Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4597_Библиотеки_им_академика_М_И_Перельмана.pdf
302
Tracheostomies
Tsunezuka, Y., Suzuki, M., Nitta, K., & Oda, M. (2005). The use of fibrous wound dressing sheets
made of carboxymethylcellulose natrium in the postoperative management of tracheos-
tomy. Kyobu Geka, 58(12), 1063–1067.
von Eiff, C., Heilmann, C., & Peters, G. (1999). New aspects in the molecular basis of polymer-
associated infections due to staphylococci. European Journal of Clinical Microbiology and
Infectious Diseases, 18, 843–846.
Waldron, J., Padgham, N. D., & Hurley, S. E. (1990). Complications of emergency and elective
tracheostomy: A retrospective study of 150 consecutive cases. Annals of the Royal College
of Surgeons of England, 72(4), 218–220.
Walvekar, R. R., & Myers, E. N. (2008). Technique and complications of tracheostomy in adults.
In E. N. Myers & J. T. Johnson (Eds.), Tracheotomy: Airway management, communication,
and swallowing (2nd ed., pp. 35–67). San Diego, CA: Plural Publishing.
Watanakunakorn, C. (1989). Successful novel drainage treatment of mediastinal abscess com-
plicating tracheostomy. Chest, 96(4), 946–948.
Weber, S. M., Hargunani, C. A., & Wax, M. K. (2006). Duraprep and the risk of fire during tra-
cheostomy. Head and Neck, 28, 649–652.
Weymuller, E. A., Jr. (1998). Acute airway management. In C. W. Cummings (Ed.), Otolaryngology.
Head and neck surgery (3rd ed.). St. Louis, MO: Mosby-Year Book.
Wilson, P. T., Igbaseimokumo, U., & Martin, J. (1994). Ignition of the tracheal tube during tra-
cheostomy. Anaesthesia, 49(8), 734–735.
Wolf, G. L., Sidebotham, G. W., & Stern, J. B. (1994). Intraluminal flame spread in tracheal tubes.
Laryngoscope, 104, 874–879.
Wolf, G. L., & Simpson, J. I. (1987). Flammability of endotracheal tubes in oxygen and nitrous
oxide enriched atmosphere. Anesthesiology, 67, 236–239.
Wright, S. E., & Van Dahm, K. (2003). Long-term care of the tracheostomy patient. Clinics in
Chest Medicine, 24, 473–487.
Yaremchuk, K. (2003). Regular tracheostomy tube changes to prevent formation of granulation
tissue. Laryngoscope, 113, 1–10.
Downsizing
and
Decannulation
Linda L. Morris
11
Unless a tracheostomy is placed for irreversible conditions, the clinician must
always consider the goal of decannulation. The decannulation process does
have some risk, but there are several benefits. Not only is the tube itself a foreign object irritating the airway, but it also interferes with swallowing, coughing,
and phonation. There are psychosocial issues associated with the presence of a
tracheostomy tube, including loss of control, anxiety, and an inability to communicate (Christopher, 2005), all of which can create frustration at best and severe
depression at worst.
Planning for downsizing and decannulation should begin as soon as the
patient has recovered from the immediate postoperative period and is looking toward the first tracheostomy change. Downsizing is the gradual process
of decreasing the size of the tracheostomy tube, usually with the eventual goal
of decannulation. Downsizing has several advantages, including decreasing
long-term complications such as tracheal stenosis and tracheomalacia as well
as improving swallow and decreasing the risk of aspiration. Another theoretical
advantage to the downsizing process is minimizing scarring; however, no studies to date have discussed the appearance of scarring related to downsizing.
303
304
Tracheostomies
Assessment for downsizing should begin with a thorough review of the
medical record and discussion with the primary care practitioner and the
surgeon who placed the tracheostomy. When the medical condition has stabilized and there are no factors that necessitate continued cannulation, planning for decannulation should take place. Decannulation should be considered
when the reason for tracheostomy placement is resolved, when airway secretions have abated, and when mechanical ventilation is no longer required
(Christopher, 2005).
