Discussion
Difficult tracheal intubation of the trauma victim may be
encountered a s a consequence of neck immobilisation,
trauma to the face and airway, or poor patient preparation
and evaluation. It is now generally accepted that. in
Table 1. Grading at laryngoscopy in 102 patients using the
McCoy laryngoscope blade in the standard Macintosh
configuration and with the tip in the activated position.
Grade at laryngoscopy
1 2 3 4
Macintosh configuration 41 29 25 1
Activated McCoy I8 22 2 0
Number of patients
( I 1 = 46) I 10 14 21
experienced hands. orotracheal intubation with manual
in-line neck inimobilisation and application of cricoid
pressure. if appropriate, is the method of choice [or securing
the airway of the trauma victim in an emergency [2. 31. Aids
to intubation should always be available and. in particular,
the gum elastic bougie has been shown to be useful in this
scenario [I].
There may be circumstances when removal of the
cervical collar is not appropriate or possible e.g. lack of
personnel or prehospital care and intubation is required
urgently [4]. Recent work has suggested that the view
obtained at laryngoscopy in the presence of a cervical
collar is considerably worse than when manual in-line
neck stabilisation is used alone [7]. This may be because
the mouth and jaw cannot be fully opened, making
laryngoscopy potentially more difficult.
The McCoy laryngoscope has been developed as a
modification of the standard Macintosh blade [5]. At the
time of this study it was only obtainable with a size 3
blade. although a size 4 is now available. The laryngoscope
blade has a hinged distal tip allowing elevation of the
epiglottis via the hyo-epiglottic ligament from a much
deeper point within the larynx. Undue force need not be
applied to the teeth or airway structures and the tendency
to further manipulate the neck can be avoided. Recent
work has confirmed that the McCoy laryngoscope uses
less force to reveal laryngeal structures than the
conventional Macintosh blade and that the stress response
to laryngoscopy is reduced [8, 91. This study was undertaken
to confirm the assertion of McCoy and Mirakhur [5]
and preliminary reports [lo] that the McCoy blade
would improve the laryngoscopic view in patients with
anatomically immobile cervical spines.
The results confirm that the view obtained at laryngoscopy
with the McCoy laryngoscope blade activated is
significantly better than when the Macintosh configuration
is used in patients wearing appropriately sized cervical
collars. In only two patients could no glottic structures be
identified when the McCoy tip was used. Of more clinical
importance were the 26 patients in whom laryngoscopy was
difficult (grade 3 or 4) using the Macintosh configuration.
Twenty-four (92.3%) of these had some part of the glottis
exposed (grade 1 or 2) when using the McCoy tip. This is
extremely important in the trauma scenario, since a grade
3 laryngoscopy is often encountered unexpectedly and
encourages the use of excessive force with a standard
laryngoscope. This may result in potentially dangerous
movement of the cervical spine. The gum elastic bougie may
prove useful in this situation, but it can cause damage and
prolongs intubation time [I]. Its use is still to be commended
in those situations when a grade 3 laryngoscopy is
encountered despite using the McCoy laryngoscope.
Finally, this study also confirms an earlier report that
many patients who have their neck immobilised in a neutral
position with a rigid, cervical collar demonstrate a poor
Annc,srhesirr. Volume 5 1. September I996
814 D.A. Gabhott
view of laryngeal structures at conventional laryngoscopy
[7] and that aids to intubation should always be available
in these circumstances.
In conclusion, the McCoy laryngoscope significantly
improves identification of glottic structures in patients
wearing a rigid. cervical neck collar. Its use is to be
encouraged if attempts are made to intubate the tracheas of
patients with potential cervical spine injuries when removal
of the cervical collar is not practical or possible.
Acknowledgments
I thank Dr C. Monk for his help and advice and 'Penlon',
UK for their loan of the McCoy laryngoscope.