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Endoscopy of the airway in infants and children
T H E J O U R N A L OF
PEDIATRICS JANUARY
1988
Volume 112
Number 1
MEDICAL PROGRESS We believethat many of our readers will appreciate having some familiarity with the procedures described in this manuscript. For those who have had difficultyin deciding whether the need for diagnosisjustifies the risk of a procedure, this perspectivewill shed new light on the problem. It is appropriate to warn our readers that complete unanimity on several points is not yet evident. For example, the indications for flexible bronchoscopy, by whom the procedure should be done, and even more specific technical aspects are questions not completely resolved. However, this article is not an effort to instruct anyone in how to do the procedure. Rather, it is an effort to acquaint our readers with progress in the field. With that in mind, we are confident that the remaining questions will be answered on the basis of the training, experience, and, ultimately, the good judgment of all the physicians involved.--R.E.M.
Endoscopy of the airway in infants and children R o b e r t E, W o o d , PhD, MD, a n d D u n c a n P o s t m a , MD From the Departments of Pediatrics and Surgery, University of North Carolina at Chapel Hill The introduction of flexible fiberoptic bronchoscopes in the early 1970s led to a dramatic increase in diagnostic bronchoscopy in adults. ~ Because of technical limitations, flexible instruments suitable for use in infants and children were not developed until nearly 10 years later. ~ In part because of this delay, bronchoscopy has been underutilized in many institutions for diagnosis in children and has been largely restricted to therapeutic procedures such as the removal of foreign bodies. Today, advances in both rigid and flexible instrumentation have made bronchoscopy a useful diagnostic and therapeutic procedure in infants and children?-5 Many pediatric pulmonologists, like their counterparts in adult pulmonology, now perform bronchoscopy.6-11 However, uncertainty persists, particularly among pediatricians, as to both the indications for bronchoscopy and the choice between rigid and flexible instruments. We present here an overview of the instrumentation, techniques, relative indications and contraindications, compli-
Reprint requests: Robert E. Wood, PhD, MD, Chief, Pediatric Pulmonary Medicine, Department of Pediatrics, 635 Burnett Womack Bldg., Box 7220, University of North Carolina, Chapel Hill, NC 27599.
cations, and usefulness of bronchoscopy in infants and children. In a review of bronchoscopy it is necessary that laryngoscopy be considered also. Upper airway problems are a common reason for endoscopic evaluation, and bronchoscopy almost always involves the examination of the upper as well as the lower airway. Similar techniques and instruments are used for both laryngoscopy and bronchoscopy (especially with flexible endoscopes). Nasopharyngoscopy is also part of the routine examination with flexible endoscopes, because they are most often passed through the nose. INSTRUMENTATION The rigid (open tube) bronchoscope is relatively large in relation to the airway and functions as an artificial airway during anesthesia. Instruments may be readily passed through the bronchoscope for operative manipulation. The optical properties of the rigid bronchoscope leave much to be desired. However, when a glass-rod telescope5 is passed through the rigid bronchoscope, the optical resolution is unequaled. Angulated telescopes may be used to look into the upper lobes, although the rigid instrument may not enter them.
2
Wood and Postma
Rigid bronchoscopes range in nominal size from 2.5 to nearly 10 mm. The nominal size of a rigid br0nchoscope refers to the smallest internal diameter through which instruments may be passed, not to the outer diameter, which may be several millimeters greater. ~2In contrast, the 3.5-mm flexible pediatric bronchoscope will pass through a 3.5-mm Storz rigid bronchoscope. This nomenclature often causes misunderstandings. The flexible bronchoscope contains bundles of glass fibers that carry the image and provide illumination. The image is composed of several thousand points of light with differing intensity and color, as in a television picture. The resolution is not as good as that obtained with a rigid instrument with a telescope. Most flexible instruments also have a small suction channel and provision for controlled angulation of the distal end of the instrument. The construction of the flexible bronchoscope has important consequences, especially for children. It is essentially solid and therefore must be small enough for the patient to breathe around it, rather than through it. Operative procedures such asextraction of foreign bodies are very difficult with flexible instruments. The standard pediatric flexible bronchoscope in use today 3 (model BF3C4/BF3C10, Olympus corp. of America, New Hyde Park, N.Y.) is 3.5 to 3.7 mm in outer diameter and has a suction channel 1.2 mm in diameter. Smaller (ultrathin) instruments".~3.14 as small as 1.8 mm have important but limited applications, primarily because they lack a suction channel or distal angulation or both. Flexible bronchoscopes Used in adults range from 4.7 to 6.3 mm in diameter and may be used in older children if the airway is large enough. For examination of the upper airway, flexible bronchoscopes or nasopharyngoscopes may be used. Nasopharyngoscopes are shorter than bronchoscopes, lack a suction channel, and are less expensive. TECHNIQUES Rigid bronchoscopy is usually performed with general anesthesia; the instrument is Passed through the mouth or (in some circumstances) through a tracheostomy stoma. A flexible bronchoscope is most often used with sedation and topical anesthesia and is usually passed through the nose. It can also be passed through the mouth, endotracheal tube, tracheostomy tube, or tracheostomy stoma. Airway size is a limiting factor in the use of any bronchoscope. In very small infants, it may be difficult to maintain adequate ventilation, even with a rigid bronchoscope. Fortunately, it is often possible for an experienced bronchoscopist to obtain sufficient diagnostic information from the lower airways of an infant in 30 seconds; the bronchoscope may be reinserted several times if necessary. Because in any patient the flexible bronchoscope partially
The Journal of Pediatrics January 1988
obstructs the airway and the patient must breathe during the procedure, careful monitoring is necessary to avoid hypoxia. In general, flexible bronchoscopes can be passed farther into the airways than rigid bronchoscopes can. Bronchoscopy, especially flexible bronchoscopy, can be performed at the bedside ~5,j6 but it should not be done unless it might be harmful to move the patient. A properly equipped and staffed procedure room or operating room is most suitable, so that provisions can be made to adequately monitor the patient and deal with any problems. Bronchoscopy may be performed on an outpatient basis in selected low-risk patients, especially when the procedure is done with sedation and a flexible instrument. Specimens for diagnostic studies may be obtained by direct aspiration (with or without saline lavage) Or with small brushes. The specimens may be subjected to microbiologic, cytologic; or chemical analysi s. BiopsieslJ ,~8 of endobronchial lesions may be obtained under direct vision, or flexible biopsy forceps may be extended into the lung parenchyma under fluoroscopic control. The pediatric flexible bronchoscope cannot be used for biopsy (the channel is too small), but it is well suited for aspirating samples. Bronchoscopic findings can be documented on film or videotape if the appropriate equipment is available. INDICATIONS