Factors to Consider Prior to Decannulation
It is important to consider the reason for the placement of the tracheostomy
in the plan for downsizing and decannulation. Decannulation of patients who
have had a prolonged period of mechanical ventilation is markedly different
from decannulation in those who have had a resolution of an upper airway obstruction (Christopher, 2005). This is because those who have had a prolonged
period of mechanical ventilation also have other comorbidities to consider as
well as poor respiratory reserve. These patients are also likely to be deconditioned and may have limited ability to protect their airway.
A retrospective study by the National Association of Long-Term Hospitals
(NALTH) found that 54% of patients were able to discontinue mechanical ventilation support after a prolonged period, but only 59% of those weaned were
ultimately decannulated (Scheinhorn et al., 2007). O’Connor, Kirby, Terrin, Hill,
and White (2009) studied the process of decannulation in patients who had received prolonged mechanical ventilation in 23 long-term-care hospitals. They
found that within a median of 45 days after tracheostomy placement, decannulation was successful in 35% of patients. The patients who were decannulated
successfully had tracheostomy tubes placed earlier and had shorter stays in the
acute care hospital. Three years later, 35% of all patients were alive, including
62% of those who were decannulated.
Resistance and Work of Breathing
The prolonged placement of an endotracheal tube and subsequent tracheostomy interferes with the normal airway-protective mechanisms of cough and
swallow. The disadvantages of tracheostomy include loss of the upper airway
for ventilation, loss of laryngeal function, and imposed resistance of the artificial airway (Moscovici da Cruz, et al., 2002). The presence of a tracheostomy
tube interferes with the normal swallowing mechanism. The vocal cords in the
larynx are bypassed by the tracheostomy tube, which interferes with effective
coughing and partial regulation of breathing. When the vocal cords are partially
closed, subglottic pressure is maintained, and physiologic PEEP maintains airway patency. Subglottic pressure also contributes to effective swallowing and
reduction of the risk of aspiration. Intrinsic PEEP is lost with a tracheostomy
tube (Christopher, 2005). Furthermore, the laryngeal blast that produces an effective cough is lost.
Compared to endotracheal tubes, tracheostomy tubes have been associated
with significant reductions in airflow resistance, work of breathing, and intrinsic
Chapter 11 Downsizing and Decannulation
PEEP (Diehl, El Atrous, Touchard, Lemaire, & Brochard, 1999; Rumbak et al.,
1997). Diehl and colleagues demonstrated a decrease in these measures comparing tracheostomy to mechanical ventilation through an endotracheal tube.
Moscovici da Cruz and colleagues (2002) showed this difference by comparing
spontaneously breathing nonintubated patients to patients with tracheostomies.
Presumably, this difference is due to decreases in airflow resistance (Rumbak
et al.).
The primary factors involved in resistance and work of breathing are the
following (Pierson, 2005):
1. The larger the diameter, the lower the resistance.
2. The shorter the tube, the lower the resistance.
3. Secretions within the walls of the tube increase resistance.
4. The sharper the curve of the tube, the greater the resistance.
5. Higher gas flows require increased pressure.
The small radius and curvature of a tracheostomy tube increase turbulence
and airway resistance. However, when compared to endotracheal tubes, these
effects are offset by the tracheostomy tube’s short length, which results in an
overall lowering of airway resistance and muscle loading. In addition, secretions within the lumen of the tracheostomy tube also increase resistance, but
the ease of suctioning and removable inner cannulas mitigate this effect (MacIntyre et al., 2001).
Downsizing allows more air to pass around the outside of the tracheostomy tube rather than through the tube. A progressively smaller size promotes
this gradual increase in airflow around the tube (see Figure 11.1). The patient
gradually becomes reacquainted with air passing through the upper airway.
The general principle during downsizing is that, as the tube gets smaller, it
is more difficult to breathe through it but easier to breathe around it. With
each change in tube size comes a change in airway dynamics. If the patient
is breathing through a smaller tube, airway resistance increases. If the patient is
breathing around a smaller tube, airway resistance decreases. The caveat here
is that the tube itself creates an increasingly hindering obstruction as the ratio
of tube size to airway diameter increases. This explains why some patients who
do not tolerate capping can be successfully decannulated (Gao et al., 2008).
