BACKGROUND
Tracheostomy has been performed since ancient times. In 1833, Armand Trousseau invented an instrument designed to dilate the incision into the airway, to allow easier passage of a tracheostomy tube (Fig. 1).1 We have observed that tracheal dilators are always included in the pack when changing a tracheostomy tube in an established tracheostomy or when there is stenosis of the stoma.2–4 We believe, however, that, in these circumstances, the Trousseau dilator impedes the insertion of a tube and could be dangerous in an emergency.
Figure 1.
The Trousseau tracheal dilator.
TECHNIQUE
We used two sheets of rubber: one cut with a circular hole to represent a stenosed stoma and one with a vertical slit to represent a tracheostomy incision. We then measured the vertical and horizontal diameters of the holes before and after using the tracheal dilator to 50% and 100% of its capacity. In a circular stoma, the vertical height decreases from 5 mm to 4 mm (20%) when dilated (Figs 2–4). Dilating a vertical slit, however, only reduces the vertical diameter by 10% from 20 mm to 18 mm (Figs 5-7).
Figure 2.
Hole cut to simulate stenosed stoma.
Figure 4.
Stenosis dilated 100%.
Figure 5.
Slit cut to simulate traditional tracheostomy incision.
Figure 7.
Slit dilated 100%.
Figure 3.
Stenosis dilated 50%.
Figure 6.
Slit dilated 50%.
DISCUSSION
A slit incision, when dilated, becomes a diamond-shaped aperture through which a tube can easily be passed. In the circular hole, the instrument constricts the available aperture by 20%. Our simple experiment has confirmed our suspicions that using a tracheal dilator in cases of annular stomal stenosis can make the task of inserting a tracheostomy tube more difficult, by narrowing the aperture. Is it time for our wards and emergency departments to consign the Trousseau dilator to the historical archive?
References
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