FOR ENDOSCOPY
Therapeutic bronchoscopy. Therapeutic bronchoscopy is indicated when there is an airway obstruction (tissue mass, foreign body, mucous plug) that may be removed with a bronchoscope. Rigid instruments are almost always used for this purpose, except for mucous plugs, which can usually be aspirated with flexible instruments. Diagnostic bronchoscopy. Diagnostic bronehoscopy is indicated when essential information within the lung or airways is most easily, definitively, or safely obtained with a bronchoscope. Abnormalities of airway structure, size, or patency, including congenital anomalies, stenosis, endobronchial masses, foregin bodies, extrinsic compression, or mucous plugging, may be seen. Patients with Stridor or persistent wheezing may have abnormal airway dynamics (laryngomalacia, tracheomalacia, or vocal cord paralysis). Inflammatory conditions of the airways or lung parenchyma may be diagnosed by inspection or by examination of secretions or lung washings. In most cases the flexible bronchoscope is the instrument of choice for diagnosis. Diagnostic laryngoscopy. Diagnostic laryngoscopy is often performed with rigid instruments, but in small children it often requires general anesthesia for an adequate examination. Airway anatomy or dynamics may be altered by rigid instruments or by general anesthesia. Flexible instruments may be passed through the nose, with
Volume 112 Number 1 or without sedation (although sedation is usually needed for an adequate examination), and are less likely to distort the anatomy. For routine examination, a flexible endoscope is probably the instrument of choice. ~9,2~ Endoscopy is often a rapid and definitive method for evaluating pulmonary problems in children. The results of 1000 examinations with a flexible instrument in children less than 10 years old4 indicated that more than 75% of the time, a diagnosis directly relevant to the primary indication for the procedure was obtained, whereas findings were normal in 9% of the examinations. In many cases, the findings were surprising, and the normal results were often important in excluding suspected abnormalities and redirecting further diagnostic studies. SPECIFIC INDICATIONS FOR ENDOSCOPIC EXAMINATION Stridor. One of the most common indications for examination of the airway in infants and children is stridor?, 21 As noted, flexible instruments are often more useful in the evaluation of abnormal airway dynamics than are rigid instruments. If the patient has stridor at the time of the examination, the vibrating structures should always be visible. Patients with typical croup do not need endoscopy, but atypical croup (prolonged symptoms in the hospital, lack of response to treatment, age less than 6 months) should be investigated. Although flexible endoscopy (which facilitates nasotracheal intubation) is inherently attractive, it should not be attempted in patients with suspected epiglottitis. Instead, these patients should undergo rigid laryngoscopy under general anesthesia. A flexible instrument may be useful later for evaluation of readiness for extubation. 22 Most infants with congenital stridor have laryngomalacia, which is self-limiting and usually requries no intervention other than reassurance. However, when the stridor persists longer than a few months or is severe, or if the parents or physicians are worried, diagnostic endoscopy should be considered. A definitive diagnosis of laryngomalacia can be very reassuring, and the endoscopic findings are often a useful guide regarding the expected duration of the stridor. Furthermore, endoscopy frequently yields a significant surprise, such as vocal cord paralysis, subglottic tumor, subglottic stenosis, or other lesion. In our experience, nearly 15% of patients with stridor also had a significant lesion below the glottis, although a plausible explanation for the stridor was seen at the glottis or above? Therefore, it is our practice to perform bronchoscopy in addition to laryngoscopy in children with stridor unless we find an area of significantly narrowed airway, through which the bronchoscope should not be passed. Ateleetasis. Another common indication for bronchosco-
Endoscopy of the airway
3
py in children is atelectasis. Premature infants often develop mucous plugs or endobronchial granulation tissue as a result of trauma from an endotracheal tube or suction catheters. Bronchoscopy may provide useful diagnostic information and immediate relief of the atelectasis. Ultrathin flexible br0nchoscopesl~, 13.14can be passed through an endotracheal tube to examine the lower airway of premature or newborn infants with minimal risk, but other instruments must be used to remove mucous plugs. Occasionally, foreign bodies or endobronchial masses discovered at flexible bronchoscopic examination will mandate a subsequent rigid bronchoscopy. 23 In older children and adults, atelectasis is less likely to respond to bronchoscopic aspiration, in comparison with atelectasis in young infants, in whom the cause is more often mucous plugs in large airways, with relatively normal peripheral airways. Not every child with atelectasis requires bronchoscopy; the majority of cases will resolve rapidly with simple therapy such as chest physiotherapy. Atelectasis that is massive, persists more than a few days despite therapy, is recurrent, or has a history consistent with foreign body aspiration should be investigated. Pneumonia. Bronchoscopy is indicated in the evaluation of patients with recurrent or persistent pneumonia, although the incidence of anatomic abnormalities or foreign bodies is not as high as might be intuitively suspected? ,4 Cytologic and microbiologic examination of bronchoalveolar washings will often reveal the infectious or inflammatory nature of the problem. Because it is possible to contaminate the bronchoscope or specimen with upper airway flora during the procedure, it is essential to correlate cytologic with bacteriologic findings (bacteria in the absence of inflammation are usually contaminants), in adults, specimens may be collected with brushes protected within a catheter to avoid contamination. 24 Available collection systems are too large to pass through the pediatric flexible bronchoscope. Bronchoscopy can be useful in patients with acute pneumonia but is usually not necessary in otherwise healthy patients with relatively uncomplicated illnesses. However, in immunocompromised or other selected patients, bronchoscopy should be considered because it may yield a quick diagnosis25 and avoid the risks of open lung biopsy. If bronchoscopy is performed early in the clinical course, before broad-spectrum antibiotic therapy is initiated, the probability of making a specific diagnosis is enhanced and the delay (and cost) inherent in a therapeutic trial may be reduced. Persistent wheezing. Persistent wheezing that is unresponsive or poorly responsive to bronchodilators should be investigated by bronchoscopy. Unsuspected foreign bodies, tracheomalacia, bronchomalacia, endobronchial mass