It is estimated that up to 10% (Frutos-Vivar et al., 2005; Kollef, Ahrens, & William, 1999; Stelfox et al., 2008) to 16.9% (Cox, Carson, Holmes, Howard, & Carey,
2004) of all mechanically ventilated patients receive a tracheostomy, and this
trend appears to be increasing. Cox and co-investigators reviewed a 10-year database comprising 144,875 patients requiring mechanical ventilation. Approximately one-third of these mechanically ventilated patients (49,872) required
longer ventilator support (greater than or equal to 4 days). Approximately onefifth of these patients who required prolonged mechanical ventilation (9,794)
underwent a tracheostomy. Of interest is that the incidence of tracheostomy
placement increased 200% over the 10-year duration of their study.
Aerodynamics not only change during the downsizing process but also
after decannulation. Chadda and others (2002) found that tidal volume increased without any change in respiratory rate, inspiratory time, or arterial
. A return to mouth breathing resulted in a 17.5% increase in tidal volume.
pCO
2
305
306
Tracheostomies
11.1
Airflow through a smaller tube compared to a larger one. Note less resistance with
breathing through a larger tube. As the tube gets smaller, resistance (and, hence,
work of breathing) increases.
These changes were due to a significant increase in physiologic dead space
and were associated with a significant increase in work of breathing. However, Dellweg, Barchfeld, Haidl, Appelhans, and Kohler (2007) found that decannulation resulted in increased or decreased respiratory burden depending
on upper airway morphology and pathology. Upper airway morphology was
shaped by anatomy, position, muscle tone, secretions, infection, edema, or the
presence of an artificial airway. Moscovici da Cruz and investigators (2002)
studied seven patients with head and neck cancer and also found that upper
airway resistance changed with individual differences in airway morphology.
Cannulation Times
The course and outcome following tracheostomy varies with the reason for
intubation. One Australian group (Leung, Campbell, MacGregor, & Berkowitz,
2003) retrospectively studied all patients in their ICU over 1 year. Of 100 patients who had tracheostomies during that time, 35 were admitted for respiratory causes, 35 for neurologic conditions, 17 due to trauma, and the remaining
13 for cardiovascular, gastrointestinal, sepsis, and metabolic complications. The
authors found that 47 patients required tracheostomies because of prolonged
mechanical ventilation, 45 for bronchial hygiene or the risk of aspiration, and 8
for an unstable or obstructed airway. During the study period, 37 patients died,
30 of whom had the tracheostomy tube in place. Seventy patients were successfully decannulated; 63 survived and 7 died after being decannulated for at least
1 week. Total cannulation times varied with the reasons for tracheostomy tube
placement. As expected, the authors noted that cannulation times were longer
for neurologic than for respiratory diagnoses and even shorter for trauma. Median cannulation time was 25 days, but 3 patients had cannulation times longer
than 6 months.
Leung and coauthors (2003) noted that patients with unstable airways were
cannulated for a mean of 13 days. Those with prolonged mechanical ventilation were cannulated for a mean of 25 days, and those with aspiration were
Chapter 11 Downsizing and Decannulation
cannulated for a mean of 33 days. Comparatively, Dellweg and colleagues (2007)
reported an average cannulation time of 37 days, and Rumbak and coauthors
(1997) reported an average intubation/cannulation time of 2.4 weeks.
O’Connor and co-investigators (2009) studied patients on prolonged mechanical ventilation. In their study of 135 patients, 58 (43%) were successfully
liberated from mechanical ventilation and 81% (47/58) of those weaned were
ultimately decannulated. Mean time to decannulation was 45 days. Of those
who were weaned, 23% were not decannulated because of an ongoing need for
airway protection. In their study, the most common diagnoses were pneumonia, COPD, and septic shock. The median time to the placement of a tracheostomy was 18 days after translaryngeal intubation. A survival analysis found that
35% of patients were alive 3.5 years later. Those who were decannulated had
improved survival compared with those who remained on mechanical ventilation ( p = 0.11).
Cannulation times in children tend to be even longer. Kontzoglou and colleagues (2006) reported an average cannulation time of 26.4 months. Other
studies reported a mean cannulation time of 21.6 months (Gray, Todd, & Jacobs,
1998; Zenk, et al., 2008). Furthermore, the duration of the decannulation process is also longer in children. Waddell, Appleford, Dunning, Papsin, and Bailey
(1997) described a detailed protocol for decannulation in children that took up
to 11 days. This prolonged decannulation schedule could be due to the much
longer cannulation times. This study involved children with tracheostomy tubes
in place for a mean of 3.5 years who had more complex airway issues. Nonetheless, it is important to consider several factors when planning for decannulation in children. More discussion on decannulation in children can be found in
chapter 8.
