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Interventional Pulmonology in the Pediatric Population Christopher R. Gilbert, DO, MS1
KoPen Wang, MD2
1 Section of Bronchoscopy and Interventional Pulmonology, Division of
Pulmonary, Allergy, and Critical Care Medicine, Penn State College of Medicine-Milton S. Hershey Medical Center, Hershey, Pennsylvania 2 Section of Interventional Pulmonology, Division of Pulmonary Disease and Critical Care Medicine, The Johns Hopkins Hospital, Baltimore, Maryland
Hans J. Lee, MD2 Address for correspondence Christopher R. Gilbert, DO, MS, Section of Bronchoscopy and Interventional Pulmonology, Department of Pulmonary, Allergy, and Critical Care Medicine, Penn State College of Medicine-Milton S. Hershey Medical Center, Mail Code H0141, 500 University Drive, Hershey, PA 17033-0850 (e-mail: [email protected]).
Abstract Keywords
► interventional pulmonology ► pediatrics ► central airway obstruction ► endobronchial ultrasound ► therapeutic bronchoscopy
Endoscopic airway interventions within pediatric populations vary considerably. Some of this variance may be related to institutional experience, however, may also be limited by operator experience and available equipment. Previous reports of pediatric bronchoscopic interventional procedures have been identified within the surgical literature; however, newer reports have identified other specialties participating in the care of these patients. Here, we will provide a review of the current relevant medical literature, including an evidence-based review of advanced diagnostic and therapeutic bronchoscopic treatments within the pediatric population.
Interventional pulmonology (IP) remains a field that continues to evolve and innovate. Over 10 years ago a joint task force from the European Respiratory Society and American Thoracic Society defined IP as “the art and science of medicine related to the performance of diagnostic and invasive therapeutic procedures that require additional training and expertise beyond that required in a standard pulmonary medicine training programme.”1 Since that time publications documenting the effectiveness and involvement of IP in various other disciplines and nonpulmonology procedures continue to appear.2–4 Previously, a few case reports documenting the use of “adult-sized” equipment by “adult-trained” pulmonologists were available,5,6 as well as a review article published in 2009 documenting the potential benefits of the more advanced diagnostic equipment currently utilized by adult pulmonologists,7 however, no data was offered at this time confirming these approaches were actually feasible. In 2014, two articles were published documenting the feasibility and effectiveness of adult-trained IP in both diagnostic and therapeutic bronchoscopy within the pediatric population.8,9
Issue Theme Interventional Pulmonology; Guest Editors: David Feller-Kopman, MD and Lonny Yarmus, DO, FCCP
Common entities encountered by IP include complex airway disease management (often malignant or nonmalignant airway obstruction), pleural disease, and advanced diagnostic endoscopic procedures, often utilizing endobronchial ultrasound (EBUS) modalities. As one can imagine, the breadth of these disease processes is rather diverse, and therefore a multidisciplinary approach is typically required. IP commonly works with other physicians from anesthesia, intensive care medicine, otolaryngology, pulmonology, and thoracic surgery on a daily basis. This current model is generally in place at most institutions, however, not often apparent depending on the degree of collaboration, and can vary from institution to institution. Review of the available literature appears to describe the similar multidisciplinary care of pediatric patients with central airway obstruction (CAO);10 however, most literature reported remains dominated by surgical teams performing both endoscopic and surgical procedures. The most common disciplines appear to be otolaryngology, thoracic, or pediatric surgery. There appear to be limited reports of pulmonologists
Copyright © 2014 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662.
DOI http://dx.doi.org/ 10.1055/s-0034-1395505. ISSN 1069-3424.
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Interventional Pulmonology in the Pediatric Population (pediatric or adult) performing therapeutic airway interventions, unless it involves foreign body removal. In adult medicine, the multidisciplinary care of patients with CAO often will involve anesthesiologists, intensivists, interventional pulmonologists, otolaryngologists, and thoracic surgeons all caring for the same patient.
Current Training Training in IP within the United States has evolved over the last 10 to 15 years and current recommendations for fellowship11,12 as well as specific procedural training1,13 currently exist. In summary, the pathway toward becoming board certified in IP involves internal medicine residency, pulmonary/critical care medicine fellowship, followed by an additional year of dedicated fellowship training in IP.14 As one can imagine, the majority of training is focused on adult medicine and the exposure to pediatrics can be minimal to even nonexistent. At the current time, pediatric pulmonology remains a subspecialty limited to those completing a pediatric residency. Pediatric pulmonologists are taught bronchoscopy as part of their fellowship training, however, the training may be variable and there remain no objective requirements for their procedural training.15 This remains in stark comparison to an adult pulmonary fellowship as well as an IP fellowship which have suggested procedural number thresholds to help define competency.12,13 While the performance of advanced diagnostic and therapeutic bronchoscopy is certainly not limited to physicians based on their initial training, the ability to obtain the proper training and experience may be. The authors are currently unaware of any pediatric pulmonology fellowships within the United States that routinely teach advanced diagnostic bronchoscopy such as EBUS or therapeutic interventions such as rigid bronchoscopy. Interventional pulmonologists evaluate and manage a diverse population of patients and diseases. The majority of patients undergo procedures related to the disease of the thorax in which advanced diagnostic bronchoscopy, therapeutic bronchoscopy, or pleural procedures. We will describe the current and potential role the trained IP can play in the care of pediatric populations.
anesthetic planning.16 A multidisciplinary approach and open dialogue between all team members, especially pediatric anesthesiologists and intensivists, is essential for pre-, intra-, and postprocedural planning. Significant head and neck changes occur during normal child growth. Initially, children have larger heads with rather small, immobile mandibles, however, normal growth decreases the proportional head size and the mandible becomes larger and more mobile. Other changes in the supraglottic portion of the airway include a decrease in the size of the tongue in proportion to the airway, decrease in size of the epiglottis, and changes to the location of the glottis opening. Within smaller children the cricoid cartilage remains the smallest diameter of the airway (as opposed to adults in which the glottic opening is the smallest), therefore an instrument that passes through the glottic opening may not pass further into the trachea.17 Airway diameter remains an important consideration for selection of appropriate equipment. In adults, the ventilating rigid bronchoscope is commonly used for safe airway control and numerous interventions, including airway dilation, passage of multiple tools, and placement of endobronchial stents. Despite the same ability to use ventilating rigid bronchoscopes (with sizes as small as 4 mm) in pediatrics, numerous differences need to be recognized. The presence of a smaller airway diameter limits the size of endotracheal appliances (rigid bronchoscope or endotracheal tube) that can be introduced, and subsequently affects the ability to utilize certain instruments. This decreased diameter also leads to increase airway resistance and airway pressures (when attempting to deliver the same volumes) which often become exaggerated when introducing additional tools through the lumen of the bronchoscope.18 Estimation of endotracheal tube size is often based on patient age or weight (►Table 1), but can also be done by selecting an outer diameter similar in size to the child’s fifth finger.19 The concerns regarding airway diameter have most likely led to minimal use of “adult-sized” bronchoscopes within pediatric populations, however, two recent publications have identified the safe and effective use of
Table 1 Pediatric airway equipment and sizes. Suggested size of endotracheal tube and laryngeal mask airway based on child’s age and weight
Pediatric Airway While many of the general principles related to airway management remain the same within the adult and pediatric airway, distinct differences are present and providers must be aware of these differences for both patient safety and procedural feasibility. Preoperative airway evaluations typically involve a patient history and physical examination, including a history of airway difficulties. When evaluating newborns and infants a maternal and perinatal history is often appropriate. In children with congenital or malformation syndromes, a thorough understanding of their defined and potentially unrecognized manifestations, especially related to head and neck anatomy, remains essential for appropriate procedural and Seminars in Respiratory and Critical Care Medicine
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Age
Weight (kg)
Endotracheal tube size (mm)
Laryngeal mask airway size
0–6 mo
0–4
2.5–3.5
1
6–12 mo
5–10
3.5–4.0
1.5
1–3 y
10–15
4.0–4.5
2
4–7 y
15–20
5.0–5.5
2–2.5
8–10 y
20–30
5.5–6.0
2.5
> 10 y
> 30
> 6.0
>3
Source: The table is adapted from Anesthesia for Children,19 Basics of Anesthesia,81 and from American Trauma Life Support for Doctors Manual.82
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standard “adult-sized” diagnostic and therapeutic equipment within a selected population of pediatric patients.8,9
Advanced Diagnostic Procedures Endobronchial Ultrasound The most promising new technology in diagnostic bronchoscopy remains the introduction of EBUS. Initially introduced in the late 1990s to the adult pulmonology community, EBUS has obtained widespread acceptance and popularity. A recent PubMed search on endobronchial ultrasound returned almost 1,000 articles with over 140 review articles; however, there remains a paucity of literature related to utilization in the pediatric population. Two types of EBUS are currently available; convex probe EBUS (CP-EBUS) and radial probe EBUS (RP-EBUS). CP-EBUS (►Fig. 1) was introduced in early 2000 and has since revolutionized the evaluation of adult patients with mediastinal and hilar lymphadenopathy, especially regarding the care of patients with suspected lung cancer.20 CP-EBUS bronchoscopes are currently designed for examination of the more central structures, often mediastinal and hilar lymphadenopathy, but can also access centrally located parenchymal lesions.21 Currently available CP-EBUS scopes are manufactured by Olympus (BF-UC180F, Tokyo, Japan), Pentax Medical (EB-1970UK, Montvale, NJ), and Fujinon Endoscopy (EB-530US, Wayne, NJ). The main potential limitation for CPEBUS utilization within the pediatric population remains the larger outer diameter of the scope, with all possessing an outer diameter of greater than 6.7 mm. The current adult literature suggests widespread adoption of EBUS-guided transbronchial needle aspiration (EBUSTBNA) and in most high volume institutions that provide
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multidisciplinary care to patients with thoracic malignancies, EBUS-TBNA has albeit replaced mediastinoscopy as an initial diagnostic test.22–24 Attractive features to EBUS-guided procedures include the excellent diagnostic yield, potential for decreased cost, complications, and hospital resource utilization.22,24 The literature in pediatrics remains scant, however, the data suggest the procedure remains quite feasible, even in small children and infants. Initial case reports noted the successful use of EBUS-TBNA in children aged between 6 and 13 years.5,6 A multicenter study has since been published identifying 21 pediatric patients safely undergoing EBUSTBNA with ages ranging from 18 months to 18 years.9 RP-EBUS was initially introduced for use within the central airways utilizing an inflatable balloon to help visualize individual layers of the trachea wall, however, its common current day use is in exploration of nodules and infiltrates within the lung parenchyma. RP-EBUS probes (►Fig. 2) for investigation of the periphery are currently manufactured in either a 1.4 mm (UM-S20–17S, Olympus) outer diameter or a 2.5 mm (UM-2R/3R, Olympus) outer diameter. The manufacturer recommendations suggest bronchoscopic working channels that range from 2.0 to 2.8 mm.25 There are currently no published reports of RP-EBUS in pediatrics, however, in theory the only limitation to the use of the RP-EBUS probe in the pediatric population remains the diameter of the probe and its required bronchoscopic working channel.
Virtual Navigational Bronchoscopy At this time, there are no available data regarding the use of advanced navigational techniques (virtual bronchoscopy and electromagnetic navigational bronchoscopy) within the pediatric population. This technology remains quite feasible for
Fig. 1 Convex probe endobronchial ultrasound (CP-EBUS) puncture scope. (A) Photograph of CP-EBUS puncture scope tip. Ultrasound probe (#) and working channel () of the scope are identified. The working channel and optics are both offset at a 30-degree angle to facilitate real-time imaging of the needle by the ultrasound probe. (B) Ultrasound image of a transbronchial needle aspiration (TBNA) needle (arrow) within a lymph node. (C) Similar ultrasound image of TBNA needle entering a lymph node, but with an inlaid endoscopic image in the bottom left hand corner (labeled). The right paratracheal lymph node (þ) and superior vena cava ($) are easily identified in this image. Seminars in Respiratory and Critical Care Medicine
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Fig. 2 Radial probe endobronchial ultrasound (RP-EBUS) probe. (A) Photograph of RP-EBUS probe emerging from working channel of standard adult bronchoscope. The ultrasound probe is identified (arrow). (B) Bronchoscopic image obtained during procedure. Inlaid within the left corner is an endoscopic view, in which the ultrasound probe can be seen entering into a bronchus. The larger image represents a 360 degree image obtained from rotation of the probe. The sharp white lines (arrows) identify the demarcation between the lung nodule ( ) and surrounding lung tissue.
use in this population and has no specific requirements or needs that would limit its use to the adults. However, the use of these technologies does require the use of specially formatted computed tomography scans (►Fig. 3). Current literature regarding the use of these virtual or navigational bronchoscopy techniques has not demonstrated a significant improvement over RP-EBUS in the diagnostic yield of peripheral pulmonary lesions and therefore may not be as desirable with the potential added radiation exposure.
