PAEDIATRIC RESPIRATORY REVIEWS (2006) 7, 175–184

MINI-SYMPOSIUM: TRACHEOSTOMY IN CHILDREN

Tracheostomy care in the hospital Ernst Eber* and Be´atrice Oberwaldner Respiratory and Allergic Disease Division, Paediatric Department, Medical University of Graz, Auenbruggerplatz 30, A-8036 Graz, Austria KEYWORDS airway obstruction; child; complication; endoscopy; humidifier; infant; speaking valve; speech; tracheostomy tube

Summary Long-term tracheostomy in infants and children is associated with significant morbidity. The majority of paediatric patients experience tracheostomy-related complications during cannulation and/or after decannulation. A large proportion of these complications are, however, preventable or may be minimised by good tracheostomy care and clinical evaluation of the patients at regular intervals, tailored to the needs of the individual child. By and large, infants and children benefit from a specialist tracheostomy service. In this article, we review different aspects of hospital-based care, covering a wide range of topics including the selection of tracheostomy tubes and adjuncts, clinical evaluation, speech/communication, and late complications and their prevention. ß 2006 Elsevier Ltd. All rights reserved.

INTRODUCTION In the tertiary care setting, children with a long-term tracheostomy constitute an important and challenging group needing a specialist tracheostomy service. Many recommendations for the standards of care for these patients are still by consensus, based on experience rather than scientific data.1 The indication for a tracheostomy, and thus the underlying problem, the presence of other medical conditions, the patient’s anatomy, respiratory mechanics and needs for speech, ventilation and airway clearance all determine aspects of hospital-based care, the duration of cannulation, the occurrence of complications and the probability of successful decannulation. Consequently, the care of the child with a longterm tracheostomy has to be individualised. This will only be possible in a specialised tertiary care unit where all the necessary diagnostic techniques and experienced staff are available.

* Corresponding author. Tel.: +43 316 385 2620; Fax: +43 316 385 4621. E-mail address: [email protected] (E. Eber). 1526-0542/$ – see front matter ß 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.prrv.2006.06.002

TRACHEOSTOMY TUBE (AND ADJUNCTS) SELECTION Tracheostomy tube selection is usually the joint responsibility of the physician who takes care of the patient and the surgeon performing the tracheotomy; in some specialised units, respiratory physiotherapists are also involved. The most important factor for determining an appropriate tracheostomy tube is the age of the patient, and for quick orientation published paediatric tracheostomy sizing charts may be used (see Table 2 in the article by Cochrane and Bailey on surgical aspects of tracheostomy in this symposium).2 However, as such charts for different ages are estimations of normal, they may not be accurate for children with small stature or patients with airway pathology. A number of imaging modalities such as chest radiography, computed tomography, magnetic resonance imaging and ultrasound imaging may all be used to estimate tracheal size, but none of these methods is in routine use.3,4 The quantitative assessment of airway dimensions was in the past generally confined to indirect physiological methods or to radiographic techniques; nowadays, flexible endoscopy not only provides a direct view of the airways (including the

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of aspiration. On the other hand, a tube that is too large will irritate the mucosa or cause damage to the tracheal wall. If possible, translaryngeal airflow should be promoted. To accomplish this, a relatively small tube with or without fenestrations (the patient breathes around a non-fenestrated, and around and through a fenestrated tube) or a relatively large tube with fenestrations (the patient breathes mainly through the tube) may be used. It is common practice to aim for the outer diameter of the tube not to exceed two-thirds of the tracheal diameter, particularly when using a speaking valve (see below).

Length of the tube Figure 1 Standard off-the-shelf tubes. Top from left to right: Shiley tracheostomy tubes size 4.0 in neonatal (34 mm) and standard paediatric (41 mm) length, and size 5.5 PDL (52 mm). Bottom from left to right: Bivona tracheostomy tubes size 4.0 in neonatal (36 mm) and standard paediatric (41 mm) length, and Portex tracheostomy tube size 4.0 (length 43 mm). Note the different outer diameters of the size 4.0 Shiley, Bivona and Portex tubes (5.9 mm versus 6.0 versus 5.5 mm).

