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The role of airway endoscopy in children
SYMPOSIUM: RESPIRATORY
The role of airway endoscopy in children
the larynx and perform therapeutic interventions have continued to develop over the recent decades, resulting in the instruments commonly used today. Flexible nasendoscopy/laryngoscopy uses a flexible endoscope to examine the nose and the larynx in clinic, down to the level of the vocal cords. Laryngotracheobronchoscopy (LTB) uses rigid instruments to assess the airway from tongue base to main bronchi under general anaesthetic: it also has therapeutic potential. Flexible bronchoscopy uses flexible endoscopes to examine the trachea and bronchi under local or general anaesthetic in children (Figure 1). These airway endoscopy techniques are complementary and may be practiced by multiple specialities such as paediatric pulmonology, anaesthesia, intensive care and otorhinolaryngology. In general, these specialities work very much as a team with complementary skills for the benefit of the patient, whether dealing with lower respiratory problems, stridor, or other airway pathology. This article describes the equipment and techniques used, along with their applications and indications, and looks at how airway endoscopy is useful in a range of common pathologies.
Sophie Wilkinson Purushothaman Sudarshan Alan R Smyth Matija Daniel
Abstract Airway endoscopy is an essential tool in the investigation and management of paediatric airway and respiratory pathology. Examination can be performed using a variety of rigid and/or flexible endoscopes, each with specific advantages and limitations. Awake fibreoptic examination of the airway enables timely and dynamic respiratory tract examination, but is limited to visualisation of more proximal anatomy, from pharynx to glottis. This technique is predominantly used for diagnostic purposes and has minimal therapeutic capabilities. Conversely, endoscopic techniques used in distal airway examination facilitate simultaneous interventional techniques, but necessitate general anaesthesia. Laryngotracheobronchoscopy using rigid instruments examines the airway to main bronchi and has multiple therapeutic applications. Flexible bronchoscopy allows examination of the respiratory tract beyond main bronchi. These techniques are complementary, and close collaboration between the different specialties involved is essential.
Flexible nasendoscopy/laryngoscopy Equipment Flexible nasendoscopy/laryngoscopy visualises the aerodigestive tract through flexible fibreoptic tubing. Housed within the cabling are several thousand individual optical fibres which abut a lens at each end of the scope. Light, provided by an external source, and attached via a port to the scope unit, traverses the fibres, reflects off the image and travels towards the proximal lens and eyepiece. Within the eyepiece the image is visualised by the physician, and picture quality adjusted using focus. The scope tip can be manipulated in one plane (up and down) using the lever, whilst horizontal movement is achieved through rotation of the entire scope unit. The self-contained, lumen-free design of the scope lends itself to easy sterilization. However, the lack of additional ports for suctioning and instrumentation limits interventional capability. The normal scope diameter is 4 mm; this can be used at any age, but a 2.7 mm scope is also available, albeit with reduced image clarity and increased fragility.
Keywords airway; bronchoscopy; child; endoscopy; laryngoscopy; otolaryngology; respiratory tract
Introduction Airway endoscopy is a key tool in the assessment and management of various airway pathologies. Several techniques are used to assess different structures, using rigid or flexible endoscopes, for either diagnostic or therapeutic purposes. Indirect visualisation of the upper aerodigestive tract was practiced by physicians as early as 1743. Initially conducted using the manipulation of paired mirrors and an external light source, Manuel Garcia, one of the fathers of laryngoscopy, demonstrated his own larynx at a medical meeting at London’s Royal Society of Medicine in 1854. Techniques used to examine
Technique The procedure is usually performed through the nose (flexible naso-laryngoscopy), but in babies can be done through the mouth. Babies under the age of 1 can be wrapped in a blanket, and sat on the parent’s knee facing forwards (Figure 2). The parent holds the baby’s body, with an assistant supporting the head. Once past the age of 1, this technique is generally no longer possible, so that awake flexible laryngoscopy cannot be used until the child is old enough to comply with the technique (typically around the age of 5e7 years). There is little evidence that the use of a local anaesthetic or vasoconstrictor spray improves procedure tolerability. Vasoconstrictor use has been reported in some cases to reduce overall discomfort, but use should be balanced with any associated side effects, such as unpleasant taste. Some patients experience a choking sensation if local anaesthetic is used. The procedure itself, although invasive, is rapidly completed and causes only minimal discomfort when conducted by a competent physician. Interestingly, research conducted by Laeeq et al., in 2010
Sophie Wilkinson BMBS BMedSci (Hons) is Surgical Trainee, Otorhinolaryngology Head and Neck Surgery, Nottingham University Hospitals, UK. Conflict of interest: none declared. Purushothaman Sudarshan MBBS MD DNB FRCA is Consultant Paediatric Anaesthetist, Department of Anaesthesia, Nottingham University Hospitals NHS Trust, QMC Campus, Nottingham, UK. Conflict of interest: none declared. Alan R Smyth MA MBBS MRCP MD FRCPCH is Professor of Child Health, Division of Child Health, Obstetrics & Gynaecology, Queens Medical Centre, Nottingham, UK. Conflict of interest: none declared. Matija Daniel PhD FRCS is Consultant in Otorhinolaryngology Head and Neck Surgery, Nottingham University Hospitals, Nottingham, UK. Conflict of interest: none declared.