Therapeutic Procedures Multiple publications are currently available regarding the use of rigid bronchoscopy within pediatrics, with many authors having received training in otolaryngology, thoracic surgery, and/or pediatric surgery. The most common reported use of rigid bronchoscopy in pediatrics is clearly related to the foreign body retrieval. We purposefully excluded foreign body removal within our review. Innumerous studies and reviews are currently available regarding the risks/benefits/indications/contraindications to the use of flexible or rigid bronchoscopy within children suspected of
a foreign body inhalation.26–28 We did not believe rereview of these articles would add further to the literature. As such, we have elected not to address this topic, but rather focus on other less described therapeutic interventions that can be performed bronchoscopically in children Within the pediatric population, it is readily apparent that nonmalignant CAO remains more common than CAO related to malignant disease. This distinction remains quite important and is the central challenge in the long-term management of pediatric CAO. Another readily apparent factor in pediatric CAO is the ability of future growth of the airway tree as the child ages. This predictable increase in airway dimension offers both advantages and disadvantages. Advantages include the potential for improvement of airway stenosis and malacia as the obstruction may represent a smaller fraction of the overall airway diameter in the future. The disadvantage includes predictable airway growth, which then entails the creation of a strategy that will maintain airway patency during growth and allow for successful removal if the benefit of an in situ stent is lost. While surgical treatment remains the optimal therapy for airway obstruction in nonmalignant disease, airway stenting
Fig. 3 Navigational bronchoscopy techniques. Screen views of LungPoint (Broncus Technology, Redmond, WA) navigational bronchoscopy software. View from main carina (A), axial planning image (B) highlighting aorta in red, three-dimensional image of airway tree and major vessels (C), and subsequent virtual image of left upper lobe (D). The software prelabels major airways with segmental anatomy identified from computed tomography scans. (For color indicators see figure in color in the online version.) Seminars in Respiratory and Critical Care Medicine
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Balloon Dilation Procedures Balloon dilation procedures are commonly performed for CAO related to stenosis, often intraluminal and nonmalignant. Balloon dilation is commonly performed in adults utilizing specially designed controlled radial expansion balloons (►Figs. 4 and 5). These nonconformal balloons can be filled with radiopaque fluid or with saline depending on preference and planned use of fluoroscopic guidance. Balloons are inflated under pressure which corresponds to a predetermined size. Reports of other balloon techniques include the use of conformal balloons (vascular embolectomy catheters,31 urinary catheters,32 etc.), however, these are not routinely recommended due to their inability to deliver a standard and uniform balloon size and distribution of dilation, in addition to the fact that they may conform to the stenosis with the maximal diameter of the balloon being in the nonstenotic segment. The use of conformal balloons in the pediatric population may be related to the difficulty obtaining nonconformal balloons that will accommodate pediatric airways and instrumentation. There are no randomized trials involving the use of balloon dilation for the treatment of airway obstruction in pediatrics. The most common indication for balloon dilation procedures
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in children remains subglottic stenosis, often resulting from complications due to intubation and tracheostomy. Numerous authors have presented retrospective series in children ranging from 1 month of age to young adults.33,34 Success rates range from 57 to 98%, often leading to successful tracheostomy tube decannulation or the avoidance of tracheotomy. Children (similar to adults) often undergo multiple dilation sessions, but complication rates remain extremely low. Other reported uses of balloon dilation involve its use in airway clearance and in malignant CAO.8 Balloon dilation in combination with mechanical debridement via forceps has been reported in a small series for the successful reestablishment of central airway patency in obstructing fibrinous tracheal pseudomembrane.35
Thermal Techniques Thermal techniques utilize energy to cause tissue destruction via vaporization, cauterization, and/or coagulation (►Fig. 6). One of the most commonly used thermal energy techniques utilized for airway obstruction is the endobronchial laser. Laser therapies are currently available in different wavelengths and size fibers for a multitude of applications. The most commonly reported medical lasers for endobronchial use are neodymium:yttrium-aluminum-garnet (Nd:YAG), carbon dioxide (CO2), and potassium-titanium-phosphate (KTP). Other options for thermal destruction of airway lesions include direct contact electrocautery techniques, as well as noncontact argon plasma coagulation (APC). Once again the majority of children undergo thermal destruction of airway lesions related to nonmalignant etiologies. The use of the Nd:YAG, KTP, and CO2 laser are all represented in case series and observational cohorts, no randomized studies or comparative efficacy trials are available. Laser destruction/resection of lesions is reported for granulation tissue,36–38 subglottic cysts,39–41 and hemangiomas.42,43 Most reports demonstrate successful outcomes, although some report recurrent disease and unsuccessful tracheostomy tube decannulation. Complications have been reported, but the lack of followup and retrospective design of the studies certainly introduces bias. The most common complication appears to be a recurrence of disease and the need for a second procedure.
Fig. 4 Balloon dilation procedure under direct visualization. (A) Bronchoscopic image of severe tracheal stenosis. (B) Bronchoscopic image of balloon bronchoplasty procedure under direct visualization. (C) Postprocedure endoscopic image with improvement in airway caliber. Seminars in Respiratory and Critical Care Medicine
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and other endoscopic interventions may provide a viable solution for nonsurgical candidates or a bridge to surgery. It is especially important to recognize the potential complications associated with airway stent placement, including granulation tissue formation, migration, and mucostasis/infection. Additionally, nonendoscopic alternatives, including aortopexy, noninvasive ventilation, and tracheostomy tube placement may be a better option depending on the underlying disease and local expertise. The above interventions in the setting of future airway growth and improving structural integrity have also been met with success.29 In some cases, airway obstruction may occur after surgical correction of airway reconstruction, congenital vascular anomalies (vascular sling, extrinsic compression, enlarged vasculature), Komerell diverticulum, or bronchogenic cyst.30 Herein, we will describe common endoscopic interventions utilized in both pediatric and adult CAO. As some of the literature in pediatric CAO is limited we will present data regarding adult use as needed.
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Fig. 5 Balloon dilation procedure under fluoroscopic guidance. (A) Fluoroscopic image of balloon bronchoplasty procedure of the left main bronchus. Note the indentation of the balloon before full expansion (arrows). (B) Fluoroscopic image of balloon bronchoplasty procedure of the left main bronchus. Note significant resolution of the balloon indentation after expansion.
Fig. 6 Thermal destruction technique for endobronchial disease. (A) Endoscopic view of endobronchial lesion causing partial airway obstruction in a 16-year-old boy with persistent cough and known recurrent respiratory papillomatosis. Argon plasma coagulation (APC) probe seen entering screen from right side (arrow). (B) Endoscopic view of endobronchial lesion after APC use causing coagulation and destruction of lesion.
Most reports of intervention for nonmalignant airway disease does result in significant successful outcome initially, however, many of these patients (particularly those with malacia, stenosis, or granulation tissue) will often have evidence of recurrence.38 Mild granulation tissue and subglottic stenosis have been reported in some series as well.39,43 Major complications such as death have been reported, however, appear extremely rare. There is a report of an airway fire in one series.36 The fire appeared to cause no significant damage (superficial ulcerations) and no long-term sequelae. Successful palliation of malignancy-related CAO has been reported with thermal energy use in pediatrics. Both the CO2 laser and APC have reported technically successful results, with no reported complications associated with the initial performance of these procedures.8,44 However, within the Wang et al series, one child died due to acute airway obstruction and asphyxiation from a presumed tissue flap created during a repeat bronchoscopy for recurrent tumor. The authors later comment that this procedure was performed earlier in their experience and utilized flexible bronchoscopy. Seminars in Respiratory and Critical Care Medicine
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They have since performed all procedures with rigid bronchoscopy and while it remains impossible to determine if the performance of the procedure under general anesthetic with the rigid bronchoscope securing the airway would have changed the outcome, it obviously begs the question.44
Mechanical Debridement Mechanical debridement techniques involve the simple concept of removing tissue with forceps (►Fig. 7) or other cold steel instruments to help improve airway patency. The main indication for mechanical debridement is that patients must have evidence of intrinsic airway disease. The presence of only extrinsic (i.e., endoluminal compression from a surrounding mass) disease is a contraindication for endoscopic debridement. The instruments utilized can range from the rigid bronchoscope barrel (►Fig. 8) to the more complex automated microdebrider instrument (►Fig. 9). Successful reports of mechanical debridement are often described in the management of excess suprastomal granuMechanical lation tissue following tracheotomy.38
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Fig. 8 Use of rigid bronchoscope barrel for mechanical dilation/debridement. A 13-year-old girl was initially diagnosed with refractory asthma. Referral for bronchoscopy occurred when she complained of stridor and voice changes. Evidence of subglottic stenosis was discovered at bronchoscopy. (A) Rigid bronchoscopic view of severe subglottic stenosis. Mechanical dilation with the tip of the rigid bronchoscope in a twisting fashion allowed for immediate relief of her airway obstruction and symptoms. (B) Postdilation bronchoscopic view noting significant improvement in airway caliber.
Fig. 9 Microdebrider. A 2-year-old boy noted to have noisy breathing with exertion and crying was identified as having a subglottic cyst during bronchoscopy. (A) Repeat bronchoscopy upon transfer confirmed presence of subglottic cyst obstructing the subglottic space. (B) Bronchoscopic view of microdebrider destroying and suctioning contents of previously identified subglottic cyst. (C) Bronchoscopic view of the subglottic space identifying significant improvement in airway caliber and relief of obstruction.
debridement can also be used in conjunction with other techniques to help provide further relief of CAO.8,38 Endobronchial forceps resection has been successfully utilized in children with CAO secondary to tuberculosis granulomata.45
The microdebrider remains a popular tool in the field of otolaryngology being marked for use in endoscopic sinus surgery and airway debulking.46–49 The microdebrider has also experienced, successful use by interventional Seminars in Respiratory and Critical Care Medicine
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Fig. 7 Mechanical debridement of endobronchial lesion. (A) Rigid bronchoscopic view of an endobronchial aspergilloma identified obstructing the right main stem bronchus in a 16-year-old patient with leukemia. Progressive respiratory failure and persistent fevers prompted bronchoscopy. (B) Mechanical debridement with forceps allowed for almost complete relief of airway obstruction and significant improvement in respiratory status.