possibility of assessing dynamic changes), but may also permit accurate measurements of airway dimensions.5 Like the above radiological methods, however, endoscopic measurements are not in regular use. In the absence of research data supporting optimal choices in tracheostomy tube selection, the latter is, in most patients, usually based on clinical judgement and experience. There are many reasons why a child might require a tracheostomy, and manufacturers produce many different models and sizes of tracheostomy tubes. Selection of the appropriate tube has to be carried out on an individualised basis, considering the indication for the tracheostomy, the tracheal width, length and shape, the upper airway resistance, lung mechanics and the needs of the child for speech, ventilation, and airway clearance.1 With the wide range of tracheostomy tubes available, standard off-the-shelf tubes fit the trachea of most patients (Fig. 1). Specially manufactured tracheostomy tubes (customised tracheostomy tubes to meet special needs) are required for only a small minority of patients (Fig. 2). As no specific research documenting optimal choices in tracheostomy tube selection is available, local standards, practices and preferences usually determine the selection. The following important details have to be taken into account when selecting a tracheostomy tube.

Diameter of the tube There is no published evidence regarding the optimum size of a tracheostomy tube within a given trachea. Usually, a relatively large tube is used to keep airway resistance and the work of breathing low6 and to allow efficient pulmonary toilet; in addition, such a tube is believed to reduce the risk

There is consensus that, in most patients, the tracheostomy tube should extend at least 2 cm beyond the stoma and be no closer than 1–2 cm to the carina.1 In general, children under the age of 1 year should be supplied with a neonatal length tube, and older children with a paediatric length tube (see Fig. 1). In patients with unusual anatomy, tracheomalacia or a short neck and poor head control, special tubes such as the Bivona Hyperflex tube, with a sliding flange and thus variable intratracheal tube length, or the Bivona Flextend tube, with a fixed flange mounted part way along the shaft (both with an embedded metallic coil to prevent closure by external pressure), may be useful (Fig. 2).2

Curvature of the tube The curvature of the tracheostomy tube should be such that the distal end of the tube is concentric and co-linear with the trachea. If this is not the case, complications such as dysphagia due to pressure-effected oesophageal obstruction, partial occlusion of the tracheostomy tube by the

Figure 2 Customised tracheostomy tubes. Top from left to right: Portex blueline tracheostomy tube size 4.0, specially manufactured tracheostomy tube with oblique tip, and Bivona Hyperflex tracheostomy tube size 4.5. Bottom from left to right: Argyle tracheostomy tube size 3.5 with oblique tip, Great Ormond Street tracheostomy tube size 3.5 with oblique tip and Ru¨schelit Tracheoflex tracheostomy tube size 4.0.

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tracheal wall, tracheal wall erosion, tracheo-oesophageal fistula or tracheo-innominate artery fistula may develop.1,7– 13 An appropriate position of the tracheostomy tube should be ensured; this can be undertaken by airway endoscopy or neck/chest radiography.14–17

Tracheostomy tube connector All paediatric tracheostomy tubes should have the standard 15 mm connector at the upper end to allow for connection to a bag or a ventilator. Metal tracheostomy tubes are not usually equipped with such an adapter.

Tracheostomy tube composition A metal or a plastic tracheostomy tube may be chosen. Silver or stainless steel tubes representing miniaturised adult tracheostomy tubes are manufactured for children. They can be built with thin walls allowing the insertion of an inner cannula that can be removed and cleaned with the outer tube in place. In small children, however, reduction of the internal diameter of the tube by the inner cannula may result in high airway resistance. Moreover, rigid tubes, although easy to care for, may be uncomfortable because of increased head and neck mobility in a child. Larger and more pliable plastic tubes that lower airway resistance and conform to the shape of the infant’s or child’s trachea have therefore been developed. Their smooth surface reduces the adherence of mucus. Thermo-sensitive polyvinyl chloride (e.g. Portex, Shiley) tubes soften at body temperature, but are still more rigid than silicone (e.g. Bivona) tubes, which are naturally soft and unaffected by temperature. Thus, Bivona tubes may be an option in children in whom a standard polyvinyl chloride tube does not provide a satisfactory fit. They are particularly useful for patients with unusual airway problems. In addition, the tip of these tubes is bevelled to reduce the risk of tracheal wall erosion. Plastic tubes are easy to clean and change and are, in many institutions (including our own), the preferred or even the solely used tracheostomy tubes.2,18 However, attention should be paid to the fact that, with use, flexible polyvinyl chloride tubes become progressively more rigid and may develop cracks.1 In contrast, silicone tubes do not stiffen with repeated use or after cleaning and disinfection.

