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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4597_Библиотеки_им_академика_М_И_Перельмана.pdf
Tracheostomies
192
6.6
Montgomery
Ventrach (left)
and Montgomery
valve (right). Photo
courtesy of Boston
Medical Products.
All rights reserved.
6.7
Passy-Muir valves.
Clockwise from far
left: PMV
PMV
007, PMV
PMV
PMA
courtesy of PassyMuir.
TM
2000,
TM
005, PMVTM
TM
2020-S,
TM
2020, and
TM
2000. Photo
closure of the valve, which is accompanied by a noticeable click. This valve
was discontinued in 2000 (based on personal communication, Rachel Proctor,
Olympic Medical, May 21, 2009). The Shiley Phonate speaking valve (Figure 6.8)
is bias-closed with a silicone diaphragm. It has a hinged cap that makes the
diaphragm available for cleaning. One model has a port to attach to an oxygen
source; however, this model was not included in the study. The Montgomery
Ventrach has a bias-open silicone diaphragm and can be used with ventilatordependent patients. The Passy-Muir PMV
TM
PMV
dependent patients. The PMV
ing, and the others are used with rubber nondisposable tubing. All the PassyMuir valves are bias closed (Zajac et al., 1999). The PMV
version of the PMV
without 15-mm adapters (Fitsimones, 2003).
the 1999 study were higher than in the earlier work because they were associated with patients on mechanical ventilation. Except for minor differences, all
the valves exhibited similar low resistance—even those with a bias-closed design. There were some differences in manufacturing specifications between the
2000 (clear), and PMVTM 2001 (purple) can also be used for ventilator-
TM
2000, was designed for use with metal tracheostomy tubes
Each of these valves was tested using different flow rates. The flow rates in
TM
007 can be used with disposable ventilator tub-
TM
005 (white), PMVTM 007 (aqua),
TM
2020, a modified
Chapter 6 Phonation With a Tracheostomy
6.8
Shiley Phonate with
oxygen port (SSVO).
Covidien.
6.9
Eliachar speaking
valve. Hood Labs
(Pembroke, MA).
193
1993 and 1999 studies. The researchers measured the thickness of the PMVTM
007 and found a thinner diaphragm than in the earlier study. This could explain
the finding of reduced resistance; however, they were unable to confirm a design change with the company (Zajac et al., 1999).
These six valves were also tested in vivo with the use of a mouthpiece;
patients repeated the sound /pa/, and the researchers tested for leakage of air
through the valve. They found that both the Olympic Trach Talk and the Montgomery Ventrach showed significant air loss during expiration when the valves
should have been closed (Zajac et al., 1999).
The Eliachar speaking valve (Figure 6.9) is made of silicone and is designed
for use with the Hood stoma stent. It has a low-profile appearance and flap
design that provide low resistance. The Hood speaking valve (Figure 6.10) and
the TRACOE Phon Assist are both flap valves. The Phon Assist has an oxygen
supply port, but its most unique feature is an adjustable airflow mechanism that
patients can use to dial up their desired level of airflow.
The Shikani-French valve uses a different mechanism than the other diaphragm valves—a unidirectional flow ball valve. It has lower resistance, a lower
profile, and is more easily hidden under clothing than the other valves (Shikani, French, & Sievens, 2000). Originally called the Hopkins valve, the ShikaniFrench valve has been adapted for use with plastic as well as metal tracheostomy
tubes. Figure 6.11 shows the mechanism of the Shikani-French ball valve. In the
6.10
Hood speaking
valve. Hood Labs
(Pembroke, MA).
6.11
Mechanism of ShikaniFrench valve. Reprinted
with permission
from “Preserving
Oral Communication
in Individuals With
Tracheostomy and
Ventilator Dependency,”
by D. C. Tippett and
A. A. Siebens, 1995.
American Journal
of Speech Language
Pathology, 4
Copyright 1995 by the
American SpeechLanguage-Hearing
Association. All rights
reserved.
(2), 55–61.