4
Wood and Postma
lesions, airway stenosis, or compression by extrinsic masses or vessels may be found2 In patients known to have asthma, bronchoscopy should be considered cautiously because of the risk of inducing bronchospasm, but it is not contraindicated if it is needed. Hemoptysis. Hemoptysis is relatively unusual in children and is often a difficult diagnostic problem that may require bronchoscopy if the bleeding is of significant magnitude or is recurrent. If possible, the examination should be performed while the bleeding is active. Rigid bronchoscopes are preferred if the bleeding is massive, but flexible instruments are superior under other circumstances because they allow the examination of the nasopharynx as well as the smaller bronchi. Foreign body aspiration. A common indication for bronchoscopy in children is aspiration of a foreign body). 23,26 In most circumstances the history, radiographic studies, or physical examination will produce a high index of suspicion, and the patient should have rigid bronchoscopy performed without delay. Some patients with foreign bodies have chronic or subtle symptoms (atelectasis, recurrent or persistent pneumonia, persistent wheezing unresponsive to bronchodilators) and no history of aspiration, or they may have a history consistent with aspiration but no physical or radiographic signs of a foreign body. Physicians are often reluctant to request rigid bronchoscopy for these patients or may not think of it. When there is doubt as to whether a patient has aspirated a foreign body, flexible bronchoscopy may be a valuable diagnostic tool. In our experience, 20% of patients in whom foreign body was suspected (not seriously enough to warrant, in our judgment, rigid bronchoscopy) were found to have a foreign body. 23 These patients then underwent rigid bronchoscopy to remove it. In some children, foreign body aspiration may be totally unsuspected. We discovered a foreign body in nearly 1% of the children in whom we performed flexible bronchoscopy for reasons other than suspected foreign body. 3 Difficult intubations. The flexible bronchoscope is an invaluable aid to accomplish difficult intubations in the intensive care unit or the operating room. 3,'3,17 With the 2.7-ram ultrathin bronchoscope, intubation may be done with tubes as small as 3.0 mm (inside diameter), whereas the standard pediatric flexible bronchoscope may be used with tubes only as large as 4.5 mm. This technique is rapid (usually requiring 30 seconds or less) and nearly infallible in the hands of an experienced bronchoscopist. In addition, it often provides useful diagnostic information. Evaluation of tracheostomies. Patients with a tracheostomy may have airway problems resulting from the underlying disease or from the tracheostomy. The flexible
The Journal of Pediatrics January 1988
bronchoscope is very useful in the evaluation of such problems. The instrument may be passed through the tracheostomy tube to study the location of the tip of the tube or the dynamics of the lower trachea and to examine the lower airways. Small flexible bronchoscopes may be passed through a tracheostomy stoma and directed upward so that the tracheal aspect of the larynx can be viewed. Evaluation of the larynx and upper trachea may greatly facilitate decannulation if the patient is otherwise ready. Rigid bronchoscopy is often necessary to remove granulation tissue from the trachea before decannulation. Other indications. There are many other indications for bronchoscopy in pediatric patients, including but not limited to abnormal cry, hoarseness, aspiration, suspected tracheoesophageal fistula, upper airway obstruction, vocal cord paralysis, prolonged intubation, mass lesions in the lungs or mediastinum, suspected hemosiderosis, suspected tuberculosis, and examination after trauma or foreign body removal. In adolescents 17 and adults, transbronchial lung biopsy can be performed through a bronchoscope. However, this procedure is more risky in children and should probably not be done unless open lung biopsy is not feasible. Bronchoscopic laser therapy is often used in adults in the treatment of tumors and other endobronchial lesions. There is little experience with these techniques in children. Bronchography helps in the diagnosis of bronchiectasis or in the delineation of anatomic abnormalities, t~ It is effective to perform bronchoscopy in any patient who is to undergo bronchography, since bronchoscopic findings may proscribe or eliminate the need for bronchograms. Bronchography may be performed with ease and safety through the flexible bronchoscope, even in small infants, with the use of sedation rather than general anesthesia. SPECIFIC INDICATIONS BRONCHOSCOPY
FOR RIGID
In general, much that can be done with a flexible bronchoscope can also be done with a rigid bronchoscope (and vice versa), and the choice is often as much a matter of individual preference as anything else. For routine diagnostic procedures, flexible instruments have many advantages, but several situations mandate the use of rigid instruments. These include removal of foreign bodies or other operative manipulations and the evaluation of massive hemoptysis during active bleeding. Rigid instruments are more useful in the search for the so-called H type of tracheoesophageal fistula and the critical evaluation of the posterior aspect of the larynx, as in a patient with bilateral vocal cord paralysis or laryngeal cleft.
Volume 112 Number 1
Endoscopy of the airway
coNTRAINDICATIONS BRONCHOSCOPY
TO
If information is needed from the lung, and if bronchoscopy is the best way to obtain that information, there are no absolute contraindications. On the other hand, if the same information can be obtained by other, safer means, bronchoscopy is not indicated. Clearly, certain patients, such as those with severe airway obstruction, pulmonary hypertension, severe coagulopathies, or profound hypoxemia, are at higher risk than others. If bronchoscopy is essential, bronchoscopy can be performed with acceptable safety in almost any situation if proper instrumentation is used and the patient is properly prepared. Often, a normal examination can be of great benefit and can circumvent more expensive or hazardous diagnostic procedures. Body size is no contraindication to bronchoscopy; using a flexible instrument, we have successfully examined the lower airways in an infant weighing 540 g? COMPLICATIONS
OF B R O N C H O S C O P Y
Bronchoscopy is not without risks. The most common complication of rigid bronchoscopy is subglottic edema z6,2s; this is extremely rare with flexible bronchoscopes, because of their small size. The highest rate of complications occurs during extensive manipulation (e.g., for extrication of foreign bodies) or when biopsy specimens are taken. Mechanical trauma, including bronchial tears, pneumothorax, or bleeding, may occur. Contamination of the lower airways with upper airway flora, either directly or by aspiration (caused by local or general anesthesia), is possible. Hypoxia, which may be caused by partial or total airway obstruction, is the greatest risk with flexible instruments. Vagal stimulation or hypoxia ~~ may produce cardiac arrhythmia. Anesthetic complications also may occur.
