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Tracheostomies
42
able. Because of this variety and the specific features of each tracheostomy
tube, most hospitals choose one line of tracheostomies for primary use by all
clinicians, supplemented with others as the need arises. This is done primarily
for safety reasons so that clinical staff can become familiar with the primary
features of one particular line of tubes.
the tracheostomies currently on the market in the United States; however, it is
important to consider that some of these tubes have limited use and information is sparse. First, we will discuss the major parts of the tracheostomy.
Parts of a Tracheostomy Tube
Most tracheostomy tubes are composed of only a few standard parts, as shown
in Figure 3.1. For clarity, it is important to be familiar with the names of the
major parts of a tracheostomy tube. The shaft of the tracheostomy tube fits,
It is important for the clinician to be aware of the many tube choices avail-
An effort will be made here to discuss the major characteristics of most of
3.1
Parts of a tracheostomy tube.
Chapter 3 Types of Tracheostomy Tubes and Related Appliances
usually entirely, within the trachea. It may be constructed of plastic, silicone, or
metal, and may be rigid or flexible. The outer diameter of the tracheostomy tube
refers to the widest diameter of the tube itself, excluding the cuff. This diameter varies based on the materials used and the presence of an inner cannula.
The outer cannula of each line of tracheostomies varies in terms of materials,
length, diameter, angle of curvature, and presence of a cuff.
The curvature of the shaft can be angled differently from one type of
tube to another. Figure 3.2 shows the varied curvature of tracheostomy tubes.
Some tubes have a 90-degree angle, or an angle like the arc of a circle, and others have a narrower angle.
The neck plate, or neck flange, fits directly against the neck and allows the
tracheostomy tube to be anchored to the neck. The outer cannula may or may
not have a cuff. There may or may not be an inner cannula. Decisions about
when and why to place a cuffed versus an uncuffed tracheostomy will be discussed in chapter 4. If a cuff is present, it is connected to the pilot balloon by
means of an inflation line. The inflation port, or inflation valve, at the distal end
of the pilot balloon allows for the attachment of a syringe to inflate the cuff.
Nothing other than a syringe should be connected to the inflation port.
Sizing of a Tracheostomy Tube
The size of the tracheostomy tube usually refers to the inner diameter of the
inner cannula. In other words, the inner diameter reflects the narrowest diameter of a particular tracheostomy tube. However, there are two sizing systems
for tracheostomies: the Jackson sizing system and the International Standards
Organization (ISO) sizing system. The Jackson sizing system was initially used
43
3.2
Curvature of shafts on different tracheostomy tubes. Note the relatively narrow angle
of the tube on the left (Shiley SCT), compared to the wide angle of the tube on the right
(Arcadia Air Cuff).
Tracheostomies
44
with metal tracheostomy tubes and is still used with the Jackson and Shiley
brands. It is important to note that the two largest tracheostomy manufacturers
in the United States (Portex and Shiley) use different sizing systems. The Shiley
tracheostomies and all of the metal tracheostomy tubes use the Jackson sizing
system, while the Portex, Bivona, TRACOE, and Arcadia tracheostomy tubes are
sized using the ISO system. The ISO sizing system refers to the inner diameter of the outer cannula; however, the Jackson sizing system does not directly
refer to the inner diameter (Dhand & Johnson, 2006; St. John & Malen, 2004).
For example, the inner diameter of a size 6 Portex cuffed tracheostomy tube is
6.0 mm; however, the inner diameter of a comparably sized Shiley 6 cuffed tracheostomy tube is 6.4 mm.
eter of the tracheostomy both with and without the inner cannula in place. Some
manufacturers state these two different inner diameters because it may make
a difference when fitting a tracheostomy. When the inner cannula is in place, it
can decrease the diameter of the tube by up to 2 mm. These 1 or 2 mm can sometimes make a surprising difference in a patient’s ability to breathe comfortably.