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pulmonologists for the management of CAO.50,51 Because of the limited length and stiffness of the microdebrider, its role is often limited to tracheal disease (or very proximal main stem disease). Reports of use for subglottic cyst management appear successful with minimal complications.47 Complications overall for mechanical debridement do exist, and can be major, such as bleeding, cardiac arrest, and death. The use of forceps during granulation tissue removal (and subsequent loss of tissue into the distal trachea) has reported to cause asphyxiation, with subsequent hospital complications leading to the child’s death.38 Excess bleeding after granuloma debridement from an airway wall led to uncontrollable hemorrhage and subsequent asphyxiation.45 No reports of major airway complications related to microdebrider use have been reported, however, major bleeding and tissue damage have been reported in endoscopic sinus surgery.49,52
Airway Stents Airway stents are commonly utilized for the relief of CAO and come in multiple different formulations, configurations, and sizes. Similar to the adult stent literature, immediate relief, and improvement from CAO is commonly reported in pediatric series. In some cases, the relief of the CAO is so vital to respiratory status that airway stenting allows for almost immediate liberation from mechanical ventilation. This benefit must be tempered with the knowledge of the known longterm outcomes/complications associated with stent placement. As such, one should never sacrifice long-term options such as a potential curative surgical resection over short-term gains. Most patients should be evaluated and managed in a multidisciplinary fashion with experts in CAO and pediatric airway reconstruction. The ideal airway stent would be: easy to place even in the smallest airways, provide structural airway integrity with minimal adverse effects, and be removable at any time or unnecessary to remove. Unfortunately, at this time, no available stent is able to meet all these properties. Therefore, the placement of airway stents should not be taken lightly as serious long-term complications can arise, especially in patients with nonmalignant CAO. Airway stents in general can be divided into different categories based on the material of the stent. We have further divided this topic into three different categories; metallic, silastic, and novel stents. While rare, stent-related morbidity/ mortality has been reported for almost all airway stents.53,54
Metallic Stents Metallic stents offer the convenience of insertion via flexible bronchoscopy and/or fluoroscopy. In infants and young children, the airway caliber becomes the main obstacle in placing larger bronchoscopes and tools without obstructing the airway. Metallic stents offer the flexibility of using only a guide wire with fluoroscopy to place the stent (►Fig. 10) even within infant-sized airways.55 Two types of metallic stents have been available; balloonexpandable and self-expanding. There are currently no Food and Drug Administration (FDA)-approved metallic airway Seminars in Respiratory and Critical Care Medicine
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Fig. 10 Self-expanding metallic stent placement under fluoroscopic guidance. Fluoroscopic view of a self-expanding metallic stent () that has been placed into the right main stem bronchus. The use of a guide wire can be seen (arrows) and is recommended when utilizing fluoroscopic guidance.
stents for use in pediatrics. Within adults, the only FDAapproved metallic airway stents are the Merit Aero (Merit Medical Systems, South Jordan, UT) self-expandable stent, and the uncovered Ultraflex stent (Boston Scientific, Needham, MA). Current sizes range from 10 to 20 mm outer diameters (when fully expanded), requiring a working diameter of 16 to 22F. The Aero stents are covered with a polyurethane coating and constructed from nickel-titanium (nitinol) allowing a shape memory effect. The currently available balloon-expandable metallic stents are often utilized for vascular or cardiac purposes. The best described balloon-expandable stent utilized in pediatrics is the Palmaz (Cordis Corporation, Miami Lakes, FL) stent. Designed as a vascular stent made of a single piece of stainless steel, its popularity appears related to the available small dimension and ease of placement. Palmaz stents can often be found in sizes ranging from 5 to 10 mm outer diameters that may only require a working channel of 6F.56 The granulation tissue has been described as the most common serious complication. The long-term risks of any metallic stent are restenosis by recurrent granulation tissue, failure of tracheal growth with age, and tracheal erosion or penetration into the great vessels. Several investigators have reported issues with recurrent granulation tissue which has been managed by serial bronchoscopy procedures requiring balloon bronchoplasty and/or debulkment of granulation tissue.54,57 The granulation tissue has also been known to be colonized with pathogenic organisms potentially increasing the risk of bacterial overgrowth/infection especially in infants with smaller airways.30,58 Regardless of the metallic stent selection, eventual endoscopic stent removal may not be possible and may require surgical resection. In the adult population, duration of more than 4 to 6 weeks marks a time for potential difficult removal due to granulation tissue and reepithelialization of the stent
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Silastic Stents Silicone stents are available in multiple sizes and configurations, including a “Y” shape for placement at the carina, as well as the Montgomery t-tube. Silicone stent placement requires the use of rigid bronchoscopy (►Fig. 11) which may be potentially more challenging in smaller pediatric airways. The smallest commercially available silicone stent in the United States is a 6-mm outer diameter (OD) stent. Another limitation includes the lack of commercially available stent deployers for the smaller rigid bronchoscopes; however, various other techniques have been described to deploy smaller silastic stents. Silicone stents can be more easily removed after having been in place for long durations when compared with metal stents. Complications include granulation, stent migration, and mucus impaction/infection. In addition, the inner diameter is less for any outer diameter when compared with a metallic stent. A long-term advantage of silastic stents is that they are nonexpanding and will not develop fatigue fracture of the stent wires. Reports of successful cases are feasible in infants; however, poor results were associated with highpressure vascular compression.62
Novel Stents Absorbable or biodegradable stents may potentially be the future of pediatric airway stents; however, none are currently available for use within the United States. These stents remain in the airway for a finite time without the complications of surgical removal. In theory, if the airway remains patent via
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the stent, in time as the child’s airway dimension grows, no further intervention may be needed. Current uses of these stents include urethral, biliary, and vascular purposes. Small series from other countries have reported success with primarily polydioxanone stents.63 The use of polydioxanone stents appears promising as they are composed of a semicrystalline, biodegradable polymer. The material has shape memory, but later degrades by random hydrolysis of its ester bonds into harmless degradation products. Further investigation is needed before large scale adoption in the airway. The current degradation properties are not well known in the airway. A small case series suggests 15 weeks for complete absorption while in an animal model 10 weeks were needed for degradation.63
Endobronchial Valves The development of an alveolar-pleural fistula and persistent air leak is a serious clinical problem and can lead to an increased morbidity and mortality.64 Air leaks after thoracic surgery remain a common complication and previous endobronchial therapies have been variably successful, including the use of endobronchial valve (EBV) placement. EBV has demonstrated clinical utility in the treatment of prolonged air leaks64–66 as well as emphysema.67,68 Currently, a one-way EBV (►Fig. 12) has been approved for use in adults for prolonged air leaks after pulmonary resection (Spiration, Redmond, WA). Off-label uses have been described in the adult population, including treatment for bronchopleural fistula,69 treatment of spontaneous pneumothorax in the setting of advanced lung cancer,70 and to facilitate lower levels of respiratory support within the intensive care unit.71 Only two reports of EBV use are available within the pediatric population. A case report has described the use of EBV in an 18-year-old patient with cystic fibrosis and recurrent pneumothorax to avoid pleurodesis while awaiting lung transplantation.72 A case series of four pediatric patients (age range, 16 months–16 years) identified successful use of EBV in patients with bronchopleural fistula related to empyema and recurrent pneumothorax related to barotrauma.73 No significant complications related to valve placement were identified within these reports.
Fig. 11 Silicone stent placement. A 17-year-old patient with tracheal obstruction secondary to metastatic small blue round cell tumor. (A) Bronchoscopic view from subglottic space identifying proximal, extrinsic tracheal obstruction. (B) Bronchoscopic view of trachea after placement of silicone tracheal stent. Placement of tracheal stent allowed for relief of dyspnea. Seminars in Respiratory and Critical Care Medicine
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within the airway.57 In addition, within the adult literature are descriptions of potentially surgically correctable nonmalignant airway obstruction rendered inoperable due to metallic stent-related complications.59 Complications and management issues related to metallic stents are well published and in 2005 the FDA warned against the placement of metallic stents in nonmalignant airways unless other options had been exhausted.60 Despite the potential complications, some experts that have experience with various metallic stents favor nitinol for pediatrics given the potential size options.61
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Fig. 12 Endobronchial valve. A 16-month-old male patient with recurrent pneumothorax and persistent air leak secondary to barotrauma. (A) Placement of a unidirectional endobronchial valve within a basilar segment of the left lower lobe. (B) Chest radiograph demonstrating multiple chest tubes in place as well as the placement of four endobronchial valves with the left lower lung field.
3 Yarmus L, Gilbert C, Lechtzin N, Imad M, Ernst A, Feller-Kopman D.
Bronchial Thermoplasty Bronchial thermoplasty (BT) is a novel endoscopic treatment currently available to adults with severe persistent asthma and receiving maximal medical therapy.74 BT attempts to smooth muscle mass within the lobar and segmental bronchi by the delivery of heat energy via a radiofrequency generator. Preliminary data had suggested a reduction of smooth muscle mass75 and clinical studies have demonstrated improvements in quality of life scores up to 1 year posttreatment76 as well as no demonstrable increased morbidity at 5 year follow-up.77 At the current time there are no reports of BT within the pediatric population. Currently, children with persistent asthma are recommended to utilize immunotherapy or omalizumab.78,79 There is little available literature about the potential use of BT in a pediatric population, however, these authors hypothesize that the current self-imposed moratorium is most likely related to the yet unclear long-term effects and role of BT in patients with severe asthma.80
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Conclusion
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Herein, we present the largest and most up-to-date review of advanced diagnostic and therapeutic bronchoscopic procedures within the pediatric population. Our review suggests that there remains sparse literature within the pediatric population regarding many of the procedures performed, demonstrating the need for further research. As the care of many of these pediatric patients is multidisciplinary, the potential collaboration for multidisciplinary research remains exciting and vital to the advancement of the field and care of these patients.
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References 1 Bolliger CT, Mathur PN, Beamis JF, et al; European Respiratory
Society/American Thoracic Society. ERS/ATS statement on interventional pulmonology. Eur Respir J 2002;19(2):356–373 2 Yarmus L, Pandian V, Gilbert C, et al. Safety and efficiency of interventional pulmonologists performing percutaneous tracheostomy. Respiration 2012;84(2):123–127