Cuffed tracheostomy tubes The indications for cuffed tracheostomy tubes are rather limited in paediatric patients. There are a few exceptions, namely the child with chronic aspiration, the child requiring ventilation with high positive pressures, and sometimes the child requiring only nocturnal ventilation (as the cuff may be inflated for ventilation at night and deflated to allow the child to breathe around the tube and to speak during the daytime). Types of cuff used include high-volume, low-

Figure 3 Cuffed tracheostomy tubes: (a) deflated cuffs and (b) inflated cuffs. From left to right: Bivona cuffed tracheostomy tube size 4.5 (tight-to-shaft cuff), Shiley cuffed tracheostomy tube size 5.0 (high-volume, low-pressure cuff) and Bivona cuffed tracheostomy tube size 5.0 (foam cuff).

pressure cuffs, tight-to-shaft (low-volume, high-pressure) cuffs and foam cuffs (Fig. 3). For cuff inflation, either air or liquid instillation may be required. Tracheostomy tubes with a foam cuff are infrequently used; the design permits the cuff, which contains auto-expanding foam, to conform to the shape of the patient’s airway, with automatic compression and expansion of the cuff during the ventilatory cycle. Today, modern high-volume, low-pressure cuffs are usually preferred over the traditional low-volume, highpressure cuffs to minimise the risks of trauma to the airway wall.19 However, even with this modern equipment, cuff pressure and volume have to be monitored to remain at ‘just seal’ or ‘minimum occlusion’ pressures/volumes in order to prevent ischaemia of the airway mucosa. The tight-to-shaft cuff minimises airflow obstruction around the tube once the cuff is deflated and is thus the ideal choice for a patient who requires only intermittent cuff inflation.

Fenestrated tracheostomy tubes A fenestrated tracheostomy tube allows the patient to breathe around and through the tube, and may thus promote translaryngeal airflow (aiding phonation) and enhance translaryngeal secretion clearance (Fig. 4). Although fenestration usually reduces the required effort to move air across the natural airway,20 a poorly fitting

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two decades, tracheostomy tubes may be fenestrated by punching holes in the shaft. Care has to be taken to achieve optimal smoothing and polishing of the cut edges to avoid irritation of the tracheal mucosa.

Passive humidifiers

Figure 4 Fenestrated tracheostomy tubes. Top from left to right: Modified Shiley tracheostomy tubes size 4.0 with four and eight fenestrations along the shaft, and Ru¨schelit Biesalski dual cannula size 5.0 with outer (fenestrated) and inner (unfenestrated) tube. Bottom from left to right: Portex tracheostomy tube size 5.0 with a single opening in the posterior portion of the tube, and Tracoe dual cannula size 5.0 with outer (fenestrated) and inner (fenestrated) tube with attached speaking valve.

fenestrated tube may substantially increase airway resistance. This risk may be decreased by the use of tracheostomy tubes with several fenestrations. With conventional fenestrations positioned at the angle of the cannula, there is a considerable risk of granuloma formation in the area of the fenestration(s), possibly resulting in obstruction of the fenestration(s) and the trachea.21 Furthermore, a fenestration at the angle of the cannula may route a suction catheter towards the posterior wall of the trachea, resulting in airway wall trauma and granuloma formation. On the basis of experience gained in both the Great Ormond Street Hospital for Children and the Children’s Hospital in Graz, multiple (4–8) small fenestrations along the sides of the tracheostomy tube may help to overcome or at least minimise these problems (Fig. 4).18 Although fenestrations may be particularly helpful in promoting both translaryngeal airflow and translaryngeal secretion clearance in children using speaking valves, the use of fenestrated tracheostomy tubes in paediatric patients is not widespread. One of the reasons for this is that a relatively unhampered expiratory flow to the larynx (as a prerequisite for coughing and speaking) may also be obtained by down-sizing unfenestrated tubes. In patients with periodic changes between spontaneous and mechanical ventilation, a dual cannula with an outer fenestrated tube and an inner unfenestrated cannula may be an advantage. This allows spontaneous breathing and phonation with the inner cannula removed and a speaking valve attached to the outer tube, and mechanical ventilation via the inserted inner cannula (Fig. 4). Custom-made fenestrated tubes can be ordered from several manufacturers. As an alternative, and this has been our practice for the last