The Inner Cannula
The inner cannula, when present, nests within the outer cannula and is secured
to it. The primary purpose of the inner cannula is to clear secretions through
cleaning or replacement at regular intervals. The standard inner cannula is
used most often in the hospital setting because it frequently provides a 15-mm
adapter—the standard connection for a manual resuscitation bag, ventilator
tubing, and other respiratory and airway appliances. Cosmetic inner cannulas
lack this adapter and give a low-profile appearance to the tracheostomy. Therefore, cosmetic or low-profile inner cannulas should probably not be used in the
hospital to avoid confusion in case of an emergency. Outside of the hospital, the
cosmetic inner cannula may be used when a low-profile appearance is desired.
place at all times. Different manufacturers provide different locking mechanisms for their tracheostomy tubes, and they are not interchangeable from one
manufacturer to another, from one model to another, or from one size to another. Failure to lock the inner cannula can result in inadvertent dislodgement,
as it may be easily coughed out.
St. John and Malen (2004) point out that one must consider the inner diam-
It is important to ensure that the inner cannula, when present, is locked in
The Obturator
The sole purpose of the obturator, sometimes called a pilot, is to assist with
the insertion of the tracheostomy tube. Typically, it is necessary to remove the
inner cannula in order for the obturator to fit within the outer cannula. The
blunted tip of the obturator cushions the distal tip of the tube as it is inserted,
avoiding potential tissue damage as it is advanced into the trachea. Immediately
following placement, the obturator should be removed and replaced with the
inner cannula (when present). The obturator should then be placed in full view,
Chapter 3 Types of Tracheostomy Tubes and Related Appliances
allowing rapid visualization and access in the event of an emergency, such as
inadvertent decannulation.
The Neck Flange or Neck Plate
The purpose of the neck flange is to stabilize the tracheostomy tube, seating it
against the neck and preventing it from migrating inward. The neck flange contains an opening at its lateral ends so it can be secured to the neck, typically by
means of cloth tape, a soft collar, or sometimes a chain. The neck flange can be
fixed to the shaft of the tube, or it can be adjustable and adaptable to a variety
of needs.
The neck flange can be rigid or flexible. If rigid, it may tilt on the horizontal
plane, the vertical plane, or both. This tilting mechanism is designed to provide
comfort as well as adjust for patient movement; however, it can also be a source
of inward traction against the stoma.
The neck flange is an important source of clinical information. The specifications of each tube are usually imprinted or embossed on it. One can usually
find the manufacturer’s name, the model name or code, the inner diameter, the
outer diameter, and sometimes the length.
The Pilot Balloon and the Inflation Line
45
The inflation line is used to inflate or deflate the cuff. At the distal end of the
inflation line is the cuff. At the proximal end of the inflation line are the pilot
balloon and the inflation valve. The shape of the pilot balloon indicates whether
or not there is air within the cuff. A completely flat pilot balloon indicates there
is no air in the cuff, and an inflated pilot balloon indicates there is some air in
the cuff. Many experienced clinicians believe they can accurately estimate cuff
pressure by palpating the pilot balloon; however, one study showed that cuff
pressure was accurately estimated by palpation only 61% of the time (Faris et al.,
2007).
The Cuff
One of the primary purposes of the cuff is to seal the airway, especially with
positive-pressure ventilation. When the cuff is inflated, there is no admixture
of room air with inspired gases, and the patient breathes entirely through the
tracheostomy tube. Deflation of the cuff allows for the admixture of room air as
part of the inspired tidal volume.
Cuffs have evolved over time. Early tracheostomy tubes were made of metal,
and early cuffs were detachable and often made of rubber. These rubber cuffs
created high pressures against the trachea and resulted in numerous complications, including airway obstruction from detached cuffs. Over the years, these
high-pressure cuffs have been almost totally replaced by high-volume, lowpressure cuffs (Quigley, 1988).
Tracheostomies
46
3.3
Shape of cuffs on different tracheostomy tubes. From left to right: Bivona TTS (low volume,
high pressure), Shiley SCT (barrel shaped, low pressure, high volume), Bivona
Fome-Cuf (low pressure, high volume), Portex Blue Line (teardrop shaped,
low pressure, high volume).
Cuffs come in different shapes, sizes, and types, some of which are illustrated in Figure 3.3. There are barrel-shaped cuffs, teardrop-shaped cuffs, and
foam-type cuffs. There are cuffs that are filled with air and others that are filled
with fluid. There are still some high-pressure cuffs, but today, most are low
pressure. Each of these cuffs has different characteristics.
The barrel-shaped cuff is designed to diffuse pressure along a wider surface area. Rather than creating specific pressure points with a circular balloon,
the barrel-shaped cuff minimizes pressure points.