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Safety and feasibility of interventional pulmonologists performing bedside percutaneous endoscopic gastrostomy tube placement. Chest 2013;144(2):436–440 Wahidi MM, Ernst A. Role of the interventional pulmonologist in the intensive care unit. J Intensive Care Med 2005;20(3):141–146 Siemsen M, Andersen NE, Nielsen KG. EBUS in a 6-year-old boy with enlarged hilar lymph nodes. J Bronchology Interv Pulmonol 2011;18(2):205 Wurzel DF, Steinfort DP, Massie J, Ryan MM, Irving LB, Ranganathan SC. Paralysis and a perihilar protuberance: an unusual presentation of sarcoidosis in a child. Pediatr Pulmonol 2009; 44(4):410–414 Steinfort DP, Wurzel D, Irving LB, Ranganathan SC. Endobronchial ultrasound in pediatric pulmonology. Pediatr Pulmonol 2009; 44(4):303–308 Gilbert CR, Feller-Kopman D, Akulian J, Hayes M, Yarmus L. Interventional pulmonology procedures in the pediatric population. Pediatr Pulmonol 2014;49(6):597–604 Gilbert CR, Chen A, Akulian JA, et al. The use of convex probe endobronchial ultrasound-guided transbronchial needle aspiration in a pediatric population: a multicenter study. Pediatr Pulmonol 2014;49(8):807–815 McLaren CA, Elliott MJ, Roebuck DJ. Tracheobronchial intervention in children. Eur J Radiol 2005;53(1):22–34 Lamb CR, Feller-Kopman D, Ernst A, et al. An approach to interventional pulmonary fellowship training. Chest 2010;137(1): 195–199 Yarmus L, Feller-Kopman D, Imad M, Kim S, Lee HJ. Procedural volume and structure of interventional pulmonary fellowships: a survey of fellows and fellowship program directors. Chest 2013; 144(3):935–939 Ernst A, Silvestri GA, Johnstone D; American College of Chest Physicians. Interventional pulmonary procedures: Guidelines from the American College of Chest Physicians. Chest 2003; 123(5):1693–1717 About Medical Specialties Matching Program (MSMP). Available at: http://www.nrmp.org/fellowships/medical-specialties-matching-program/. Accessed October 28, 2014 Masters IB, Cooper P. Paediatric flexible bronchoscopy. J Paediatr Child Health 2002;38(6):555–559 Yastor M, Elliot RA. Preoperative Assessment of the Newborn. New York, NY: McGraw Hill Medical; 2008:300–309 Wetzel RC. Evaluation of Children. New York, NY: McGraw Hill; 2008:310–340 Lockhart CH, Elliot JL. Potential hazards of pediatric rigid bronchoscopy. J Pediatr Surg 1984;19(3):239–242
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19 Everett LL. Anesthesia for Children. New York, NY: McGraw Hill; 20
21
22
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29
30
31
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2008:1520–1540 Yasufuku K, Chiyo M, Sekine Y, et al. Real-time endobronchial ultrasound-guided transbronchial needle aspiration of mediastinal and hilar lymph nodes. Chest 2004;126(1):122–128 Nakajima T, Yasufuku K, Fujiwara T, et al. Endobronchial ultrasound-guided transbronchial needle aspiration for the diagnosis of intrapulmonary lesions. J Thorac Oncol 2008;3(9):985–988 Gilbert C, Yarmus L, Feller-Kopman D. Use of endobronchial ultrasound and endoscopic ultrasound to stage the mediastinum in early-stage lung cancer. J Natl Compr Canc Netw 2012;10(10): 1277–1282 Yasufuku K, Nakajima T, Fujiwara T, et al. Role of endobronchial ultrasound-guided transbronchial needle aspiration in the management of lung cancer. Gen Thorac Cardiovasc Surg 2008;56(6): 268–276 Yasufuku K, Pierre A, Darling G, et al. A prospective controlled trial of endobronchial ultrasound-guided transbronchial needle aspiration compared with mediastinoscopy for mediastinal lymph node staging of lung cancer. J Thorac Cardiovasc Surg 2011; 142(6):1393–1400, e1 Olympus. Endoscopic ultrasound probes. http://medical.olympusamerica.com/products. Available at: Accessed October 28, 2014 Boufersaoui A, Smati L, Benhalla KN, et al. Foreign body aspiration in children: experience from 2624 patients. Int J Pediatr Otorhinolaryngol 2013;77(10):1683–1688 Foltran F, Ballali S, Passali FM, et al. Foreign bodies in the airways: a meta-analysis of published papers. Int J Pediatr Otorhinolaryngol 2012;76(Suppl 1):S12–S19 Swanson KL, Prakash UB, Midthun DE, et al. Flexible bronchoscopic management of airway foreign bodies in children. Chest 2002; 121(5):1695–1700 Pillai JB, Smith J, Hasan A, Spencer D. Review of pediatric airway malacia and its management, with emphasis on stenting. Eur J Cardiothorac Surg 2005;27(1):35–44 Jacobs JP, Quintessenza JA, Botero LM, et al. The role of airway stents in the management of pediatric tracheal, carinal, and bronchial disease. Eur J Cardiothorac Surg 2000;18(5):505–512 Fouty BW, Pomeranz M, Thigpen TP, Martin RJ. Dilatation of bronchial stenoses due to sarcoidosis using a flexible fiberoptic bronchoscope. Chest 1994;106(3):677–680 Malik AM, Ahmed Z, Durgham N, Stockmann PT, Belenky WM, Zestos M. Airway and ventilation management during repair of a large acquired tracheoesophageal fistula: the novel use of a readily available tool. J Clin Anesth 2012;24(2):133–136 Maksoud-Filho JG, Gonçalves MEP, Cardoso SR, Tannuri U. Early diagnostic and endoscopic dilatation for the treatment of acquired upper airway stenosis after intubation in children. J Pediatr Surg 2008;43(7):1254–1258 Whigham AS, Howell R, Choi S, Peña M, Zalzal G, Preciado D. Outcomes of balloon dilation in pediatric subglottic stenosis. Ann Otol Rhinol Laryngol 2012;121(7):442–448 Soong WJ, Jeng MJ, Lee YS, Tsao PC, Yang CF, Soong YH. Pediatric obstructive fibrinous tracheal pseudomembrane—characteristics and management with flexible bronchoscopy. Int J Pediatr Otorhinolaryngol 2011;75(8):1005–1009 Mandell DL, Yellon RF. Endoscopic KTP laser excision of severe tracheotomy-associated suprastomal collapse. Int J Pediatr Otorhinolaryngol 2004;68(11):1423–1428 Sharp HR, Hartley BEJ. KTP laser treatment of suprastomal obstruction prior to decannulation in paediatric tracheostomy. Int J Pediatr Otorhinolaryngol 2002;66(2):125–130 Yellon RF. Totally obstructing tracheotomy-associated suprastomal granulation tissue. Int J Pediatr Otorhinolaryngol 2000;53(1): 49–55 Madgy D, Ahsan SF, Kest D, Stein I. The application of the potassium-titanyl-phosphate (KTP) laser in the management of subglot-
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tic hemangioma. Arch Otolaryngol Head Neck Surg 2001;127(1): 47–50 Aksoy EA, Elsürer C, Serin GM, Unal OF. Evaluation of pediatric subglottic cysts. Int J Pediatr Otorhinolaryngol 2012;76(2): 240–243 Lim J, Hellier W, Harcourt J, Leighton S, Albert D. Subglottic cysts: the Great Ormond Street experience. Int J Pediatr Otorhinolaryngol 2003;67(5):461–465 Cholewa D, Waldschmidt J. Laser treatment of hemangiomas of the larynx and trachea. Lasers Surg Med 1998;23(4):221–232 Nicolai T, Fischer-Truestedt C, Reiter K, Grantzow R. Subglottic hemangioma: a comparison of CO2 laser, Neodym-Yag laser, and tracheostomy. Pediatr Pulmonol 2005;39(3):233–237 Wang H, Zhang N, Tao M, et al. Application of interventional bronchoscopic therapy in eight pediatric patients with malignant airway tumors. Tumori 2012;98(5):581–587 Hewitson JP, Von Oppell UO. Role of thoracic surgery for childhood tuberculosis. World J Surg 1997;21(5):468–474 Powered ENT. Instruments. 2013 Available at: http://www.medtronic.com/for-healthcare-professionals/products-therapies/earnose-throat/powered-ent-instruments/powered-ent-instruments/index.htm. Accessed February 10, 2014 Ransom ER, Antunes MB, Smith LP, Jacobs IN. Microdebrider resection of acquired subglottic cysts: case series and review of the literature. Int J Pediatr Otorhinolaryngol 2009;73(12): 1833–1836 Kirse DJ. Use of the microdebrider in pediatric endoscopic airway surgery. Curr Opin Otolaryngol Head Neck Surg 2009;17(6): 477–482 Hackman TG, Ferguson BJ. Powered instrumentation and tissue effects in the nose and paranasal sinuses. Curr Opin Otolaryngol Head Neck Surg 2005;13(1):22–26 Lunn W, Garland R, Ashiku S, Thurer RL, Feller-Kopman D, Ernst A. Microdebrider bronchoscopy: a new tool for the interventional bronchoscopist. Ann Thorac Surg 2005;80(4):1485–1488 Casal RF, Iribarren J, Eapen G, et al. Safety and effectiveness of microdebrider bronchoscopy for the management of central airway obstruction. Respirology 2013;18(6):1011–1015 Graham SM, Nerad JA. Orbital complications in endoscopic sinus surgery using powered instrumentation. Laryngoscope 2003; 113(5):874–878 Filler RM, Forte V, Chait P. Tracheobronchial stenting for the treatment of airway obstruction. J Pediatr Surg 1998;33(2): 304–311 Antón-Pacheco JL, Cabezalí D, Tejedor R, et al. The role of airway stenting in pediatric tracheobronchial obstruction. Eur J Cardiothorac Surg 2008;33(6):1069–1075 Santoro G, Picardo S, Testa G, et al. Balloon-expandable metallic stents in the management of tracheomalacia in neonates. J Thorac Cardiovasc Surg 1995;110(4 Pt 1):1145–1148 Eurpoe C. Pre-mounted PALMAZ GENESIS stent. Available at: http://www.cordis.com/sites/default/files/pdf/Endo-and-BiliaryCatalog-for-website.pdf#zoom=100. Accessed October 28, 2014 Maeda K, Ono S, Tazuke Y, Baba K. Long-term outcomes of congenital tracheal stenosis treated by metallic airway stenting. J Pediatr Surg 2013;48(2):293–296 Shin JH, Hong S-J, Song H-Y, et al. Placement of covered retrievable expandable metallic stents for pediatric tracheobronchial obstruction. J Vasc Interv Radiol 2006;17(2 Pt 1):309–317 Gaissert HA, Grillo HC, Wright CD, Donahue DM, Wain JC, Mathisen DJ. Complication of benign tracheobronchial strictures by selfexpanding metal stents. J Thorac Cardiovasc Surg 2003;126(3): 744–747 FDA public health notification: complications from metallic tracheal stents in patients with benign airway disorders. 2005. Available at: http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PublicHealthNotifications/ucm062115.htm. Accessed October 28, 2014
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Mantel K. Metal airway stent implantation in children: follow-up of seven children. Pediatr Pulmonol 2001;31(4): 289–296 Fayon M, Donato L, de Blic J, et al. French experience of silicone tracheobronchial stenting in children. Pediatr Pulmonol 2005; 39(1):21–27 Novotny L, Crha M, Rauser P, et al. Novel biodegradable polydioxanone stents in a rabbit airway model. J Thorac Cardiovasc Surg 2012;143(2):437–444 Wood DE, Cerfolio RJ, Gonzalez X, Springmeyer SC. Bronchoscopic management of prolonged air leak. Clin Chest Med 2010;31(1): 127–133 Gillespie CT, Sterman DH, Cerfolio RJ, et al. Endobronchial valve treatment for prolonged air leaks of the lung: a case series. Ann Thorac Surg 2011;91(1):270–273 Travaline JM, McKenna RJ Jr, De Giacomo T, et al; Endobronchial Valve for Persistent Air Leak Group. Treatment of persistent pulmonary air leaks using endobronchial valves. Chest 2009; 136(2):355–360 Lee HJ, Shojaee S, Sterman DH. Endoscopic lung volume reduction. An American perspective. Ann Am Thorac Soc 2013;10(6): 667–679 Gompelmann D, Eberhardt R, Herth FJ. Endoscopic lung volume reduction. A European perspective. Ann Am Thorac Soc 2013; 10(6):657–666 Feller-Kopman D, Bechara R, Garland R, Ernst A, Ashiku S. Use of a removable endobronchial valve for the treatment of bronchopleural fistula. Chest 2006;130(1):273–275 Gilbert CR, Toth JW, Kaifi JT, Belani CP, Varlotto J, Reed MF. Endobronchial valve placement for spontaneous pneumothorax from stage IIIA non-small cell lung cancer facilitates neoadjuvant therapy. Ann Thorac Surg 2013;96(6):2225–2227 Mahajan AK, Verhoef P, Patel SB, Carr G, Kyle Hogarth D. Intrabronchial valves: a case series describing a minimally invasive approach to bronchopleural fistulas in medical intensive care unit patients. J Bronchology Interv Pulmonol 2012;19(2): 137–141
Endobronchial valve therapy for pneumothorax as a bridge to lung transplantation. J Heart Lung Transplant 2012;31(3):334–336 Reed MF, Podany A, Rocourt D, Dillon P, Gilbert C, Toth JW. Endobronchial occlusion with one-way endobronchial valves: A novel technique for persistent air leaks in children. In: Proceedings of the Annual Meeting of American Pediatric Surgical Association; May 29–June 1, 2014; Phoenix, AZ Silvestri GA, Feller-Kopman D, Chen A, Wahidi M, Yasufuku K, Ernst A. Latest advances in advanced diagnostic and therapeutic pulmonary procedures. Chest 2012;142(6):1636–1644 Cox PG, Miller J, Mitzner W, Leff AR. Radiofrequency ablation of airway smooth muscle for sustained treatment of asthma: preliminary investigations. Eur Respir J 2004;24(4):659–663 Castro M, Rubin AS, Laviolette M, et al; AIR2 Trial Study Group. Effectiveness and safety of bronchial thermoplasty in the treatment of severe asthma: a multicenter, randomized, double-blind, sham-controlled clinical trial. Am J Respir Crit Care Med 2010; 181(2):116–124 Wechsler ME, Laviolette M, Rubin AS, et al; Asthma Intervention Research 2 Trial Study Group. Bronchial thermoplasty: Long-term safety and effectiveness in patients with severe persistent asthma. J Allergy Clin Immunol 2013;132(6):1295–1302 Busse WW; National Asthma Education and Prevention Program. Expert Panel Report 3 (EPR-3): Guidelines for the Diagnosis and Management of Asthma-Summary Report 2007. J Allergy Clin Immunol 2007;120(5, Suppl)S94–S138 Bush A, Saglani S. Management of severe asthma in children. Lancet 2010;376(9743):814–825 Chung KF, Wenzel SE, Brozek JL, et al. International ERS/ATS guidelines on definition, evaluation and treatment of severe asthma. Eur Respir J 2014;43(2):343–373 Stackhouse RA, Infosino A. Airway management. In: Stoelting RK, Miller RD, eds. Basics of Anesthesia. 5th ed. Philadelphia, PA: Churchill Livingstone; 2007:207–239 American College of Surgeons. American Trauma Life Support for Doctors. Student Course Manual. 7th ed. Chicago, IL: First Impression; 2004:262
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Interventional Pulmonology in the Pediatric Population Christopher R. Gilbert, DO, MS1
KoPen Wang, MD2
1 Section of Bronchoscopy and Interventional Pulmonology, Division of
Pulmonary, Allergy, and Critical Care Medicine, Penn State College of Medicine-Milton S. Hershey Medical Center, Hershey, Pennsylvania 2 Section of Interventional Pulmonology, Division of Pulmonary Disease and Critical Care Medicine, The Johns Hopkins Hospital, Baltimore, Maryland
Hans J. Lee, MD2 Address for correspondence Christopher R. Gilbert, DO, MS, Section of Bronchoscopy and Interventional Pulmonology, Department of Pulmonary, Allergy, and Critical Care Medicine, Penn State College of Medicine-Milton S. Hershey Medical Center, Mail Code H0141, 500 University Drive, Hershey, PA 17033-0850 (e-mail: [email protected]).