307
Reason for Initial Placement of Tracheostomy
The most important factor when considering decannulation is the initial reason
for tracheostomy placement. If the primary issues are not resolved, attempts to
downsize and decannulate will not be successful. Factors affecting the decision
to place a tracheostomy are the same factors affecting the decision to decannulate. An easy way to remember the indications for the placement of an artificial
airway is the acronym VOPS: ventilation, obstruction, protection, and secretions
(Shapiro, Harrison, Kacmarek, & Cane, 1985).
Ventilation.
tilation will benefit from continued use of the tracheostomy. Noninvasive means
of positive-pressure ventilation are often met with other complications—such
as gastric insufflation, discomfort, and air leak—that can contribute to less than
optimal delivery of volume. If the tracheostomy was placed because of the need
for prolonged mechanical ventilation, it is usually safe to consider downsizing
and decannulation as soon as the patient has been liberated from continuous
positive-pressure ventilation for at least 24 hours.
Obstruction.
tube can usually be decannulated after the obstruction is relieved. A direct view
of the trachea is often indicated if obstruction is suspected or documented.
Patients who continue to require any form of positive-pressure ven-
Depending on the nature of the obstruction, the tracheostomy
308
Tracheostomies
Causes of obstruction include vocal cord paralysis, head or neck masses, edema
after prolonged surgery (especially in the prone position), granulation tissue,
stenosis, and obstructive sleep apnea.
Protection.
are an adequate cough and an adequate swallow. Patients who cannot protect
their airway require a cuffed tracheostomy tube, but even an inflated cuff provides imperfect protection.
Cough effectiveness should be evaluated during the downsizing and decannulation process. Failure to produce an adequate cough can result in atelectasis,
inspissation of secretions, or tube obstruction because of the incomplete clearance of secretions. The clinical measure of cough effectiveness is vital capacity,
and a normal measurement is considered to be 70 ml / kg ideal body weight
(Adams & Lim, 2003). The accepted minimum vital capacity is considered to be
15 ml / kg ideal body weight; below this point, patients are unable to effectively
clear secretions. A regression equation has been described for calculating accepted minimum vital capacity based on gender, age, and height (Douce, 2003);
however, a simpler formula to calculate ideal body weight is used most often:
Add 5 pounds for each inch over 5 feet. Convert pounds to kilograms by dividing by 2.2 and multiply by 15 ml / kg to find the minimum acceptable vital capacity in milliliters.
It is common for patients to be quite deconditioned after a long stay in the
ICU, so a vigorous program of physical mobility is required to provide them
with the strength to mobilize secretions themselves. When patients can effectively mobilize secretions on their own, they may no longer require suctioning.
The two primary mechanisms that contribute to airway protection
female: 5 feet = 100 pounds; male: 5 feet = 105 pounds
Swallowing Function. Swallowing physiology provides intermittent alimentation
and continuous airway protection. The action of swallowing consists of several
phases. The oral phase consists of preparing the food for transport. This includes
mastication and the addition of saliva to create a bolus. During the pharyngeal
stage, the food bolus is pushed downward past the nasopharynx. As it enters the
vallecular space, the epiglottis tilts downward. The muscles of the larynx contract,
causing it to close tightly, and respiration momentarily ceases. The pharyngeal
muscles constrict, and the tongue pushes the bolus posteriorly and downward,
propelling it toward the esophagus. The cricopharyngeus muscle relaxes, and
the anterior pharyngeal wall is pulled forward. This action allows the bolus to
pass into the esophagus. During the esophageal stage, the bolus moves through
the esophagus and into the stomach by peristalsis (Tippett, 2000).