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and can be conducted largely within the outpatient setting; if performed through the nose it also assesses the nose and nasopharynx. Avoidance of the operating theatre not only reduces any associated anaesthetic risks, but also minimises undue delay. The flexible endoscope can also be used in sleep nasendoscopy; the procedure is performed in theatre under simulated sleep, and is used to assess the site of obstruction in a child with sleep apnoea (typically when adenotonsillectomy has not been curative). Flexible endoscopy is also used in fibreoptic endoscopic evaluation of swallowing. Flexible laryngoscopy does not facilitate visualisation of the subglottis and trachea. Thus, when history and examination suggest the existence of airway pathology but flexible laryngoscopy is normal, then examination below the vocal cords, under general anaesthetic, is still required. Importantly, even when laryngomalacia, the commonest cause of stridor, is identified, one should remember that up to half of children with laryngomalacia have second airway pathology (Thompson 2010), so if the history is atypical further examination is warranted. Although therapeutic procedures are not generally possible, the flexible laryngoscope can be used as an aid in awake (or asleep) fibreoptic intubation when difficult intubation is anticipated, for example in Pierre-Robin sequence. Modern slim line flexible laryngoscopes have enabled direct visualisation and passage through the tiniest of paediatric airways, making anaesthetic management of these patients much easier.
Figure 1 Schematic airway anatomy illustrating areas that can be examined by the different endoscopy techniques.
examined the learning curve for competency in flexible laryngoscopy, and concluded that novice medical students could be trained to an appropriate level using only six passes of the scope. Ease of skill development and an increase in numbers of competent physicians facilitates the use of flexible laryngoscopy as a diagnostic tool within the outpatient clinic environment.
Rigid laryngotracheobronchoscopy Equipment The Hopkins rod lens telescope (Figure 3d), a rigid endoscope used in examination of the respiratory tract, is a key tool in LTB. Depending on size, the scope can be used to visualise more proximal anatomy, within the nasal passages, to more distal structures within the trachea and bronchi. The telescope relies on a rigid tube to house the relay lenses and illumination; combinations of lenses transmit images towards the proximal eyepiece and correct inversion is produced en route. The result is superb optical quality. They can also be combined with rigid ventilating bronchoscopes (Figure 3c), particularly in therapeutic applications. The Hopkins rod can be used with an intubating laryngoscope typically used by anaesthetists, or it can be used with dedicated laryngoscopes (Figure 3b), particularly in therapeutic applications. The equipment is generally robust and more hardwearing than flexible endoscopes.
Uses Flexible laryngoscopy allows awake and dynamic airway assessment of tongue base, supraglottic region and vocal cords,
Technique The procedure requires general anaesthesia. The patient is spontaneously breathing (ideally), with a volatile anaesthetic (sevoflurane) administered via a nasopharyngeal or oropharyngeal tube, supplemented with intravenous propofol, as needed. Alternatively, Total Intravenous Anaesthesia (TIVA) can be used using continuous infusions of propofol, along with an opioid, usually remifentanil although alfentanil has been used. The larynx and trachea are sprayed with topical lignocaine to minimize laryngotracheal irritability during the procedure. Anti-cholinergic premedication may be considered to reduce secretions. For a diagnostic examination, a standard anaesthetic laryngoscope is used to open the airway, and the Hopkins rod then
Figure 2 Technique used for flexible nasendoscopy/laryngoscopy in an infant under one.
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It is also possible to place an endotracheal tube over a Hopkins rod; this can be a useful way to achieve intubation in some patients with a difficult upper airway, for example in congenital high airway obstruction necessitating the Ex-utero Intrapartum Treatment procedure. When examining the bronchial tree beyond the main bronchi, rigid techniques become increasingly more difficult, and flexible bronchoscopy is then usually a better tool.
Flexible bronchoscopy Equipment Most modern flexible bronchoscopes are of the “videoscope” design, with a camera chip at the distal end of the scope and the image relayed to a monitor. Unlike the flexible laryngoscopes, the bronchoscope central unit houses additional channels, enabling both suction and irrigation to the operative field. Although increasing its functionality, additional ports increase complexity of sterilisation, fragility, and scope cost, while reducing image quality. Technique The flexible bronchoscope in children is typically used under general anaesthesia, and can be inserted via an endotracheal tube or via the laryngeal mask airway (Figure 3e). The latter technique permits the use of a wider bronchoscope with better views. Thus, using a laryngeal mask airway means that therapeutic applications are feasible in much younger children than would be possible if an endotracheal tube were to be used (Smyth et al., 1996). Uses Flexible bronchoscopy allows examination of supraglottis/ glottis/subglottis (if laryngeal mask airway is used), trachea and bronchial tree, and allows more distal examination than rigid endoscopy. It is useful in investigation of tracheal pathology, lobar collapse, persistent wheeze, and opportunistic infections. It allows removal of secretions, bronchoalveolar lavage, collection of microbiology specimens, and endobronchial and transbronchial biopsy. It can also be used with flexible laser technology. It is chiefly performed by paediatric pulmonologists. Thus, it is clear that a variety of different ways of examining the paediatric airway exist, each with its own advantages. The techniques and medical teams using them typically work in a complementary fashion. Good communication between the team members is an absolute pre-requisite for a successful outcome as these children can have intra or post operative problems (in the form of hypoxia, laryngo/bronchospasm, or even pneumothorax) that need to be identified and managed promptly and appropriately. The remainder of this article focuses on some common and/or important conditions, and details how airway endoscopy is useful in diagnosis or treatment.
