Pediatric emergency medicine trisk 4640 4640
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Tracheostomy Tubes
Modern tracheostomy tubes are made of polyvinylchloride, a soft substance that
conforms to the shape of the trachea, but is rigid enough to avoid collapse. Unlike
their metal predecessors, they have little tissue reactivity, causing less tracheal
wall irritation. Several manufacturers package sterile tracheostomy tubes for onetime use. Intensivists directing the long-term airway management of their patients
may prefer one manufacturer to another, but the emergency physician does not
need to know the minor differences among the products. However, the emergency
physician should know what types of tracheostomy tubes are stocked by the ED’s
facility and how to convert from the patient’s brand and size to an available tube
with suitable dimensions.
Three dimensions determine the size of a tracheostomy tube: the inner
diameter, the outer diameter, and the length. The inner diameter refers to the same
measurement used in describing the size of an endotracheal tube, ranging from
2.5 to 10 mm. This measurement is generally imprinted on the flanges of the
tracheostomy tube and is standardized among manufacturers. The outer diameter
and length are often not identified on the tube and can vary considerably among
manufacturers. When a tracheostomy tube change is indicated and an identical
replacement is not available, the clinician should choose a tube that has
dimensions as close as possible to the patient’s original. Select a replacement tube
that has all three dimensions either equal to or slightly smaller than the patient’s
usual tube. Down sizing to a smaller tube may be indicated as a temporizing
measure until a more suitable replacement tube can be located.
A tracheostomy tube may be cuffed or uncuffed. An infant or young child may
have a cuffed tracheostomy tube, especially if he or she has an airway anomaly or
has developed tracheomegaly. Checking for the presence of a cuff is important
because the cuff must be deflated before removing the tube.
Some tracheostomy tubes are fenestrated. The hole in the posterior aspect of
the tube facilitates retrograde movement of air through the larynx, allowing
vocalization. In addition, some tracheostomy tubes have an inner cannula that is
positioned within the lumen of the tracheostomy tube (i.e., the outer cannula) so
that it can be removed for cleaning while the airway is maintained by the outer
cannula. Importantly, the proximal portion of the inner cannula is required to
connect the tracheostomy to the manual resuscitator bag; therefore, the inner
cannula must be in place when bag–valve ventilation is performed ( Fig. 135.2 ).