Abstract Keywords
► interventional pulmonology ► pediatrics ► central airway obstruction ► endobronchial ultrasound ► therapeutic bronchoscopy
Endoscopic airway interventions within pediatric populations vary considerably. Some of this variance may be related to institutional experience, however, may also be limited by operator experience and available equipment. Previous reports of pediatric bronchoscopic interventional procedures have been identified within the surgical literature; however, newer reports have identified other specialties participating in the care of these patients. Here, we will provide a review of the current relevant medical literature, including an evidence-based review of advanced diagnostic and therapeutic bronchoscopic treatments within the pediatric population.
Interventional pulmonology (IP) remains a field that continues to evolve and innovate. Over 10 years ago a joint task force from the European Respiratory Society and American Thoracic Society defined IP as “the art and science of medicine related to the performance of diagnostic and invasive therapeutic procedures that require additional training and expertise beyond that required in a standard pulmonary medicine training programme.”1 Since that time publications documenting the effectiveness and involvement of IP in various other disciplines and nonpulmonology procedures continue to appear.2–4 Previously, a few case reports documenting the use of “adult-sized” equipment by “adult-trained” pulmonologists were available,5,6 as well as a review article published in 2009 documenting the potential benefits of the more advanced diagnostic equipment currently utilized by adult pulmonologists,7 however, no data was offered at this time confirming these approaches were actually feasible. In 2014, two articles were published documenting the feasibility and effectiveness of adult-trained IP in both diagnostic and therapeutic bronchoscopy within the pediatric population.8,9
Issue Theme Interventional Pulmonology; Guest Editors: David Feller-Kopman, MD and Lonny Yarmus, DO, FCCP
Common entities encountered by IP include complex airway disease management (often malignant or nonmalignant airway obstruction), pleural disease, and advanced diagnostic endoscopic procedures, often utilizing endobronchial ultrasound (EBUS) modalities. As one can imagine, the breadth of these disease processes is rather diverse, and therefore a multidisciplinary approach is typically required. IP commonly works with other physicians from anesthesia, intensive care medicine, otolaryngology, pulmonology, and thoracic surgery on a daily basis. This current model is generally in place at most institutions, however, not often apparent depending on the degree of collaboration, and can vary from institution to institution. Review of the available literature appears to describe the similar multidisciplinary care of pediatric patients with central airway obstruction (CAO);10 however, most literature reported remains dominated by surgical teams performing both endoscopic and surgical procedures. The most common disciplines appear to be otolaryngology, thoracic, or pediatric surgery. There appear to be limited reports of pulmonologists
Copyright © 2014 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662.
DOI http://dx.doi.org/ 10.1055/s-0034-1395505. ISSN 1069-3424.
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Interventional Pulmonology in the Pediatric Population (pediatric or adult) performing therapeutic airway interventions, unless it involves foreign body removal. In adult medicine, the multidisciplinary care of patients with CAO often will involve anesthesiologists, intensivists, interventional pulmonologists, otolaryngologists, and thoracic surgeons all caring for the same patient.
Current Training Training in IP within the United States has evolved over the last 10 to 15 years and current recommendations for fellowship11,12 as well as specific procedural training1,13 currently exist. In summary, the pathway toward becoming board certified in IP involves internal medicine residency, pulmonary/critical care medicine fellowship, followed by an additional year of dedicated fellowship training in IP.14 As one can imagine, the majority of training is focused on adult medicine and the exposure to pediatrics can be minimal to even nonexistent. At the current time, pediatric pulmonology remains a subspecialty limited to those completing a pediatric residency. Pediatric pulmonologists are taught bronchoscopy as part of their fellowship training, however, the training may be variable and there remain no objective requirements for their procedural training.15 This remains in stark comparison to an adult pulmonary fellowship as well as an IP fellowship which have suggested procedural number thresholds to help define competency.12,13 While the performance of advanced diagnostic and therapeutic bronchoscopy is certainly not limited to physicians based on their initial training, the ability to obtain the proper training and experience may be. The authors are currently unaware of any pediatric pulmonology fellowships within the United States that routinely teach advanced diagnostic bronchoscopy such as EBUS or therapeutic interventions such as rigid bronchoscopy. Interventional pulmonologists evaluate and manage a diverse population of patients and diseases. The majority of patients undergo procedures related to the disease of the thorax in which advanced diagnostic bronchoscopy, therapeutic bronchoscopy, or pleural procedures. We will describe the current and potential role the trained IP can play in the care of pediatric populations.
anesthetic planning.16 A multidisciplinary approach and open dialogue between all team members, especially pediatric anesthesiologists and intensivists, is essential for pre-, intra-, and postprocedural planning. Significant head and neck changes occur during normal child growth. Initially, children have larger heads with rather small, immobile mandibles, however, normal growth decreases the proportional head size and the mandible becomes larger and more mobile. Other changes in the supraglottic portion of the airway include a decrease in the size of the tongue in proportion to the airway, decrease in size of the epiglottis, and changes to the location of the glottis opening. Within smaller children the cricoid cartilage remains the smallest diameter of the airway (as opposed to adults in which the glottic opening is the smallest), therefore an instrument that passes through the glottic opening may not pass further into the trachea.17 Airway diameter remains an important consideration for selection of appropriate equipment. In adults, the ventilating rigid bronchoscope is commonly used for safe airway control and numerous interventions, including airway dilation, passage of multiple tools, and placement of endobronchial stents. Despite the same ability to use ventilating rigid bronchoscopes (with sizes as small as 4 mm) in pediatrics, numerous differences need to be recognized. The presence of a smaller airway diameter limits the size of endotracheal appliances (rigid bronchoscope or endotracheal tube) that can be introduced, and subsequently affects the ability to utilize certain instruments. This decreased diameter also leads to increase airway resistance and airway pressures (when attempting to deliver the same volumes) which often become exaggerated when introducing additional tools through the lumen of the bronchoscope.18 Estimation of endotracheal tube size is often based on patient age or weight (►Table 1), but can also be done by selecting an outer diameter similar in size to the child’s fifth finger.19 The concerns regarding airway diameter have most likely led to minimal use of “adult-sized” bronchoscopes within pediatric populations, however, two recent publications have identified the safe and effective use of
Table 1 Pediatric airway equipment and sizes. Suggested size of endotracheal tube and laryngeal mask airway based on child’s age and weight
Pediatric Airway While many of the general principles related to airway management remain the same within the adult and pediatric airway, distinct differences are present and providers must be aware of these differences for both patient safety and procedural feasibility. Preoperative airway evaluations typically involve a patient history and physical examination, including a history of airway difficulties. When evaluating newborns and infants a maternal and perinatal history is often appropriate. In children with congenital or malformation syndromes, a thorough understanding of their defined and potentially unrecognized manifestations, especially related to head and neck anatomy, remains essential for appropriate procedural and Seminars in Respiratory and Critical Care Medicine
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Age
Weight (kg)
Endotracheal tube size (mm)
Laryngeal mask airway size
0–6 mo
0–4
2.5–3.5
1
6–12 mo
5–10
3.5–4.0
1.5
1–3 y
10–15
4.0–4.5
2
4–7 y
15–20
5.0–5.5
2–2.5
8–10 y
20–30
5.5–6.0
2.5
> 10 y
> 30
> 6.0
>3
Source: The table is adapted from Anesthesia for Children,19 Basics of Anesthesia,81 and from American Trauma Life Support for Doctors Manual.82
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standard “adult-sized” diagnostic and therapeutic equipment within a selected population of pediatric patients.8,9
Advanced Diagnostic Procedures Endobronchial Ultrasound The most promising new technology in diagnostic bronchoscopy remains the introduction of EBUS. Initially introduced in the late 1990s to the adult pulmonology community, EBUS has obtained widespread acceptance and popularity. A recent PubMed search on endobronchial ultrasound returned almost 1,000 articles with over 140 review articles; however, there remains a paucity of literature related to utilization in the pediatric population. Two types of EBUS are currently available; convex probe EBUS (CP-EBUS) and radial probe EBUS (RP-EBUS). CP-EBUS (►Fig. 1) was introduced in early 2000 and has since revolutionized the evaluation of adult patients with mediastinal and hilar lymphadenopathy, especially regarding the care of patients with suspected lung cancer.20 CP-EBUS bronchoscopes are currently designed for examination of the more central structures, often mediastinal and hilar lymphadenopathy, but can also access centrally located parenchymal lesions.21 Currently available CP-EBUS scopes are manufactured by Olympus (BF-UC180F, Tokyo, Japan), Pentax Medical (EB-1970UK, Montvale, NJ), and Fujinon Endoscopy (EB-530US, Wayne, NJ). The main potential limitation for CPEBUS utilization within the pediatric population remains the larger outer diameter of the scope, with all possessing an outer diameter of greater than 6.7 mm. The current adult literature suggests widespread adoption of EBUS-guided transbronchial needle aspiration (EBUSTBNA) and in most high volume institutions that provide
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multidisciplinary care to patients with thoracic malignancies, EBUS-TBNA has albeit replaced mediastinoscopy as an initial diagnostic test.22–24 Attractive features to EBUS-guided procedures include the excellent diagnostic yield, potential for decreased cost, complications, and hospital resource utilization.22,24 The literature in pediatrics remains scant, however, the data suggest the procedure remains quite feasible, even in small children and infants. Initial case reports noted the successful use of EBUS-TBNA in children aged between 6 and 13 years.5,6 A multicenter study has since been published identifying 21 pediatric patients safely undergoing EBUSTBNA with ages ranging from 18 months to 18 years.9 RP-EBUS was initially introduced for use within the central airways utilizing an inflatable balloon to help visualize individual layers of the trachea wall, however, its common current day use is in exploration of nodules and infiltrates within the lung parenchyma. RP-EBUS probes (►Fig. 2) for investigation of the periphery are currently manufactured in either a 1.4 mm (UM-S20–17S, Olympus) outer diameter or a 2.5 mm (UM-2R/3R, Olympus) outer diameter. The manufacturer recommendations suggest bronchoscopic working channels that range from 2.0 to 2.8 mm.25 There are currently no published reports of RP-EBUS in pediatrics, however, in theory the only limitation to the use of the RP-EBUS probe in the pediatric population remains the diameter of the probe and its required bronchoscopic working channel.
Virtual Navigational Bronchoscopy At this time, there are no available data regarding the use of advanced navigational techniques (virtual bronchoscopy and electromagnetic navigational bronchoscopy) within the pediatric population. This technology remains quite feasible for
Fig. 1 Convex probe endobronchial ultrasound (CP-EBUS) puncture scope. (A) Photograph of CP-EBUS puncture scope tip. Ultrasound probe (#) and working channel () of the scope are identified. The working channel and optics are both offset at a 30-degree angle to facilitate real-time imaging of the needle by the ultrasound probe. (B) Ultrasound image of a transbronchial needle aspiration (TBNA) needle (arrow) within a lymph node. (C) Similar ultrasound image of TBNA needle entering a lymph node, but with an inlaid endoscopic image in the bottom left hand corner (labeled). The right paratracheal lymph node (þ) and superior vena cava ($) are easily identified in this image. Seminars in Respiratory and Critical Care Medicine
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Fig. 2 Radial probe endobronchial ultrasound (RP-EBUS) probe. (A) Photograph of RP-EBUS probe emerging from working channel of standard adult bronchoscope. The ultrasound probe is identified (arrow). (B) Bronchoscopic image obtained during procedure. Inlaid within the left corner is an endoscopic view, in which the ultrasound probe can be seen entering into a bronchus. The larger image represents a 360 degree image obtained from rotation of the probe. The sharp white lines (arrows) identify the demarcation between the lung nodule ( ) and surrounding lung tissue.
use in this population and has no specific requirements or needs that would limit its use to the adults. However, the use of these technologies does require the use of specially formatted computed tomography scans (►Fig. 3). Current literature regarding the use of these virtual or navigational bronchoscopy techniques has not demonstrated a significant improvement over RP-EBUS in the diagnostic yield of peripheral pulmonary lesions and therefore may not be as desirable with the potential added radiation exposure.