The upper airway, i.e. the nose, pharynx, larynx and trachea, works as a filter, heater and humidifier of the inspired air. When the upper airway is bypassed, as in endotracheally intubated or tracheostomised patients, unheated, nonhumidified air is inhaled. A significant humidity deficit can result in pathological changes in the structure and function of the airways.22 In addition, the resistive function of the upper airway (especially the nose, which is responsible for about half of total airway resistance) appears to be important for maintaining the optimum lung ventilation–perfusion relationship.23 Heat and humidity may be added to the inspired gas by different methodologies. Heated humidifiers, usually employed during mechanical ventilation in intensive care units, are efficient and safe but are also costly and inconvenient. Nebulisers combine efficacy and safety with low cost compared with heated humidifiers; however, the necessary equipment, including a gas flow generator and tubing, makes them inconvenient in active children. Preservation of heat and humidity may also be achieved by passive humidifiers, so called ‘artificial noses’ (Fig. 5). These devices pick up heat and moisture during exhalation and part-return it during inspiration; in addition, these filters prevent the aspiration of foreign bodies. However, they do not work with speaking valves unless they are specially designed to. Data in the literature are scarce; in adult tracheostomised patients, the use of a passive humidifier was shown to improve secretion viscosity and lung function compared with controls.24 Artificial noses add some extra resistance and dead space, and differently sized devices are available for children with different tidal volumes. Special requirements such as oxygen dependence may also influence the choice of the device. There are different types of passive humidifier on the market, the most frequently used being heat and moisture exchangers, followed by hygroscopic condenser humidifiers.24,25 When lithium-coated devices are used, the risk/ benefit ratio between good performance and systemic reabsorption must be evaluated carefully, particularly in children, in whom the risk of toxicity is much greater than it is in adults.26 The devices should be replaced every 24 hours or as needed to prevent the accumulation of secretions.

Speaking valves One-way speaking valves allow inspiration via the tracheostomy tube and direct the expiratory flow around the tube and (if present) via fenestrations up to the vocal

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179 3. It allows the child to develop positive end-expiratory pressure, which may be most important to reduce the risk of atelectasis with wheezy bronchitis or bronchiolitis.

Figure 5 Top from left to right: Hygroscopic condenser humidifier (Vital Signs HCH), and heat and moisture exchanger with an oxygen port and an opening for the introduction of a suction catheter (Hydro-Trach T HME). Bottom from left to right: Heat and moisture exchangers in two sizes (Humid-Vent and Trach-Vent).

cords (Fig. 6). There are several potential advantages of the combination of a fenestrated tube with a speaking valve: 1. It permits the acquisition of normal phonation, which is an important process in the speech and psychosocial development of a child. 2. It allows for effective coughing, which is of special importance as the mucociliary clearance is disturbed by the tracheostomy tube.

Figure 6 Top from left to right: Ru¨sch Spiro speaking valve with (capped) oxygen port and filter, speaking valve for Ru¨schelit Biesalski dual cannula and Shiley tracheostomy tube cap. Bottom from left to right: Shiley speaking valve with oxygen port and (closed) lid, Passy-Muir speaking valve, and Passy-Muir speaking valve with Secure-It.

Speaking valves typically have a bias-closed diaphragm (a thin silicone membrane) that opens with inspiration and automatically closes at the end of the inspiratory effort, thus allowing for spontaneous phonation. These devices should be lightweight, the flaps should cause only low resistance and make minimal noise during breathing, and the valve should fit the standard 15 mm connector (e.g. Bivona and Passy-Muir speaking valves).2 The use of a speaking valve may even be possible in children with mild-to-moderate extrathoracic airway obstruction,27 as this part of the airway may be sufficiently dilated during expiration to allow proper airflow via the native airway. However, in such patients the use of a speaking valve has to be tested individually. Care has to be taken to ensure that the device does not produce any problem such as overinflation of the lungs. Speaking valves should not be used in very small or very ill children due to the additional work of breathing that they impose. In addition, they should not be used in children at high risk of aspiration, who should be managed with a tube of larger diameter or a cuffed tube. With careful selection of candidates for the use of a speaking valve, the majority tolerate its use without problems.27,28 Successful use, however, often requires conditioning of both the child and the family.27 One often encounters the problem of transiently diminished vocal cord abduction, usually a neurological result of the tracheostomy with chronic lack of airflow through the larynx.29,30

