Indications
Both the indications of tracheostomy and characteristics of children
with tracheostomy have profoundly changed in the last 50 years
reflecting the changes that took place in the managment of children in a
delicate condition. Until half of the 20th century and
before the introduction of generalized vaccination - haemophilus
influenza and corynebacterium diphtheriae - viral infections and acute
bacteriophage infections, the diphtheria, and epiglottitis, were the
main causes of airway complication leading to the first practices of
pediatric tracheostomy. At the end of the 1900’s an increase in the use
of endotracheal intubation and respiratory support for premature infants
had led to a higher rate of premature babies with the need of
mechanical ventilation and associated upper airway
abnormalities. (3-4)
This is how vaccination programs, better intubation procedures and the
development of new technologies in intensive care have diminished
emergency tracheotomy and, far from diminishing its incidence, this
situation has led to the appearance of other indicators like prolonged
mechanical ventilation turning tracheostomy in a programmed, long term
elective procedure.(5) Most of the published studies
developed in The United States and Europe consider that the most
frequent causes of tracheostomy are congenital upper airway
abnormalities and prolonged mechanical
ventilation.(4-5)
In his review published in 2017, Watters mentioned that in a
retrospective study on 917 tracheostomized children aged between 0 and
18 collected from 36 pediatric hospitals, the most frequent underlying
conditions were chronic lung disease (56%), worsening of neurological
function (48%) and upper airways anomalies(47%).(4)
(6)
However, the situation in developing countries is probably quite
different, especially in the prevalence of tracheostomy.
There is an overall increase in the prevalence of patients who need
prolonged mechanical ventilation (PMV) and also in the number of
children who survive with complex medical conditions for whom
tracheostomy and domiciliary mechanical ventilation could be part of
their treatment.
In 2008 a study that was conducted in Ricardo Gutierrez Children’s
Hospital in Argentina analysed the prevalence of tracheostomy in
children on mechanical ventilation support (MVS), and it was 20% during
a 6-month period. It was higher than shown in other published
series.(7-11)
Coinciding with previous studies, patients who underwent tracheostomy
presented more length of stay and mechanical ventilation (MV) than
non-tracheostomized ones. However, the mortality rate was higher in
non-tracheostomized patients with more than 14 days of MV. This could
probably be because of the prolonged use of mechanical ventilation and
the chronicity of this children’s situation.(12)
At this moment pediatric tracheostomy mortality rate ranks from 0.5% to
5%.(4)
In 2016, a Transference Program of mechanical ventilation chronic
dependant patients or technology dependant patients was tested in the
same hospital, ranging from intensive care areas to pediatric rooms.
During the study, 247 patients entered the pediatric intensive care
unit. Twenty four were tracheostomized. They were ventilation
dependants, and clinically stable. There were 9.7% of technology
dependant patients in the intensive care unit (ICU), which means the
same number of beds required for severe acute
patients.(13) It is because of all this that the there
is a need to strengthen and implement programs, protocols and action
algorithms on these patients that lead to a quick and effective
dischargement whenever possible considering each particular case. Long
term tracheostomy leads to a higher medical mortality rate and to a
negative psychosocial impact. Because of this, decannulation is a
priority when a tracheostomy is done.(14)
Up to this date, literature lacks well-established guidelines to
determine the steps for decannulation. There is scarce evidence about
protocols and algorithms for making decisions to support the
decannulation process of the pediatric patients.
The lack of consensus for an optimal decannulation protocol may be, in
part, attributed to the low amount of prospective studies centered on
decannulation or the lack of studies comparing different decannulation
methods.
Regarding the factors that predict success in decannulation, studies
have attempted to define clinical predictors of successful
decannulation. There is a consensus among authors that prior to
decannulation, certain assessments must be done, and clear criteria must
be established. Decannulation protocols vary widely in these reports
with success rates ranging from 67% to 94%.(4)
In 2015 Knolman & Col in their review about decannulation protocols
found that the studies obtained were case series or retrospective
studies, with differences in the variables measured between them before
decannulation. In spite of discrepancies and heterogeneity, they agreed
in the different steps or goals accomplishment. Once a tracheostomy
underlying indication gets corrected or solved, the patient can be
considered a candidate for an eventual decannulation. A previous
endoscopic assessment and progressive capping trials ensure a proper
static and dynamic permeability of the airway.(15)
In 2013 Mitchell et Al published a clinical consensus about pediatric
and adult tracheostomy manage. Experts agreed in that criteria must be
established before a decannulation process. There was consensus in that
children who underwent tracheostomy should be weaned off from mechanical
support during 2 to 4 months. They should not present bronchoaspiration
events and the need of tracheal secretions suction. Flexible
laryngoscopy is recommended to confirm both permeability and mobility of
at least one vocal cord and the elimination of any suprastomal
obstructive granulation before attempting a decannulation. Children up
to 2 years old must be tested capping the cannula during the day and
releasing it during the night for several weeks. Other options are also
mentioned, for example a sleep assessment and an exercise test. These
recommendations are based on expert’s opinions and serve as solid
evidence guidelines even though they are for adult patients. But there
is room for further discussions and investigations regarding this
topic.(16)
The role of polysomnography (PSG) in the decannulation process has been
slowly increasing in acceptance even though its daily use is
questionable. This is because of the financial cost it implies, the
length of stay, availability of medical supplies and the need for
trained physicians and health personnel. Several authors conclude that
it is useful as complement of the fibronoschopy in preparing for a
decannulation.(17-19)
Despite decannulation being so relevant, there are no studies in which
the efficiency of the protocols has been proved.
In order to provide a better understanding on the topic in this area, a
systematic review has been performed, to research the scientific
evidence that is currently available, which evaluates decannulation
protocols on pediatric patients.