Therapeutic Procedures Multiple publications are currently available regarding the use of rigid bronchoscopy within pediatrics, with many authors having received training in otolaryngology, thoracic surgery, and/or pediatric surgery. The most common reported use of rigid bronchoscopy in pediatrics is clearly related to the foreign body retrieval. We purposefully excluded foreign body removal within our review. Innumerous studies and reviews are currently available regarding the risks/benefits/indications/contraindications to the use of flexible or rigid bronchoscopy within children suspected of
a foreign body inhalation.26–28 We did not believe rereview of these articles would add further to the literature. As such, we have elected not to address this topic, but rather focus on other less described therapeutic interventions that can be performed bronchoscopically in children Within the pediatric population, it is readily apparent that nonmalignant CAO remains more common than CAO related to malignant disease. This distinction remains quite important and is the central challenge in the long-term management of pediatric CAO. Another readily apparent factor in pediatric CAO is the ability of future growth of the airway tree as the child ages. This predictable increase in airway dimension offers both advantages and disadvantages. Advantages include the potential for improvement of airway stenosis and malacia as the obstruction may represent a smaller fraction of the overall airway diameter in the future. The disadvantage includes predictable airway growth, which then entails the creation of a strategy that will maintain airway patency during growth and allow for successful removal if the benefit of an in situ stent is lost. While surgical treatment remains the optimal therapy for airway obstruction in nonmalignant disease, airway stenting
Fig. 3 Navigational bronchoscopy techniques. Screen views of LungPoint (Broncus Technology, Redmond, WA) navigational bronchoscopy software. View from main carina (A), axial planning image (B) highlighting aorta in red, three-dimensional image of airway tree and major vessels (C), and subsequent virtual image of left upper lobe (D). The software prelabels major airways with segmental anatomy identified from computed tomography scans. (For color indicators see figure in color in the online version.) Seminars in Respiratory and Critical Care Medicine
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Balloon Dilation Procedures Balloon dilation procedures are commonly performed for CAO related to stenosis, often intraluminal and nonmalignant. Balloon dilation is commonly performed in adults utilizing specially designed controlled radial expansion balloons (►Figs. 4 and 5). These nonconformal balloons can be filled with radiopaque fluid or with saline depending on preference and planned use of fluoroscopic guidance. Balloons are inflated under pressure which corresponds to a predetermined size. Reports of other balloon techniques include the use of conformal balloons (vascular embolectomy catheters,31 urinary catheters,32 etc.), however, these are not routinely recommended due to their inability to deliver a standard and uniform balloon size and distribution of dilation, in addition to the fact that they may conform to the stenosis with the maximal diameter of the balloon being in the nonstenotic segment. The use of conformal balloons in the pediatric population may be related to the difficulty obtaining nonconformal balloons that will accommodate pediatric airways and instrumentation. There are no randomized trials involving the use of balloon dilation for the treatment of airway obstruction in pediatrics. The most common indication for balloon dilation procedures
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in children remains subglottic stenosis, often resulting from complications due to intubation and tracheostomy. Numerous authors have presented retrospective series in children ranging from 1 month of age to young adults.33,34 Success rates range from 57 to 98%, often leading to successful tracheostomy tube decannulation or the avoidance of tracheotomy. Children (similar to adults) often undergo multiple dilation sessions, but complication rates remain extremely low. Other reported uses of balloon dilation involve its use in airway clearance and in malignant CAO.8 Balloon dilation in combination with mechanical debridement via forceps has been reported in a small series for the successful reestablishment of central airway patency in obstructing fibrinous tracheal pseudomembrane.35
Thermal Techniques Thermal techniques utilize energy to cause tissue destruction via vaporization, cauterization, and/or coagulation (►Fig. 6). One of the most commonly used thermal energy techniques utilized for airway obstruction is the endobronchial laser. Laser therapies are currently available in different wavelengths and size fibers for a multitude of applications. The most commonly reported medical lasers for endobronchial use are neodymium:yttrium-aluminum-garnet (Nd:YAG), carbon dioxide (CO2), and potassium-titanium-phosphate (KTP). Other options for thermal destruction of airway lesions include direct contact electrocautery techniques, as well as noncontact argon plasma coagulation (APC). Once again the majority of children undergo thermal destruction of airway lesions related to nonmalignant etiologies. The use of the Nd:YAG, KTP, and CO2 laser are all represented in case series and observational cohorts, no randomized studies or comparative efficacy trials are available. Laser destruction/resection of lesions is reported for granulation tissue,36–38 subglottic cysts,39–41 and hemangiomas.42,43 Most reports demonstrate successful outcomes, although some report recurrent disease and unsuccessful tracheostomy tube decannulation. Complications have been reported, but the lack of followup and retrospective design of the studies certainly introduces bias. The most common complication appears to be a recurrence of disease and the need for a second procedure.
Fig. 4 Balloon dilation procedure under direct visualization. (A) Bronchoscopic image of severe tracheal stenosis. (B) Bronchoscopic image of balloon bronchoplasty procedure under direct visualization. (C) Postprocedure endoscopic image with improvement in airway caliber. Seminars in Respiratory and Critical Care Medicine
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and other endoscopic interventions may provide a viable solution for nonsurgical candidates or a bridge to surgery. It is especially important to recognize the potential complications associated with airway stent placement, including granulation tissue formation, migration, and mucostasis/infection. Additionally, nonendoscopic alternatives, including aortopexy, noninvasive ventilation, and tracheostomy tube placement may be a better option depending on the underlying disease and local expertise. The above interventions in the setting of future airway growth and improving structural integrity have also been met with success.29 In some cases, airway obstruction may occur after surgical correction of airway reconstruction, congenital vascular anomalies (vascular sling, extrinsic compression, enlarged vasculature), Komerell diverticulum, or bronchogenic cyst.30 Herein, we will describe common endoscopic interventions utilized in both pediatric and adult CAO. As some of the literature in pediatric CAO is limited we will present data regarding adult use as needed.
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Fig. 5 Balloon dilation procedure under fluoroscopic guidance. (A) Fluoroscopic image of balloon bronchoplasty procedure of the left main bronchus. Note the indentation of the balloon before full expansion (arrows). (B) Fluoroscopic image of balloon bronchoplasty procedure of the left main bronchus. Note significant resolution of the balloon indentation after expansion.
Fig. 6 Thermal destruction technique for endobronchial disease. (A) Endoscopic view of endobronchial lesion causing partial airway obstruction in a 16-year-old boy with persistent cough and known recurrent respiratory papillomatosis. Argon plasma coagulation (APC) probe seen entering screen from right side (arrow). (B) Endoscopic view of endobronchial lesion after APC use causing coagulation and destruction of lesion.
Most reports of intervention for nonmalignant airway disease does result in significant successful outcome initially, however, many of these patients (particularly those with malacia, stenosis, or granulation tissue) will often have evidence of recurrence.38 Mild granulation tissue and subglottic stenosis have been reported in some series as well.39,43 Major complications such as death have been reported, however, appear extremely rare. There is a report of an airway fire in one series.36 The fire appeared to cause no significant damage (superficial ulcerations) and no long-term sequelae. Successful palliation of malignancy-related CAO has been reported with thermal energy use in pediatrics. Both the CO2 laser and APC have reported technically successful results, with no reported complications associated with the initial performance of these procedures.8,44 However, within the Wang et al series, one child died due to acute airway obstruction and asphyxiation from a presumed tissue flap created during a repeat bronchoscopy for recurrent tumor. The authors later comment that this procedure was performed earlier in their experience and utilized flexible bronchoscopy. Seminars in Respiratory and Critical Care Medicine
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They have since performed all procedures with rigid bronchoscopy and while it remains impossible to determine if the performance of the procedure under general anesthetic with the rigid bronchoscope securing the airway would have changed the outcome, it obviously begs the question.44
Mechanical Debridement Mechanical debridement techniques involve the simple concept of removing tissue with forceps (►Fig. 7) or other cold steel instruments to help improve airway patency. The main indication for mechanical debridement is that patients must have evidence of intrinsic airway disease. The presence of only extrinsic (i.e., endoluminal compression from a surrounding mass) disease is a contraindication for endoscopic debridement. The instruments utilized can range from the rigid bronchoscope barrel (►Fig. 8) to the more complex automated microdebrider instrument (►Fig. 9). Successful reports of mechanical debridement are often described in the management of excess suprastomal granuMechanical lation tissue following tracheotomy.38
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Fig. 8 Use of rigid bronchoscope barrel for mechanical dilation/debridement. A 13-year-old girl was initially diagnosed with refractory asthma. Referral for bronchoscopy occurred when she complained of stridor and voice changes. Evidence of subglottic stenosis was discovered at bronchoscopy. (A) Rigid bronchoscopic view of severe subglottic stenosis. Mechanical dilation with the tip of the rigid bronchoscope in a twisting fashion allowed for immediate relief of her airway obstruction and symptoms. (B) Postdilation bronchoscopic view noting significant improvement in airway caliber.
Fig. 9 Microdebrider. A 2-year-old boy noted to have noisy breathing with exertion and crying was identified as having a subglottic cyst during bronchoscopy. (A) Repeat bronchoscopy upon transfer confirmed presence of subglottic cyst obstructing the subglottic space. (B) Bronchoscopic view of microdebrider destroying and suctioning contents of previously identified subglottic cyst. (C) Bronchoscopic view of the subglottic space identifying significant improvement in airway caliber and relief of obstruction.
debridement can also be used in conjunction with other techniques to help provide further relief of CAO.8,38 Endobronchial forceps resection has been successfully utilized in children with CAO secondary to tuberculosis granulomata.45
The microdebrider remains a popular tool in the field of otolaryngology being marked for use in endoscopic sinus surgery and airway debulking.46–49 The microdebrider has also experienced, successful use by interventional Seminars in Respiratory and Critical Care Medicine
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Fig. 7 Mechanical debridement of endobronchial lesion. (A) Rigid bronchoscopic view of an endobronchial aspergilloma identified obstructing the right main stem bronchus in a 16-year-old patient with leukemia. Progressive respiratory failure and persistent fevers prompted bronchoscopy. (B) Mechanical debridement with forceps allowed for almost complete relief of airway obstruction and significant improvement in respiratory status.