Figure 3 Flexible nasolaryngoscope (a), laryngoscope used in suspension laryngoscope (b), Storz ventilating bronchoscope (c), Hopkins rod lens telescope (d), flexible bronchoscope used through a laryngeal mask airway (e).
inserted. For therapeutic procedures on the vocal cords and subglottis, a laryngoscope (such as the Lindholm Figure 3b) can be used with suspension apparatus and an operating microscope; this gives the operator two free hands. The rigid ventilating bronchoscope (Figure 3c) is used when spontaneous ventilation is not possible (typically in a compromised child), or for therapeutic applications in the trachea or main bronchi (such as foreign bodies). For foreign body removal, optical grasping forceps are used; these forceps have an integral space for a Hopkins telescope that allows good view combined with therapeutic application. Uses LTB using rigid instruments allows examination of tongue base, supraglottis and vocal cords, plus also subglottis, trachea, and main bronchi that cannot be examined using flexible laryngoscopy. It is chiefly performed by Otorhinolaryngologists. The suspension laryngoscopy technique is useful in laryngeal surgery such as surgery for laryngomalacia, removal of granulation or cysts, repair of small laryngeal clefts, balloon dilatation or other endoscopic procedures to deal with laryngotracheal stenosis.
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Laryngomalacia Laryngomalacia (floppy larynx) is the commonest cause of stridor during infancy, and is characterised by supraglottic airway collapse during inspiration. It typically presents within a few weeks or months of birth, and is often self-limiting, with complete resolution by two years common. At time of presentation symptoms of inspiratory stridor predominate, and in more severe
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cases there may be respiratory difficulty particularly during feeding, and failure to thrive. Aetiology of laryngomalacia is still widely debated, but it is thought to develop as a result of abnormally integrated innervation of the larynx with poor tone, muscular weakness and prolapse; gastroeosophageal reflux may be a contributing factor. Confirmation of laryngomalacia is obtained at flexible laryngoscopy on the awake child. Visualisation during respiration allows for dynamic airway assessment, typically demonstrating collapse of posterior laryngeal soft tissue during inspiration, often with an omega-shaped or retroflexed epiglottis (Figure 4a and b). Research suggests that up to 72% of patients will experience resolution of their symptoms within the first year of diagnosis. Subsequently, surgical intervention is reserved for those presenting with severe disease. In theatre, a diagnostic LTB is performed first to exclude dual pathology (present in up to 50%), followed by the surgical procedure of supraglottoplasty that typically involves division of the short aryepiglottic folds and excision redundant mucosa above the arytenoid cartilages.
airway compromise usually predominate, with evidence of stridor and/or respiratory distress (tracheal tug/recession). It is caused by Human Papilloma Virus (typically types 6 and 11); these subtypes typically present as urogenital papillomatous lesions (genital warts), and consequently, transmission of disease within the paediatric age group is thought to stem from vertical transmission. Once acquired, pathological progression is somewhat variable, but with a great propensity for recurrence. RRP typically involves the larynx, and can be diagnosed using flexible nasendoscopy. However, presentation often does not occur until the child is over 1 years old, making flexible nasendoscopy impossible. The diagnosis is thus usually made using LTB in a child presenting with dysphonia or airway obstruction. LTB also allows the detection of papillomata beyond the vocal cords, plus it has therapeutic applications where papillomata can be removed (usually as a microlaryngoscopy procedure). A variety of surgical techniques are available, with the microdebrider being commony used, but recurrence is the norm so that multiple procedures are required. Adjuvant chemotherapy directed towards viral eradication has been attempted, but current data remains insufficient to draw reliable conclusions regarding efficacy.
Respiratory papillomatosis Vocal cord motion impairment
Recurrent respiratory papillomatosis (RRP) is characterised by the presence of multiple papillomata within the respiratory tract (Figure 4c). The prevalence of the paediatric subtype is two-fold higher than in adults, with an estimated incidence of four cases per one hundred thousand children. Papillomata can occur throughout the respiratory tract, with more distal lesions indicative of worsening disease. Classic clinical presentation centres around symptoms of progressive dysphonia, but aggressive forms of the disease can quickly result in airway obstruction and rapid clinical deterioration. In these cases, features suggestive of
Vocal cord motion impairment (VCMI) is the second most common cause of paediatric stridor, and the commonest cause of stridor in a newborn. It can be unilateral or bilateral, and can be caused by motor nerve disruption to the laryngeal structures (palsy) or vocal cord fixation. Presentation of disease differs according to vocal cord involvement, with unilateral cases typically demonstrating dysphonic symptoms (breathy or weak cry) and feeding difficulties, but bilateral VCMI presenting as an airway emergency with severe stridor. Weakness in both
Figure 4 Laryngomalacia (a, b), respiratory papillomata (c), subglottic oedema (d), and foreign body (e, f ).
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up alternative pathology. Removal of foreign bodies should not be attempted using the flexible bronchoscope.
abductor muscles results in close apposition of the cords and significant reduction in airway diameter. Congenital bilateral VCMI is thought to be due to delayed neural maturation, whilst unilateral VCMI is usually a palsy due to an iatrogenic cause such as cardiothoracic surgery. Awake flexible laryngoscpy is a key diagnostic tool that allows one to assess vocal cord movement, but LTB also allows assessment of active movement plus it allows the surgeon to palpate the arytenoids to look for fixation as a cause of VCMI. Once diagnosed, treatment of VCMI is largely dependent on disease severity. In unilateral VCMI, the airway is usually good, and treatment is directed towards avoidance of any aspiration and, in the older child, voice production. Speech and language therapists are key in both situations. Bilateral VCMI may cause severe respiratory distress at birth, and roughly half of neonates require a tracheostomy. A variety of surgical procedures are being developed to increase airway diameter, as an aid to tracheostomy removal. Both therapeutic airway endoscopy and open procedures have been described. However, airway widening is often achieved at the expense of voice quality, and with as many as 66% of infants achieving at least some degree of spontaneous vocal cord movement, surgery to the larynx is typically delayed for at least a few years.