In our series of 1095 procedures performed with flexible instruments in children,3 there were four significant complications; none was fatal. Two patients developed a pneumothorax (one required a chest tube), one had laryngospasm requiring brief intubation, and one developed a lung abscess after a bronchogram performed before a scheduled lobectomy for congenital cystadenomatoid malformation. Minor epistaxis, minor reactions to sedative drugs, very transient laryngospasm, or transient bradycardia (in very small or critically ill patients) occurred in 28 patients; none required intervention. Generally, high-risk patients are more likely to undergo rigid bronchoscopy, and procedures performed with rigid instruments (e.g., foreign body extraction, biopsy) have a higher inherent risk. When bronchoscopy is carefully and skillfully performed with proper equipment, the risks are low.
5
CONCLUSIONS Bronchoscopy is a generally safe and effective diagnostic procedure for the evaluation of respiratory problems in children of all ages. A variety of instruments, both rigid and flexible, are now available and may be used as the clinical circumstances warrant. Although no procedure should be used unless the cost- and risk-benefit ratios are favorable, diagnostic bronchoscopy appears to be underutilized in pediatric practice today. REFERENCES
1. Sackner MA. State of the art: Bronchofiberscopy. Am Rev Respir Dis 1975;111:62-88. 2. Wood RE, Sherman JM. Pediatric flexible bronchoscopy. Ann Otol Rhinol Laryngol 1980;89:414-6. 3. Wood RE. Spelunking in the pediatric airway: explorations with the flexiblefiberoptic bronchoscope. Ped Clin North Am 1984;31:785-99. 4. Wood RE. The diagnostic effectiveness of the flexible bronchoscope in children. Pediatr Pulmonol 1985;1:188-92. 5. Gans SL, Berci G. Advances in endoscopy of infants and children. J Pediatr Surg 1971;6:199-233. 6. Fitzpatrick SB, Marsh B, Stokes D, Wang KP. Indications for flexible fiberoptic bronchoscopy in pediatric patients. Am J Dis Child 1983;137:595-7. 7. Nussbaum E. Flexible fiberoptic bronchoscopyand laryngoscopy in infants and children. Laryngoscope 1983;93:1073-5. 8. HopkinsRL. Pediatric flexible fiberoptic bronchoscopy. J La State Med Soc 1984;136:23-4. 9. Labbe A, Dalens B, Lusson JR, Dechelotte P, Meyer M. Flexible bronchoscopy in infants and children. Endoscopy 1984;16:13-5. 10. Godfrey S, Springer C, Maayan C, Avital A, Vatashky E, Belin B. Is there a place for rigid bronchoscopy in the management of pediatric lung disease? Pediatr Pulmonol 1987;3:179-84. 11. Fann LL, Sparks LM, Dulinski JP. Applications of an ultrathin flexible bronchoscope for neonatal and pediatric airway problems. Chest 1986;89:673-6. 12. Lockhart CH, Elliot JL. Potential hazards of pediatric rigid bronchoscopy. J Pediatr Surg 1984;19:239-42. 13. Wood RE. Clinical applications of ultrathin bronchoscopes. Pediatr Pulmonol 1985;1:255-8. 14. Vigneswaren R, Whitfield JM. The use of a new ultra-thin fiberoptic bronchoscopeto determine endotracheal tube position in the sick newborn infant. Chest 1981;80:174-7. 15. Wanner A, Landa JF, Nieman RE Jr, Vevaina J, Delgado I. Bedside bronchofiberscopyfor atelectasis and lung abscess. JAMA 1973;224:1281-3. 16. Muntz HR. Therapeutic rigid bronchoscopyin the neonatal intensive care unit. Ann Otol Rhinol Laryngol 1985;94: ~62-5. 17. Fitzpatrick SB, Stokes DC, Marsh B, Wang KP. Transbronchial lung biopsy in pediatric and adolescent patients. Am J Dis Child 1985;139:46-9. 18. Smith TF, Ireland TA, Zaatari GS, Gay BB, Zwiren GT. Andrews HG. Characteristics of children with endoscopically proved chronic bronchitis. Am J Dis Child 1985;139:103944.
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The Journal of Pediatrics January 1988
19. Fann LL, Flynn JW. Laryngoscopy in neonates and infants: experience with the flexible fiberoptic bronchoscope. Laryngoscope 1981;91:541-6. 20. Silberman HD. The use of the flexible fiberoptic nasopharyngoscope in the pediatric upper airway. Otolaryngol Clin North Am 1978;11:365-70. 21. Holinger LD. Eitology of stridor in the neonate, infant and child. Ann Otol Rhinol Laryngol 1980;89:397-400. 22. Nussbaum E. Fiberoptic laryngoscopy as a guide to tracheal extubation in acute epiglottitis. J Pediatr 1983;102:269-70. 23. Wood RE, Gauderer MWL. Flexible fiberoptic bronchoscopy in the management of tracheobronchial foreign bodies in children: the value of a combined approach with open tube bronchoscopy. J Pediatr Surg 1984;19:693-8. 24. Wimberly N, Faling L J, Bartlett JG. A fiberoptic bronchoscopy technique to obtain uncontaminated lower airway secre-
25.
26.
27.
28.
tions for bacterial culture. Am Rev Respir Dis 1979;119:33743. Leigh MW, Henshaw NG, Wood RE. Diagnosis of Pne~mocystis carinii pneumonia in pediatric patients using bronchoscopic bronchoalveolar lavage. Pediatr Infect Dis 1985;4:40810. Cohen SR, Herbert WI, Lewis GB, Geller KA. Foreign bodies in the airway: five-year retrospective study with special reference to management. Ann Otol Rhinol Laryngol 1980;89:437-42. Rucker RW, Silva W J, Worcester CC. Fiberoptic bronchoscopic nasotracheal intubation in children. Chest 1979;76: 56-8. Friedman EM, Williams M, Healy GB, McGill TFI. Pediatric endoscopy: a review of 616 cases. Ann Otol Rhinol Laryngol 1984;93:517-9.