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pulmonologists for the management of CAO.50,51 Because of the limited length and stiffness of the microdebrider, its role is often limited to tracheal disease (or very proximal main stem disease). Reports of use for subglottic cyst management appear successful with minimal complications.47 Complications overall for mechanical debridement do exist, and can be major, such as bleeding, cardiac arrest, and death. The use of forceps during granulation tissue removal (and subsequent loss of tissue into the distal trachea) has reported to cause asphyxiation, with subsequent hospital complications leading to the child’s death.38 Excess bleeding after granuloma debridement from an airway wall led to uncontrollable hemorrhage and subsequent asphyxiation.45 No reports of major airway complications related to microdebrider use have been reported, however, major bleeding and tissue damage have been reported in endoscopic sinus surgery.49,52
Airway Stents Airway stents are commonly utilized for the relief of CAO and come in multiple different formulations, configurations, and sizes. Similar to the adult stent literature, immediate relief, and improvement from CAO is commonly reported in pediatric series. In some cases, the relief of the CAO is so vital to respiratory status that airway stenting allows for almost immediate liberation from mechanical ventilation. This benefit must be tempered with the knowledge of the known longterm outcomes/complications associated with stent placement. As such, one should never sacrifice long-term options such as a potential curative surgical resection over short-term gains. Most patients should be evaluated and managed in a multidisciplinary fashion with experts in CAO and pediatric airway reconstruction. The ideal airway stent would be: easy to place even in the smallest airways, provide structural airway integrity with minimal adverse effects, and be removable at any time or unnecessary to remove. Unfortunately, at this time, no available stent is able to meet all these properties. Therefore, the placement of airway stents should not be taken lightly as serious long-term complications can arise, especially in patients with nonmalignant CAO. Airway stents in general can be divided into different categories based on the material of the stent. We have further divided this topic into three different categories; metallic, silastic, and novel stents. While rare, stent-related morbidity/ mortality has been reported for almost all airway stents.53,54
Metallic Stents Metallic stents offer the convenience of insertion via flexible bronchoscopy and/or fluoroscopy. In infants and young children, the airway caliber becomes the main obstacle in placing larger bronchoscopes and tools without obstructing the airway. Metallic stents offer the flexibility of using only a guide wire with fluoroscopy to place the stent (►Fig. 10) even within infant-sized airways.55 Two types of metallic stents have been available; balloonexpandable and self-expanding. There are currently no Food and Drug Administration (FDA)-approved metallic airway Seminars in Respiratory and Critical Care Medicine
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Fig. 10 Self-expanding metallic stent placement under fluoroscopic guidance. Fluoroscopic view of a self-expanding metallic stent () that has been placed into the right main stem bronchus. The use of a guide wire can be seen (arrows) and is recommended when utilizing fluoroscopic guidance.
stents for use in pediatrics. Within adults, the only FDAapproved metallic airway stents are the Merit Aero (Merit Medical Systems, South Jordan, UT) self-expandable stent, and the uncovered Ultraflex stent (Boston Scientific, Needham, MA). Current sizes range from 10 to 20 mm outer diameters (when fully expanded), requiring a working diameter of 16 to 22F. The Aero stents are covered with a polyurethane coating and constructed from nickel-titanium (nitinol) allowing a shape memory effect. The currently available balloon-expandable metallic stents are often utilized for vascular or cardiac purposes. The best described balloon-expandable stent utilized in pediatrics is the Palmaz (Cordis Corporation, Miami Lakes, FL) stent. Designed as a vascular stent made of a single piece of stainless steel, its popularity appears related to the available small dimension and ease of placement. Palmaz stents can often be found in sizes ranging from 5 to 10 mm outer diameters that may only require a working channel of 6F.56 The granulation tissue has been described as the most common serious complication. The long-term risks of any metallic stent are restenosis by recurrent granulation tissue, failure of tracheal growth with age, and tracheal erosion or penetration into the great vessels. Several investigators have reported issues with recurrent granulation tissue which has been managed by serial bronchoscopy procedures requiring balloon bronchoplasty and/or debulkment of granulation tissue.54,57 The granulation tissue has also been known to be colonized with pathogenic organisms potentially increasing the risk of bacterial overgrowth/infection especially in infants with smaller airways.30,58 Regardless of the metallic stent selection, eventual endoscopic stent removal may not be possible and may require surgical resection. In the adult population, duration of more than 4 to 6 weeks marks a time for potential difficult removal due to granulation tissue and reepithelialization of the stent
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Silastic Stents Silicone stents are available in multiple sizes and configurations, including a “Y” shape for placement at the carina, as well as the Montgomery t-tube. Silicone stent placement requires the use of rigid bronchoscopy (►Fig. 11) which may be potentially more challenging in smaller pediatric airways. The smallest commercially available silicone stent in the United States is a 6-mm outer diameter (OD) stent. Another limitation includes the lack of commercially available stent deployers for the smaller rigid bronchoscopes; however, various other techniques have been described to deploy smaller silastic stents. Silicone stents can be more easily removed after having been in place for long durations when compared with metal stents. Complications include granulation, stent migration, and mucus impaction/infection. In addition, the inner diameter is less for any outer diameter when compared with a metallic stent. A long-term advantage of silastic stents is that they are nonexpanding and will not develop fatigue fracture of the stent wires. Reports of successful cases are feasible in infants; however, poor results were associated with highpressure vascular compression.62
Novel Stents Absorbable or biodegradable stents may potentially be the future of pediatric airway stents; however, none are currently available for use within the United States. These stents remain in the airway for a finite time without the complications of surgical removal. In theory, if the airway remains patent via
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the stent, in time as the child’s airway dimension grows, no further intervention may be needed. Current uses of these stents include urethral, biliary, and vascular purposes. Small series from other countries have reported success with primarily polydioxanone stents.63 The use of polydioxanone stents appears promising as they are composed of a semicrystalline, biodegradable polymer. The material has shape memory, but later degrades by random hydrolysis of its ester bonds into harmless degradation products. Further investigation is needed before large scale adoption in the airway. The current degradation properties are not well known in the airway. A small case series suggests 15 weeks for complete absorption while in an animal model 10 weeks were needed for degradation.63
Endobronchial Valves The development of an alveolar-pleural fistula and persistent air leak is a serious clinical problem and can lead to an increased morbidity and mortality.64 Air leaks after thoracic surgery remain a common complication and previous endobronchial therapies have been variably successful, including the use of endobronchial valve (EBV) placement. EBV has demonstrated clinical utility in the treatment of prolonged air leaks64–66 as well as emphysema.67,68 Currently, a one-way EBV (►Fig. 12) has been approved for use in adults for prolonged air leaks after pulmonary resection (Spiration, Redmond, WA). Off-label uses have been described in the adult population, including treatment for bronchopleural fistula,69 treatment of spontaneous pneumothorax in the setting of advanced lung cancer,70 and to facilitate lower levels of respiratory support within the intensive care unit.71 Only two reports of EBV use are available within the pediatric population. A case report has described the use of EBV in an 18-year-old patient with cystic fibrosis and recurrent pneumothorax to avoid pleurodesis while awaiting lung transplantation.72 A case series of four pediatric patients (age range, 16 months–16 years) identified successful use of EBV in patients with bronchopleural fistula related to empyema and recurrent pneumothorax related to barotrauma.73 No significant complications related to valve placement were identified within these reports.
Fig. 11 Silicone stent placement. A 17-year-old patient with tracheal obstruction secondary to metastatic small blue round cell tumor. (A) Bronchoscopic view from subglottic space identifying proximal, extrinsic tracheal obstruction. (B) Bronchoscopic view of trachea after placement of silicone tracheal stent. Placement of tracheal stent allowed for relief of dyspnea. Seminars in Respiratory and Critical Care Medicine
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within the airway.57 In addition, within the adult literature are descriptions of potentially surgically correctable nonmalignant airway obstruction rendered inoperable due to metallic stent-related complications.59 Complications and management issues related to metallic stents are well published and in 2005 the FDA warned against the placement of metallic stents in nonmalignant airways unless other options had been exhausted.60 Despite the potential complications, some experts that have experience with various metallic stents favor nitinol for pediatrics given the potential size options.61
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Fig. 12 Endobronchial valve. A 16-month-old male patient with recurrent pneumothorax and persistent air leak secondary to barotrauma. (A) Placement of a unidirectional endobronchial valve within a basilar segment of the left lower lobe. (B) Chest radiograph demonstrating multiple chest tubes in place as well as the placement of four endobronchial valves with the left lower lung field.
3 Yarmus L, Gilbert C, Lechtzin N, Imad M, Ernst A, Feller-Kopman D.
Bronchial Thermoplasty Bronchial thermoplasty (BT) is a novel endoscopic treatment currently available to adults with severe persistent asthma and receiving maximal medical therapy.74 BT attempts to smooth muscle mass within the lobar and segmental bronchi by the delivery of heat energy via a radiofrequency generator. Preliminary data had suggested a reduction of smooth muscle mass75 and clinical studies have demonstrated improvements in quality of life scores up to 1 year posttreatment76 as well as no demonstrable increased morbidity at 5 year follow-up.77 At the current time there are no reports of BT within the pediatric population. Currently, children with persistent asthma are recommended to utilize immunotherapy or omalizumab.78,79 There is little available literature about the potential use of BT in a pediatric population, however, these authors hypothesize that the current self-imposed moratorium is most likely related to the yet unclear long-term effects and role of BT in patients with severe asthma.80
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Herein, we present the largest and most up-to-date review of advanced diagnostic and therapeutic bronchoscopic procedures within the pediatric population. Our review suggests that there remains sparse literature within the pediatric population regarding many of the procedures performed, demonstrating the need for further research. As the care of many of these pediatric patients is multidisciplinary, the potential collaboration for multidisciplinary research remains exciting and vital to the advancement of the field and care of these patients.
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References 1 Bolliger CT, Mathur PN, Beamis JF, et al; European Respiratory
Society/American Thoracic Society. ERS/ATS statement on interventional pulmonology. Eur Respir J 2002;19(2):356–373 2 Yarmus L, Pandian V, Gilbert C, et al. Safety and efficiency of interventional pulmonologists performing percutaneous tracheostomy. Respiration 2012;84(2):123–127