Chapter 6 Phonation With a Tracheostomy
resting state, the ball lies on the wall of the air chamber (A). On inspiration, the
ball moves toward the opening of the cannula, allowing air to enter the cannula
(B). Airflow pushes the ball back, but it is prevented from entering the cannula by a wire stop. On expiration (C), the ball seals the port, forcing air into
the upper airway. Because of this design, less pressure is required for valve
closure, which is almost instantaneous. This is especially important in patients
with very low tidal volumes and vital capacities. The valve is more compact than
the other valves and can be used in the standard versions of all commercially
available tracheostomy tubes. The valve can also replace the inner cannulas of
these tubes and provide lower resistance (Shikani et al.).
One study compared the Shikani-French ball valve (named Hopkins at the
time of the study) with the Passy-Muir valve and found less inspiratory resistance and easier cleaning with the ball valve (Tippett & Vogelman, 2000).
The Tucker valve uses a different mechanism. The Tucker tracheostomy
tube is composed of metal with a fenestrated flap on the inner cannula that
opens on inhalation and closes on exhalation. This action forces air up through
the upper airway (Tippett & Vogelman, 2000). Airflow during inspiration rotates
the flap to an open position and then to a closed position during expiration
(Tippett & Siebens, 1995).
195
The Clinical Use of Speaking Valves.
speaking valves are externally placed on the 15-mm or low-profile connector
of a cuffless or deflated-cuff tracheostomy tube. Patients and their caregivers require education to effectively use the valve and to alleviate any anxiety
about shortness of breath. They also need to know how to remove the valve in
the event of acute dyspnea. Patients should not be left unsupervised with the
valve in place until their ability to tolerate it has been established (Tippett &
Vogelman, 2000).
Initially, a schedule for using the speaking valve should be structured to target continuous wearing during daytime hours. The manufacturer recommends
that the Passy-Muir valve not be used while sleeping; however, one study established its potential usefulness for one night in seriously ill tracheostomy
patients without any untoward effects such as apnea, desaturation, respiratory
distress, or cardiac arrhythmias. Accordingly, recommendations for testing these
valves for longer night duration were concluded (Gross, Atwood, Grayhack, &
Shaiman, 2003).
Studies have shown that speaking valves provide more benefits than merely
verbal communication. Lichtman and colleagues (1995) studied the potential
secondary benefits of speaking valves. They found that patients accumulated
significantly fewer secretions with speaking valves than without. Other reported benefits include more effective swallowing, more effective coughing, a
restoration of intrinsic PEEP, an enhanced Valsalva maneuver, and the prevention of aspiration.
Several studies have examined the effect of speaking valves on aspiration.
Dettelbach, Gross, Mahlmann, and Eibling (1995) studied 11 patients with tracheostomies and clinical evidence of aspiration. They found that aspiration was
reduced or eliminated in all patients when a speaking valve was in place. Suiter
and others (2003) studied swallow physiology as well as the incidence of aspiration with tracheostomized nonventilator-dependent patients under three
With the exception of the Tucker valve,
Tracheostomies
196
different conditions: cuff inflated, cuff deflated/cuffless tube, and with a PassyMuir speaking valve. They found that cuff deflation significantly improved
swallowing ability by increasing both pharyngeal transit duration as well as
duration of hyoid excursion. In addition, they found that cuff status had no effect on aspiration. However, there was significantly less incidence of aspiration
with the speaking valve when compared to the cuff-inflation and cuff-deflation
conditions. Eight out of 10 patients who aspirated thin liquids with cuff inflation or deflation were able to safely take liquids with the valve in place. The
authors concluded that the speaking valve might restore subglottal air pressure
lost with use of a tracheostomy tube and that patients who are unable to tolerate thin liquids may be able to ingest them safely with the valve in place.
Elpern, Okonek, Bacon, Gerstung, and Skrzynski (2000) also studied the
effect of the Passy-Muir valve on aspiration and obtained different results. In
their study of 15 patients with tracheostomies and evidence of aspiration, 7 patients aspirated thin liquids, 5 patients aspirated only when the valve was off,
and 2 patients aspirated with and without the valve. They found that aspiration
was less frequent with the valve in place and concluded that a speaking valve
can reduce, but not eliminate, aspiration in patients with a tracheostomy.
Manzano and colleagues (1993) found that the use of a speaking valve decreased the amount of secretions, improved the ability to cough, reduced the
need for tracheal suctioning, and improved the sense of smell in patients. Although they did not specifically study patient mood, they also found that patients appeared to be happier and interacted better with their families and
nursing staff.