BOUND VOLUMES AVAILABLE TO SUBSCRIBERS Bound volumes of the 1988 issues of THE JOURNAL OF PEDIATRICS are available to subscribers (only) from the Publisher, at a cost of $46.00 ($62.00 international) for Vol. 112 (January-June) and Vol. 113 (July-December), shipping charges included. Each bound volume contains subject and author indexes, and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the volume. The binding is durable buckram, with the Journal name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact The C. V. Mosby Company, Circulation Department, 11830 Westline Industrial Dr., St. Louis, M O 63146, USA/800-325-4177, ext. 351. Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular Journal subscription.
PEDIATRICS JANUARY
1988
Volume 112
Number 1
MEDICAL PROGRESS We believethat many of our readers will appreciate having some familiarity with the procedures described in this manuscript. For those who have had difficultyin deciding whether the need for diagnosisjustifies the risk of a procedure, this perspectivewill shed new light on the problem. It is appropriate to warn our readers that complete unanimity on several points is not yet evident. For example, the indications for flexible bronchoscopy, by whom the procedure should be done, and even more specific technical aspects are questions not completely resolved. However, this article is not an effort to instruct anyone in how to do the procedure. Rather, it is an effort to acquaint our readers with progress in the field. With that in mind, we are confident that the remaining questions will be answered on the basis of the training, experience, and, ultimately, the good judgment of all the physicians involved.--R.E.M.
Endoscopy of the airway in infants and children R o b e r t E, W o o d , PhD, MD, a n d D u n c a n P o s t m a , MD From the Departments of Pediatrics and Surgery, University of North Carolina at Chapel Hill The introduction of flexible fiberoptic bronchoscopes in the early 1970s led to a dramatic increase in diagnostic bronchoscopy in adults. ~ Because of technical limitations, flexible instruments suitable for use in infants and children were not developed until nearly 10 years later. ~ In part because of this delay, bronchoscopy has been underutilized in many institutions for diagnosis in children and has been largely restricted to therapeutic procedures such as the removal of foreign bodies. Today, advances in both rigid and flexible instrumentation have made bronchoscopy a useful diagnostic and therapeutic procedure in infants and children?-5 Many pediatric pulmonologists, like their counterparts in adult pulmonology, now perform bronchoscopy.6-11 However, uncertainty persists, particularly among pediatricians, as to both the indications for bronchoscopy and the choice between rigid and flexible instruments. We present here an overview of the instrumentation, techniques, relative indications and contraindications, compli-
Reprint requests: Robert E. Wood, PhD, MD, Chief, Pediatric Pulmonary Medicine, Department of Pediatrics, 635 Burnett Womack Bldg., Box 7220, University of North Carolina, Chapel Hill, NC 27599.
cations, and usefulness of bronchoscopy in infants and children. In a review of bronchoscopy it is necessary that laryngoscopy be considered also. Upper airway problems are a common reason for endoscopic evaluation, and bronchoscopy almost always involves the examination of the upper as well as the lower airway. Similar techniques and instruments are used for both laryngoscopy and bronchoscopy (especially with flexible endoscopes). Nasopharyngoscopy is also part of the routine examination with flexible endoscopes, because they are most often passed through the nose. INSTRUMENTATION The rigid (open tube) bronchoscope is relatively large in relation to the airway and functions as an artificial airway during anesthesia. Instruments may be readily passed through the bronchoscope for operative manipulation. The optical properties of the rigid bronchoscope leave much to be desired. However, when a glass-rod telescope5 is passed through the rigid bronchoscope, the optical resolution is unequaled. Angulated telescopes may be used to look into the upper lobes, although the rigid instrument may not enter them.
2
Wood and Postma
Rigid bronchoscopes range in nominal size from 2.5 to nearly 10 mm. The nominal size of a rigid br0nchoscope refers to the smallest internal diameter through which instruments may be passed, not to the outer diameter, which may be several millimeters greater. ~2In contrast, the 3.5-mm flexible pediatric bronchoscope will pass through a 3.5-mm Storz rigid bronchoscope. This nomenclature often causes misunderstandings. The flexible bronchoscope contains bundles of glass fibers that carry the image and provide illumination. The image is composed of several thousand points of light with differing intensity and color, as in a television picture. The resolution is not as good as that obtained with a rigid instrument with a telescope. Most flexible instruments also have a small suction channel and provision for controlled angulation of the distal end of the instrument. The construction of the flexible bronchoscope has important consequences, especially for children. It is essentially solid and therefore must be small enough for the patient to breathe around it, rather than through it. Operative procedures such asextraction of foreign bodies are very difficult with flexible instruments. The standard pediatric flexible bronchoscope in use today 3 (model BF3C4/BF3C10, Olympus corp. of America, New Hyde Park, N.Y.) is 3.5 to 3.7 mm in outer diameter and has a suction channel 1.2 mm in diameter. Smaller (ultrathin) instruments".~3.14 as small as 1.8 mm have important but limited applications, primarily because they lack a suction channel or distal angulation or both. Flexible bronchoscopes Used in adults range from 4.7 to 6.3 mm in diameter and may be used in older children if the airway is large enough. For examination of the upper airway, flexible bronchoscopes or nasopharyngoscopes may be used. Nasopharyngoscopes are shorter than bronchoscopes, lack a suction channel, and are less expensive. TECHNIQUES Rigid bronchoscopy is usually performed with general anesthesia; the instrument is Passed through the mouth or (in some circumstances) through a tracheostomy stoma. A flexible bronchoscope is most often used with sedation and topical anesthesia and is usually passed through the nose. It can also be passed through the mouth, endotracheal tube, tracheostomy tube, or tracheostomy stoma. Airway size is a limiting factor in the use of any bronchoscope. In very small infants, it may be difficult to maintain adequate ventilation, even with a rigid bronchoscope. Fortunately, it is often possible for an experienced bronchoscopist to obtain sufficient diagnostic information from the lower airways of an infant in 30 seconds; the bronchoscope may be reinserted several times if necessary. Because in any patient the flexible bronchoscope partially
The Journal of Pediatrics January 1988