Mucus plugging Both LTB and flexible bronchoscopy are useful in mucus plugging, which may be encountered in cystic fibrosis or following prolonged intubation. Flexible bonchoscopy alone may not be able to remove the plug, but once the plug is removed using rigid techniques then flexible bronchoscopy allows detailed assessment of more distal airway. This can be combined with bronchoalveolar lavage. A FURTHER READING 1 Daniel M, Cheng A. Neonatal stridor. Int J Pediatr 2012; 2012: 859104. http://dx.doi.org/10.1155/2012/859104. Epub 2011 Dec 25. 2 Dickson JM, Richter GT, Meinzen-Derr J, Rutter MJ, Thompson DM. Secondary airway lesions in infants with laryngomalacia. Ann Otol Rhinol Laryngol 2009 Jan; 118: 37e43. 3 Malherbe S, Whyte S, Singh P, et al. Total intravenous anaesthesia and spontaneous respiration for airway endoscopy in children e a prospective evaluation. Paediatr Anaesth 2010; 20: 434e8. 4 Berkenbosch JW, Graff GR, Stark JM, Ner Z, Tobias JD. Use of a remifentanilpropofol mixture for pediatric flexible fiberoptic bronchoscopy sedation. Paediatr Anaesth 2004 Nov; 14: 941e6. 5 Smyth AR, Bowhay AR, Heaf LJ, Smyth RL. The laryngeal mask airway in fibreoptic bronchoscopy. Arch Dis Child 1996; 75: 344e5. 6 Monnier P. Paediatric airway surgery: management of laryngotracheal stenosis in infants and children. Springer, 2011. ISBN: 978-3-64213534-7. 7 Oshan V, Walker R. Anaesthesia for complex airway surgery in children. Cont Edu Anaes Crit Care Pain 2013; 13: 47e51. 8 Mausser G, Friedrich G, Schwarz G. Airway management and anesthesia in neonates, infants and children during endolaryngotracheal surgery. Paediatr Anaesth 2007; 17: 942e7. 9 Donato LL, Mai Hong Tran T, Ammouche C, Musani AI. Paediatric interventional bronchoscopy. Clin Chest Med 2013; Sep; 34: 569e82. 10 Graham JM, Scadding GK, Bull PD. Paediatric ENT. Springer, 2008. ISBN: 978-3-540-69930-9. 11 Thompson DM. Laryngomalacia: factors that influence disease severity and outcomes of management. Curr Opin Otolaryngol Head Neck Surg 2010 Dec; 18: 564e70. 12 Buckmiller LM. Propranolol treatment for infantile hemangiomas. Curr Opin Otolaryngol Head Neck Surg 2009 Dec; 17: 458e9.
Subglottic stenosis SGS can be congenital, or more commonly acquired. The typical presentation is with biphasic stridor, often in a child that has required prolonged intubation for another illness presenting with post-extubation stridor, failed extubation, or when it is not possible to insert an age-appropriate endotracheal tube size. Flexible laryngoscopy (if patient is awake) or direct laryngoscopy (in PICU) is useful to look for a glottic or supraglottic cause of stridor such as granulation tissue, but SGS cannot be diagnosed on this limited visualisation. LTB is useful to confirm the diagnosis (Figure 4d), and can be combined with therapeutic procedures such as removal of vocal cord granulation, endoscopic balloon dilatation of SGS, or endoscopic cricoid split to allow subglottic oedema to dissipate. In established SGS open airway reconstruction may be needed, but endoscopic placement of a cartilage graft to widen the subglottis has also been described. Mucosal lesions of the lower airway are commonly formed secondary to iatrogenic trauma and instrumentation with complex airway adjuncts (tracheostomy tubes and tracheal stents). Subsequent inflammatory changes and granuloma formation results in airway narrowing, and in extensive cases, impending airway obstruction. Although often managed with systemic steroid therapy, resolution of obstruction can be short lived, with further endoscopic or open interventions often being required.
Practical points C
C
Foreign body aspiration Flexible laryngoscopy has limited role in the management of a foreign body, as these children are usually of an age where they do not tolerate the procedure and at any rate the foreign body would typically not be seen at the larynx. The foreign body (Figure 4e and f) is usually removed with optical grasping forceps, which may be combined with the use of a ventilating bronchoscope. Flexible bronchoscopy is also useful when no foreign body is seen in the main bronchi, as it allows more distal visualisation and may pick
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C
C
C
186
Airway endoscopy encompasses a range of complementary techniques Flexible nasolaryngoscopy allows examination of the nose, pharynx and larynx to level of vocal cords. It can be done without anaesthetic in babies and compliant older children Rigid laryngotracheobronchoscopy allows examination of pharynx, larynx, trachea and main bronchi, and requires general anaesthesia Flexible bronchoscopy allows examination of the larynx, trachea, and bronchial tree, typically under general anaesthetic in children Close co-operation between the different specialties involved in these procedures is essential for good patient care
Ó 2015 Elsevier Ltd. All rights reserved.