Contraindications for Speaking Valves.
benefits in addition to speech, not all patients can tolerate them. Patients with
poor pulmonary reserves can develop hypercarbia. Because some degree of air
trapping can occur with speaking valves, patients with severe lung disease may
not be able to fully exhale (Kazandjian & Dikeman, 2008). The contraindications
for the use of a speaking valve are listed as follows:
■
Inability to tolerate cuff deflation (risk of aspiration)
Hemodynamic instability ■
Severe pulmonary disease ■
Total laryngectomy ■
Vocal cord paralysis ■
While speaking valves provide many
Patients Who Require Intermittent Positive-Pressure Ventilation
It is clear that patients who require continuous positive-pressure ventilation
need a cuffed tube; however, patients who use intermittent ventilation require
cuff inflation only during that time. Intermittent positive-pressure ventilation is
applied to patients during weaning from mechanical ventilation, for nocturnal
ventilation, and for bronchial hygiene. As patients are weaned from continuous
mechanical ventilation, they spend increasing amounts of time free from the
Chapter 6 Phonation With a Tracheostomy
ventilator at which time the cuff can be deflated. During the weaning process,
altering the tracheostomy tube can accommodate the patient’s changing goals.
When patients do not require continuous cuff inflation, it is usually relatively easy to restore phonation when they are without the ventilator. This can
be done by simply deflating the cuff and occluding the tube to allow air up to
the vocal cords, while assessing for the adequate movement of air around the
deflated cuff. However, cuffed tubes should never be capped. Thus, these patients will require a different type of tracheostomy tube.
The Bivona TTS and the Arcadia CTS are ideal choices to accommodate a
patient who requires intermittent cuff inflation. In contrast to standard lowpressure, high-volume cuffs, these tubes have low-volume, high-pressure cuffs.
When inflated, they can exert high pressures against the tracheal wall, so careful attention to minimizing cuff pressure should guide practice. The significant
advantage of this type of tube is its deflation characteristics, which allow it to
lie flush against the shaft of the tube when deflated, creating no obstruction
to airflow outside the tube. When deflated, the TTS and CTS tubes function as
cuffless tubes, and they are the only cuffed tubes currently on the market that
can be capped safely.
A TTS or CTS tube can be capped while the patient is free from the ventilator, and the cuff can be inflated when returning to the ventilator. This technique
often speeds up the weaning process and frequently marks the beginning of
freedom from the ventilator.
When inflating the cuff of the TTS or CTS tubes, the clinician must take
care to ensure minimal pressure in the cuff. Because of the inflation characteristics of the high-pressure cuff, direct cuff pressure measurement will result in
a high reading; thus, the minimal leak technique is recommended. In order to
distribute pressure evenly and prevent a loss of cuff volume from the diffusion
of gas, the cuff should be inflated with sterile water (not saline).
A CTS or TTS tube is also ideal for patients who require intermittent cuff
inflation because of bronchial hygiene or administration of inhaled medications. The cuff can be inflated during these maneuvers and deflated after
completion.
In addition to concerns with the high-pressure cuff, the primary disadvantage of the TTS and CTS tubes is that they are single-cannula tubes. Patients
who have large volumes of thick secretions may be at particular risk for tube
obstruction because these tubes lack an inner cannula. In this case, measures
should be taken to ensure optimal mobilization of secretions, or it may be necessary to change to a tube with an inner cannula.
197
Patients Who Require Continuous Mechanical Ventilation
Unless there are extenuating circumstances, phonation should not be attempted
in patients who are hemodynamically unstable and on mechanical ventilation.
In most cases, it is best to wait until patients are more stable and can tolerate
cuff deflation because most options for phonation require cuff deflation or tube
change.
There is competition between airflow requirements for speech and gas exchange in the ventilator-dependent tracheostomy patient (Shea, Hoit, & Banzett,
Tracheostomies
198
1998). Normally, patients speak during expiration using air that has already been
used for gas exchange. Competition occurs when patients “steal” air from alveolar ventilation during the inhalation phase, producing sound by diverting air
around the tracheostomy tube and up to the larynx. Speech during inhalation
produces relative hypoventilation.