obstructs the airway and the patient must breathe during the procedure, careful monitoring is necessary to avoid hypoxia. In general, flexible bronchoscopes can be passed farther into the airways than rigid bronchoscopes can. Bronchoscopy, especially flexible bronchoscopy, can be performed at the bedside ~5,j6 but it should not be done unless it might be harmful to move the patient. A properly equipped and staffed procedure room or operating room is most suitable, so that provisions can be made to adequately monitor the patient and deal with any problems. Bronchoscopy may be performed on an outpatient basis in selected low-risk patients, especially when the procedure is done with sedation and a flexible instrument. Specimens for diagnostic studies may be obtained by direct aspiration (with or without saline lavage) Or with small brushes. The specimens may be subjected to microbiologic, cytologic; or chemical analysi s. BiopsieslJ ,~8 of endobronchial lesions may be obtained under direct vision, or flexible biopsy forceps may be extended into the lung parenchyma under fluoroscopic control. The pediatric flexible bronchoscope cannot be used for biopsy (the channel is too small), but it is well suited for aspirating samples. Bronchoscopic findings can be documented on film or videotape if the appropriate equipment is available. INDICATIONS
FOR ENDOSCOPY
Therapeutic bronchoscopy. Therapeutic bronchoscopy is indicated when there is an airway obstruction (tissue mass, foreign body, mucous plug) that may be removed with a bronchoscope. Rigid instruments are almost always used for this purpose, except for mucous plugs, which can usually be aspirated with flexible instruments. Diagnostic bronchoscopy. Diagnostic bronehoscopy is indicated when essential information within the lung or airways is most easily, definitively, or safely obtained with a bronchoscope. Abnormalities of airway structure, size, or patency, including congenital anomalies, stenosis, endobronchial masses, foregin bodies, extrinsic compression, or mucous plugging, may be seen. Patients with Stridor or persistent wheezing may have abnormal airway dynamics (laryngomalacia, tracheomalacia, or vocal cord paralysis). Inflammatory conditions of the airways or lung parenchyma may be diagnosed by inspection or by examination of secretions or lung washings. In most cases the flexible bronchoscope is the instrument of choice for diagnosis. Diagnostic laryngoscopy. Diagnostic laryngoscopy is often performed with rigid instruments, but in small children it often requires general anesthesia for an adequate examination. Airway anatomy or dynamics may be altered by rigid instruments or by general anesthesia. Flexible instruments may be passed through the nose, with
Volume 112 Number 1 or without sedation (although sedation is usually needed for an adequate examination), and are less likely to distort the anatomy. For routine examination, a flexible endoscope is probably the instrument of choice. ~9,2~ Endoscopy is often a rapid and definitive method for evaluating pulmonary problems in children. The results of 1000 examinations with a flexible instrument in children less than 10 years old4 indicated that more than 75% of the time, a diagnosis directly relevant to the primary indication for the procedure was obtained, whereas findings were normal in 9% of the examinations. In many cases, the findings were surprising, and the normal results were often important in excluding suspected abnormalities and redirecting further diagnostic studies. SPECIFIC INDICATIONS FOR ENDOSCOPIC EXAMINATION Stridor. One of the most common indications for examination of the airway in infants and children is stridor?, 21 As noted, flexible instruments are often more useful in the evaluation of abnormal airway dynamics than are rigid instruments. If the patient has stridor at the time of the examination, the vibrating structures should always be visible. Patients with typical croup do not need endoscopy, but atypical croup (prolonged symptoms in the hospital, lack of response to treatment, age less than 6 months) should be investigated. Although flexible endoscopy (which facilitates nasotracheal intubation) is inherently attractive, it should not be attempted in patients with suspected epiglottitis. Instead, these patients should undergo rigid laryngoscopy under general anesthesia. A flexible instrument may be useful later for evaluation of readiness for extubation. 22 Most infants with congenital stridor have laryngomalacia, which is self-limiting and usually requries no intervention other than reassurance. However, when the stridor persists longer than a few months or is severe, or if the parents or physicians are worried, diagnostic endoscopy should be considered. A definitive diagnosis of laryngomalacia can be very reassuring, and the endoscopic findings are often a useful guide regarding the expected duration of the stridor. Furthermore, endoscopy frequently yields a significant surprise, such as vocal cord paralysis, subglottic tumor, subglottic stenosis, or other lesion. In our experience, nearly 15% of patients with stridor also had a significant lesion below the glottis, although a plausible explanation for the stridor was seen at the glottis or above? Therefore, it is our practice to perform bronchoscopy in addition to laryngoscopy in children with stridor unless we find an area of significantly narrowed airway, through which the bronchoscope should not be passed. Ateleetasis. Another common indication for bronchosco-
Endoscopy of the airway
3
py in children is atelectasis. Premature infants often develop mucous plugs or endobronchial granulation tissue as a result of trauma from an endotracheal tube or suction catheters. Bronchoscopy may provide useful diagnostic information and immediate relief of the atelectasis. Ultrathin flexible br0nchoscopesl~, 13.14can be passed through an endotracheal tube to examine the lower airway of premature or newborn infants with minimal risk, but other instruments must be used to remove mucous plugs. Occasionally, foreign bodies or endobronchial masses discovered at flexible bronchoscopic examination will mandate a subsequent rigid bronchoscopy. 23 In older children and adults, atelectasis is less likely to respond to bronchoscopic aspiration, in comparison with atelectasis in young infants, in whom the cause is more often mucous plugs in large airways, with relatively normal peripheral airways. Not every child with atelectasis requires bronchoscopy; the majority of cases will resolve rapidly with simple therapy such as chest physiotherapy. Atelectasis that is massive, persists more than a few days despite therapy, is recurrent, or has a history consistent with foreign body aspiration should be investigated. Pneumonia. Bronchoscopy is indicated in the evaluation of patients with recurrent or persistent pneumonia, although the incidence of anatomic abnormalities or foreign bodies is not as high as might be intuitively suspected? ,4 Cytologic and microbiologic examination of bronchoalveolar washings will often reveal the infectious or inflammatory nature of the problem. Because it is possible to contaminate the bronchoscope or specimen with upper airway flora during the procedure, it is essential to correlate cytologic with bacteriologic findings (bacteria in the absence of inflammation are usually contaminants), in adults, specimens may be collected with brushes protected within a catheter to avoid contamination. 24 Available collection systems are too large to pass through the pediatric flexible bronchoscope. Bronchoscopy can be useful in patients with acute pneumonia but is usually not necessary in otherwise healthy patients with relatively uncomplicated illnesses. However, in immunocompromised or other selected patients, bronchoscopy should be considered because it may yield a quick diagnosis25 and avoid the risks of open lung biopsy. If bronchoscopy is performed early in the clinical course, before broad-spectrum antibiotic therapy is initiated, the probability of making a specific diagnosis is enhanced and the delay (and cost) inherent in a therapeutic trial may be reduced. Persistent wheezing. Persistent wheezing that is unresponsive or poorly responsive to bronchodilators should be investigated by bronchoscopy. Unsuspected foreign bodies, tracheomalacia, bronchomalacia, endobronchial mass