Prolonged intubation interferes with the glottic mechanism, and it may take
some time for normal function to return. This could explain the high incidence of
aspiration in patients with tracheostomies, which has been reported by some
authors as 69% (Cameron, Reynolds, & Zuidema, 1973) and 64.8%, with a reported range from 50%–87% (Ding & Logemann, 2005). An inflated cuff elevates
during the swallow and desensitizes the larynx. In addition, it can bulge posteriorly and compress the esophagus. The tube can also partially interfere with
the elevation of the larynx and its anterior movement during swallowing. This
Chapter 11 Downsizing and Decannulation
tethering effect is magnified with cuff inflation (Tippett, 2000). Silent (clinically
nonobservable) aspiration is a common problem in patients with tracheostomies
and has been reported to be 46.2%. Silent aspiration was significantly higher
with an inflated cuff compared to a deflated cuff (Ding & Logemann).
Swallow physiology is different with various medical conditions. Patients
with neuromuscular disorders show significantly greater frequencies of reduced
tongue manipulation, slow oral transit, delayed pharyngeal triggering, and aspiration after the swallow. In contrast, patients with head and neck cancer show
significantly higher frequencies of reduced laryngeal closure, aspiration during
the swallow, and aspiration after the swallow (Ding & Logemann, 2005). Pooled
salivary secretions are a predictor of dysphagia (McGowan, Gleason, Smith,
Hirsch, & Shuldham, 2007; Murray, Langmore, Ginsberg, & Dostie, 1996). Gross,
Tedla, and Ross (2007) found a significantly higher number of inhalations during the swallow in patients with a tracheostomy tube compared to normal controls without a tracheostomy tube. They concluded that this increased tendency
to inhale during a swallow places patients with a tracheostomy at higher risk
for aspiration. Finally, while the inflated cuff provides some measure of airway
protection, it also interferes with the coughing mechanism. It has been implicated in contributing to aspiration because the larynx is desensitized due to the
diversion of airflow through the tracheostomy tube.
309
Secretions.
for the continued placement of a tracheostomy tube. The underlying condition
may contribute to the production of secretions, but it is often the tracheostomy
itself that produces significant secretions (Wright & Van Dahm, 2003). Fortunately, secretions commonly decrease during the capping process. Chapter 7
outlines the management of secretions.
The failure of patients to manage secretions is a common reason
Tube Size
Tube size is an important consideration—both the size of the tube in situ and the
size of the tube under consideration. When patients breathe through a cuffed
tube, the general rule of thumb is to choose a tube with the largest inner diameter in order to minimize resistance and decrease airway pressures. As downsizing is considered, however, it is necessary to choose a tube with a smaller outer
diameter in order to allow the patient to breathe more easily around the tube.
Future Need for Artificial Airway
Before decannulation is performed, there should be an inquiry into any impending need for an artificial airway. If a patient is scheduled for a surgical
procedure within the next few days or weeks, it may be beneficial to wait until
the recovery is complete.
Determining Readiness for Decannulation
There is no standard method to determine a patient’s readiness for decannulation. Some rely on clinical judgment, some on endoscopy or radiography. Stelfox
Tracheostomies
310
and others (2008) conducted a survey of physicians and respiratory therapists
to determine usual practices regarding decannulation. They found that the most
important factors influencing readiness for decannulation were the patient’s
level of consciousness, cough effectiveness, amount of secretions, and ability to
tolerate tracheostomy tube capping. Of moderate importance were patient comorbidities, etiology of respiratory failure, swallowing function, respiratory rate,
and oxygenation. Compared to respiratory therapists, physicians rated level of
consciousness significantly more important and ability to tolerate tracheostomy
tube capping significantly less important.
Capping is also called plugging, corking, or blocking; the principle is the
same, but the means may be slightly different. They all involve obstructing the
tube. With capping, the uncuffed tracheostomy tube is obstructed so the patient breathes around the tube rather than through it. The potential problem
is that the blocked tube occupies a significant portion of the airway, depending
on its size.
Gao and others (2008) developed a simple device for measuring airflow and
subglottal pressure in order to determine a patient’s readiness for decannulation. Two groups were compared: a decannulation group (deemed ready based
on the usual clinical criteria of capping the tracheostomy tube for 24– 48 hours)
and a second group determined unsuitable for decannulation. The researchers
took airflow measurements during shallow and deep breathing. A routine examination using a flexible fiberoptic bronchoscope determined the resolution
of the initial anatomic reasons for tracheostomy placement as well as assessed
any changes in the airway. The decision to decannulate was determined by a
surgeon, who made the decision on clinical criteria but was uninformed of the
airway resistance measurements. All patients were observed in the hospital for
at least 24 hours after decannulation, and all were followed for 3 months by
telephone.