Shea and others (1998) asked five patients with long-term tracheostomies
to perform two speaking tasks. The patients read a standard text and spoke
extemporaneously while the investigators measured speech ventilation volumes. All the subjects had either a fenestrated tracheostomy tube or a deflated
cuff. They performed both tasks under normal conditions with 100% oxygen
and under experimentally induced hypercapnic conditions using a mixture of
carbon dioxide and oxygen. Normal individuals at rest will hyperventilate during speaking. The investigators noted an average loss of 14% of alveolar ventilation when speaking. During induced hypercapnia, which caused shortness
of breath, all the subjects could still speak adequately. Two patients adapted
to hypercapnia by reducing the amount of air used for speaking. One patient
increased the airflow used per syllable during hypocapnic speech, which is a
maladaptive strategy. The investigators concluded that there is complete antagonism between the airflow requirements for speaking and gas exchange
during the ventilator’s inspiratory phase. In their experiment, the behavioral drive to speak was modified but never fully suppressed by increasing
respiratory drive.
Leak Speech (Cuff Deflated)
Leak speech involves creating a leak in the seal between the cuff and the trachea so that some air can be diverted up to the vocal cords. The ventilator
provides the power behind the voice, and ventilator settings are adjusted to
accommodate the leak. Leak speech is possible only when the patient uses a
deflated cuff, a cuffless tube, or a fenestrated tracheostomy (MacBean et al.,
2008). In addition, leak speech is possible only when airflow is sufficient to
generate adequate subglottal pressure. This pressure is usually limited to the
inspiratory cycle and the beginning of the expiratory cycle. For this reason, leak
speech is characterized by bursts of short phrases and long pauses (Hoit et al.,
2003; MacBean et al.).
Leak speech is beneficial because it improves patient quality of life by restoring communication, and the required cuff deflation reduces pressure against
the trachea. However, it also involves trial and error until the optimal settings are
achieved. Optimal leak speech requires ventilator adjustments to produce the
best voice quality without discomfort or shortness of breath.
Inspiratory speech is something of a paradox because normal speech commences during expiration. Competition of tidal volume use between speech and
ventilation varies with glottic resistance, which can be consciously controlled by
the patient. When the glottis is narrowed, more tidal volume is delivered to the
lungs; when there is little laryngeal resistance, less tidal volume is delivered to
the lungs (Tippet & Vogelman, 2000).
Typically, the first step toward leak speech is to assess the size of the tracheostomy tube with the cuff deflated. One must ensure the patient can move
enough air comfortably around the deflated cuff. If the patient is unable to
Chapter 6 Phonation With a Tracheostomy
move enough air, it may be necessary to downsize the tracheostomy tube. Following cuff deflation, the tidal volume should be increased up to 50% more than
for resting ventilation, and the inspiratory time can also be increased to permit comfortable and longer speech. During initial trials, the patient will require
some coaching to speak on inspiration when the ventilator breath is delivered.
Inspiratory speech often requires some practice because it is the opposite of
normal.
Some patients report anxiety or discomfort with leak speech because of the
flow of air through the upper airway; this is especially common in those who
have not experienced this sensation for a long time. This is often resolved by
coaching the patient to time their voicing with inspiration. It may also help to
instruct patients to push down, hold their breath, or tighten their throat. Patients
can be taught to widen or narrow their glottic aperture in order to increase or
decrease the volume delivered to the lungs (Tippet & Vogelman, 2000).
If patients become breathless during a leak speech trial, tidal volume or
flow rate can be increased. Another strategy is to add PEEP. The addition of
PEEP has several advantages, including lengthening the duration of tracheal
pressure for voicing into the exhalation phase. Adding PEEP can allow patients
to speak through 80% of the respiratory cycle (Hess, 2005; Hoit et al., 2003;
Hoit & Banzett, 1997; Hoit, Shea, & Banzett, 1994; MacBean et al., 2008; Shea
et al., 1998). The addition of 4–15 cm H
produce higher quality speech, and allow more syllables per ventilator cycle.
Patients using leak speech with PEEP have been observed to speak through the
entire ventilator cycle without any pauses for breathing (Hess).