4
Wood and Postma
lesions, airway stenosis, or compression by extrinsic masses or vessels may be found2 In patients known to have asthma, bronchoscopy should be considered cautiously because of the risk of inducing bronchospasm, but it is not contraindicated if it is needed. Hemoptysis. Hemoptysis is relatively unusual in children and is often a difficult diagnostic problem that may require bronchoscopy if the bleeding is of significant magnitude or is recurrent. If possible, the examination should be performed while the bleeding is active. Rigid bronchoscopes are preferred if the bleeding is massive, but flexible instruments are superior under other circumstances because they allow the examination of the nasopharynx as well as the smaller bronchi. Foreign body aspiration. A common indication for bronchoscopy in children is aspiration of a foreign body). 23,26 In most circumstances the history, radiographic studies, or physical examination will produce a high index of suspicion, and the patient should have rigid bronchoscopy performed without delay. Some patients with foreign bodies have chronic or subtle symptoms (atelectasis, recurrent or persistent pneumonia, persistent wheezing unresponsive to bronchodilators) and no history of aspiration, or they may have a history consistent with aspiration but no physical or radiographic signs of a foreign body. Physicians are often reluctant to request rigid bronchoscopy for these patients or may not think of it. When there is doubt as to whether a patient has aspirated a foreign body, flexible bronchoscopy may be a valuable diagnostic tool. In our experience, 20% of patients in whom foreign body was suspected (not seriously enough to warrant, in our judgment, rigid bronchoscopy) were found to have a foreign body. 23 These patients then underwent rigid bronchoscopy to remove it. In some children, foreign body aspiration may be totally unsuspected. We discovered a foreign body in nearly 1% of the children in whom we performed flexible bronchoscopy for reasons other than suspected foreign body. 3 Difficult intubations. The flexible bronchoscope is an invaluable aid to accomplish difficult intubations in the intensive care unit or the operating room. 3,'3,17 With the 2.7-ram ultrathin bronchoscope, intubation may be done with tubes as small as 3.0 mm (inside diameter), whereas the standard pediatric flexible bronchoscope may be used with tubes only as large as 4.5 mm. This technique is rapid (usually requiring 30 seconds or less) and nearly infallible in the hands of an experienced bronchoscopist. In addition, it often provides useful diagnostic information. Evaluation of tracheostomies. Patients with a tracheostomy may have airway problems resulting from the underlying disease or from the tracheostomy. The flexible
The Journal of Pediatrics January 1988
bronchoscope is very useful in the evaluation of such problems. The instrument may be passed through the tracheostomy tube to study the location of the tip of the tube or the dynamics of the lower trachea and to examine the lower airways. Small flexible bronchoscopes may be passed through a tracheostomy stoma and directed upward so that the tracheal aspect of the larynx can be viewed. Evaluation of the larynx and upper trachea may greatly facilitate decannulation if the patient is otherwise ready. Rigid bronchoscopy is often necessary to remove granulation tissue from the trachea before decannulation. Other indications. There are many other indications for bronchoscopy in pediatric patients, including but not limited to abnormal cry, hoarseness, aspiration, suspected tracheoesophageal fistula, upper airway obstruction, vocal cord paralysis, prolonged intubation, mass lesions in the lungs or mediastinum, suspected hemosiderosis, suspected tuberculosis, and examination after trauma or foreign body removal. In adolescents 17 and adults, transbronchial lung biopsy can be performed through a bronchoscope. However, this procedure is more risky in children and should probably not be done unless open lung biopsy is not feasible. Bronchoscopic laser therapy is often used in adults in the treatment of tumors and other endobronchial lesions. There is little experience with these techniques in children. Bronchography helps in the diagnosis of bronchiectasis or in the delineation of anatomic abnormalities, t~ It is effective to perform bronchoscopy in any patient who is to undergo bronchography, since bronchoscopic findings may proscribe or eliminate the need for bronchograms. Bronchography may be performed with ease and safety through the flexible bronchoscope, even in small infants, with the use of sedation rather than general anesthesia. SPECIFIC INDICATIONS BRONCHOSCOPY
FOR RIGID
In general, much that can be done with a flexible bronchoscope can also be done with a rigid bronchoscope (and vice versa), and the choice is often as much a matter of individual preference as anything else. For routine diagnostic procedures, flexible instruments have many advantages, but several situations mandate the use of rigid instruments. These include removal of foreign bodies or other operative manipulations and the evaluation of massive hemoptysis during active bleeding. Rigid instruments are more useful in the search for the so-called H type of tracheoesophageal fistula and the critical evaluation of the posterior aspect of the larynx, as in a patient with bilateral vocal cord paralysis or laryngeal cleft.
Volume 112 Number 1
Endoscopy of the airway
coNTRAINDICATIONS BRONCHOSCOPY
TO
If information is needed from the lung, and if bronchoscopy is the best way to obtain that information, there are no absolute contraindications. On the other hand, if the same information can be obtained by other, safer means, bronchoscopy is not indicated. Clearly, certain patients, such as those with severe airway obstruction, pulmonary hypertension, severe coagulopathies, or profound hypoxemia, are at higher risk than others. If bronchoscopy is essential, bronchoscopy can be performed with acceptable safety in almost any situation if proper instrumentation is used and the patient is properly prepared. Often, a normal examination can be of great benefit and can circumvent more expensive or hazardous diagnostic procedures. Body size is no contraindication to bronchoscopy; using a flexible instrument, we have successfully examined the lower airways in an infant weighing 540 g? COMPLICATIONS
OF B R O N C H O S C O P Y
Bronchoscopy is not without risks. The most common complication of rigid bronchoscopy is subglottic edema z6,2s; this is extremely rare with flexible bronchoscopes, because of their small size. The highest rate of complications occurs during extensive manipulation (e.g., for extrication of foreign bodies) or when biopsy specimens are taken. Mechanical trauma, including bronchial tears, pneumothorax, or bleeding, may occur. Contamination of the lower airways with upper airway flora, either directly or by aspiration (caused by local or general anesthesia), is possible. Hypoxia, which may be caused by partial or total airway obstruction, is the greatest risk with flexible instruments. Vagal stimulation or hypoxia ~~ may produce cardiac arrhythmia. Anesthetic complications also may occur.