The role of airway endoscopy in children
the larynx and perform therapeutic interventions have continued to develop over the recent decades, resulting in the instruments commonly used today. Flexible nasendoscopy/laryngoscopy uses a flexible endoscope to examine the nose and the larynx in clinic, down to the level of the vocal cords. Laryngotracheobronchoscopy (LTB) uses rigid instruments to assess the airway from tongue base to main bronchi under general anaesthetic: it also has therapeutic potential. Flexible bronchoscopy uses flexible endoscopes to examine the trachea and bronchi under local or general anaesthetic in children (Figure 1). These airway endoscopy techniques are complementary and may be practiced by multiple specialities such as paediatric pulmonology, anaesthesia, intensive care and otorhinolaryngology. In general, these specialities work very much as a team with complementary skills for the benefit of the patient, whether dealing with lower respiratory problems, stridor, or other airway pathology. This article describes the equipment and techniques used, along with their applications and indications, and looks at how airway endoscopy is useful in a range of common pathologies.
Sophie Wilkinson Purushothaman Sudarshan Alan R Smyth Matija Daniel
Abstract Airway endoscopy is an essential tool in the investigation and management of paediatric airway and respiratory pathology. Examination can be performed using a variety of rigid and/or flexible endoscopes, each with specific advantages and limitations. Awake fibreoptic examination of the airway enables timely and dynamic respiratory tract examination, but is limited to visualisation of more proximal anatomy, from pharynx to glottis. This technique is predominantly used for diagnostic purposes and has minimal therapeutic capabilities. Conversely, endoscopic techniques used in distal airway examination facilitate simultaneous interventional techniques, but necessitate general anaesthesia. Laryngotracheobronchoscopy using rigid instruments examines the airway to main bronchi and has multiple therapeutic applications. Flexible bronchoscopy allows examination of the respiratory tract beyond main bronchi. These techniques are complementary, and close collaboration between the different specialties involved is essential.
Flexible nasendoscopy/laryngoscopy Equipment Flexible nasendoscopy/laryngoscopy visualises the aerodigestive tract through flexible fibreoptic tubing. Housed within the cabling are several thousand individual optical fibres which abut a lens at each end of the scope. Light, provided by an external source, and attached via a port to the scope unit, traverses the fibres, reflects off the image and travels towards the proximal lens and eyepiece. Within the eyepiece the image is visualised by the physician, and picture quality adjusted using focus. The scope tip can be manipulated in one plane (up and down) using the lever, whilst horizontal movement is achieved through rotation of the entire scope unit. The self-contained, lumen-free design of the scope lends itself to easy sterilization. However, the lack of additional ports for suctioning and instrumentation limits interventional capability. The normal scope diameter is 4 mm; this can be used at any age, but a 2.7 mm scope is also available, albeit with reduced image clarity and increased fragility.
Keywords airway; bronchoscopy; child; endoscopy; laryngoscopy; otolaryngology; respiratory tract
Introduction Airway endoscopy is a key tool in the assessment and management of various airway pathologies. Several techniques are used to assess different structures, using rigid or flexible endoscopes, for either diagnostic or therapeutic purposes. Indirect visualisation of the upper aerodigestive tract was practiced by physicians as early as 1743. Initially conducted using the manipulation of paired mirrors and an external light source, Manuel Garcia, one of the fathers of laryngoscopy, demonstrated his own larynx at a medical meeting at London’s Royal Society of Medicine in 1854. Techniques used to examine
Technique The procedure is usually performed through the nose (flexible naso-laryngoscopy), but in babies can be done through the mouth. Babies under the age of 1 can be wrapped in a blanket, and sat on the parent’s knee facing forwards (Figure 2). The parent holds the baby’s body, with an assistant supporting the head. Once past the age of 1, this technique is generally no longer possible, so that awake flexible laryngoscopy cannot be used until the child is old enough to comply with the technique (typically around the age of 5e7 years). There is little evidence that the use of a local anaesthetic or vasoconstrictor spray improves procedure tolerability. Vasoconstrictor use has been reported in some cases to reduce overall discomfort, but use should be balanced with any associated side effects, such as unpleasant taste. Some patients experience a choking sensation if local anaesthetic is used. The procedure itself, although invasive, is rapidly completed and causes only minimal discomfort when conducted by a competent physician. Interestingly, research conducted by Laeeq et al., in 2010
Sophie Wilkinson BMBS BMedSci (Hons) is Surgical Trainee, Otorhinolaryngology Head and Neck Surgery, Nottingham University Hospitals, UK. Conflict of interest: none declared. Purushothaman Sudarshan MBBS MD DNB FRCA is Consultant Paediatric Anaesthetist, Department of Anaesthesia, Nottingham University Hospitals NHS Trust, QMC Campus, Nottingham, UK. Conflict of interest: none declared. Alan R Smyth MA MBBS MRCP MD FRCPCH is Professor of Child Health, Division of Child Health, Obstetrics & Gynaecology, Queens Medical Centre, Nottingham, UK. Conflict of interest: none declared. Matija Daniel PhD FRCS is Consultant in Otorhinolaryngology Head and Neck Surgery, Nottingham University Hospitals, Nottingham, UK. Conflict of interest: none declared.