SPEECH Clinical experience and research have shown that the presence of a tracheostomy may adversely influence speech acquisition in infants and children.31–35 Other factors that can affect language development in tracheostomised children include repeated and/or extended periods of hospitalisation, neurological problems, chronic middle ear problems, lack of normal feeding experiences, and inadequate muscle strength due to chronic lung disease, neuromuscular disorders or spinal cord injuries. Early forms of communication such as crying and babbling are not produced by tracheostomised infants, and babbling was suggested to normally facilitate the development of language and speech.33 Furthermore, lack of early forms of communication might alter the quality of child– caretaker interactions, creating a less responsive environment for language development. On the other hand, there is evidence that extensive, audible prespeech practice (i.e. cooing and babbling) may not be necessary for later spoken language development when the child is decannulated during the prelinguistic stage.31 These early decannulated children typically exhibit speech and language skills commensurate with intellectual functioning, and only some of

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them show problems in vocal quality and breath support during follow-up. In contrast, children decannulated during the linguistic stage, at least temporarily, demonstrate expressive language delays and severe phonological impairment after the absence or interruption of babbling experiences.31 In a paper describing a group of children without underlying neurological disorders, the median age at decannulation of patients with delayed speech was reported to be 23 months compared with 14.5 months in those with normal speech.35 These authors concluded that the crucial factors affecting speech and language development within neurologically normal children are the age at and duration of cannulation, with early decannulation improving the chance of normal development. Others have found an age-dependent delay in expressive language functioning, with a clear pattern of language disability in older children.32 In any case, the facilitation of swallowing and vocal communication are important goals in children who require a long-term tracheostomy.1 These goals are dependent on a variety of factors such as cognitive, medical and pulmonary status. As soon as the medical and pulmonary status have been stabilised, all patients with a tracheostomy should be referred to the speech therapist, who should play a role not only in evaluation and management, but also in educating families and hospital staff.36 In children who are tracheostomised after having developed speech, restoration of vocal communication may be obtained by the use of a speaking valve, whereas in patients who undergo tracheostomy prior to the development of speech, a speaking valve may be a most valuable tool for learning speech. Measurement of trans-tracheal pressures was suggested to be of value in the assessment of patients for speaking valve usage.37 Virtually all children, including ventilator-dependent patients, who tolerate a speaking valve will achieve phonation.28,38–40 Depending on the age and the neurological development of the patient, vocalisations may range from audible crying and non-specific vocalisations to verbalisation.40 In contrast to phonation, possible secondary benefits of speaking valves, such as improved coughing, secretion management, swallowing, olfactory function and arterial oxygenation, have not been consistently reported.38,40,41 For children who are not candidates for a speaking valve or who do not tolerate such a device, alternative methods of communication, including sign language, language boards, silent speech/lip-reading, writing or typing, and an electrolarynx, are available. Although problems with all these options may be identified, for example the need for extensive training of the patient, the family and also the staff, alternative communication modalities are crucial in reducing communicative frustrations during cannulation.31

CLINICAL EVALUATION Most physicians follow up stable patients with tracheostomies every 1–3 months.18,42

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After the immediate postoperative period, we do not perform chest or neck radiographs or other imaging studies on a routine basis but as required when complications develop.18 Microbiological studies are occasionally performed to allow targetted antibacterial treatment.18,43 Recently, a significant neutrophilic inflammatory reaction in the lower respiratory tract was shown in asymptomatic children with a long-term tracheostomy; this inflammation was more pronounced in those children from whom a higher number of bacteria were recovered.44 Few data are available to support the routine use of flexible airway endoscopy in children with a long-term tracheostomy. Based on experience, it is recommended that children should undergo routine endoscopic evaluation, preferably by flexible bronchoscopy, on a 6–12monthly basis to assess the underlying airway pathology and determine the readiness for decannulation, to detect (and treat) complications such as granuloma formation, tracheal stenosis, tracheomalacia, and suprastomal collapse at an early stage and to assess tracheostomy tube size and position.1 Selected patients such as infants (i.e. those with rapid growth), patients with cerebral palsy or spinal deformity resulting in a tortuous trachea, those with an unstable or rapidly changing medical condition, and those with severe complications usually require more frequent endoscopic evaluation. Endoscopy is also indicated in every child with acute complications such as bleeding or symptoms of upper airway obstruction.1,14– 16 Therefore, tracheostomy evaluation is one of the most common indications for flexible bronchoscopy.14–16 When performing airway endoscopy in decannulation candidates with the tracheostomy tube in place, suprastomal obstruction may be overestimated. It is therefore recommended to remove the tube during endoscopy to enable granulation tissue to fall anteriorly so as not to significantly interfere with airflow.45