The teardrop-shaped cuff was designed to minimize the pistoning effect—
the up-and-down movement of the cuff with positive-pressure breaths. Pistoning will be discussed in chapter 5.
The foam-type cuff tracheostomy tube has an extra-large cuff that naturally expands to fit the shape of the trachea. It was designed to overcome problems with continued leaks around the cuff, while minimizing pressure-related
problems.
A deflated cuff that lies tight to the shaft of the tracheostomy tube allows
laminar airflow around it, lessening resistance. This is in contrast to the cuffs of
most tracheostomy tubes, which have some bulk when deflated. Decisions regarding the most appropriate type of cuff are discussed in chapter 4.
The inflated cuff is used to protect the airway when the patient is unable
to do so. It also creates a seal in the airway when delivering positive-pressure
Chapter 3 Types of Tracheostomy Tubes and Related Appliances
ventilation. Inflation of the cuff can help prevent secretions, fluid, or food from
entering the lungs, but its success depends on many factors and is not guaranteed. It is important to realize that inflation of the cuff does not prevent aspiration. For a patient who cannot protect his airway, aspiration precautions must
be maintained even though the cuff is inflated. This includes elevation of the
head of the bed, checking residuals for the patient with enteral feedings, optimizing cuff pressure, and so forth.
Capillary perfusion pressure is considered to be between 20–30 cm H
(conversion factor to kPa: 1 cm water = 0.098 kPa; Bernhard, Yost, Joynes, Cothalis, & Turndorf, 1985; Duguet et al., 2007). The challenge is to maintain a cuff
pressure high enough to ensure an adequate seal to provide optimal delivery
of positive-pressure breaths and prevent the seepage of secretions around the
cuff yet low enough to minimize pressure against the trachea.
Another purpose of the cuff is to seat the tube squarely in the center of the
trachea and protect it from creating erosion against the trachea. Lateralization
of the tube can result from herniation of the cuff and/or additional pressure
against the trachea. Lateralization can also lessen optimal delivery of positive
pressure, which can result in increased airway pressures.
O
2
General Types of Tracheostomy Tubes
47
Tracheostomy tubes can be classified into four major groups: dual-cannula,
cuffed; dual-cannula, uncuffed; single-cannula, cuffed; and single-cannula,
uncuffed. However, there are certain types of tracheostomy tubes that, while
they fit into one of these general categories, have other unique features that
have certain implications and require further discussion. These unique tubes
include metal tracheostomy tubes, fenestrated tubes, and extra-length tubes.
The following is a discussion of the wide variety of tracheostomy tubes available today, with some explanation of their strengths, weaknesses, and indications for use.
Standard Dual-Cannula Cuffed
Tracheostomy Tubes
The standard dual-cannula cuffed tracheostomy tube is often the first choice
for a patient who requires positive-pressure ventilation or otherwise cannot
protect his or her airway. The inner cannula provides added protection for patients with copious secretions, as it can be easily removed and cleaned or replaced. It is locked in place to the outer cannula, and the method of securing the
inner cannula varies by model. The features of different types of dual-cannula
tracheostomy tubes are described in the following.
Tracheostomies
48
Shiley LPC (Low-Pressure Cuff )
Structure: Cuffed, dual-cannula, arc
of circle curvature
Material: Rigid polyvinyl chloride
Manufacturer: Covidien
Unique Features: Nondisposable
inner cannula, rigid neck flange
that tilts on horizontal plane
Use: Patients who require a cuffed
tube for positive-pressure ventilation, airway protection, or when
secretions are a concern
Shiley LPC tracheostomy tube (Covidien).
The Shiley LPC dual-cannula tracheostomy tube is made of a rigid polyvinyl chloride. The neck flange has a horizontal swivel mechanism that can accommodate some patient movement. The inner cannula locks in place with a
twist-lock mechanism. When the blue dot on the outer cannula aligns with the
blue dot on the inner cannula, it is locked in place. Unless the blue dots are
aligned, the inner cannula can be easily dislodged or coughed out.
The 15-mm connector is built into the inner cannula of all Shiley dualcannula tracheostomy tubes; therefore, an inner cannula must be with the patient at all times because respiratory and anesthesia equipment can only be
attached when the inner cannula is in place. On the neck flange is printed
the size, type, and internal and outer diameter of the tube. The lateral edges of
the neck flange have openings of a somewhat softer material so it is easier to
attach tracheostomy ties.