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and can be conducted largely within the outpatient setting; if performed through the nose it also assesses the nose and nasopharynx. Avoidance of the operating theatre not only reduces any associated anaesthetic risks, but also minimises undue delay. The flexible endoscope can also be used in sleep nasendoscopy; the procedure is performed in theatre under simulated sleep, and is used to assess the site of obstruction in a child with sleep apnoea (typically when adenotonsillectomy has not been curative). Flexible endoscopy is also used in fibreoptic endoscopic evaluation of swallowing. Flexible laryngoscopy does not facilitate visualisation of the subglottis and trachea. Thus, when history and examination suggest the existence of airway pathology but flexible laryngoscopy is normal, then examination below the vocal cords, under general anaesthetic, is still required. Importantly, even when laryngomalacia, the commonest cause of stridor, is identified, one should remember that up to half of children with laryngomalacia have second airway pathology (Thompson 2010), so if the history is atypical further examination is warranted. Although therapeutic procedures are not generally possible, the flexible laryngoscope can be used as an aid in awake (or asleep) fibreoptic intubation when difficult intubation is anticipated, for example in Pierre-Robin sequence. Modern slim line flexible laryngoscopes have enabled direct visualisation and passage through the tiniest of paediatric airways, making anaesthetic management of these patients much easier.
Figure 1 Schematic airway anatomy illustrating areas that can be examined by the different endoscopy techniques.
examined the learning curve for competency in flexible laryngoscopy, and concluded that novice medical students could be trained to an appropriate level using only six passes of the scope. Ease of skill development and an increase in numbers of competent physicians facilitates the use of flexible laryngoscopy as a diagnostic tool within the outpatient clinic environment.
Rigid laryngotracheobronchoscopy Equipment The Hopkins rod lens telescope (Figure 3d), a rigid endoscope used in examination of the respiratory tract, is a key tool in LTB. Depending on size, the scope can be used to visualise more proximal anatomy, within the nasal passages, to more distal structures within the trachea and bronchi. The telescope relies on a rigid tube to house the relay lenses and illumination; combinations of lenses transmit images towards the proximal eyepiece and correct inversion is produced en route. The result is superb optical quality. They can also be combined with rigid ventilating bronchoscopes (Figure 3c), particularly in therapeutic applications. The Hopkins rod can be used with an intubating laryngoscope typically used by anaesthetists, or it can be used with dedicated laryngoscopes (Figure 3b), particularly in therapeutic applications. The equipment is generally robust and more hardwearing than flexible endoscopes.
Uses Flexible laryngoscopy allows awake and dynamic airway assessment of tongue base, supraglottic region and vocal cords,
Technique The procedure requires general anaesthesia. The patient is spontaneously breathing (ideally), with a volatile anaesthetic (sevoflurane) administered via a nasopharyngeal or oropharyngeal tube, supplemented with intravenous propofol, as needed. Alternatively, Total Intravenous Anaesthesia (TIVA) can be used using continuous infusions of propofol, along with an opioid, usually remifentanil although alfentanil has been used. The larynx and trachea are sprayed with topical lignocaine to minimize laryngotracheal irritability during the procedure. Anti-cholinergic premedication may be considered to reduce secretions. For a diagnostic examination, a standard anaesthetic laryngoscope is used to open the airway, and the Hopkins rod then
Figure 2 Technique used for flexible nasendoscopy/laryngoscopy in an infant under one.
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SYMPOSIUM: RESPIRATORY
It is also possible to place an endotracheal tube over a Hopkins rod; this can be a useful way to achieve intubation in some patients with a difficult upper airway, for example in congenital high airway obstruction necessitating the Ex-utero Intrapartum Treatment procedure. When examining the bronchial tree beyond the main bronchi, rigid techniques become increasingly more difficult, and flexible bronchoscopy is then usually a better tool.
Flexible bronchoscopy Equipment Most modern flexible bronchoscopes are of the “videoscope” design, with a camera chip at the distal end of the scope and the image relayed to a monitor. Unlike the flexible laryngoscopes, the bronchoscope central unit houses additional channels, enabling both suction and irrigation to the operative field. Although increasing its functionality, additional ports increase complexity of sterilisation, fragility, and scope cost, while reducing image quality. Technique The flexible bronchoscope in children is typically used under general anaesthesia, and can be inserted via an endotracheal tube or via the laryngeal mask airway (Figure 3e). The latter technique permits the use of a wider bronchoscope with better views. Thus, using a laryngeal mask airway means that therapeutic applications are feasible in much younger children than would be possible if an endotracheal tube were to be used (Smyth et al., 1996). Uses Flexible bronchoscopy allows examination of supraglottis/ glottis/subglottis (if laryngeal mask airway is used), trachea and bronchial tree, and allows more distal examination than rigid endoscopy. It is useful in investigation of tracheal pathology, lobar collapse, persistent wheeze, and opportunistic infections. It allows removal of secretions, bronchoalveolar lavage, collection of microbiology specimens, and endobronchial and transbronchial biopsy. It can also be used with flexible laser technology. It is chiefly performed by paediatric pulmonologists. Thus, it is clear that a variety of different ways of examining the paediatric airway exist, each with its own advantages. The techniques and medical teams using them typically work in a complementary fashion. Good communication between the team members is an absolute pre-requisite for a successful outcome as these children can have intra or post operative problems (in the form of hypoxia, laryngo/bronchospasm, or even pneumothorax) that need to be identified and managed promptly and appropriately. The remainder of this article focuses on some common and/or important conditions, and details how airway endoscopy is useful in diagnosis or treatment.
