Veni, video, vici:
the slow retreat of the
direct laryngoscope
Almost a year has passed since the
Cochrane Anaesthesia Research
Group's systematic review update
titled Videolaryngoscopy versus direct
laryngoscopy for adults undergoing
tracheal intubation first saw the light
of day [1]. With the entire formatted
manuscript spanning just north of
590 pages, most readers would
be forgiven for not committing to
a deep dive into the nitty gritty of
forest plots and subgroup analyses
comparing various devices used
for intubating the trachea during a
leisurely weekend away. In brief, our
work reaffirmed and strengthened
the findings of the original review
by Lewis et al. from 2016 [2];
videolaryngoscopy reduces overall
intubation failure, improves firstpass
success, improves laryngeal
views, reduces trauma, and is likely
to reduce rates of oesophageal
intubation when compared with
direct laryngoscopy.
These findings come from 222 randomised controlled
trials of 26,149 participants undergoing tracheal
intubation in any setting, comparing outcomes of interest
across the three broad categories of videolaryngoscopes:
Macintosh-style, hyperangulated, and channelled. One
of the highlights was the strong signal of benefit in
a prespecified subgroup analysis looking at patients
with features of airway difficulty, where hyperangulated
devices, such as the GlideScope, the C-MAC D-Blade or
the McGrath X-blade, outperformed direct laryngoscopes
by a wide margin (RR 0.29, 95% CI 0.17 - 0.48). It is worth
pointing out, however, that our study was not designed
to answer the question which of these device types may
perform better than others, a knowledge gap addressed
to some extent by de Carvalho et al. in Anaesthesia [3].
The conclusions of their ranking network meta-analysis
are broadly in keeping with our findings, yet offer the
interested reader a slightly different lens to view the
evidence.
Recently the concept of universal videolaryngoscopy,
first popularised by Cook et al. [4], came under scrutiny
in a somewhat controversial editorial by Lyons and Harte
that generated a fair amount of correspondence among
interested parties [5]. Ideas for alternative terms were
floated on social media, and it is yet to be seen whether
the era of universal videolaryngoscopy will be renamed
something else entirely, now that the die has been cast
and the Rubicon is slowly being traversed. However,
more importantly, the editorial and the river it referenced
provided anaesthetists with an unlikely mirror, and an
opportunity to reflect: what is the evidence threshold that
needs to be crossed for us to update our tools? I suspect
factors that have little to do with evidence-based medicine
and practice are at play. Embarrassingly, I have little in the
way of published evidence to support this assertion, so
it may present a ripe area for future qualitative research
to anyone interested in exploring clinicians' biases and
aversion to change.
In closing, I can only hope that readers will take the
evidence presented at face value, consider how it
may apply to their practice setting, and adjust their
approach to securing the airway accordingly; I know
with what I would want to be intubated. I will finish off
with a very unscientific (n = 1) anecdote. When Professor Andrew Smith first presented me with the opportunity to
work on our review, I was what some might call an ardent
direct laryngoscopist but was also comfortable with both
commonly-used videolaryngoscope designs. I entered my
Cochrane journey with clinical equipoise, and having seen the
evidence at first from close up, followed later with an overview
of the whole forest, I now opt, conditions permitting, for a
videolaryngoscope on most occasions.
Jan Hansel
NIHR Academic Clinical Fellow in Intensive Care Medicine
Wythenshawe Hospital, Manchester University NHS
Foundation Trust
Twitter: @VirtueOfNothing
References
- Hansel J, Rogers AM, Lewis SR, Cook TM, Smith AF.
Videolaryngoscopy versus direct laryngoscopy for adults
undergoing tracheal intubation. Cochrane Database of Systematic
Reviews 2022; 4: CD011136.
- Lewis SR, Butler AR, Parker J, Cook TM, Smith AF.
Videolaryngoscopy versus direct laryngoscopy for adult patients
requiring tracheal intubation. Cochrane Database of Systematic
Reviews 2016; 11: CD011136.
- de Carvalho CC, da Silva DM, Lemos VM, et al. Videolaryngoscopy
vs. direct Macintosh laryngoscopy in tracheal intubation in
adults: a ranking systematic review and network meta-analysis.
Anaesthesia 2022; 77: 326-38.
- Cook TM, Boniface NJ, Seller C, et al. Universal
videolaryngoscopy: a structured approach to conversion to
videolaryngoscopy for all intubations in an anaesthetic and
intensive care department. British Journal of Anaesthesia 2018;
120: 173-80.
- Lyons C, Harte BH. Universal videolaryngoscopy: take care when
crossing the Rubicon. Anaesthesia 2023; in press
doi.org/10.1111/anae.15977.
Cochrane Review Conclusion
Videolaryngoscopy is likely to provide a safer
risk profile compared to direct laryngoscopy
for all adults undergoing tracheal intubation.
Videolaryngoscopes of all designs are likely to
- reduce rates of failed intubation,
- result in higher rates of successful intubation
on the first attempt,
- improve glottic views.
Macintosh-style and channelled videolaryngoscopes
are likely to reduce rates of hypoxaemic events.
Hyperangulated videolaryngoscopes probably
reduce rates of oesophageal intubation.