O of PEEP can extend speech duration,
2
199
Leak Speech With a Speaking Valve.
speaking valve rather than PEEP. Only three speaking valves are approved by
the FDA for use with ventilator-dependent patients—the Montgomery Ventrach
and Passy-Muir models PMV
Speaking valves allow the ventilator to deliver a breath through the tracheostomy tube while the exhaled air is redirected around the tube—and so,
it is essential that the cuff be completely deflated. Manzano and others (1993)
used the Passy-Muir valve in their series of ventilator-dependent patients to
determine its usefulness, advantages, and disadvantages during mechanical
ventilation. Because cuff deflation is vital to the use of the speaking valve, they
recommended that a cuffless tracheostomy tube be used while the valve is in
place. The presence of a deflated cuff makes aspiration possible, and because
of this, it is necessary to closely monitor tidal volume peak inspiratory pressure, thoracic movements, the elimination of secretions, and continuous airflow
through the mouth and nose.
Figure 6.12 shows the placement of the valve within the ventilator circuit.
The speaking valve can be applied one of two ways. For patients with a
closed suction system, the valve should be applied to the side port to allow
the suction catheter to pass easily into the tracheostomy tube (Hess, 2005). For
patients who are not using a closed suction system, the valve can be applied
directly between the ventilator tubing and the 15-mm connector. An HME is
not functional with a speaking valve because no exhaled gas will pass through
when it is in place. Some patients report discomfort when initially using a
speaking valve due to drying of the pharyngeal membranes or decreased tone
TM
005 and PMVTM 007 (MacBean et al., 2008).
Leak speech can also be used with a
200
Tracheostomies
6.12
Proper placement of speaking valve within ventilator circuit. Valve is positioned between
the tracheostomy tube and ventilator circuit to allow intake of air into the tube.
from weakness and lack of airflow through the upper airway. This effect can be
mitigated by slow cuff deflation over several minutes (Hess).
In a study of 15 ventilator-dependent patients, Passy, Baydur, Prentice, and
Darnell-Neal (1993) found that all the subjects using the Passy-Muir valve
showed marked improvement in speech intelligibility, speech flow, elimination
of speech hesitancy, and speech time. MacBean and colleagues (2008) studied
the use of leak speech in two patients with cervical spinal cord injuries. They
found that the use of PEEP in addition to a speaking valve provided the best
quality speech.
Figure 6.13 shows airflow when a speaking valve is used with a ventilator.
With a speaking valve, air will be redirected through the upper airway upon exhalation and not returned to the ventilator. Therefore, the exhaled tidal volume
alarm must be adjusted accordingly. In addition, the tidal volume and highpressure alarms must be carefully monitored to avoid excessive air trapping
(Kazandjian & Dikeman, 2008).
Most critical care ventilators will not easily tolerate a speaking valve; however, the Puritan Bennett 760 has a speaking valve mode (Hess, 2005). The
Respironics Esprit and the new Respironics V200 ventilator also have speaking modes in which the exhalation valve is closed, allowing gas flow past the
vocal cords. In speaking modes, exhaled gas pressure is measured to evaluate
whether the tube has become disconnected or obstructed.
Chapter 6 Phonation With a Tracheostomy
6.13
Airflow with valve
and ventilator circuit.
(A) Normal ventilator
circuit. Note inflation of
the cuff with inflow of
air from the ventilator
and exhaled air through
exhalation valve.
(B) Ventilator circuit
with speaking valve.
Note deflation of the
cuff, with all exhaled
air passing through
the upper airway and
bypassing the ventilator.
201
Cuffed Fenestrated Tracheostomy Tube (Cuff Inflated)
Patients who are ventilator dependent will usually require a cuffed tracheostomy tube. In order for these patients to phonate, one option is a cuffed fenestrated tracheostomy tube. The proper fit of the fenestration within the airway is
vital for the proper functioning of the tube as well as preventing complications
such as granulation tissue. See chapter 4 for a discussion of the proper fitting of
a fenestrated tracheostomy tube.
Figure 6.14 shows airflow through fenestrated tracheostomy tubes. View
A shows inspiration and expiration through a cuffless fenestrated tracheostomy tube. Air moves through the upper airway and through the tube. In View
B, when the cuff is inflated on a cuffed fenestrated tube, inspiration and expiration occur primarily through the tube; however, a small amount of air moves
through the upper airway. In View C, the cuff is deflated on a cuffed fenestrated
tube. Inspiration is primarily through the tube; however, a small amount of air
is inspired though the upper airway. On exhalation, air must pass around the
deflated cuff and though the fenestration to reach the upper airway.