Figure 3 Flexible nasolaryngoscope (a), laryngoscope used in suspension laryngoscope (b), Storz ventilating bronchoscope (c), Hopkins rod lens telescope (d), flexible bronchoscope used through a laryngeal mask airway (e).
inserted. For therapeutic procedures on the vocal cords and subglottis, a laryngoscope (such as the Lindholm Figure 3b) can be used with suspension apparatus and an operating microscope; this gives the operator two free hands. The rigid ventilating bronchoscope (Figure 3c) is used when spontaneous ventilation is not possible (typically in a compromised child), or for therapeutic applications in the trachea or main bronchi (such as foreign bodies). For foreign body removal, optical grasping forceps are used; these forceps have an integral space for a Hopkins telescope that allows good view combined with therapeutic application. Uses LTB using rigid instruments allows examination of tongue base, supraglottis and vocal cords, plus also subglottis, trachea, and main bronchi that cannot be examined using flexible laryngoscopy. It is chiefly performed by Otorhinolaryngologists. The suspension laryngoscopy technique is useful in laryngeal surgery such as surgery for laryngomalacia, removal of granulation or cysts, repair of small laryngeal clefts, balloon dilatation or other endoscopic procedures to deal with laryngotracheal stenosis.
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Laryngomalacia Laryngomalacia (floppy larynx) is the commonest cause of stridor during infancy, and is characterised by supraglottic airway collapse during inspiration. It typically presents within a few weeks or months of birth, and is often self-limiting, with complete resolution by two years common. At time of presentation symptoms of inspiratory stridor predominate, and in more severe
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cases there may be respiratory difficulty particularly during feeding, and failure to thrive. Aetiology of laryngomalacia is still widely debated, but it is thought to develop as a result of abnormally integrated innervation of the larynx with poor tone, muscular weakness and prolapse; gastroeosophageal reflux may be a contributing factor. Confirmation of laryngomalacia is obtained at flexible laryngoscopy on the awake child. Visualisation during respiration allows for dynamic airway assessment, typically demonstrating collapse of posterior laryngeal soft tissue during inspiration, often with an omega-shaped or retroflexed epiglottis (Figure 4a and b). Research suggests that up to 72% of patients will experience resolution of their symptoms within the first year of diagnosis. Subsequently, surgical intervention is reserved for those presenting with severe disease. In theatre, a diagnostic LTB is performed first to exclude dual pathology (present in up to 50%), followed by the surgical procedure of supraglottoplasty that typically involves division of the short aryepiglottic folds and excision redundant mucosa above the arytenoid cartilages.
airway compromise usually predominate, with evidence of stridor and/or respiratory distress (tracheal tug/recession). It is caused by Human Papilloma Virus (typically types 6 and 11); these subtypes typically present as urogenital papillomatous lesions (genital warts), and consequently, transmission of disease within the paediatric age group is thought to stem from vertical transmission. Once acquired, pathological progression is somewhat variable, but with a great propensity for recurrence. RRP typically involves the larynx, and can be diagnosed using flexible nasendoscopy. However, presentation often does not occur until the child is over 1 years old, making flexible nasendoscopy impossible. The diagnosis is thus usually made using LTB in a child presenting with dysphonia or airway obstruction. LTB also allows the detection of papillomata beyond the vocal cords, plus it has therapeutic applications where papillomata can be removed (usually as a microlaryngoscopy procedure). A variety of surgical techniques are available, with the microdebrider being commony used, but recurrence is the norm so that multiple procedures are required. Adjuvant chemotherapy directed towards viral eradication has been attempted, but current data remains insufficient to draw reliable conclusions regarding efficacy.
Respiratory papillomatosis Vocal cord motion impairment
Recurrent respiratory papillomatosis (RRP) is characterised by the presence of multiple papillomata within the respiratory tract (Figure 4c). The prevalence of the paediatric subtype is two-fold higher than in adults, with an estimated incidence of four cases per one hundred thousand children. Papillomata can occur throughout the respiratory tract, with more distal lesions indicative of worsening disease. Classic clinical presentation centres around symptoms of progressive dysphonia, but aggressive forms of the disease can quickly result in airway obstruction and rapid clinical deterioration. In these cases, features suggestive of
Vocal cord motion impairment (VCMI) is the second most common cause of paediatric stridor, and the commonest cause of stridor in a newborn. It can be unilateral or bilateral, and can be caused by motor nerve disruption to the laryngeal structures (palsy) or vocal cord fixation. Presentation of disease differs according to vocal cord involvement, with unilateral cases typically demonstrating dysphonic symptoms (breathy or weak cry) and feeding difficulties, but bilateral VCMI presenting as an airway emergency with severe stridor. Weakness in both
Figure 4 Laryngomalacia (a, b), respiratory papillomata (c), subglottic oedema (d), and foreign body (e, f ).
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up alternative pathology. Removal of foreign bodies should not be attempted using the flexible bronchoscope.
abductor muscles results in close apposition of the cords and significant reduction in airway diameter. Congenital bilateral VCMI is thought to be due to delayed neural maturation, whilst unilateral VCMI is usually a palsy due to an iatrogenic cause such as cardiothoracic surgery. Awake flexible laryngoscpy is a key diagnostic tool that allows one to assess vocal cord movement, but LTB also allows assessment of active movement plus it allows the surgeon to palpate the arytenoids to look for fixation as a cause of VCMI. Once diagnosed, treatment of VCMI is largely dependent on disease severity. In unilateral VCMI, the airway is usually good, and treatment is directed towards avoidance of any aspiration and, in the older child, voice production. Speech and language therapists are key in both situations. Bilateral VCMI may cause severe respiratory distress at birth, and roughly half of neonates require a tracheostomy. A variety of surgical procedures are being developed to increase airway diameter, as an aid to tracheostomy removal. Both therapeutic airway endoscopy and open procedures have been described. However, airway widening is often achieved at the expense of voice quality, and with as many as 66% of infants achieving at least some degree of spontaneous vocal cord movement, surgery to the larynx is typically delayed for at least a few years.