In our series of 1095 procedures performed with flexible instruments in children,3 there were four significant complications; none was fatal. Two patients developed a pneumothorax (one required a chest tube), one had laryngospasm requiring brief intubation, and one developed a lung abscess after a bronchogram performed before a scheduled lobectomy for congenital cystadenomatoid malformation. Minor epistaxis, minor reactions to sedative drugs, very transient laryngospasm, or transient bradycardia (in very small or critically ill patients) occurred in 28 patients; none required intervention. Generally, high-risk patients are more likely to undergo rigid bronchoscopy, and procedures performed with rigid instruments (e.g., foreign body extraction, biopsy) have a higher inherent risk. When bronchoscopy is carefully and skillfully performed with proper equipment, the risks are low.
5
CONCLUSIONS Bronchoscopy is a generally safe and effective diagnostic procedure for the evaluation of respiratory problems in children of all ages. A variety of instruments, both rigid and flexible, are now available and may be used as the clinical circumstances warrant. Although no procedure should be used unless the cost- and risk-benefit ratios are favorable, diagnostic bronchoscopy appears to be underutilized in pediatric practice today. REFERENCES
1. Sackner MA. State of the art: Bronchofiberscopy. Am Rev Respir Dis 1975;111:62-88. 2. Wood RE, Sherman JM. Pediatric flexible bronchoscopy. Ann Otol Rhinol Laryngol 1980;89:414-6. 3. Wood RE. Spelunking in the pediatric airway: explorations with the flexiblefiberoptic bronchoscope. Ped Clin North Am 1984;31:785-99. 4. Wood RE. The diagnostic effectiveness of the flexible bronchoscope in children. Pediatr Pulmonol 1985;1:188-92. 5. Gans SL, Berci G. Advances in endoscopy of infants and children. J Pediatr Surg 1971;6:199-233. 6. Fitzpatrick SB, Marsh B, Stokes D, Wang KP. Indications for flexible fiberoptic bronchoscopy in pediatric patients. Am J Dis Child 1983;137:595-7. 7. Nussbaum E. Flexible fiberoptic bronchoscopyand laryngoscopy in infants and children. Laryngoscope 1983;93:1073-5. 8. HopkinsRL. Pediatric flexible fiberoptic bronchoscopy. J La State Med Soc 1984;136:23-4. 9. Labbe A, Dalens B, Lusson JR, Dechelotte P, Meyer M. Flexible bronchoscopy in infants and children. Endoscopy 1984;16:13-5. 10. Godfrey S, Springer C, Maayan C, Avital A, Vatashky E, Belin B. Is there a place for rigid bronchoscopy in the management of pediatric lung disease? Pediatr Pulmonol 1987;3:179-84. 11. Fann LL, Sparks LM, Dulinski JP. Applications of an ultrathin flexible bronchoscope for neonatal and pediatric airway problems. Chest 1986;89:673-6. 12. Lockhart CH, Elliot JL. Potential hazards of pediatric rigid bronchoscopy. J Pediatr Surg 1984;19:239-42. 13. Wood RE. Clinical applications of ultrathin bronchoscopes. Pediatr Pulmonol 1985;1:255-8. 14. Vigneswaren R, Whitfield JM. The use of a new ultra-thin fiberoptic bronchoscopeto determine endotracheal tube position in the sick newborn infant. Chest 1981;80:174-7. 15. Wanner A, Landa JF, Nieman RE Jr, Vevaina J, Delgado I. Bedside bronchofiberscopyfor atelectasis and lung abscess. JAMA 1973;224:1281-3. 16. Muntz HR. Therapeutic rigid bronchoscopyin the neonatal intensive care unit. Ann Otol Rhinol Laryngol 1985;94: ~62-5. 17. Fitzpatrick SB, Stokes DC, Marsh B, Wang KP. Transbronchial lung biopsy in pediatric and adolescent patients. Am J Dis Child 1985;139:46-9. 18. Smith TF, Ireland TA, Zaatari GS, Gay BB, Zwiren GT. Andrews HG. Characteristics of children with endoscopically proved chronic bronchitis. Am J Dis Child 1985;139:103944.
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19. Fann LL, Flynn JW. Laryngoscopy in neonates and infants: experience with the flexible fiberoptic bronchoscope. Laryngoscope 1981;91:541-6. 20. Silberman HD. The use of the flexible fiberoptic nasopharyngoscope in the pediatric upper airway. Otolaryngol Clin North Am 1978;11:365-70. 21. Holinger LD. Eitology of stridor in the neonate, infant and child. Ann Otol Rhinol Laryngol 1980;89:397-400. 22. Nussbaum E. Fiberoptic laryngoscopy as a guide to tracheal extubation in acute epiglottitis. J Pediatr 1983;102:269-70. 23. Wood RE, Gauderer MWL. Flexible fiberoptic bronchoscopy in the management of tracheobronchial foreign bodies in children: the value of a combined approach with open tube bronchoscopy. J Pediatr Surg 1984;19:693-8. 24. Wimberly N, Faling L J, Bartlett JG. A fiberoptic bronchoscopy technique to obtain uncontaminated lower airway secre-
25.
26.
27.
28.
tions for bacterial culture. Am Rev Respir Dis 1979;119:33743. Leigh MW, Henshaw NG, Wood RE. Diagnosis of Pne~mocystis carinii pneumonia in pediatric patients using bronchoscopic bronchoalveolar lavage. Pediatr Infect Dis 1985;4:40810. Cohen SR, Herbert WI, Lewis GB, Geller KA. Foreign bodies in the airway: five-year retrospective study with special reference to management. Ann Otol Rhinol Laryngol 1980;89:437-42. Rucker RW, Silva W J, Worcester CC. Fiberoptic bronchoscopic nasotracheal intubation in children. Chest 1979;76: 56-8. Friedman EM, Williams M, Healy GB, McGill TFI. Pediatric endoscopy: a review of 616 cases. Ann Otol Rhinol Laryngol 1984;93:517-9.
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