LATE COMPLICATIONS Late complications occur more frequently than early ones and have been reported in up to 60% of children with a tracheostomy.1,7–13 The overall mortality rate in tracheostomised children, which is mainly associated with the underlying medical condition, is up to 40%. Mortality directly associated with the tracheostomy appears to be much lower, in the range of 0.5–3%.9–13 The most common tracheostomy-related causes of death are accidental decannulation and blockage of the tracheostomy tube.7,10–13 Minor complications are, however, common. The most frequently reported complication is granuloma formation.10–12 The incidence appears to be higher in infants and young children, in preterm babies and in those with an emergency tracheostomy.1,7,9,10,12,13

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Accidental decannulation

Aspiration of fractured tracheostomy tubes

This complication can occur at any time, particularly in older children and in children who are ventilated, because of the weight and torque of the ventilator tubing.13,46 It may be prevented by appropriate tube selection and placement and by tracheostomy ties that reliably secure the tracheostomy tube. All care-givers of a tracheostomised child should be trained to react appropriately to an accidental decannulation.

This very rare complication was reported for metal and polyvinyl chloride tubes, with all fractures occurring at the same site: the junction of the cannula and the neck plate.48,49 Most reports on fractured tracheostomy tubes come from developing countries, prolonged usage of the tubes and repeated sterilisation being the most important risk factors.

Granuloma formation Blockage of the tracheostomy tube Obstruction of the cannula is one of the most frequent tracheostomy-associated complications; in particular, it occurs in premature babies and newborns, mainly due to the small tracheostomy tubes used.13 This complication can be avoided by regular tracheostomy tube care. The care-givers should be trained in the management of this complication.

Infection Mild tracheal infections are usually treated with short courses of oral antibiotics.43 In children with long-term tracheostomies, colonisation with Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa and Streptococcus species is frequently seen.47 Without signs of infection, most physicians do not prescribe antibiotics.43 As in any child with chronic lung disease, the supportive care of tracheostomised children should include annual immunisation with influenza vaccine along with other routine immunisations against respiratory pathogens.

Bleeding The tip of the tracheostomy tube may exert pressure on the tracheal wall, resulting in local irritation, inflammation and ulceration of the wall with bleeding; a tracheal wall erosion of the anterior wall can reach the innominate artery and cause serious haemorrhage. Similar to accidental decannulation, this complication is more likely to occur in ventilated children.46 To prevent this complication, adequate humidification and good tracheostomy care, as well as appropriately sized tubes, are imperative. Any bleeding from the tracheostomy requires airway endoscopy.

Tracheo-oesophageal fistula Corresponding to what has been described for the anterior tracheal wall, posterior wall trauma can result in the development of a tracheo-oesophageal fistula, which also represents a life-threatening problem causing contamination of the tracheobronchial tree.

Granulomas most frequently occur just superior to the internal stoma site on the anterior tracheal wall, most likely as a result of frictional trauma from the tube; other factors such as low-grade inflammation resulting from stasis of secretions and infection are also believed to contribute to their development.50,51 The formation of suprastomal granulation tissue is a common complication of paediatric tracheostomy, with an incidence of up to 80%.11,51,52 In the first weeks after tracheotomy, the granulation tissue is soft and fragile, but it becomes fibrous and firm over the months and years.52 Treatment depends on size. The majority are small and asymptomatic; consequently, no intervention is required. Interval excision of non-obstructing granulomas is not recommended because of the tendency for recurrence following excision. In contrast, large and obstructing granulomas may cause bleeding with tracheostomy tube changes, aphonia, delayed decannulation, or even death with accidental decannulation. Surgery may be indicated for these.50,51 Granulation tissue commonly grows around the external stoma site; it usually can be treated locally with silver nitrate application. Granulomas may also arise on the anterior or posterior tracheal wall at the site of the tube tip.52 They may be caused by a faulty tube position or by traumatic suction.