Mucus plugging Both LTB and flexible bronchoscopy are useful in mucus plugging, which may be encountered in cystic fibrosis or following prolonged intubation. Flexible bonchoscopy alone may not be able to remove the plug, but once the plug is removed using rigid techniques then flexible bronchoscopy allows detailed assessment of more distal airway. This can be combined with bronchoalveolar lavage. A FURTHER READING 1 Daniel M, Cheng A. Neonatal stridor. Int J Pediatr 2012; 2012: 859104. http://dx.doi.org/10.1155/2012/859104. Epub 2011 Dec 25. 2 Dickson JM, Richter GT, Meinzen-Derr J, Rutter MJ, Thompson DM. Secondary airway lesions in infants with laryngomalacia. Ann Otol Rhinol Laryngol 2009 Jan; 118: 37e43. 3 Malherbe S, Whyte S, Singh P, et al. Total intravenous anaesthesia and spontaneous respiration for airway endoscopy in children e a prospective evaluation. Paediatr Anaesth 2010; 20: 434e8. 4 Berkenbosch JW, Graff GR, Stark JM, Ner Z, Tobias JD. Use of a remifentanilpropofol mixture for pediatric flexible fiberoptic bronchoscopy sedation. Paediatr Anaesth 2004 Nov; 14: 941e6. 5 Smyth AR, Bowhay AR, Heaf LJ, Smyth RL. The laryngeal mask airway in fibreoptic bronchoscopy. Arch Dis Child 1996; 75: 344e5. 6 Monnier P. Paediatric airway surgery: management of laryngotracheal stenosis in infants and children. Springer, 2011. ISBN: 978-3-64213534-7. 7 Oshan V, Walker R. Anaesthesia for complex airway surgery in children. Cont Edu Anaes Crit Care Pain 2013; 13: 47e51. 8 Mausser G, Friedrich G, Schwarz G. Airway management and anesthesia in neonates, infants and children during endolaryngotracheal surgery. Paediatr Anaesth 2007; 17: 942e7. 9 Donato LL, Mai Hong Tran T, Ammouche C, Musani AI. Paediatric interventional bronchoscopy. Clin Chest Med 2013; Sep; 34: 569e82. 10 Graham JM, Scadding GK, Bull PD. Paediatric ENT. Springer, 2008. ISBN: 978-3-540-69930-9. 11 Thompson DM. Laryngomalacia: factors that influence disease severity and outcomes of management. Curr Opin Otolaryngol Head Neck Surg 2010 Dec; 18: 564e70. 12 Buckmiller LM. Propranolol treatment for infantile hemangiomas. Curr Opin Otolaryngol Head Neck Surg 2009 Dec; 17: 458e9.
Subglottic stenosis SGS can be congenital, or more commonly acquired. The typical presentation is with biphasic stridor, often in a child that has required prolonged intubation for another illness presenting with post-extubation stridor, failed extubation, or when it is not possible to insert an age-appropriate endotracheal tube size. Flexible laryngoscopy (if patient is awake) or direct laryngoscopy (in PICU) is useful to look for a glottic or supraglottic cause of stridor such as granulation tissue, but SGS cannot be diagnosed on this limited visualisation. LTB is useful to confirm the diagnosis (Figure 4d), and can be combined with therapeutic procedures such as removal of vocal cord granulation, endoscopic balloon dilatation of SGS, or endoscopic cricoid split to allow subglottic oedema to dissipate. In established SGS open airway reconstruction may be needed, but endoscopic placement of a cartilage graft to widen the subglottis has also been described. Mucosal lesions of the lower airway are commonly formed secondary to iatrogenic trauma and instrumentation with complex airway adjuncts (tracheostomy tubes and tracheal stents). Subsequent inflammatory changes and granuloma formation results in airway narrowing, and in extensive cases, impending airway obstruction. Although often managed with systemic steroid therapy, resolution of obstruction can be short lived, with further endoscopic or open interventions often being required.
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Foreign body aspiration Flexible laryngoscopy has limited role in the management of a foreign body, as these children are usually of an age where they do not tolerate the procedure and at any rate the foreign body would typically not be seen at the larynx. The foreign body (Figure 4e and f) is usually removed with optical grasping forceps, which may be combined with the use of a ventilating bronchoscope. Flexible bronchoscopy is also useful when no foreign body is seen in the main bronchi, as it allows more distal visualisation and may pick
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Airway endoscopy encompasses a range of complementary techniques Flexible nasolaryngoscopy allows examination of the nose, pharynx and larynx to level of vocal cords. It can be done without anaesthetic in babies and compliant older children Rigid laryngotracheobronchoscopy allows examination of pharynx, larynx, trachea and main bronchi, and requires general anaesthesia Flexible bronchoscopy allows examination of the larynx, trachea, and bronchial tree, typically under general anaesthetic in children Close co-operation between the different specialties involved in these procedures is essential for good patient care
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