All patients in the decannulation group were successfully decannulated
without any breathing difficulties during the 3-month follow-up period. However, resistance was significantly higher in the group that was not decannulated on all measures of upper airway resistance: inspiratory resistance during
shallow breathing, expiratory resistance during shallow breathing, inspiratory resistance during deep breathing, and expiratory resistance during deep
breathing. The causes of this increased airway resistance were postoperative
scarring, vocal cord paralysis, or neoplasms (Gao et al., 2008).
Turbulent airflow requires a greater pressure gradient than laminar flow.
The irregular airways noted in the patients who were not decannulated generated more turbulent flow. The investigators found that glottis width was narrower in those patients who failed the protocol. Furthermore, they reported that
some patients who could not tolerate plugging or capping were still ready for
decannulation. The tube itself created a significant obstruction, and removal of
the tube improved breathing. The authors suggested that an objective assessment of airway resistance could lead to quicker decannulation without the need
for 24– 48 hour capping and potentially decrease costs and length of stay.
There is no accepted definition for decannulation failure; however, Stelfox and colleagues (2008) found that most clinicians considered decannulation
failure to be the reinsertion of an artificial airway between 48 to 96 hours after
decannulation. In their study, respiratory therapists considered shorter time
Chapter 11 Downsizing and Decannulation
frames than physicians for defining decannulation failure: 48 hours versus
96 hours (p = 0.002). They also found significant differences in practice between those working in acute care facilities and those working in chronic care
facilities (Stelfox et al.).
The decision to decannulate is based on clinical judgment and falls within
a spectrum of approaches. The more methodical approach requires a host of
clinical measures to determine the patient’s readiness for decannulation and a
very slow downsizing progression from one step to the next before the patient is
actually decannulated. A trial-and-error approach is much more rapid and inherently riskier. There are no studies to determine the optimal duration for the
process of decannulation. Choate, Barbetti, and Currey (2008) studied patients
at a tertiary care hospital over a 4.5-year period and recorded a 4.8% decannulation failure rate (40 out of 823 decisions to decannulate). Stomal recannulation
was required in 25 cases, whereas 15 cases resulted in reintubation. There was
no associated mortality or other adverse events. The most common reason for
decannulation failure was sputum retention. The authors advised that nursing
staff should closely monitor newly decannulated patients for the initial 4 hours
and for up to 24 hours after decannulation (Choate et al.).
Barnes, Barbetti, and Currey (1999) studied patients in a rehabilitation
facility over 18 months to determine the duration of decannulation. The patients’ disorders included spinal cord injury, traumatic brain injury, neuromuscular dysfunction, and ventilator-dependent respiratory failure. A protocol
was developed, and an interdisciplinary team was established to implement
the decannulation protocol. The team consisted of a respiratory therapist,
a nurse practitioner, a primary nurse, and a physician. The study evaluated
93 patients, and 93.5% of them qualified for decannulation; however, 6.5%
did not meet criteria because of a prolonged inability to protect their airway
and continued ventilator support. All patients who qualified were eventually
decannulated within 50 days. The average time for the entire decannulation
process in an uncomplicated patient was 10 days, which represented 74% of
their population.
Godwin and Heffner (1991) recommended several principles to guide the
evaluation for decannulation, including adequate ventilatory reserve (spontaneous breathing for 24– 48 hours), adequate nutritional state, patent upper
airway, absence of bronchopulmonary infection and impending need for mechanical ventilation, adequate cough without suctioning, minimal aspiration,
and medical stability.
311
Decannulation Protocol
There is no set protocol currently recommended for downsizing and decannulation. Some protocols simply recommend cuff deflation and assessment for
movement of air around the cuff. Others recommend a fenestrated tracheostomy
tube for an added boost of air. Still others recommend capping trials. Downsizing usually begins with cuff deflation, which serves two purposes: to assess
airway protection and to assess the movement of air through the upper airway.
Cuff deflation involves the admixture of room air, which lowers overall FiO
creates the potential for hypoxemia. If significant hypoxemia results from cuff
and
2