

Becoming fixated on achieving a perfect Grade 1 view can paradoxically make tube passage more difficult, as noted by the British Journal of Anaesthesia 8
Failing to shape the stylet appropriately to match the blade curvature can lead to failed intubation despite good visualization 10
Not recognizing when to withdraw the blade slightly from a perfect view to facilitate tube passage 8

Metal blades should be used for direct laryngoscopy in ICU settings to improve endotracheal intubation success rates, as recommended by Anaesthesia 11
Proficiency with any video laryngoscope device requires training and regular practice to understand its optimal positioning, according to the British Journal of Anaesthesia 8