Suprastomal collapse Pressure on the tracheal cartilages superior to the stoma caused by the tracheostomy tube and local inflammation may cause chondritis with subsequent weakening of cartilages, resulting in some degree of suprastomal collapse. Suprastomal collapse and granuloma formation are often associated, mutually aggravating airway obstruction.53 In a few children, particularly infants with prolonged tracheostomy, Suprastomal collapse may be severe enough to make decannulation impossible.54

Stenosis Subglottic stenosis after a tracheostomy may be caused by intraoperative damage to the cricoid, too high placement of the tracheostomy with the tube exerting pressure on the

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cricoid, mucosal trauma prior to the tracheostomy, or lowgrade chronic inflammation originating from the peristomal region. With appropriate surgical technique and tracheostomy care, this complication can be avoided in the majority of patients. Tracheal stenosis can also occur, either at the site of the tracheostomy due to fibrosis and loss of cartilage, particularly after emergency surgery,53 or at the level of the tube tip due to incorrect tube position and/or suctioning.

Persistent tracheocutaneous fistula This is the most common complication of decannulation, occurring in up to 40% of children, with a relationship between the persistence of such a fistula and both younger age at tracheostomy and longer duration of cannulation.10,12,55 Starplasty, an alternative technique for paediatric tracheostomy, is associated with a persistent tracheocutaneous fistula.56 The placement of maturation sutures, however, does not necessarily increase the incidence of this complication.57 Persistent tracheocutaneous fistula necessitates surgical closure. However, the fistula may signal an underlying airway obstruction; thus, airway patency has to be thoroughly evaluated before such a fistula is closed.

Post-decannulation After decannulation, children require close observation because they are at risk of both aspiration and airway obstruction. Among other factors, such as dysfunctional swallowing, a poorly coordinated laryngeal closure reflex may contribute to an increased risk of aspiration.29 As shown in an animal model, vocal cord abduction may be compromised in patients with long-term tracheostomies, resulting in a risk of functional upper airway obstruction after decannulation.58 Severe complications following elective decannulation have been reported, including cardiorespiratory arrest and even death.8,59 Sometimes decannulation fails despite an endoscopically assessed, apparently adequate airway and no obvious pulmonary or neurological abnormalities; this problem was named as ‘decannulation panic’.60 Although it is in theory conceivable that decannulation may fail because the child is unhappy or because of parental anxiety, major physiological changes occurring after decannulation more likely explain the problem, such as an increase in dead space with no other detectable loading, resulting in an increased work of breathing.61 Airway endoscopy is routinely used to assess any underlying airway pathology and to detect tracheostomy-related complications. It is an invaluable tool for evaluating decannulation candidates. Tidal flow measurements and polysomnography may also be useful in the prediction of the child’s readiness for decannulation.62,63 A recent study sought to identify predictors of early decannulation and

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found a tracheostomy indication, namely pulmonary toilet, and neurological and trauma-related diagnoses to be independent variables predicting early decannulation.64 Currently reported decannulation rates average 65%.64,65

ACKNOWLEDGEMENT The authors would like to thank Professor Maximilian Zach, Graz, Austria, for reviewing this manuscript and for his valuable comments.

PRACTICE POINTS  The selection of an appropriate tracheostomy tube will minimise the incidence of complications.  In paediatric patients, indications for cuffed tracheostomy tubes are limited.  Preservation of heat and humidity may be achieved by passive humidifiers (‘artificial noses’).  The combination of a fenestrated tube with a speaking valve permits the acquisition of normal phonation and allows for effective coughing.  With careful selection of candidates for the use of a speaking valve, the majority tolerate its use. Virtually all children (including ventilator-dependent patients) who tolerate a speaking valve will achieve phonation.  The facilitation of swallowing and vocal communication are important goals in children with a long-term tracheostomy.  Endoscopic evaluation is an essential part of the care of children with a tracheostomy.  Long-term tracheostomy in infants and children is associated with significant morbidity, and the majority of paediatric patients experience tracheostomy-related complications.  Many complications are preventable or may at least be minimised by good tracheostomy tube care and clinical evaluation of the patient at regular intervals.  Bleeding should prompt endoscopic evaluation.  The most frequently reported complication is granuloma formation.  The mortality rate directly associated with the tracheostomy is in the range of 0.5–3%, and the most common tracheostomy-related causes of death are accidental decannulation and blockage of the tracheostomy tube.  After decannulation, children require close observation because they are at risk of both aspiration and airway obstruction.  Infants and children clearly benefit from a specialist tracheostomy service.

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