Chapter 3 Types of Tracheostomy Tubes and Related Appliances
Shiley DCT (Disposable Inner Cannula)
Structure: Cuffed, dual-cannula, arc
of circle curvature
Material: Rigid polyvinyl chloride
Manufacturer: Covidien
Unique Features: Disposable inner
cannula, rigid neck flange that tilts
on horizontal plane
Use: Patients who require a cuffed
tube for positive-pressure ventilation, airway protection, or when
secretions are a concern
49
Shiley DCT tracheostomy tube (without inner cannula) (Covidien).
Covidien makes two standard-sized dual-cannula cuffed tracheostomy
tubes. The Shiley LPC provides a nondisposable rigid inner cannula, and the
Shiley DCT provides a somewhat softer, disposable inner cannula. The outer
cannulas of the Shiley LPC and DCT tracheostomies are almost identical and
are constructed of rigid polyvinyl chloride. The primary difference between
these two tubes is their locking mechanisms and that the inner cannulas are
not interchangeable. With the Shiley DCT, “wings” on each side are pinched
together and provide a clipping mechanism (not unlike a telephone jack) when
the inner cannula is locked in place. This is in contrast to the twist-lock mechanism of the LPC. The inner cannula of the Shiley DCT is constructed of a softer
and more flexible material than the inner cannula of the LPC, and it is intended
for limited-time use.
Another difference between the Shiley LPC and DCT tubes is the neck
flange. The neck flange of the LPC is rounded and semiflexible; however, the
neck flange of the DCT can be rectangular and rigid. For both the Shiley LPC
and DCT, the inflation line lies on the shaft of the outer cannula. With all Shiley
dual-cannula tracheostomy tubes, the attachment of a manual resuscitation bag
or ventilator is possible only when the inner cannula is locked in place.
Tracheostomies
50
Shiley PERC (Percutaneous)
Structure: Cuffed, dual-cannula, arc
of circle curvature
Material: Rigid polyvinyl chloride
Manufacturer: Covidien
Unique Features: Tapered distal tip
and inverted cuff shoulder allow
ease of insertion when loaded on
dilator
Use: For use with percutaneous
procedure
Shiley PERC tracheostomy tube loaded on Blue Rhino dilator
(Covidien).
The Shiley percutaneous tracheostomy tube, PERC, is included in a kit
manufactured by Cook Medical in their line of percutaneous tracheostomy
introducer sets and trays. The tube itself is very similar to the Shiley DCT
tube; however, the distal tip is tapered and the cuff has an inverted shoulder
to facilitate its placement with an introducer. With the PERC, the introducer
is also a dilator. Using the modified Ciaglia technique, the PERC is advanced
into place while it is loaded on the dilator—called the Blue Rhino or the newer,
fluid-filled Blue Dolphin.
Chapter 3 Types of Tracheostomy Tubes and Related Appliances
Portex Per-fit
Structure: Cuffed, dual-cannula
Material: Flexible polyvinyl chloride
Manufacturer: Smiths Medical
Unique Features: Tapered distal tip allows ease
of insertion over dilator
Use: For use with percutaneous procedure
Portex Per-fit tracheostomy tube. Note tapered distal tip
of percutaneous tube for easier insertion over dilator.
Photo courtesy of Smiths Medical.
The Portex version of the percutaneous tracheostomy is called the Portex
Per-fit. The tube itself is made of flexible polyvinyl chloride with a tapered distal tip and low-profile cuff. The percutaneous tracheostomy kit has a series of
dilators for use with the Ciaglia technique. (The percutaneous technique of tracheostomy placement is discussed in chapter 2.) The tapered distal tips of both
the Shiley PERC and the Portex Per-fit are designed for an easier fit over a dilator, facilitating easier insertion.
51
Portex DIC
Portex DIC cuffed tracheostomy tube. Photo courtesy of
Smiths Medical.
Structure: Cuffed, dual-cannula, arched curve
Material: Rigid polyvinyl chloride
Manufacturer: Smiths Medical
Unique Features: Color-coded inner cannula
to identify size; the 15-mm connector is fused
with the outer cannula so a manual resuscitation bag can be used without the inner
cannula in place
Use: Patients who require a cuffed tube for
positive-pressure ventilation, airway protection, or when secretions are a concern