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Safety and feasibility of interventional pulmonologists performing bedside percutaneous endoscopic gastrostomy tube placement. Chest 2013;144(2):436–440 Wahidi MM, Ernst A. Role of the interventional pulmonologist in the intensive care unit. J Intensive Care Med 2005;20(3):141–146 Siemsen M, Andersen NE, Nielsen KG. EBUS in a 6-year-old boy with enlarged hilar lymph nodes. J Bronchology Interv Pulmonol 2011;18(2):205 Wurzel DF, Steinfort DP, Massie J, Ryan MM, Irving LB, Ranganathan SC. Paralysis and a perihilar protuberance: an unusual presentation of sarcoidosis in a child. Pediatr Pulmonol 2009; 44(4):410–414 Steinfort DP, Wurzel D, Irving LB, Ranganathan SC. Endobronchial ultrasound in pediatric pulmonology. Pediatr Pulmonol 2009; 44(4):303–308 Gilbert CR, Feller-Kopman D, Akulian J, Hayes M, Yarmus L. Interventional pulmonology procedures in the pediatric population. Pediatr Pulmonol 2014;49(6):597–604 Gilbert CR, Chen A, Akulian JA, et al. The use of convex probe endobronchial ultrasound-guided transbronchial needle aspiration in a pediatric population: a multicenter study. Pediatr Pulmonol 2014;49(8):807–815 McLaren CA, Elliott MJ, Roebuck DJ. Tracheobronchial intervention in children. Eur J Radiol 2005;53(1):22–34 Lamb CR, Feller-Kopman D, Ernst A, et al. An approach to interventional pulmonary fellowship training. Chest 2010;137(1): 195–199 Yarmus L, Feller-Kopman D, Imad M, Kim S, Lee HJ. Procedural volume and structure of interventional pulmonary fellowships: a survey of fellows and fellowship program directors. Chest 2013; 144(3):935–939 Ernst A, Silvestri GA, Johnstone D; American College of Chest Physicians. Interventional pulmonary procedures: Guidelines from the American College of Chest Physicians. Chest 2003; 123(5):1693–1717 About Medical Specialties Matching Program (MSMP). Available at: http://www.nrmp.org/fellowships/medical-specialties-matching-program/. Accessed October 28, 2014 Masters IB, Cooper P. Paediatric flexible bronchoscopy. J Paediatr Child Health 2002;38(6):555–559 Yastor M, Elliot RA. Preoperative Assessment of the Newborn. New York, NY: McGraw Hill Medical; 2008:300–309 Wetzel RC. Evaluation of Children. New York, NY: McGraw Hill; 2008:310–340 Lockhart CH, Elliot JL. Potential hazards of pediatric rigid bronchoscopy. J Pediatr Surg 1984;19(3):239–242
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19 Everett LL. Anesthesia for Children. New York, NY: McGraw Hill; 20
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29
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2008:1520–1540 Yasufuku K, Chiyo M, Sekine Y, et al. Real-time endobronchial ultrasound-guided transbronchial needle aspiration of mediastinal and hilar lymph nodes. Chest 2004;126(1):122–128 Nakajima T, Yasufuku K, Fujiwara T, et al. Endobronchial ultrasound-guided transbronchial needle aspiration for the diagnosis of intrapulmonary lesions. J Thorac Oncol 2008;3(9):985–988 Gilbert C, Yarmus L, Feller-Kopman D. Use of endobronchial ultrasound and endoscopic ultrasound to stage the mediastinum in early-stage lung cancer. J Natl Compr Canc Netw 2012;10(10): 1277–1282 Yasufuku K, Nakajima T, Fujiwara T, et al. Role of endobronchial ultrasound-guided transbronchial needle aspiration in the management of lung cancer. Gen Thorac Cardiovasc Surg 2008;56(6): 268–276 Yasufuku K, Pierre A, Darling G, et al. A prospective controlled trial of endobronchial ultrasound-guided transbronchial needle aspiration compared with mediastinoscopy for mediastinal lymph node staging of lung cancer. J Thorac Cardiovasc Surg 2011; 142(6):1393–1400, e1 Olympus. Endoscopic ultrasound probes. http://medical.olympusamerica.com/products. Available at: Accessed October 28, 2014 Boufersaoui A, Smati L, Benhalla KN, et al. Foreign body aspiration in children: experience from 2624 patients. Int J Pediatr Otorhinolaryngol 2013;77(10):1683–1688 Foltran F, Ballali S, Passali FM, et al. Foreign bodies in the airways: a meta-analysis of published papers. Int J Pediatr Otorhinolaryngol 2012;76(Suppl 1):S12–S19 Swanson KL, Prakash UB, Midthun DE, et al. Flexible bronchoscopic management of airway foreign bodies in children. Chest 2002; 121(5):1695–1700 Pillai JB, Smith J, Hasan A, Spencer D. Review of pediatric airway malacia and its management, with emphasis on stenting. Eur J Cardiothorac Surg 2005;27(1):35–44 Jacobs JP, Quintessenza JA, Botero LM, et al. The role of airway stents in the management of pediatric tracheal, carinal, and bronchial disease. Eur J Cardiothorac Surg 2000;18(5):505–512 Fouty BW, Pomeranz M, Thigpen TP, Martin RJ. Dilatation of bronchial stenoses due to sarcoidosis using a flexible fiberoptic bronchoscope. Chest 1994;106(3):677–680 Malik AM, Ahmed Z, Durgham N, Stockmann PT, Belenky WM, Zestos M. Airway and ventilation management during repair of a large acquired tracheoesophageal fistula: the novel use of a readily available tool. J Clin Anesth 2012;24(2):133–136 Maksoud-Filho JG, Gonçalves MEP, Cardoso SR, Tannuri U. Early diagnostic and endoscopic dilatation for the treatment of acquired upper airway stenosis after intubation in children. J Pediatr Surg 2008;43(7):1254–1258 Whigham AS, Howell R, Choi S, Peña M, Zalzal G, Preciado D. Outcomes of balloon dilation in pediatric subglottic stenosis. Ann Otol Rhinol Laryngol 2012;121(7):442–448 Soong WJ, Jeng MJ, Lee YS, Tsao PC, Yang CF, Soong YH. Pediatric obstructive fibrinous tracheal pseudomembrane—characteristics and management with flexible bronchoscopy. Int J Pediatr Otorhinolaryngol 2011;75(8):1005–1009 Mandell DL, Yellon RF. Endoscopic KTP laser excision of severe tracheotomy-associated suprastomal collapse. Int J Pediatr Otorhinolaryngol 2004;68(11):1423–1428 Sharp HR, Hartley BEJ. KTP laser treatment of suprastomal obstruction prior to decannulation in paediatric tracheostomy. Int J Pediatr Otorhinolaryngol 2002;66(2):125–130 Yellon RF. Totally obstructing tracheotomy-associated suprastomal granulation tissue. Int J Pediatr Otorhinolaryngol 2000;53(1): 49–55 Madgy D, Ahsan SF, Kest D, Stein I. The application of the potassium-titanyl-phosphate (KTP) laser in the management of subglot-
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tic hemangioma. Arch Otolaryngol Head Neck Surg 2001;127(1): 47–50 Aksoy EA, Elsürer C, Serin GM, Unal OF. Evaluation of pediatric subglottic cysts. Int J Pediatr Otorhinolaryngol 2012;76(2): 240–243 Lim J, Hellier W, Harcourt J, Leighton S, Albert D. Subglottic cysts: the Great Ormond Street experience. Int J Pediatr Otorhinolaryngol 2003;67(5):461–465 Cholewa D, Waldschmidt J. Laser treatment of hemangiomas of the larynx and trachea. Lasers Surg Med 1998;23(4):221–232 Nicolai T, Fischer-Truestedt C, Reiter K, Grantzow R. Subglottic hemangioma: a comparison of CO2 laser, Neodym-Yag laser, and tracheostomy. Pediatr Pulmonol 2005;39(3):233–237 Wang H, Zhang N, Tao M, et al. Application of interventional bronchoscopic therapy in eight pediatric patients with malignant airway tumors. Tumori 2012;98(5):581–587 Hewitson JP, Von Oppell UO. Role of thoracic surgery for childhood tuberculosis. World J Surg 1997;21(5):468–474 Powered ENT. Instruments. 2013 Available at: http://www.medtronic.com/for-healthcare-professionals/products-therapies/earnose-throat/powered-ent-instruments/powered-ent-instruments/index.htm. Accessed February 10, 2014 Ransom ER, Antunes MB, Smith LP, Jacobs IN. Microdebrider resection of acquired subglottic cysts: case series and review of the literature. Int J Pediatr Otorhinolaryngol 2009;73(12): 1833–1836 Kirse DJ. Use of the microdebrider in pediatric endoscopic airway surgery. Curr Opin Otolaryngol Head Neck Surg 2009;17(6): 477–482 Hackman TG, Ferguson BJ. Powered instrumentation and tissue effects in the nose and paranasal sinuses. Curr Opin Otolaryngol Head Neck Surg 2005;13(1):22–26 Lunn W, Garland R, Ashiku S, Thurer RL, Feller-Kopman D, Ernst A. Microdebrider bronchoscopy: a new tool for the interventional bronchoscopist. Ann Thorac Surg 2005;80(4):1485–1488 Casal RF, Iribarren J, Eapen G, et al. Safety and effectiveness of microdebrider bronchoscopy for the management of central airway obstruction. Respirology 2013;18(6):1011–1015 Graham SM, Nerad JA. Orbital complications in endoscopic sinus surgery using powered instrumentation. Laryngoscope 2003; 113(5):874–878 Filler RM, Forte V, Chait P. Tracheobronchial stenting for the treatment of airway obstruction. J Pediatr Surg 1998;33(2): 304–311 Antón-Pacheco JL, Cabezalí D, Tejedor R, et al. The role of airway stenting in pediatric tracheobronchial obstruction. Eur J Cardiothorac Surg 2008;33(6):1069–1075 Santoro G, Picardo S, Testa G, et al. Balloon-expandable metallic stents in the management of tracheomalacia in neonates. J Thorac Cardiovasc Surg 1995;110(4 Pt 1):1145–1148 Eurpoe C. Pre-mounted PALMAZ GENESIS stent. Available at: http://www.cordis.com/sites/default/files/pdf/Endo-and-BiliaryCatalog-for-website.pdf#zoom=100. Accessed October 28, 2014 Maeda K, Ono S, Tazuke Y, Baba K. Long-term outcomes of congenital tracheal stenosis treated by metallic airway stenting. J Pediatr Surg 2013;48(2):293–296 Shin JH, Hong S-J, Song H-Y, et al. Placement of covered retrievable expandable metallic stents for pediatric tracheobronchial obstruction. J Vasc Interv Radiol 2006;17(2 Pt 1):309–317 Gaissert HA, Grillo HC, Wright CD, Donahue DM, Wain JC, Mathisen DJ. Complication of benign tracheobronchial strictures by selfexpanding metal stents. J Thorac Cardiovasc Surg 2003;126(3): 744–747 FDA public health notification: complications from metallic tracheal stents in patients with benign airway disorders. 2005. Available at: http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PublicHealthNotifications/ucm062115.htm. Accessed October 28, 2014
Seminars in Respiratory and Critical Care Medicine
Vol. 35
No. 6/2014
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Downloaded by: Scott Memorial Library, AISR. Copyrighted material.
Interventional Pulmonology in the Pediatric Population
Interventional Pulmonology in the Pediatric Population
Gilbert et al.
61 Nicolai T, Huber RM, Reiter K, Merkenschlager A, Hautmann H,
72 Fischer W, Feller-Kopman D, Shah A, Orens J, Illei P, Yarmus L.
Mantel K. Metal airway stent implantation in children: follow-up of seven children. Pediatr Pulmonol 2001;31(4): 289–296 Fayon M, Donato L, de Blic J, et al. French experience of silicone tracheobronchial stenting in children. Pediatr Pulmonol 2005; 39(1):21–27 Novotny L, Crha M, Rauser P, et al. Novel biodegradable polydioxanone stents in a rabbit airway model. J Thorac Cardiovasc Surg 2012;143(2):437–444 Wood DE, Cerfolio RJ, Gonzalez X, Springmeyer SC. Bronchoscopic management of prolonged air leak. Clin Chest Med 2010;31(1): 127–133 Gillespie CT, Sterman DH, Cerfolio RJ, et al. Endobronchial valve treatment for prolonged air leaks of the lung: a case series. Ann Thorac Surg 2011;91(1):270–273 Travaline JM, McKenna RJ Jr, De Giacomo T, et al; Endobronchial Valve for Persistent Air Leak Group. Treatment of persistent pulmonary air leaks using endobronchial valves. Chest 2009; 136(2):355–360 Lee HJ, Shojaee S, Sterman DH. Endoscopic lung volume reduction. An American perspective. Ann Am Thorac Soc 2013;10(6): 667–679 Gompelmann D, Eberhardt R, Herth FJ. Endoscopic lung volume reduction. A European perspective. Ann Am Thorac Soc 2013; 10(6):657–666 Feller-Kopman D, Bechara R, Garland R, Ernst A, Ashiku S. Use of a removable endobronchial valve for the treatment of bronchopleural fistula. Chest 2006;130(1):273–275 Gilbert CR, Toth JW, Kaifi JT, Belani CP, Varlotto J, Reed MF. Endobronchial valve placement for spontaneous pneumothorax from stage IIIA non-small cell lung cancer facilitates neoadjuvant therapy. Ann Thorac Surg 2013;96(6):2225–2227 Mahajan AK, Verhoef P, Patel SB, Carr G, Kyle Hogarth D. Intrabronchial valves: a case series describing a minimally invasive approach to bronchopleural fistulas in medical intensive care unit patients. J Bronchology Interv Pulmonol 2012;19(2): 137–141
Endobronchial valve therapy for pneumothorax as a bridge to lung transplantation. J Heart Lung Transplant 2012;31(3):334–336 Reed MF, Podany A, Rocourt D, Dillon P, Gilbert C, Toth JW. Endobronchial occlusion with one-way endobronchial valves: A novel technique for persistent air leaks in children. In: Proceedings of the Annual Meeting of American Pediatric Surgical Association; May 29–June 1, 2014; Phoenix, AZ Silvestri GA, Feller-Kopman D, Chen A, Wahidi M, Yasufuku K, Ernst A. Latest advances in advanced diagnostic and therapeutic pulmonary procedures. Chest 2012;142(6):1636–1644 Cox PG, Miller J, Mitzner W, Leff AR. Radiofrequency ablation of airway smooth muscle for sustained treatment of asthma: preliminary investigations. Eur Respir J 2004;24(4):659–663 Castro M, Rubin AS, Laviolette M, et al; AIR2 Trial Study Group. Effectiveness and safety of bronchial thermoplasty in the treatment of severe asthma: a multicenter, randomized, double-blind, sham-controlled clinical trial. Am J Respir Crit Care Med 2010; 181(2):116–124 Wechsler ME, Laviolette M, Rubin AS, et al; Asthma Intervention Research 2 Trial Study Group. Bronchial thermoplasty: Long-term safety and effectiveness in patients with severe persistent asthma. J Allergy Clin Immunol 2013;132(6):1295–1302 Busse WW; National Asthma Education and Prevention Program. Expert Panel Report 3 (EPR-3): Guidelines for the Diagnosis and Management of Asthma-Summary Report 2007. J Allergy Clin Immunol 2007;120(5, Suppl)S94–S138 Bush A, Saglani S. Management of severe asthma in children. Lancet 2010;376(9743):814–825 Chung KF, Wenzel SE, Brozek JL, et al. International ERS/ATS guidelines on definition, evaluation and treatment of severe asthma. Eur Respir J 2014;43(2):343–373 Stackhouse RA, Infosino A. Airway management. In: Stoelting RK, Miller RD, eds. Basics of Anesthesia. 5th ed. Philadelphia, PA: Churchill Livingstone; 2007:207–239 American College of Surgeons. American Trauma Life Support for Doctors. Student Course Manual. 7th ed. Chicago, IL: First Impression; 2004:262
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